bambuddy/backend/app/services/bambu_mqtt.py

"""Bambu Lab MQTT communication service.

IMPORTANT: Always use qos=1 for all MQTT publish calls!
The printer ignores qos=0 messages when busy broadcasting status updates.
Using qos=1 ensures the printer acknowledges and processes our commands immediately.
This was discovered when K-profile requests with qos=0 took 20-30 seconds,
but with qos=1 they respond instantly.
"""

import asyncio
import json
import logging
import os
import ssl
import threading
import time
from collections import deque
from collections.abc import Callable
from dataclasses import dataclass, field
from datetime import datetime, timezone

import paho.mqtt.client as mqtt

logger = logging.getLogger(__name__)

# AMS module name prefixes used in get_version responses.
# The numeric suffix after '/' is the AMS unit ID as reported in push_status.
#   "ams/<id>"  – original AMS (X1C, X1E, P1S, …)
#   "n3f/<id>"  – AMS 2 Pro (H2D Pro and similar)
#   "n3s/<id>"  – AMS HT (H2D Pro and similar; IDs typically start at 128)
_AMS_MODULE_PREFIXES = ("ams/", "n3f/", "n3s/")


@dataclass
class MQTTLogEntry:
    """Log entry for MQTT message debugging."""

    timestamp: str
    topic: str
    direction: str  # "in" or "out"
    payload: dict


@dataclass
class HMSError:
    """Health Management System error from printer."""

    code: str
    attr: int  # Attribute value for constructing wiki URL
    module: int
    severity: int  # 1=fatal, 2=serious, 3=common, 4=info
    message: str = ""


# HMS short codes the firmware emits during normal user-cancel sequences.
# These aren't faults — they're status echoes that confirm the cancel happened.
# Filtering them at parse-time keeps them out of state.hms_errors entirely,
# so they don't drive the printer card's "X problem" badge, the red pip, or
# any other consumer that treats hms_errors as the active-fault list.
_HMS_USER_ACTION_CODES: frozenset[str] = frozenset(
    {
        "0300_400C",  # "The task was canceled."
        "0500_400E",  # "Printing was cancelled."
    }
)


@dataclass
class KProfile:
    """Pressure advance (K) calibration profile from printer."""

    slot_id: int
    extruder_id: int
    nozzle_id: str
    nozzle_diameter: str
    filament_id: str
    name: str
    k_value: str
    n_coef: str = "0.000000"
    ams_id: int = 0
    tray_id: int = -1
    setting_id: str | None = None


@dataclass
class NozzleInfo:
    """Nozzle hardware configuration."""

    nozzle_type: str = ""  # "stainless_steel" or "hardened_steel"
    nozzle_diameter: str = ""  # e.g., "0.4"


@dataclass
class FilaSwitchState:
    """Filament Track Switch (FTS) accessory state.

    The FTS is an external accessory that mediates filament routing between an
    AMS and the printer's extruders. When installed, the AMS no longer has a
    fixed extruder assignment — any slot can be routed to any extruder via the
    track switch. Detected from print.device.fila_switch in MQTT.
    """

    installed: bool = False
    # in[track] = currently loaded slot for that track (-1 = empty). The slot
    # value is reported as observed in MQTT (treated as a global tray ID).
    in_slots: list[int] = field(default_factory=list)
    # out[track] = extruder this track terminates at (0 = right/main, 1 = left)
    out_extruders: list[int] = field(default_factory=list)
    stat: int = 0  # status flags (0 = idle)
    info: int = 0  # info flags


@dataclass
class PrintOptions:
    """AI detection and print options from xcam data."""

    # Core AI detectors
    spaghetti_detector: bool = False
    print_halt: bool = False
    halt_print_sensitivity: str = "medium"  # Spaghetti sensitivity
    first_layer_inspector: bool = False
    printing_monitor: bool = False  # AI print quality monitoring
    buildplate_marker_detector: bool = False
    allow_skip_parts: bool = False
    # Additional AI detectors - decoded from cfg bitmask
    nozzle_clumping_detector: bool = True
    nozzle_clumping_sensitivity: str = "medium"
    pileup_detector: bool = True
    pileup_sensitivity: str = "medium"
    airprint_detector: bool = True
    airprint_sensitivity: str = "medium"
    auto_recovery_step_loss: bool = True  # Uses print.print_option command
    filament_tangle_detect: bool = False


@dataclass
class PrinterState:
    connected: bool = False
    state: str = "unknown"
    current_print: str | None = None
    subtask_name: str | None = None
    progress: float = 0.0
    remaining_time: int = 0
    layer_num: int = 0
    total_layers: int = 0
    temperatures: dict = field(default_factory=dict)
    raw_data: dict = field(default_factory=dict)
    gcode_file: str | None = None
    subtask_id: str | None = None
    hms_errors: list = field(default_factory=list)  # List of HMSError
    kprofiles: list = field(default_factory=list)  # List of KProfile
    sdcard: bool = False  # SD card inserted
    store_to_sdcard: bool = False  # Store sent files on SD card (home_flag bit 11)
    timelapse: bool = False  # Timelapse recording active
    ipcam: bool = False  # Live view / camera streaming enabled
    wifi_signal: int | None = None  # WiFi signal strength in dBm
    wired_network: bool = False  # Ethernet connection detected (home_flag bit 18)
    door_open: bool = False  # Enclosure door open (home_flag bit 23, X1/P1S/P2S/H2*)
    # Nozzle hardware info (for dual nozzle printers, index 0 = left, 1 = right)
    nozzles: list = field(default_factory=lambda: [NozzleInfo(), NozzleInfo()])
    # AI detection and print options
    print_options: PrintOptions = field(default_factory=PrintOptions)
    # Calibration stage tracking (from stg_cur and stg fields)
    stg_cur: int = -1  # Current stage index (-1 = not calibrating)
    stg: list = field(default_factory=list)  # List of stages to execute
    # Air conditioning mode (0=cooling, 1=heating)
    airduct_mode: int = 0
    # Print speed level (1=silent, 2=standard, 3=sport, 4=ludicrous)
    speed_level: int = 2
    # Chamber light on/off
    chamber_light: bool = False
    # Active extruder for dual nozzle (0=right, 1=left) - from device.extruder.info[X].hnow
    active_extruder: int = 0
    # Currently loaded tray (global ID): 254/255 = external spools, 255 = no filament on legacy printers
    tray_now: int = 255
    # Last valid tray_now (0-253) — survives unload (255) for usage tracking after print completes
    last_loaded_tray: int = -1
    # Pending load target - used to track what tray we're loading for H2D disambiguation
    pending_tray_target: int | None = None
    # AMS status for filament change tracking (from print.ams.ams_status field)
    # ams_status is a combined value: lower 8 bits = sub status, bits 8-15 = main status
    # Main status: 0=idle, 1=filament_change, 2=rfid_identifying, 3=assist, 4=calibration, etc.
    ams_status: int = 0
    ams_status_main: int = 0  # (ams_status >> 8) & 0xFF
    ams_status_sub: int = 0  # ams_status & 0xFF
    # mc_print_sub_stage - filament change step indicator from print.mc_print_sub_stage
    # Used by OrcaSlicer/BambuStudio to track progress during filament load/unload
    mc_print_sub_stage: int = 0
    # AMS mapping for dual nozzle: which slot is active (from ams.ams_exist_bits/tray_exist_bits)
    ams_mapping: list = field(default_factory=list)
    # Per-AMS extruder map: {ams_id: extruder_id} where 0=right/main, 1=left/deputy
    ams_extruder_map: dict = field(default_factory=dict)
    # Filament Track Switch (FTS) accessory — when installed, AMS info reports
    # bits 8-11 = 0xE (uninitialized) because routing is dynamic. See #1162.
    fila_switch: "FilaSwitchState" = field(default_factory=lambda: FilaSwitchState())
    # Plate dispatched by Bambuddy for the current print. Some firmware versions
    # (P1S 01.10.00.00) only put the .3mf filename in print.gcode_file, so the
    # regex used to derive the plate number from the path always falls back to
    # plate 1 — and the printer card shows the wrong thumbnail (#1166). When
    # Bambuddy dispatches the print itself we know the plate authoritatively;
    # we record it here and prefer it over the gcode_file regex. The subtask
    # field guards against staleness: if the printer is currently running a
    # different subtask (e.g. a Studio-direct dispatch), these values are
    # ignored. Cleared on disconnect.
    dispatched_plate_id: int | None = None
    dispatched_subtask: str | None = None
    # H2D per-extruder tray_now from snow field: {extruder_id: normalized_global_tray_id}
    # snow encodes AMS ID in high byte: ams_id = snow >> 8, slot = snow & 0xFF
    h2d_extruder_snow: dict = field(default_factory=dict)
    # H2C nozzle rack: full device.nozzle.info array for tool-changer printers (>2 nozzles)
    nozzle_rack: list = field(default_factory=list)
    # Timestamp of last AMS data update (for RFID refresh detection)
    last_ams_update: float = 0.0
    # Printable objects for skip object functionality: {identify_id: object_name}
    printable_objects: dict = field(default_factory=dict)
    # Objects that have been skipped during the current print
    skipped_objects: list = field(default_factory=list)
    # Fan speeds (0-100 percentage, None if not available for this model)
    cooling_fan_speed: int | None = None  # Part cooling fan
    big_fan1_speed: int | None = None  # Auxiliary fan
    big_fan2_speed: int | None = None  # Chamber/exhaust fan
    heatbreak_fan_speed: int | None = None  # Hotend heatbreak fan
    # Tray change history during current print: [(global_tray_id, layer_num), ...]
    # Used by usage tracker to split filament weight on mid-print tray switch
    tray_change_log: list = field(default_factory=list)
    # Firmware version info (from info.module[name="ota"].sw_ver)
    firmware_version: str | None = None
    # Developer LAN mode: parsed from MQTT "fun" field bit 0x20000000
    # True = dev mode ON (no encryption), False = dev mode OFF (encryption required), None = unknown
    developer_mode: bool | None = None


# Stage name mapping from BambuStudio DeviceManager.cpp
STAGE_NAMES = {
    0: "Printing",
    1: "Auto bed leveling",
    2: "Heatbed preheating",
    3: "Vibration compensation",
    4: "Changing filament",
    5: "M400 pause",
    6: "Paused (filament ran out)",
    7: "Heating nozzle",
    8: "Calibrating dynamic flow",
    9: "Scanning bed surface",
    10: "Inspecting first layer",
    11: "Identifying build plate type",
    12: "Calibrating Micro Lidar",
    13: "Homing toolhead",
    14: "Cleaning nozzle tip",
    15: "Checking extruder temperature",
    16: "Paused by the user",
    17: "Pause (front cover fall off)",
    18: "Calibrating the micro lidar",
    19: "Calibrating flow ratio",
    20: "Pause (nozzle temperature malfunction)",
    21: "Pause (heatbed temperature malfunction)",
    22: "Filament unloading",
    23: "Pause (step loss)",
    24: "Filament loading",
    25: "Motor noise cancellation",
    26: "Pause (AMS offline)",
    27: "Pause (low speed of the heatbreak fan)",
    28: "Pause (chamber temperature control problem)",
    29: "Cooling chamber",
    30: "Pause (Gcode inserted by user)",
    31: "Motor noise showoff",
    32: "Pause (nozzle clumping)",
    33: "Pause (cutter error)",
    34: "Pause (first layer error)",
    35: "Pause (nozzle clog)",
    36: "Measuring motion precision",
    37: "Enhancing motion precision",
    38: "Measure motion accuracy",
    39: "Nozzle offset calibration",
    40: "High temperature auto bed leveling",
    41: "Auto Check: Quick Release Lever",
    42: "Auto Check: Door and Upper Cover",
    43: "Laser Calibration",
    44: "Auto Check: Platform",
    45: "Confirming BirdsEye Camera location",
    46: "Calibrating BirdsEye Camera",
    47: "Auto bed leveling - phase 1",
    48: "Auto bed leveling - phase 2",
    49: "Heating chamber",
    50: "Cooling heatbed",
    51: "Printing calibration lines",
    52: "Auto Check: Material",
    53: "Live View Camera Calibration",
    54: "Waiting for heatbed temperature",
    55: "Auto Check: Material Position",
    56: "Cutting Module Offset Calibration",
    57: "Measuring Surface",
    58: "Thermal Preconditioning",
    59: "Homing Blade Holder",
    60: "Calibrating Camera Offset",
    61: "Calibrating Blade Holder Position",
    62: "Hotend Pick and Place Test",
    63: "Waiting for Chamber temperature",
    64: "Preparing Hotend",
    65: "Calibrating nozzle clumping detection",
    66: "Purifying the chamber air",
    74: "Preparing",  # Seen on H2D during print preparation
    77: "Preparing AMS",
}


def get_stage_name(stage: int) -> str:
    """Get human-readable stage name from stage number."""
    return STAGE_NAMES.get(stage, f"Unknown stage ({stage})")


class BambuMQTTClient:
    """MQTT client for Bambu Lab printer communication."""

    MQTT_PORT = 8883

    # Class-level cache: serial_number -> False when request topic is known unsupported.
    # Persists across client instances so reconnects don't re-trigger failed subscriptions.
    _request_topic_cache: dict[str, bool] = {}
    # Counter for generating unique MQTT client IDs across instances.
    _client_instance_counter: int = 0

    def __init__(
        self,
        ip_address: str,
        serial_number: str,
        access_code: str,
        model: str | None = None,
        on_state_change: Callable[[PrinterState], None] | None = None,
        on_print_start: Callable[[dict], None] | None = None,
        on_print_complete: Callable[[dict], None] | None = None,
        on_ams_change: Callable[[list], None] | None = None,
        on_layer_change: Callable[[int], None] | None = None,
        on_bed_temp_update: Callable[[float], None] | None = None,
        on_drying_complete: Callable[[int], None] | None = None,
        on_print_running_observed: Callable[[dict], None] | None = None,
    ):
        self.ip_address = ip_address
        self.serial_number = serial_number
        self.access_code = access_code
        self.model = model
        self.on_state_change = on_state_change
        self.on_print_start = on_print_start
        self.on_print_complete = on_print_complete
        self.on_ams_change = on_ams_change
        self.on_layer_change = on_layer_change
        self.on_bed_temp_update = on_bed_temp_update
        # #1349: fired when an AMS unit's dry_time falls from >0 to 0 — i.e.
        # the drying cycle just finished (auto- or manually-triggered).
        # Receives the AMS id of the unit that finished drying.
        self.on_drying_complete = on_drying_complete
        # #1485 follow-up: fired the first time we see RUNNING state in a
        # session WHEN on_print_start was suppressed (Bambuddy started mid-
        # print, the #1304 first-push guard skipped the start event). Lets
        # main.py capture a fresh timelapse baseline at restart-recovery
        # time so the completion-time snapshot-diff still works. Receives
        # the same shape as on_print_start (filename / subtask_name /
        # remaining_time / raw_data / ams_mapping).
        self.on_print_running_observed = on_print_running_observed
        # Per-AMS previous dry_time, used to detect the falling edge above.
        # Seeded lazily as we observe each AMS unit.
        self._previous_dry_times: dict[int, int] = {}

        self.state = PrinterState()
        self._client: mqtt.Client | None = None
        self._loop: asyncio.AbstractEventLoop | None = None
        self._previous_gcode_state: str | None = None
        self._previous_gcode_file: str | None = None
        self._was_running: bool = False  # Track if we've seen RUNNING state for current print
        self._completion_triggered: bool = False  # Prevent duplicate completion triggers
        self._timelapse_during_print: bool = False  # Track if timelapse was active during this print
        self._last_valid_progress: float = 0.0  # Last non-zero progress (firmware resets on cancel)
        self._last_valid_layer_num: int = 0  # Last non-zero layer (firmware resets on cancel)
        # The subtask_id minted for the most recent start_print() command. The
        # printer echoes it back in status, but often not within the first few
        # seconds — so on_print_start uses this as the id source when the
        # printer hasn't reported it yet, letting queue/scheduled archives
        # persist a restart-stable id from the moment they dispatch (#1485).
        self.last_dispatch_subtask_id: str | None = None
        self._is_dual_nozzle: bool = False  # Set when device.extruder.info has >= 2 entries
        self._message_log: deque[MQTTLogEntry] = deque(maxlen=100)
        self._logging_enabled: bool = False
        self._last_message_time: float = 0.0  # Track when we last received a message
        # Count of report-topic messages received since the last (re)connect.
        # Lets check_staleness() distinguish "printer never sent a status
        # report" (typically a wrong / mis-cased serial) from a normal quiet
        # gap mid-session. _zero_report_hint_logged keeps the actionable hint
        # to once per client lifetime so the stale loop doesn't spam it (#1465).
        self._report_messages_since_connect: int = 0
        self._zero_report_hint_logged: bool = False
        # Raw-message fan-out for VP MQTT bridge (non-proxy modes republish the
        # printer's pushes verbatim to slicers connected to a virtual printer).
        # Handlers receive (topic, payload_bytes) before JSON parsing.
        self._raw_message_handlers: list[Callable[[str, bytes], None]] = []
        self._disconnection_event: threading.Event | None = None
        self._previous_ams_hash: str | None = None  # Track AMS changes

        # Cache AMS firmware/SN from get_version in case it arrives before AMS status
        # Key: ams_id (int). Value: {'sw_ver': str, 'sn': str}
        self._ams_version_cache: dict[int, dict[str, str]] = {}

        # Track which (ams_id, field) warnings have already been emitted this connection
        # so that missing-serial / missing-firmware warnings fire only once per connection.
        self._ams_version_warned: set[tuple[int | str, str]] = set()

        # K-profile command tracking
        self._sequence_id: int = 0
        self._pending_kprofile_response: asyncio.Event | None = None
        self._kprofile_response_data: list | None = None

        # Xcam hold timers - OrcaSlicer pattern: ignore incoming data for 3 seconds after command
        # Key: module_name, Value: timestamp when command was sent
        self._xcam_hold_start: dict[str, float] = {}
        self._xcam_hold_time: float = 3.0  # Ignore incoming data for 3 seconds after command

        # Track last requested tray ID for H2D dual-nozzle printers
        # H2D only reports slot number (0-3) in tray_now, not global tray ID
        # We use our tracked value to resolve the correct global ID
        self._last_load_tray_id: int | None = None

        # Captured ams_mapping from print commands on the request topic
        # Intercepts slicer/Bambuddy print commands to get the slot-to-tray mapping
        self._captured_ams_mapping: list[int] | None = None

        # Request topic subscription tracking
        # Some printer MQTT brokers (e.g. P1S, A1) reject subscriptions to the request
        # topic by killing the TCP connection. We detect this and gracefully degrade.
        # Check class-level cache first so new client instances don't retry known-bad subscriptions.
        self._request_topic_supported: bool = BambuMQTTClient._request_topic_cache.get(self.serial_number, True)
        self._request_topic_sub_mid: int | None = None
        self._request_topic_sub_time: float = 0.0
        self._request_topic_confirmed: bool = False

        # Developer mode probe: when the "fun" field is absent (A1/P1 printers),
        # we probe by sending an ams_filament_setting and checking the response.
        # "mqtt message verify failed" → dev mode OFF, success → dev mode ON.
        self._dev_mode_probed: bool = False
        self._dev_mode_needs_probe: bool = False  # True after seeing a pushall without "fun"
        self._dev_mode_probe_seq: str | None = None
        self._dev_mode_probe_time: float = 0.0  # monotonic timestamp when probe was sent
        self._dev_mode_probe_failures: int = 0  # consecutive unanswered probes
        self._connect_time: float = 0.0  # monotonic timestamp of last _on_connect

        # Set when check_staleness() force-closes the socket to trigger reconnect.
        # Prevents _on_disconnect from redundantly broadcasting state (already done).
        self._stale_reconnecting: bool = False
        # Timestamp of last stale reconnect — prevents rapid-fire socket closes
        # when the frontend polls status faster than paho can reconnect.
        self._last_stale_reconnect: float = 0.0

        # Zombie session detection via ams_filament_setting response tracking (#887).
        # The dev-mode probe only runs on first connect; this catches zombie sessions
        # that develop later (telemetry flows but publishes silently fail).
        self._last_ams_cmd_time: float = 0.0  # monotonic time of last published command
        self._ams_cmd_unanswered: int = 0  # consecutive commands with no response

    @property
    def topic_subscribe(self) -> str:
        return f"device/{self.serial_number}/report"

    @property
    def topic_publish(self) -> str:
        return f"device/{self.serial_number}/request"

    @property
    def report_messages_since_connect(self) -> int:
        """Count of report-topic messages received since the latest (re)connect.

        Exposed for the connection diagnostic so it can distinguish "MQTT
        broker accepted us but the printer never published" (typically a
        wrong / mis-cased serial — #1622 follow-up to #1602) from a healthy
        bridge that happens to be idle right now. Zero immediately after a
        fresh connect is normal; zero after a full status push cycle is the
        wrong-serial failure mode.
        """
        return self._report_messages_since_connect

    # Maximum time (seconds) without a message before considering connection stale
    STALE_TIMEOUT = 60.0

    def is_stale(self) -> bool:
        """Check if the connection is stale (no messages for too long)."""
        if self._last_message_time == 0:
            return False  # Never received a message yet
        time_since_last = time.time() - self._last_message_time
        return time_since_last > self.STALE_TIMEOUT

    # Minimum seconds between stale reconnect attempts.  Frontend polls
    # status every few seconds — without a cooldown, each poll would
    # force-close the socket before paho has time to reconnect.
    STALE_RECONNECT_COOLDOWN = 30.0

    def check_staleness(self) -> bool:
        """Check staleness and update connected state if stale. Returns True if connected."""
        if self.state.connected and self.is_stale():
            # Don't force-close again if we already did recently — give paho
            # time to reconnect and the printer time to send its first message.
            now = time.time()
            if now - self._last_stale_reconnect < self.STALE_RECONNECT_COOLDOWN:
                return self.state.connected

            logger.warning(
                f"[{self.serial_number}] Connection stale - no message for {now - self._last_message_time:.1f}s, forcing reconnect"
            )
            # A connection that keeps going stale without ever receiving a
            # status report is almost always a wrong or mis-cased serial
            # number — the broker accepts the connection and the subscription
            # regardless, but the printer publishes to device/<real-serial>/
            # report, which is case-sensitive. Surface that once so the user
            # has something actionable instead of an endless reconnect loop.
            if self._report_messages_since_connect == 0 and not self._zero_report_hint_logged:
                self._zero_report_hint_logged = True
                logger.warning(
                    "[%s] Connected and subscribed, but the printer has sent zero "
                    "status reports. The most common cause is a wrong or mis-cased "
                    "serial number — the device/<serial>/report MQTT topic is "
                    "case-sensitive. Verify the serial number configured in Bambuddy "
                    "exactly matches the printer.",
                    self.serial_number,
                )
            self._last_stale_reconnect = now
            self.state.connected = False
            if self.on_state_change:
                self.on_state_change(self.state)
            # Route based on caller thread — see force_reconnect_stale_session.
            # check_staleness is normally called from FastAPI handlers (async,
            # gets the hard-reset path) but the dispatcher exists for safety.
            self._stale_reconnecting = True
            self._reset_client_for_reconnect()
        return self.state.connected

    def force_reconnect_stale_session(self, reason: str) -> None:
        # Heals the #887/#936/#1136 half-broken session: telemetry keeps
        # arriving but our publishes don't reach the printer.
        #
        # Two routing paths:
        #
        # Async-context callers (background_dispatch.py:993 — dispatch deadline)
        #   → full client teardown + fresh client_id. Wipes paho's client-side
        #     QoS 1 queue, which is exactly the #1136 reproducer: an unacked
        #     `project_file` from the broken session would otherwise replay on
        #     reconnect, mixing stale commands into the next dispatch and
        #     triggering 0500_4003 SD R/W on the printer.
        #
        # Paho-network-thread callers (line ~2604/~2623 — dev-mode probe and
        # ams_filament_setting zombie detection inside `_update_state`)
        #   → socket-close fallback. Calling `loop_stop()` from inside the
        #     network thread would self-join and deadlock; the safe pattern is
        #     to close the socket and let paho's own loop detect the broken
        #     connection and auto-reconnect (same instance, same client_id —
        #     queue replay is theoretically possible here but those paths have
        #     always done socket-close and #1136 was specifically triggered
        #     from the dispatch path).
        logger.warning("[%s] Forcing MQTT reconnect: %s", self.serial_number, reason)
        self._stale_reconnecting = True
        self.state.connected = False
        if self.on_state_change:
            self.on_state_change(self.state)
        self._reset_client_for_reconnect()

    def _reset_client_for_reconnect(self) -> None:
        """Route between hard-reset and socket-close based on caller thread.

        Hard-reset (preferred) requires we're not running on paho's network
        thread, since `loop_stop()` on the same thread deadlocks. Detect via
        ``asyncio.get_running_loop()`` — paho's callback thread has no loop;
        every legitimate hard-reset caller (FastAPI handlers, background
        async tasks) does."""
        try:
            loop = asyncio.get_running_loop()
        except RuntimeError:
            loop = None

        if loop is not None:
            self._loop = loop
            self._hard_reset_client()
        else:
            self._socket_close_for_reconnect()

    def _hard_reset_client(self) -> None:
        """Tear down the paho client entirely and rebuild it with a fresh
        client_id, so the broker drops the old session and paho's local
        QoS 1 queue is gone. Must NOT be called from paho's network thread.
        Caller is responsible for setting ``_stale_reconnecting`` and
        broadcasting the disconnected state."""
        old_client = self._client
        self._client = None
        if old_client is not None:
            try:
                old_client.disconnect()  # MQTT DISCONNECT — broker drops session
            except Exception:
                pass
            try:
                old_client.loop_stop()  # blocks briefly until the network thread exits
            except Exception:
                pass
        # Skip reconnect if no asyncio loop is available (test environment or
        # pre-init). The next initial connect() call from PrinterManager will
        # set up the client fresh.
        if self._loop is None:
            return
        try:
            self.connect(loop=self._loop)
        except Exception as e:
            logger.error("[%s] Hard reset reconnect failed: %s", self.serial_number, e)

    def _socket_close_for_reconnect(self) -> None:
        """Close the underlying socket so paho's loop thread detects the
        broken connection and triggers auto-reconnect on the SAME client
        instance. Safe to call from paho's own network thread (the loop
        polls the socket on every iteration and handles a closed socket
        gracefully). Used as a fallback when hard-reset isn't safe; queue
        replay remains theoretically possible here but #1136 specifically
        traced through the dispatch-deadline path which now hard-resets."""
        if self._client:
            try:
                sock = self._client.socket()
                if sock:
                    sock.close()
            except Exception:
                pass

    def _on_connect(self, client, userdata, flags, rc, properties=None):
        if rc == 0:
            self.state.connected = True
            self._stale_reconnecting = False  # Clear stale-reconnect flag on successful connect
            # Reset per-connection warning state so warnings fire once per (re)connection
            self._ams_version_warned = set()
            # Preserve cached developer_mode across auto-reconnects to avoid
            # re-probing on every reconnect.  The probe (ams_filament_setting to
            # ext slot) can destabilize some firmware MQTT brokers, causing a
            # reconnect → probe → disconnect feedback loop (#887).  Only probe
            # once when developer_mode is truly unknown (first connect).
            # Reset probe tracking so stale timeout state doesn't carry over.
            self._dev_mode_probed = False
            self._dev_mode_needs_probe = False
            self._dev_mode_probe_seq = None
            self._dev_mode_probe_time = 0.0
            self._dev_mode_probe_failures = 0
            self._connect_time = time.monotonic()
            self._report_messages_since_connect = 0
            self._last_ams_cmd_time = 0.0
            self._ams_cmd_unanswered = 0
            client.subscribe(self.topic_subscribe)
            # Subscribe to request topic for ams_mapping capture (if supported by broker)
            if self._request_topic_supported:
                result, mid = client.subscribe(self.topic_publish)
                if result == mqtt.MQTT_ERR_SUCCESS:
                    self._request_topic_sub_mid = mid
                    self._request_topic_sub_time = time.time()
                    self._request_topic_confirmed = False
                else:
                    logger.warning(
                        "[%s] Failed to send request topic subscription",
                        self.serial_number,
                    )
                    self._request_topic_supported = False
                    BambuMQTTClient._request_topic_cache[self.serial_number] = False
            # Request full status update (includes nozzle info in push_status response)
            self._request_push_all()
            # Request firmware version info
            self._request_version()
            # Note: get_accessories returns stale nozzle data on H2D, so we don't use it.
            # The correct nozzle data comes from push_status.
            # Prime K-profile request (Bambu printers often ignore first request)
            self._prime_kprofile_request()
            # Immediately broadcast connection state change
            if self.on_state_change:
                self.on_state_change(self.state)
        else:
            self.state.connected = False

    def _on_subscribe(self, client, userdata, mid, reason_code_list, properties=None):
        """Handle SUBACK responses to detect request topic subscription rejection."""
        if mid == self._request_topic_sub_mid:
            for rc in reason_code_list:
                if rc.is_failure:
                    logger.warning(
                        "[%s] Request topic subscription rejected (code=%d: %s). "
                        "ams_mapping capture from slicer-initiated prints unavailable.",
                        self.serial_number,
                        rc.value,
                        rc.getName(),
                    )
                    self._request_topic_supported = False
                    BambuMQTTClient._request_topic_cache[self.serial_number] = False
                else:
                    logger.info(
                        "[%s] Request topic subscription accepted. "
                        "ams_mapping capture enabled for slicer-initiated prints.",
                        self.serial_number,
                    )
                    self._request_topic_confirmed = True
                    BambuMQTTClient._request_topic_cache[self.serial_number] = True
            self._request_topic_sub_mid = None
            self._request_topic_sub_time = 0.0

    def _on_disconnect(self, client, userdata, disconnect_flags=None, rc=None, properties=None):
        # Always unblock disconnect() callers, regardless of whether we suppress
        # the state broadcast below.  disconnect() sets _disconnection_event and
        # waits on it — every callback path must fire it.
        if self._disconnection_event:
            self._disconnection_event.set()

        # If we intentionally closed the socket for stale reconnect, don't broadcast
        # another state change — check_staleness() already set connected=False and
        # notified the UI.  Just log and let paho auto-reconnect.
        if self._stale_reconnecting:
            logger.info(
                "[%s] Disconnect callback after stale reconnect (expected), rc=%s",
                self.serial_number,
                rc,
            )
            return

        # Ignore spurious disconnect callbacks if we've received a message recently
        # Paho-mqtt sometimes fires disconnect callbacks while the connection is still active.
        # BUT: never suppress error disconnects (keepalive timeout, connection lost, etc.)
        # — only suppress when rc indicates a clean/normal disconnect.
        is_error_disconnect = rc is not None and hasattr(rc, "is_failure") and rc.is_failure
        time_since_last_message = time.time() - self._last_message_time
        if not is_error_disconnect and time_since_last_message < 10.0 and self._last_message_time > 0:
            logger.debug(
                f"[{self.serial_number}] Ignoring spurious disconnect (last message {time_since_last_message:.1f}s ago)"
            )
            return

        logger.warning("[%s] MQTT disconnected: rc=%s, flags=%s", self.serial_number, rc, disconnect_flags)

        # Detect if request topic subscription caused the disconnect.
        # If we just subscribed and got disconnected before any SUBACK confirmation,
        # the broker likely killed the connection due to the unauthorized subscription.
        if (
            self._request_topic_sub_time > 0
            and not self._request_topic_confirmed
            and time.time() - self._request_topic_sub_time < 10.0
        ):
            logger.warning(
                "[%s] Disconnected shortly after request topic subscription. Disabling request topic for this printer.",
                self.serial_number,
            )
            self._request_topic_supported = False
            BambuMQTTClient._request_topic_cache[self.serial_number] = False
        self._request_topic_sub_mid = None
        self._request_topic_sub_time = 0.0

        self.state.connected = False
        if self.on_state_change:
            self.on_state_change(self.state)

    def _on_message(self, client, userdata, msg):
        for handler in self._raw_message_handlers:
            try:
                handler(msg.topic, msg.payload)
            except Exception:
                logger.exception(
                    "[%s] raw-message handler crashed for topic=%s",
                    self.serial_number,
                    msg.topic,
                )
        try:
            try:
                raw = msg.payload.decode()
            except UnicodeDecodeError:
                # Some firmware versions (e.g. A1 Mini 01.07.02.00) send payloads
                # with non-UTF-8 bytes. Replace invalid bytes to keep JSON parseable.
                raw = msg.payload.decode(errors="replace")
                logger.warning(
                    "[%s] MQTT payload contained non-UTF-8 bytes (topic=%s, len=%d)",
                    self.serial_number,
                    msg.topic,
                    len(msg.payload),
                )
            payload = json.loads(raw)
            # Track last message time - receiving a message proves we're connected
            self._last_message_time = time.time()
            self.state.connected = True

            # Intercept request-topic messages (print commands from slicer/Bambuddy)
            if msg.topic == self.topic_publish:
                self._handle_request_message(payload)
                return

            # Count status reports per connection so check_staleness() can tell
            # "printer never sent a report" apart from a mid-session quiet gap.
            if msg.topic == self.topic_subscribe:
                self._report_messages_since_connect += 1

            # Log message if logging is enabled
            if self._logging_enabled:
                self._message_log.append(
                    MQTTLogEntry(
                        timestamp=datetime.now(timezone.utc).isoformat(),
                        topic=msg.topic,
                        direction="in",
                        payload=payload,
                    )
                )
            self._process_message(payload)
        except json.JSONDecodeError:
            pass  # Ignore non-JSON MQTT messages (e.g. binary or malformed payloads)

    def _handle_request_message(self, data: dict) -> None:
        """Intercept print commands on the request topic to capture ams_mapping."""
        print_data = data.get("print", {})
        if not isinstance(print_data, dict):
            return
        command = print_data.get("command", "")
        if command == "project_file":
            if "ams_mapping" in print_data:
                self._captured_ams_mapping = print_data["ams_mapping"]
                logger.info(
                    "[%s] Captured ams_mapping from print command: %s",
                    self.serial_number,
                    self._captured_ams_mapping,
                )
            # Diagnostic for #1162 follow-up (X2D + FTS routing): when a
            # slicer-launched project_file passes through the request topic,
            # log the full payload so we can diff Studio's field set against
            # ours. We pin our own sequence_id to "20000" (line ~3195), so
            # any other value means the command came from Studio/Orca, not
            # from us.
            if print_data.get("sequence_id") != "20000":
                logger.info(
                    "[%s] External project_file payload: %s",
                    self.serial_number,
                    json.dumps(print_data),
                )

    def _process_message(self, payload: dict):
        """Process incoming MQTT message from printer."""
        # Handle top-level AMS data (comes outside of "print" key)
        # Wrap in try/except to prevent breaking the MQTT connection
        if "ams" in payload:
            try:
                self._handle_ams_data(payload["ams"])
            except Exception as e:
                logger.error("[%s] Error handling AMS data: %s", self.serial_number, e)

        # Handle xcam data (camera settings and AI detection) at top level
        if "xcam" in payload:
            xcam_data = payload["xcam"]
            logger.debug("[%s] Received xcam data at top level: %s", self.serial_number, xcam_data)
            self._parse_xcam_data(xcam_data)
            # Fire state change callback for top-level xcam (not nested in "print")
            if "print" not in payload and self.on_state_change:
                self.on_state_change(self.state)

        # Handle system responses (accessories info, etc.)
        if "system" in payload:
            system_data = payload["system"]
            logger.debug("[%s] Received system data: %s", self.serial_number, system_data)
            self._handle_system_response(system_data)

        # Handle info responses (firmware version info from get_version command)
        if "info" in payload:
            info_data = payload["info"]
            if isinstance(info_data, dict) and info_data.get("command") == "get_version":
                self._handle_version_info(info_data)

        # Parse WiFi signal at top level (some printers send it here)
        if "wifi_signal" in payload:
            wifi_signal = payload["wifi_signal"]
            if isinstance(wifi_signal, (int, float)):
                self.state.wifi_signal = int(wifi_signal)
            elif isinstance(wifi_signal, str):
                try:
                    self.state.wifi_signal = int(wifi_signal.replace("dBm", "").strip())
                except ValueError:
                    pass  # Ignore unparseable wifi_signal strings; field is non-critical

            # Detect ethernet: wifi_signal == -90 is a sentinel for "WiFi disabled/ethernet"
            from backend.app.utils.printer_models import has_ethernet

            if has_ethernet(self.model):
                self.state.wired_network = self.state.wifi_signal == -90

        # Parse developer LAN mode from top-level "fun" field
        # Some firmware versions send "fun" at the top level, others inside "print"
        if "fun" in payload:
            try:
                fun_val = payload["fun"]
                fun_int = fun_val if isinstance(fun_val, int) else int(fun_val, 16)
                self.state.developer_mode = (fun_int & 0x20000000) == 0
            except (ValueError, TypeError):
                pass

        if "print" in payload:
            print_data = payload["print"]

            # Check if xcam is nested inside print data
            if "xcam" in print_data:
                logger.debug("[%s] Found xcam inside print data: %s", self.serial_number, print_data["xcam"])
                self._parse_xcam_data(print_data["xcam"])

            # Log when we see gcode_state changes
            if "gcode_state" in print_data:
                logger.debug(
                    f"[{self.serial_number}] Received gcode_state: {print_data.get('gcode_state')}, "
                    f"gcode_file: {print_data.get('gcode_file')}, subtask_name: {print_data.get('subtask_name')}"
                )

            # Detect dual-nozzle BEFORE processing AMS data (tray_now disambiguation needs it)
            # device.extruder.info with >= 2 entries only exists on dual-nozzle printers (H2D, H2D Pro)
            if not self._is_dual_nozzle and "device" in print_data:
                dev = print_data.get("device")
                if isinstance(dev, dict):
                    ext_info = dev.get("extruder", {}).get("info", [])
                    if isinstance(ext_info, list) and len(ext_info) >= 2:
                        self._is_dual_nozzle = True
                        logger.info("[%s] Detected dual-nozzle printer from device.extruder.info", self.serial_number)

            # Handle AMS data that comes inside print key
            if "ams" in print_data:
                try:
                    self._handle_ams_data(print_data["ams"])
                except Exception as e:
                    logger.error("[%s] Error handling AMS data from print: %s", self.serial_number, e)

            # Handle vir_slot (H2-series external spool data) — list of external trays
            # Process vir_slot FIRST so it takes priority over vt_tray
            if "vir_slot" in print_data:
                vir_slot = print_data["vir_slot"]
                if isinstance(vir_slot, list) and vir_slot:
                    # Fix: single-nozzle printers (X1C, P1S, A1) report their single
                    # external slot with id=255 in vir_slot, but tray_now=254 when active.
                    # Remap id=255→254 for single-slot printers so active detection works.
                    # Dual-nozzle (H2D) has 2 slots: id=254 (Ext-L) and id=255 (Ext-R).
                    if len(vir_slot) == 1 and str(vir_slot[0].get("id", "")) == "255":
                        vir_slot[0]["id"] = "254"
                    self.state.raw_data["vt_tray"] = vir_slot

            # Handle vt_tray (virtual tray / external spool) data
            # Only use vt_tray if vir_slot is NOT in this message AND we don't already
            # have vir_slot data (H2-series sends vt_tray as a single active spool dict
            # which would overwrite the correct multi-slot vir_slot data)
            if "vt_tray" in print_data and "vir_slot" not in print_data:
                vt_tray = print_data["vt_tray"]
                existing = self.state.raw_data.get("vt_tray")
                # Don't let a single-spool vt_tray dict overwrite multi-slot vir_slot data
                if isinstance(vt_tray, dict) and isinstance(existing, list) and len(existing) > 1:
                    pass  # Keep the vir_slot data
                else:
                    if isinstance(vt_tray, dict):
                        vt_tray = [vt_tray]
                    self.state.raw_data["vt_tray"] = vt_tray

            # Parse ams_status directly from print data (NOT from print.ams)
            # ams_status is a combined value: lower 8 bits = sub status, bits 8-15 = main status
            # Main status: 0=idle, 1=filament_change, 2=rfid_identifying, 3=assist, 4=calibration
            # Sub status (when main=1): 2=heating, 3=AMS feeding, 4=retract, 6=push, 7=purge
            if "ams_status" in print_data:
                raw_ams_status = print_data["ams_status"]
                if isinstance(raw_ams_status, str):
                    try:
                        self.state.ams_status = int(raw_ams_status)
                    except ValueError:
                        self.state.ams_status = 0
                else:
                    self.state.ams_status = raw_ams_status if raw_ams_status is not None else 0

                # Compute main and sub status
                self.state.ams_status_sub = self.state.ams_status & 0xFF
                self.state.ams_status_main = (self.state.ams_status >> 8) & 0xFF

                # Log when ams_status changes (for filament change tracking debug)
                logger.debug(
                    f"[{self.serial_number}] ams_status: {self.state.ams_status} "
                    f"(main={self.state.ams_status_main}, sub={self.state.ams_status_sub})"
                )

            # Check for command responses
            if "command" in print_data:
                cmd = print_data.get("command")
                logger.debug("[%s] Received command response: %s", self.serial_number, cmd)
                if cmd in ("extrusion_cali_sel", "extrusion_cali_set", "extrusion_cali_del", "ams_filament_setting"):
                    logger.debug("[%s] %s response: %s", self.serial_number, cmd, print_data)
                # AMS drying responses are rare (user-initiated only) and the
                # full payload — including `result` and any `reason` code —
                # is the only way to diagnose silent rejections like #1447.
                # INFO level so the body lands in support bundles by default.
                elif cmd == "ams_filament_drying":
                    logger.info("[%s] ams_filament_drying response: %s", self.serial_number, print_data)
                # Check for developer mode probe response
                if (
                    cmd == "ams_filament_setting"
                    and self._dev_mode_probe_seq is not None
                    and print_data.get("sequence_id") == self._dev_mode_probe_seq
                ):
                    self._handle_dev_mode_probe_response(print_data)
                # Track user-initiated ams_filament_setting responses (#887
                # zombie detection). Reset both the timer AND the unanswered
                # counter on ANY response — the response proves the channel is
                # alive, so the counter must not stay armed even when the
                # watchdog already zeroed `_last_ams_cmd_time` on a previous
                # tick. The original `and self._last_ams_cmd_time > 0` guard
                # caused #1164: one sluggish response (>10s) would set the
                # counter to 1 and zero the timer; the late response arrived
                # but was ignored by this branch (timer is 0); the counter
                # stayed at 1 indefinitely; the very next slow response —
                # possibly hours later, on a totally unrelated command — would
                # take it to 2 and force-reconnect, surfacing as "filament
                # config doesn't reach the printer ~6 changes in".
                elif cmd == "ams_filament_setting":
                    self._last_ams_cmd_time = 0.0
                    self._ams_cmd_unanswered = 0
            if "command" in print_data and print_data.get("command") == "extrusion_cali_get":
                self._handle_kprofile_response(print_data)

            self._update_state(print_data)

    def _handle_system_response(self, data: dict):
        """Handle system responses including accessories info.

        Note: get_accessories returns stale/incorrect nozzle_type data on H2D.
        The correct nozzle data comes from push_status, so we don't update
        nozzle type/diameter from get_accessories. We just log the response
        for debugging purposes.
        """
        command = data.get("command")

        if command == "get_accessories":
            # Log response for debugging - but DON'T use it to update nozzle data
            # because it returns stale values (e.g., 'stainless_steel' when the
            # actual nozzle is 'HH01' hardened steel high-flow)
            logger.debug("[%s] Accessories response (not used for nozzle data): %s", self.serial_number, data)

    def _handle_version_info(self, data: dict):
        """Handle version info response from get_version command.

        Parses firmware version from the 'ota' module in the module list.
        Also extracts AMS unit firmware versions from AMS modules and stores
        them on the corresponding AMS unit in raw_data so the status route can
        expose them to the frontend.

        AMS module naming conventions (numeric suffix is the AMS unit ID):
        - ``ams/<id>``  – original AMS
        - ``n3f/<id>``  – AMS 2 Pro (H2D Pro and similar)
        - ``n3s/<id>``  – AMS HT (H2D Pro and similar)

        Message format:
        {
            "command": "get_version",
            "module": [
                {"name": "ota", "sw_ver": "01.08.05.00"},
                {"name": "rv1126", "sw_ver": "00.00.14.74"},
                {"name": "ams/0", "sw_ver": "00.00.06.96", "sn": "ABC123"},
                {"name": "n3f/0", "sw_ver": "03.00.21.29", "sn": "19C06A552504488"},
                {"name": "n3s/128", "sw_ver": "03.00.21.29", "sn": "19F06A561801096"},
                ...
            ]
        }
        """
        modules = data.get("module", [])
        if not isinstance(modules, list):
            return

        state_changed = False
        for module in modules:
            if not isinstance(module, dict):
                continue
            if module.get("name") == "ota":
                version = module.get("sw_ver")
                if version:
                    old_version = self.state.firmware_version
                    self.state.firmware_version = version
                    if old_version != version:
                        logger.info("[%s] Firmware version: %s", self.serial_number, version)
                    state_changed = True
                break

        # Extract AMS unit firmware versions from AMS modules.
        # See module-level _AMS_MODULE_PREFIXES for supported naming conventions.
        # Always cache regardless of whether AMS data has arrived yet — get_version
        # often arrives before the first push_status, so caching must be unconditional.
        ams_raw = self.state.raw_data.get("ams")
        for module in modules:
            if not isinstance(module, dict):
                continue
            name = module.get("name", "")
            if not any(name.startswith(prefix) for prefix in _AMS_MODULE_PREFIXES):
                continue
            try:
                ams_id = int(name.split("/", 1)[1])
            except (ValueError, IndexError):
                continue
            sw_ver = module.get("sw_ver", "")
            sn = module.get("sn", "")

            # Extract module type from prefix (e.g. "ams/0" → "ams", "n3f/0" → "n3f")
            module_type = name.split("/", 1)[0]

            # Always cache so _apply_ams_version_cache can apply it when AMS data arrives
            if sw_ver or sn or module_type:
                self._ams_version_cache[ams_id] = {"sw_ver": sw_ver, "sn": sn, "module_type": module_type}
                state_changed = True

            # Also directly update any AMS unit already present in raw_data
            if ams_raw and isinstance(ams_raw, list):
                for ams_unit in ams_raw:
                    if not isinstance(ams_unit, dict):
                        continue
                    try:
                        unit_id = int(ams_unit.get("id")) if ams_unit.get("id") is not None else None
                    except (ValueError, TypeError):
                        unit_id = None
                    if unit_id == ams_id:
                        if sw_ver:
                            ams_unit["sw_ver"] = sw_ver
                            logger.debug("[%s] AMS %s firmware: %s", self.serial_number, ams_id, sw_ver)
                        # Only set sn from version info if not already present in AMS data
                        if sn and not ams_unit.get("sn"):
                            ams_unit["sn"] = sn
                        if module_type:
                            ams_unit["module_type"] = module_type
                        break

        # Trigger state change callback AFTER both loops so AMS sn/sw_ver are
        # included in the broadcast (not just the printer firmware version).
        if state_changed and self.on_state_change:
            self.on_state_change(self.state)

        # Warn if any AMS unit is still missing serial number or firmware version
        # after processing the version info response. Warn only once per connection
        # to avoid repeated noise on older firmware that doesn't report these fields.
        if ams_raw and isinstance(ams_raw, list):
            for ams_unit in ams_raw:
                if not isinstance(ams_unit, dict):
                    continue
                ams_id = ams_unit.get("id", "?")
                if not ams_unit.get("sn") and not ams_unit.get("serial_number"):
                    key = (ams_id, "sn")
                    if key not in self._ams_version_warned:
                        self._ams_version_warned.add(key)
                        logger.warning(
                            "[%s] AMS unit %s: serial number not available in version info",
                            self.serial_number,
                            ams_id,
                        )
                if not ams_unit.get("sw_ver"):
                    key = (ams_id, "sw_ver")
                    if key not in self._ams_version_warned:
                        self._ams_version_warned.add(key)
                        logger.warning(
                            "[%s] AMS unit %s: firmware version not available in version info",
                            self.serial_number,
                            ams_id,
                        )

    def _apply_ams_version_cache(self, ams_list: list) -> None:
        """Apply cached AMS firmware/SN (from get_version) onto an AMS list in-place.

        get_version may arrive before pushall/AMS status, and AMS unit IDs may be
        strings in MQTT payloads. This helper normalizes IDs and fills missing
        sw_ver/sn fields without overwriting values already present.
        """
        if not ams_list or not isinstance(ams_list, list):
            return
        cache = self._ams_version_cache
        if not cache:
            return
        for unit in ams_list:
            if not isinstance(unit, dict):
                continue
            raw_id = unit.get("id")
            try:
                unit_id = int(raw_id) if raw_id is not None else None
            except (ValueError, TypeError):
                unit_id = None
            if unit_id is None:
                continue
            cached = cache.get(unit_id)
            if not cached:
                continue
            sw_ver = cached.get("sw_ver") or ""
            sn = cached.get("sn") or ""
            if sw_ver and not unit.get("sw_ver"):
                unit["sw_ver"] = sw_ver
            # Only set sn if not already present in AMS data
            if sn and not unit.get("sn") and not unit.get("serial_number"):
                unit["sn"] = sn
            module_type = cached.get("module_type") or ""
            if module_type and not unit.get("module_type"):
                unit["module_type"] = module_type

    def _parse_xcam_data(self, xcam_data):
        """Parse xcam data for camera settings and AI detection options."""
        if not isinstance(xcam_data, dict):
            return

        current_time = time.time()

        # Helper to check if we should accept incoming value for a module
        # OrcaSlicer pattern: simple hold timer, ignore ALL data for 3 seconds after command
        def should_accept_value(module_name: str, incoming_value: bool) -> bool:
            """Check if we should accept an incoming xcam value.

            OrcaSlicer pattern: After sending a command, ignore incoming data
            for 3 seconds. After that, accept whatever the printer sends.
            """
            if module_name not in self._xcam_hold_start:
                return True  # No hold timer, accept incoming

            hold_start = self._xcam_hold_start[module_name]
            elapsed = current_time - hold_start

            if elapsed > self._xcam_hold_time:
                # Hold timer expired - accept incoming and clear hold
                del self._xcam_hold_start[module_name]
                logger.debug("[%s] Hold expired for %s, accepting %s", self.serial_number, module_name, incoming_value)
                return True

            # Within hold period - ignore incoming data
            logger.debug(
                f"[{self.serial_number}] Ignoring {module_name}={incoming_value} "
                f"(hold active, {elapsed:.1f}s < {self._xcam_hold_time}s)"
            )
            return False

        # Log all xcam fields for debugging
        logger.debug("[%s] Parsing xcam data - all fields: %s", self.serial_number, list(xcam_data.keys()))

        # The cfg bitmask contains the ACTUAL detector states - the individual boolean
        # fields (spaghetti_detector, etc.) are often stale/cached.
        # CFG bitmask structure (each detector uses 3 bits: [sens_low, sens_high, enabled]):
        # - Bits 5-7: spaghetti_detector (sens in 5-6, enabled in 7)
        # - Bits 8-10: pileup_detector (sens in 8-9, enabled in 10)
        # - Bits 11-13: clump_detector/nozzle_clumping (sens in 11-12, enabled in 13)
        # - Bits 14-16: airprint_detector (sens in 14-15, enabled in 16)
        # Sensitivity values: 0=low, 1=medium, 2=high
        if "cfg" in xcam_data:
            cfg = xcam_data["cfg"]
            logger.debug("[%s] xcam cfg bitmask: %s (binary: %s)", self.serial_number, cfg, bin(cfg))

            def decode_detector(start_bit):
                """Decode a detector from cfg: returns (enabled, sensitivity_str)"""
                sens_bits = (cfg >> start_bit) & 0x3
                enabled = bool((cfg >> (start_bit + 2)) & 1)
                sensitivity = {0: "low", 1: "medium", 2: "high"}.get(sens_bits, "medium")
                return enabled, sensitivity

            # Spaghetti detector (bits 5-7)
            cfg_spaghetti, cfg_sensitivity = decode_detector(5)
            if should_accept_value("spaghetti_detector", cfg_spaghetti):
                old_value = self.state.print_options.spaghetti_detector
                if cfg_spaghetti != old_value:
                    logger.debug(
                        f"[{self.serial_number}] spaghetti_detector changed (from cfg): {old_value} -> {cfg_spaghetti}"
                    )
                self.state.print_options.spaghetti_detector = cfg_spaghetti

            # Check hold timer for sensitivity before accepting
            if "halt_print_sensitivity" not in self._xcam_hold_start:
                if cfg_sensitivity != self.state.print_options.halt_print_sensitivity:
                    logger.debug(
                        f"[{self.serial_number}] Sensitivity changed (from cfg): "
                        f"{self.state.print_options.halt_print_sensitivity} -> {cfg_sensitivity}"
                    )
                    self.state.print_options.halt_print_sensitivity = cfg_sensitivity
            else:
                hold_start = self._xcam_hold_start["halt_print_sensitivity"]
                elapsed = current_time - hold_start
                if elapsed <= self._xcam_hold_time:
                    logger.debug(
                        f"[{self.serial_number}] Ignoring cfg sensitivity={cfg_sensitivity} "
                        f"(hold active, {elapsed:.1f}s < {self._xcam_hold_time}s)"
                    )
                else:
                    # Hold expired - accept from cfg
                    if cfg_sensitivity != self.state.print_options.halt_print_sensitivity:
                        logger.debug(
                            f"[{self.serial_number}] Sensitivity synced (from cfg after hold): "
                            f"{self.state.print_options.halt_print_sensitivity} -> {cfg_sensitivity}"
                        )
                        self.state.print_options.halt_print_sensitivity = cfg_sensitivity
                    del self._xcam_hold_start["halt_print_sensitivity"]

            # Pileup detector (bits 8-10)
            cfg_pileup, cfg_pileup_sens = decode_detector(8)
            if should_accept_value("pileup_detector", cfg_pileup):
                if cfg_pileup != self.state.print_options.pileup_detector:
                    logger.debug(
                        f"[{self.serial_number}] pileup_detector changed (from cfg): {self.state.print_options.pileup_detector} -> {cfg_pileup}"
                    )
                    self.state.print_options.pileup_detector = cfg_pileup
            # Pileup sensitivity with hold timer
            if "pileup_sensitivity" not in self._xcam_hold_start:
                if cfg_pileup_sens != self.state.print_options.pileup_sensitivity:
                    logger.debug(
                        f"[{self.serial_number}] pileup_sensitivity changed (from cfg): {self.state.print_options.pileup_sensitivity} -> {cfg_pileup_sens}"
                    )
                    self.state.print_options.pileup_sensitivity = cfg_pileup_sens
            else:
                hold_start = self._xcam_hold_start["pileup_sensitivity"]
                elapsed = current_time - hold_start
                if elapsed > self._xcam_hold_time:
                    if cfg_pileup_sens != self.state.print_options.pileup_sensitivity:
                        logger.debug(
                            f"[{self.serial_number}] pileup_sensitivity synced (from cfg after hold): {self.state.print_options.pileup_sensitivity} -> {cfg_pileup_sens}"
                        )
                        self.state.print_options.pileup_sensitivity = cfg_pileup_sens
                    del self._xcam_hold_start["pileup_sensitivity"]

            # Clump/nozzle clumping detector (bits 11-13)
            cfg_clump, cfg_clump_sens = decode_detector(11)
            if should_accept_value("clump_detector", cfg_clump):
                if cfg_clump != self.state.print_options.nozzle_clumping_detector:
                    logger.debug(
                        f"[{self.serial_number}] nozzle_clumping_detector changed (from cfg): {self.state.print_options.nozzle_clumping_detector} -> {cfg_clump}"
                    )
                    self.state.print_options.nozzle_clumping_detector = cfg_clump
            # Clump sensitivity with hold timer
            if "nozzle_clumping_sensitivity" not in self._xcam_hold_start:
                if cfg_clump_sens != self.state.print_options.nozzle_clumping_sensitivity:
                    logger.debug(
                        f"[{self.serial_number}] nozzle_clumping_sensitivity changed (from cfg): {self.state.print_options.nozzle_clumping_sensitivity} -> {cfg_clump_sens}"
                    )
                    self.state.print_options.nozzle_clumping_sensitivity = cfg_clump_sens
            else:
                hold_start = self._xcam_hold_start["nozzle_clumping_sensitivity"]
                elapsed = current_time - hold_start
                if elapsed > self._xcam_hold_time:
                    if cfg_clump_sens != self.state.print_options.nozzle_clumping_sensitivity:
                        logger.debug(
                            f"[{self.serial_number}] nozzle_clumping_sensitivity synced (from cfg after hold): {self.state.print_options.nozzle_clumping_sensitivity} -> {cfg_clump_sens}"
                        )
                        self.state.print_options.nozzle_clumping_sensitivity = cfg_clump_sens
                    del self._xcam_hold_start["nozzle_clumping_sensitivity"]

            # Airprint detector (bits 14-16)
            cfg_airprint, cfg_airprint_sens = decode_detector(14)
            if should_accept_value("airprint_detector", cfg_airprint):
                if cfg_airprint != self.state.print_options.airprint_detector:
                    logger.debug(
                        f"[{self.serial_number}] airprint_detector changed (from cfg): {self.state.print_options.airprint_detector} -> {cfg_airprint}"
                    )
                    self.state.print_options.airprint_detector = cfg_airprint
            # Airprint sensitivity with hold timer
            if "airprint_sensitivity" not in self._xcam_hold_start:
                if cfg_airprint_sens != self.state.print_options.airprint_sensitivity:
                    logger.debug(
                        f"[{self.serial_number}] airprint_sensitivity changed (from cfg): {self.state.print_options.airprint_sensitivity} -> {cfg_airprint_sens}"
                    )
                    self.state.print_options.airprint_sensitivity = cfg_airprint_sens
            else:
                hold_start = self._xcam_hold_start["airprint_sensitivity"]
                elapsed = current_time - hold_start
                if elapsed > self._xcam_hold_time:
                    if cfg_airprint_sens != self.state.print_options.airprint_sensitivity:
                        logger.debug(
                            f"[{self.serial_number}] airprint_sensitivity synced (from cfg after hold): {self.state.print_options.airprint_sensitivity} -> {cfg_airprint_sens}"
                        )
                        self.state.print_options.airprint_sensitivity = cfg_airprint_sens
                    del self._xcam_hold_start["airprint_sensitivity"]

        # Camera settings
        if "ipcam_record" in xcam_data:
            self.state.ipcam = xcam_data.get("ipcam_record") == "enable"
        if "timelapse" in xcam_data:
            self.state.timelapse = xcam_data.get("timelapse") == "enable"
            # Track if timelapse was ever active during this print
            if self.state.timelapse and self._was_running:
                self._timelapse_during_print = True

        # Skip spaghetti_detector boolean field - we read from cfg bitmask above
        if "print_halt" in xcam_data:
            self.state.print_options.print_halt = bool(xcam_data.get("print_halt"))
        # Skip halt_print_sensitivity field - it's always stale ("medium")
        # We read the actual sensitivity from cfg bits 5-6 above
        if "first_layer_inspector" in xcam_data:
            new_value = bool(xcam_data.get("first_layer_inspector"))
            if should_accept_value("first_layer_inspector", new_value):
                self.state.print_options.first_layer_inspector = new_value
        if "printing_monitor" in xcam_data:
            new_value = bool(xcam_data.get("printing_monitor"))
            if should_accept_value("printing_monitor", new_value):
                self.state.print_options.printing_monitor = new_value
        if "buildplate_marker_detector" in xcam_data:
            new_value = bool(xcam_data.get("buildplate_marker_detector"))
            if should_accept_value("buildplate_marker_detector", new_value):
                self.state.print_options.buildplate_marker_detector = new_value
        if "allow_skip_parts" in xcam_data:
            new_value = bool(xcam_data.get("allow_skip_parts"))
            if should_accept_value("allow_skip_parts", new_value):
                self.state.print_options.allow_skip_parts = new_value

        # Additional AI detectors - these are decoded from cfg bitmask above, not from
        # individual boolean fields (which are not sent by the printer)
        # pileup_detector, nozzle_clumping_detector, airprint_detector - from cfg
        # auto_recovery_step_loss and filament_tangle_detect - tracked locally only
        if "auto_recovery_step_loss" in xcam_data:
            self.state.print_options.auto_recovery_step_loss = bool(xcam_data.get("auto_recovery_step_loss"))
        if "filament_tangle_detect" in xcam_data:
            self.state.print_options.filament_tangle_detect = bool(xcam_data.get("filament_tangle_detect"))

    @staticmethod
    def _resolve_local_slot_from_mapping(local_slot: int, mapping_raw: list | None) -> int | None:
        """Resolve a local AMS slot ID to a global tray ID using the MQTT mapping field.

        The MQTT mapping field is an array of snow-encoded values:
        each entry = ams_hw_id * 256 + slot_id (65535 = unmapped).

        Finds entries where the local slot matches, then computes the global tray ID.
        Returns the global ID if exactly one AMS matches, or None if ambiguous/unavailable.
        """
        if not isinstance(mapping_raw, list) or not mapping_raw:
            return None

        candidates: set[int] = set()
        for value in mapping_raw:
            if not isinstance(value, int) or value >= 65535:
                continue
            ams_hw_id = value >> 8
            slot = value & 0xFF
            if 0 <= ams_hw_id <= 3 and (slot & 0x03) == local_slot:
                candidates.add(ams_hw_id * 4 + local_slot)
            elif 128 <= ams_hw_id <= 135 and local_slot == 0:
                candidates.add(ams_hw_id)

        if len(candidates) == 1:
            return candidates.pop()
        return None

    def _handle_ams_data(self, ams_data):
        """Handle AMS data changes for Spoolman integration.

        This is called when we receive top-level AMS data in MQTT messages.
        It detects changes and triggers the callback for Spoolman sync.
        """
        import hashlib

        # Handle nested ams structure: {"ams": {"ams": [...]}} or {"ams": [...]}
        # Also handle P1S partial updates: {"tray_now": ..., "tray_tar": ...} without "ams" key
        ams_list = None
        if isinstance(ams_data, dict):
            if "ams" in ams_data:
                ams_list = ams_data["ams"]
            # Log all AMS dict fields to debug tray_now for H2D dual-nozzle
            non_list_fields = {k: v for k, v in ams_data.items() if k != "ams"}
            if non_list_fields:
                logger.debug("[%s] AMS dict fields: %s", self.serial_number, non_list_fields)

            # IMPORTANT: Parse ams_status FIRST before tray_now, so we have fresh status
            # when checking if we're in filament change mode for tray_now disambiguation
            if "ams_status" in ams_data:
                raw_ams_status = ams_data["ams_status"]
                if isinstance(raw_ams_status, str):
                    try:
                        self.state.ams_status = int(raw_ams_status)
                    except ValueError:
                        self.state.ams_status = 0
                else:
                    self.state.ams_status = raw_ams_status if raw_ams_status is not None else 0
                # Compute main and sub status
                self.state.ams_status_sub = self.state.ams_status & 0xFF
                self.state.ams_status_main = (self.state.ams_status >> 8) & 0xFF
                logger.debug(
                    f"[{self.serial_number}] ams_status: {self.state.ams_status} "
                    f"(main={self.state.ams_status_main}, sub={self.state.ams_status_sub})"
                )

            # Parse tray_now from AMS dict - this is the currently loaded tray global ID
            # Note: tray_tar is also available but on H2D it's just slot number (0-3), not global ID
            if "tray_now" in ams_data:
                raw_tray_now = ams_data["tray_now"]
                # Convert string to int if needed
                if isinstance(raw_tray_now, str):
                    try:
                        parsed_tray_now = int(raw_tray_now)
                    except ValueError:
                        parsed_tray_now = 255
                else:
                    parsed_tray_now = raw_tray_now if raw_tray_now is not None else 255

                # H2D dual-nozzle printers report only slot number (0-3), not global tray ID
                # Use active_extruder + ams_extruder_map to determine which AMS the slot belongs to
                # Single-nozzle printers with multiple AMS (e.g. P2S) also report local slot IDs (#420)
                # — disambiguated below using MQTT mapping field
                ams_map = self.state.ams_extruder_map
                if self._is_dual_nozzle and 0 <= parsed_tray_now <= 3:
                    # First, check if we have a pending target that matches this slot
                    pending_target = self.state.pending_tray_target
                    if pending_target is not None:
                        pending_slot = pending_target % 4
                        if pending_slot == parsed_tray_now:
                            # Slot matches our pending target - use the full global ID
                            logger.debug(
                                f"[{self.serial_number}] H2D tray_now disambiguation: "
                                f"slot {parsed_tray_now} matches pending_tray_target {pending_target} -> using global ID {pending_target}"
                            )
                            self.state.tray_now = pending_target
                            # Clear pending target now that load is confirmed
                            self.state.pending_tray_target = None
                        else:
                            # Slot doesn't match our pending target - something changed, use slot as-is
                            logger.warning(
                                f"[{self.serial_number}] H2D tray_now: slot {parsed_tray_now} doesn't match "
                                f"pending_tray_target {pending_target} (slot {pending_slot}) - using slot as global ID"
                            )
                            self.state.tray_now = parsed_tray_now
                            # Clear pending target since it's stale
                            self.state.pending_tray_target = None
                    else:
                        # No pending target - use h2d_extruder_snow for accurate disambiguation
                        # H2D sends snow field in device.extruder.info with AMS ID in high byte
                        active_ext = self.state.active_extruder  # 0=right, 1=left

                        # Best source: use snow value from device.extruder.info if available
                        snow_tray = self.state.h2d_extruder_snow.get(active_ext)
                        if snow_tray is not None and snow_tray != 255:
                            # snow_tray is already normalized to global ID
                            # Verify the slot matches what we see in tray_now
                            # Regular AMS: slot = global_id % 4; AMS HT (128-135): single slot = 0
                            snow_slot = snow_tray % 4 if snow_tray < 128 else (0 if snow_tray <= 135 else -1)
                            if snow_slot == parsed_tray_now:
                                if self.state.tray_now != snow_tray:
                                    logger.debug(
                                        f"[{self.serial_number}] H2D tray_now from snow: "
                                        f"extruder[{active_ext}] snow={snow_tray} (slot {snow_slot})"
                                    )
                                self.state.tray_now = snow_tray
                            else:
                                # Slot mismatch - snow field may not have updated yet, trust snow
                                logger.debug(
                                    f"[{self.serial_number}] H2D tray_now: ams.tray_now slot {parsed_tray_now} "
                                    f"!= snow slot {snow_slot}, using snow value {snow_tray}"
                                )
                                self.state.tray_now = snow_tray
                        else:
                            # Fallback: snow not available, use ams_extruder_map (less reliable)
                            # Find ALL AMS units on the active extruder
                            ams_on_extruder = []
                            for ams_id_str, ext_id in ams_map.items():
                                if ext_id == active_ext:
                                    try:
                                        ams_on_extruder.append(int(ams_id_str))
                                    except ValueError:
                                        pass  # Skip AMS IDs that aren't valid integers

                            if len(ams_on_extruder) == 1:
                                # Single AMS on this extruder - unambiguous
                                active_ams_id = ams_on_extruder[0]
                                if 128 <= active_ams_id <= 135:
                                    # AMS-HT: single slot per unit, global ID = unit ID
                                    global_tray_id = active_ams_id
                                else:
                                    global_tray_id = active_ams_id * 4 + parsed_tray_now
                                logger.debug(
                                    f"[{self.serial_number}] H2D tray_now fallback: "
                                    f"slot {parsed_tray_now} + single AMS {active_ams_id} -> global ID {global_tray_id}"
                                )
                                self.state.tray_now = global_tray_id
                            elif len(ams_on_extruder) > 1:
                                # Multiple AMS on this extruder - keep current if valid, else try to narrow down
                                current_tray = self.state.tray_now
                                # Determine which AMS unit and slot the current tray belongs to
                                if 0 <= current_tray <= 15:
                                    current_ams = current_tray // 4
                                    current_slot = current_tray % 4
                                elif 128 <= current_tray <= 135:
                                    current_ams = current_tray  # AMS-HT: ID = tray ID
                                    current_slot = 0
                                else:
                                    current_ams = -1
                                    current_slot = -1
                                if current_ams in ams_on_extruder and current_slot == parsed_tray_now:
                                    # Current is valid and matches slot - keep it
                                    logger.debug(
                                        f"[{self.serial_number}] H2D tray_now: multiple AMS {ams_on_extruder}, "
                                        f"keeping current {current_tray} (matches slot {parsed_tray_now})"
                                    )
                                else:
                                    # Filter candidates: AMS-HT (128-135) only valid for slot 0
                                    if parsed_tray_now > 0:
                                        candidates = [a for a in ams_on_extruder if a <= 3]
                                    else:
                                        candidates = ams_on_extruder
                                    if len(candidates) == 1:
                                        cand = candidates[0]
                                        resolved = cand if 128 <= cand <= 135 else cand * 4 + parsed_tray_now
                                        logger.debug(
                                            f"[{self.serial_number}] H2D tray_now: multiple AMS {ams_on_extruder}, "
                                            f"narrowed to AMS {cand} -> global ID {resolved}"
                                        )
                                        self.state.tray_now = resolved
                                    else:
                                        # Genuinely ambiguous - use slot as-is (will be wrong for non-first AMS)
                                        logger.warning(
                                            f"[{self.serial_number}] H2D tray_now: multiple AMS {ams_on_extruder} on extruder {active_ext}, "
                                            f"no snow field, using slot {parsed_tray_now} (may be incorrect)"
                                        )
                                        self.state.tray_now = parsed_tray_now
                            else:
                                # No AMS on this extruder - use slot as-is
                                logger.warning(
                                    f"[{self.serial_number}] H2D tray_now: no AMS on extruder {active_ext}, "
                                    f"using slot {parsed_tray_now}"
                                )
                                self.state.tray_now = parsed_tray_now
                elif not self._is_dual_nozzle and 0 <= parsed_tray_now <= 3:
                    # Single-nozzle printer with tray_now in 0-3 range.
                    # P2S (and possibly other models) with multiple AMS units sends LOCAL slot IDs
                    # in tray_now, not global tray IDs (#420). Use the MQTT mapping field
                    # (snow-encoded) to resolve the correct AMS unit.
                    ams_exist_raw = ams_data.get("ams_exist_bits", "0")
                    try:
                        ams_exist = int(ams_exist_raw, 16) if isinstance(ams_exist_raw, str) else int(ams_exist_raw)
                    except (ValueError, TypeError):
                        ams_exist = 0
                    num_ams = bin(ams_exist).count("1")

                    if num_ams > 1:
                        # Multiple AMS on single-nozzle — tray_now is likely a local slot ID.
                        # Cross-reference with MQTT mapping field to find the correct AMS unit.
                        mapping_raw = self.state.raw_data.get("mapping")
                        resolved = self._resolve_local_slot_from_mapping(parsed_tray_now, mapping_raw)
                        if resolved is not None:
                            if resolved != parsed_tray_now:
                                logger.debug(
                                    f"[{self.serial_number}] Multi-AMS tray_now: "
                                    f"local slot {parsed_tray_now} -> global ID {resolved} (from mapping)"
                                )
                            self.state.tray_now = resolved
                        else:
                            # No mapping available (not printing, or ambiguous) — use as-is.
                            # This matches the old behavior and is correct for AMS 0.
                            self.state.tray_now = parsed_tray_now
                    else:
                        # Single AMS — local slot 0-3 equals global ID
                        self.state.tray_now = parsed_tray_now
                else:
                    # tray_now > 3 means it's already a global ID, or 255 means unloaded
                    # Note: Do NOT clear pending_tray_target on tray_now=255 here.
                    # During filament change, the printer sends 255 first (unload), then the slot.
                    # We only clear pending_tray_target explicitly in ams_unload_filament().
                    # Trust the printer's reported value.
                    self.state.tray_now = parsed_tray_now

                # Track last valid tray for usage tracking (survives retract → 255 at print end)
                # Valid physical trays: 0-15 (regular AMS), 128-135 (AMS-HT), 254 (external spool)
                tn = self.state.tray_now
                if (0 <= tn <= 15) or (128 <= tn <= 135) or tn == 254:
                    # Log tray change for mid-print usage splitting. Gate on the
                    # print-lifecycle flags (`_was_running` set on first RUNNING /
                    # new print, `_completion_triggered` set when on_print_complete
                    # fires) instead of `state in ("RUNNING", "PAUSE")` — P2S
                    # firmware briefly transitions out of RUNNING during AMS
                    # auto-fallback (#957), so a literal-string gate misses the
                    # switch and the usage tracker double-credits at completion.
                    if tn != self.state.last_loaded_tray and self._was_running and not self._completion_triggered:
                        self.state.tray_change_log.append((tn, self.state.layer_num))
                        logger.info(
                            "[%s] Tray change during print: tray=%d at layer=%d",
                            self.serial_number,
                            tn,
                            self.state.layer_num,
                        )
                    self.state.last_loaded_tray = self.state.tray_now

                logger.debug("[%s] tray_now updated: %s", self.serial_number, self.state.tray_now)

            # NOTE: ams_status is parsed BEFORE tray_now (see above) to ensure correct
            # state when checking filament change mode for H2D disambiguation

            # P1S/P1P send partial updates without "ams" key - this is valid, not an error
            # We've already processed the status fields above, so just return if no ams list
            if ams_list is None:
                logger.debug("[%s] AMS partial update (no tray data)", self.serial_number)
                return
        elif isinstance(ams_data, list):
            ams_list = ams_data
        else:
            logger.warning("[%s] Unexpected AMS data format: %s", self.serial_number, type(ams_data))
            return

        # Merge AMS data instead of replacing, to handle partial updates
        # During prints, the printer may only send updates for active AMS units
        # We need deep merging at the tray level to preserve fields like tray_sub_brands
        existing_ams = self.state.raw_data.get("ams", [])
        existing_by_id = {ams.get("id"): ams for ams in existing_ams if ams.get("id") is not None}

        # Update existing units with new data, add new units
        for ams_unit in ams_list:
            ams_id = ams_unit.get("id")
            if ams_id is not None:
                existing_unit = existing_by_id.get(ams_id)
                if existing_unit and "tray" in ams_unit:
                    # Deep merge trays to preserve fields from previous updates
                    existing_trays = {t.get("id"): t for t in existing_unit.get("tray", []) if t.get("id") is not None}
                    merged_trays = []
                    for new_tray in ams_unit.get("tray", []):
                        tray_id = new_tray.get("id")
                        if tray_id is not None and tray_id in existing_trays:
                            # Merge: start with existing, update with new non-empty values
                            merged_tray = existing_trays[tray_id].copy()
                            # Detect slot-clearing updates (spool removal):
                            # When tray_type is explicitly empty, clear everything
                            # including RFID data (tag_uid/tray_uuid).
                            slot_clearing = new_tray.get("tray_type") == ""
                            # Some printers (e.g. H2D) only send {id, state} in
                            # incremental updates when a tray is not fully loaded.
                            # state=11 means loaded; other values (9=empty,
                            # 10=spool present but filament not in feeder) indicate
                            # the slot should be cleared.  Without this, old
                            # tray_type/tray_color persist indefinitely (#784).
                            tray_state = new_tray.get("state")
                            if (
                                tray_state is not None
                                and tray_state != 11
                                and "tray_type" not in new_tray
                                and merged_tray.get("tray_type")
                            ):
                                logger.info(
                                    "[%s] AMS %s tray %s: state=%s (not loaded) — clearing stale tray data",
                                    self.serial_number,
                                    ams_id,
                                    tray_id,
                                    tray_state,
                                )
                                slot_clearing = True
                                # The incremental update only has {id, state} — inject
                                # empty values for all content fields so the merge loop
                                # below clears the stale data from merged_tray.
                                new_tray.update(
                                    {
                                        "tray_type": "",
                                        "tray_sub_brands": "",
                                        "tray_color": "",
                                        "tray_id_name": "",
                                        "tray_info_idx": "",
                                        "tag_uid": "0000000000000000",
                                        "tray_uuid": "00000000000000000000000000000000",
                                        "remain": 0,
                                        "k": None,
                                        "cali_idx": None,
                                    }
                                )
                            for key, value in new_tray.items():
                                # Fields that should always be updated (even with empty/zero values):
                                # - remain, k, id, cali_idx: status indicators where 0 is valid
                                # - tray_type, tray_sub_brands, tray_info_idx, tray_color,
                                #   tray_id_name: slot content indicators that must be cleared
                                #   when a spool is removed (fixes #147 - old AMS empty slot)
                                # NOTE: tag_uid and tray_uuid are NOT in always_update_fields.
                                # They are only cleared during spool removal (slot_clearing=True).
                                # Periodic AMS updates often include empty RFID fields which
                                # would overwrite valid data from the initial pushall.
                                always_update_fields = (
                                    "remain",
                                    "k",
                                    "id",
                                    "cali_idx",
                                    "tray_type",
                                    "tray_sub_brands",
                                    "tray_info_idx",
                                    "tray_color",
                                    "tray_id_name",
                                )
                                if (
                                    key in always_update_fields
                                    or slot_clearing
                                    or value
                                    not in (
                                        None,
                                        "",
                                        "0000000000000000",
                                        "00000000000000000000000000000000",
                                    )
                                ):
                                    merged_tray[key] = value
                            merged_trays.append(merged_tray)
                        else:
                            merged_trays.append(new_tray)
                    # Update ams_unit with merged trays. Spread existing_unit
                    # FIRST so top-level fields the partial update omits —
                    # dry_time, info (which drives dry_status / dry_sub_status),
                    # humidity, temp — are preserved instead of dropped. The
                    # printer sends tray-bearing partials that carry no drying
                    # fields; without this, dry_time reads as absent → 0 and the
                    # falling-edge detector below fires a false "drying complete"
                    # (#1462). Mirrors the no-tray branch's merge semantics.
                    ams_unit = {**existing_unit, **ams_unit, "tray": merged_trays}
                elif existing_unit:
                    # Partial update without tray data: merge new fields into existing
                    # unit to preserve tray, sn, sw_ver, and other accumulated data.
                    ams_unit = {**existing_unit, **ams_unit}
                existing_by_id[ams_id] = ams_unit

        # Convert back to list, sorted by ID for consistent ordering
        merged_ams = sorted(existing_by_id.values(), key=lambda x: x.get("id", 0))

        # Check tray_exist_bits to clear empty slots (Issue #147)
        # New AMS models don't send empty tray data - they just update tray_exist_bits
        # Each bit in tray_exist_bits represents a slot: bit=0 means empty, bit=1 means has spool
        # Skip ONLY the printer-shutdown pattern: all-zero bits paired with
        # power_on_flag=False (#765). On shutdown that combination would wipe all
        # slot data and cause auto-unlink to remove spool assignments. Non-zero
        # bits with power_on_flag=False are valid AMS state from an idle printer
        # (#1365 — X1C reports power_on_flag=False between prints while the AMS
        # keeps reporting its actual slot inventory); the update MUST be applied
        # so spool removal is detected without requiring a manual reconnect.
        tray_exist_bits_str = ams_data.get("tray_exist_bits") if isinstance(ams_data, dict) else None
        power_on = ams_data.get("power_on_flag", True) if isinstance(ams_data, dict) else True
        if tray_exist_bits_str:
            try:
                tray_exist_bits = int(tray_exist_bits_str, 16)
            except (ValueError, TypeError) as e:
                logger.debug("[%s] Could not parse tray_exist_bits: %s", self.serial_number, e)
                tray_exist_bits = None

            if tray_exist_bits is not None and not (tray_exist_bits == 0 and not power_on):
                for ams_unit in merged_ams:
                    ams_id_raw = ams_unit.get("id")
                    if ams_id_raw is None:
                        continue
                    # Convert to int (may be string from JSON)
                    ams_id = int(ams_id_raw) if isinstance(ams_id_raw, str) else ams_id_raw
                    if ams_id >= 128:  # Skip HT AMS (id >= 128)
                        continue
                    # Bits for this AMS unit: bits (ams_id*4) to (ams_id*4 + 3)
                    for tray in ams_unit.get("tray", []):
                        tray_id_raw = tray.get("id")
                        if tray_id_raw is None:
                            continue
                        # Convert to int (may be string from JSON)
                        tray_id = int(tray_id_raw) if isinstance(tray_id_raw, str) else tray_id_raw
                        global_bit = ams_id * 4 + tray_id
                        slot_exists = (tray_exist_bits >> global_bit) & 1
                        if not slot_exists:
                            # #1322 follow-up (by @RosdasHH): the bitmask is
                            # BambuStudio's canonical "no spool" signal, and
                            # works across every firmware variant (P1S, A1
                            # Mini, post-restart, post-Reset-Slot, steady-
                            # state). Promote to state=9 (firmware's
                            # explicit "no spool" code) so downstream
                            # readers — printers.py's API serializer,
                            # inventory.py's `tray_state in {9, 10}`
                            # short-circuit, the AMS card — see one
                            # canonical signal instead of guessing from
                            # payload shape. Int (not "9") to match the
                            # downstream `==` comparison.
                            tray["state"] = 9
                            if tray.get("tray_type"):
                                # Stale data from before the slot went empty
                                # — clear it so the AMS view doesn't render a
                                # colour/material that's no longer there.
                                logger.debug(
                                    f"[{self.serial_number}] Clearing empty slot: AMS {ams_id} slot {tray_id} "
                                    f"(tray_exist_bits bit {global_bit} = 0)"
                                )
                                tray["tray_type"] = ""
                                tray["tray_sub_brands"] = ""
                                tray["tray_color"] = ""
                                tray["tray_id_name"] = ""
                                tray["tag_uid"] = "0000000000000000"
                                tray["tray_uuid"] = "00000000000000000000000000000000"
                                tray["tray_info_idx"] = ""
                                tray["remain"] = 0

        self.state.raw_data["ams"] = merged_ams

        # Apply cached AMS firmware/SN from get_version (handles ordering and id type mismatches)
        self._apply_ams_version_cache(merged_ams)
        # Update timestamp for RFID refresh detection (frontend can detect "new data arrived")
        self.state.last_ams_update = time.time()
        logger.debug("[%s] Merged AMS data: %s new units, %s total", self.serial_number, len(ams_list), len(merged_ams))

        # Extract ams_extruder_map from each AMS unit's info field
        # BambuStudio DevFilaSystem.cpp parses info as hex string:
        #   type_id    = get_flag_bits(info, 0, 4)   // bits 0-3: AMS type
        #   extruder_id = get_flag_bits(info, 8, 4)  // bits 8-11: extruder assignment
        # where get_flag_bits uses std::stoull(str, nullptr, 16) — hex parsing.
        # extruder_id: 0=right/main, 1=left/deputy, 0xE=uninitialized (skip)
        #
        # Use merged_ams (not ams_list) to avoid partial MQTT updates overwriting
        # the full map. Merge into existing map to preserve entries from prior updates.

        ams_extruder_map = dict(self.state.ams_extruder_map) if self.state.ams_extruder_map else {}
        for ams_unit in merged_ams:
            ams_id = ams_unit.get("id")
            info = ams_unit.get("info")
            if ams_id is not None and info is not None:
                try:
                    # info is a hex-encoded string in MQTT JSON (e.g. "10001003")
                    info_val = int(str(info), 16)
                    # Extract 4 bits starting at bit 8 for extruder assignment
                    extruder_id = (info_val >> 8) & 0xF
                    if extruder_id == 0xE:
                        # 0xE = uninitialized AMS, skip
                        continue
                    ams_extruder_map[str(ams_id)] = extruder_id
                    logger.debug(f"[{self.serial_number}] AMS {ams_id} info=0x{info} -> extruder {extruder_id}")
                except (ValueError, TypeError):
                    pass  # Skip AMS units with unparseable info bitmask values
        if ams_extruder_map:
            self.state.raw_data["ams_extruder_map"] = ams_extruder_map
            self.state.ams_extruder_map = ams_extruder_map
            logger.debug("[%s] ams_extruder_map: %s", self.serial_number, ams_extruder_map)

        # Extract drying status from info hex string and dry_sf_reason per AMS unit
        # BambuStudio DevFilaSystem.cpp parses info bits:
        #   dry_status     = get_flag_bits(info, 4, 4)   // bits 4-7
        #   dry_sub_status = get_flag_bits(info, 22, 4)  // bits 22-25
        for ams_unit in merged_ams:
            info = ams_unit.get("info")
            if info is not None:
                try:
                    info_val = int(str(info), 16)
                    ams_unit["dry_status"] = (info_val >> 4) & 0xF
                    ams_unit["dry_sub_status"] = (info_val >> 22) & 0xF
                except (ValueError, TypeError):
                    pass  # Skip unparseable info values
            # dry_sf_reason is a per-unit array of cannot-dry reason codes
            if "dry_sf_reason" in ams_unit:
                sf_reason = ams_unit["dry_sf_reason"]
                if isinstance(sf_reason, list):
                    ams_unit["dry_sf_reason"] = [
                        int(r) for r in sf_reason if isinstance(r, int) or (isinstance(r, str) and r.isdigit())
                    ]
                else:
                    ams_unit["dry_sf_reason"] = []

        # Persist updated drying fields back to raw_data
        self.state.raw_data["ams"] = merged_ams

        # Detect AMS drying-complete falling edge per-unit (#1349). When an
        # AMS's `dry_time` transitions from >0 to 0 the cycle just finished
        # — fire the callback so smart-plug auto-off-after-drying can run.
        # Works identically for queue-triggered, ambient, and manual drying
        # because we observe the firmware-reported state, not our own intent.
        if self.on_drying_complete:
            for ams_unit in merged_ams:
                try:
                    ams_id = int(ams_unit.get("id", -1))
                except (TypeError, ValueError):
                    continue
                if ams_id < 0:
                    continue
                # Only evaluate the edge when this update carries an explicit
                # dry_time. An absent / unparseable value is NOT zero — treating
                # it as 0 lets a tray-only partial fake a drying-complete edge
                # (#1462). Skip without touching the remembered value so the
                # next update that DOES carry dry_time sees the true previous.
                raw_dry_time = ams_unit.get("dry_time")
                if raw_dry_time is None:
                    continue
                try:
                    current = int(raw_dry_time)
                except (TypeError, ValueError):
                    continue
                previous = self._previous_dry_times.get(ams_id, 0)
                self._previous_dry_times[ams_id] = current
                if previous > 0 and current == 0:
                    logger.info(
                        "[%s] AMS %d drying complete (dry_time %d → 0)",
                        self.serial_number,
                        ams_id,
                        previous,
                    )
                    self.on_drying_complete(ams_id)

        # Create a hash of relevant AMS data to detect changes
        ams_hash_data = []
        for ams_unit in ams_list:
            for tray in ams_unit.get("tray", []):
                # Include fields that matter for filament tracking
                ams_hash_data.append(
                    f"{ams_unit.get('id')}:{tray.get('id')}:"
                    f"{tray.get('tray_type')}:{tray.get('tag_uid')}:{tray.get('remain')}"
                )
        ams_hash = hashlib.md5(":".join(ams_hash_data).encode(), usedforsecurity=False).hexdigest()

        # Only trigger callback if AMS data actually changed
        if ams_hash != self._previous_ams_hash:
            self._previous_ams_hash = ams_hash
            if self.on_ams_change:
                logger.debug("[%s] AMS data changed, triggering sync callback", self.serial_number)
                # Pass merged AMS data (not raw ams_list) — partial MQTT updates
                # may lack fields like 'remain' that the merged state preserves
                self.on_ams_change(merged_ams)

    def _update_state(self, data: dict):
        """Update printer state from message data."""
        _previous_state = self.state.state

        # Update state fields
        if "gcode_state" in data:
            self.state.state = data["gcode_state"]
        if "gcode_file" in data:
            self.state.gcode_file = data["gcode_file"]
            self.state.current_print = data["gcode_file"]
        if "subtask_name" in data:
            self.state.subtask_name = data["subtask_name"]
            # Prefer subtask_name as current_print if available
            if data["subtask_name"]:
                self.state.current_print = data["subtask_name"]
        if "subtask_id" in data:
            self.state.subtask_id = data["subtask_id"]
        if "mc_percent" in data:
            # Save last non-zero progress for usage tracking (firmware resets to 0 on cancel)
            if self.state.progress > 0:
                self._last_valid_progress = self.state.progress
            self.state.progress = float(data["mc_percent"])
        if "mc_remaining_time" in data:
            self.state.remaining_time = int(data["mc_remaining_time"])
        if "mc_print_sub_stage" in data:
            new_sub_stage = int(data["mc_print_sub_stage"])
            if new_sub_stage != self.state.mc_print_sub_stage:
                logger.debug(
                    f"[{self.serial_number}] mc_print_sub_stage changed: "
                    f"{self.state.mc_print_sub_stage} -> {new_sub_stage}"
                )
            self.state.mc_print_sub_stage = new_sub_stage
        if "layer_num" in data:
            new_layer = int(data["layer_num"])
            old_layer = self.state.layer_num
            # Save last non-zero layer for usage tracking (firmware resets to 0 on cancel)
            if old_layer > 0:
                self._last_valid_layer_num = old_layer
            self.state.layer_num = new_layer
            # Trigger layer change callback if layer increased
            if new_layer > old_layer and self.on_layer_change:
                self.on_layer_change(new_layer)
        if "total_layer_num" in data:
            self.state.total_layers = int(data["total_layer_num"])

        # Fan speeds (MQTT sends as string "0"-"15" representing speed levels, or percentage)
        # Convert to 0-100 percentage for display
        def parse_fan_speed(value: str | int | None) -> int | None:
            if value is None:
                return None
            try:
                speed = int(value)
                # MQTT reports 0-15 speed levels, convert to percentage (0-100)
                # 15 = 100%, so multiply by 100/15 ≈ 6.67
                if speed <= 15:
                    return round(speed * 100 / 15)
                # If already a percentage (0-255 scale from some printers), convert
                elif speed <= 255:
                    return round(speed * 100 / 255)
                return speed
            except (ValueError, TypeError):
                return None

        # Log fan fields once for debugging
        if not hasattr(self, "_fan_fields_logged"):
            fan_fields = {k: v for k, v in data.items() if "fan" in k.lower()}
            if fan_fields:
                logger.debug("[%s] Fan fields in MQTT data: %s", self.serial_number, fan_fields)
                self._fan_fields_logged = True

        if "cooling_fan_speed" in data:
            self.state.cooling_fan_speed = parse_fan_speed(data["cooling_fan_speed"])
        if "big_fan1_speed" in data:
            self.state.big_fan1_speed = parse_fan_speed(data["big_fan1_speed"])
        if "big_fan2_speed" in data:
            self.state.big_fan2_speed = parse_fan_speed(data["big_fan2_speed"])
        if "heatbreak_fan_speed" in data:
            self.state.heatbreak_fan_speed = parse_fan_speed(data["heatbreak_fan_speed"])

        # Calibration stage tracking
        if "stg_cur" in data:
            new_stg = data["stg_cur"]
            # Always log ANY stg_cur change for debugging filament operations
            if new_stg != self.state.stg_cur:
                logger.debug(
                    f"[{self.serial_number}] stg_cur changed: {self.state.stg_cur} -> {new_stg} ({get_stage_name(new_stg)})"
                )
            self.state.stg_cur = new_stg
        if "stg" in data:
            self.state.stg = data["stg"] if isinstance(data["stg"], list) else []

        # Temperature data
        temps = {}
        # Log all fields for debugging dual-nozzle temperature discovery (only once)
        if "bed_temper" in data and not hasattr(self, "_temp_fields_logged"):
            temp_fields = {k: v for k, v in data.items() if "temp" in k.lower() or "chamber" in k.lower()}
            logger.debug("[%s] Temperature-related fields: %s", self.serial_number, temp_fields)
            # Log ALL keys in print data for H2D temperature discovery
            all_keys = sorted(data.keys())
            logger.debug("[%s] ALL print data keys (%s): %s", self.serial_number, len(all_keys), all_keys)
            self._temp_fields_logged = True

        # Log vir_slot data (once) - this may contain per-extruder slot mapping for H2D
        if "vir_slot" in data and not hasattr(self, "_vir_slot_logged"):
            logger.debug("[%s] vir_slot data: %s", self.serial_number, data["vir_slot"])
            self._vir_slot_logged = True

        # Log nozzle hardware info fields (once)
        nozzle_fields = {
            k: v
            for k, v in data.items()
            if "nozzle" in k.lower() or "hw" in k.lower() or "extruder" in k.lower() or "upgrade" in k.lower()
        }
        if nozzle_fields and not hasattr(self, "_nozzle_fields_logged"):
            logger.debug("[%s] Nozzle/hardware fields in MQTT data: %s", self.serial_number, nozzle_fields)
            self._nozzle_fields_logged = True
        # Parse active extruder from device.extruder.state bit 8
        # bit 8 = 0 → RIGHT extruder (active_extruder=0)
        # bit 8 = 1 → LEFT extruder (active_extruder=1)
        if "device" in data and isinstance(data.get("device"), dict):
            device = data["device"]
            # One-shot identification probe: surface whatever the firmware uses to
            # name itself so an unknown model in a support bundle becomes self-
            # diagnosing. INFO level so it shows up without debug logging. Falls
            # back to dumping device.keys() if none of the known fields are present
            # (so a future Bambu rename like `model_name` is still observable).
            if not getattr(self, "_device_id_logged", False):
                id_fields = {
                    k: device.get(k)
                    for k in ("dev_model_name", "dev_product_name", "dev_id", "project_name")
                    if k in device
                }
                if id_fields:
                    logger.info("[%s] Device identification: %s", self.serial_number, id_fields)
                else:
                    logger.info(
                        "[%s] Device identification: no known id fields; device.keys=%s",
                        self.serial_number,
                        sorted(device.keys()),
                    )
                self._device_id_logged = True
            if "extruder" in device and "state" in device["extruder"]:
                state_val = device["extruder"]["state"]
                # Extract bit 8 for extruder position
                new_extruder = (state_val >> 8) & 0x1
                if new_extruder != self.state.active_extruder:
                    logger.debug(
                        f"[{self.serial_number}] ACTIVE EXTRUDER CHANGED (state bit 8): {self.state.active_extruder} -> {new_extruder} (0=right, 1=left) [state={state_val}]"
                    )
                    self.state.active_extruder = new_extruder

        # Log device.extruder structure for active extruder
        if "device" in data and isinstance(data.get("device"), dict):
            device = data["device"]
            if "extruder" in device:
                ext_data = device["extruder"]
                # Log 'state' field - OrcaSlicer uses bits 12-14 for switch state
                if "state" in ext_data:
                    state_val = ext_data["state"]
                    # Extract bits 12-14 (3 bits) for switch state
                    switch_state = (state_val >> 12) & 0x7
                    logger.debug(
                        f"[{self.serial_number}] device.extruder.state={state_val} (switch_state bits 12-14: {switch_state})"
                    )
                # Log 'cur' field if present (might indicate current/active extruder)
                if "cur" in ext_data:
                    logger.debug("[%s] device.extruder.cur: %s", self.serial_number, ext_data["cur"])

        # Filament Track Switch (FTS) detection — #1162. Presence of
        # device.fila_switch in MQTT means the FTS accessory is installed.
        if "device" in data and isinstance(data.get("device"), dict):
            fs_data = data["device"].get("fila_switch")
            if isinstance(fs_data, dict):
                in_raw = fs_data.get("in")
                out_raw = fs_data.get("out")
                self.state.fila_switch = FilaSwitchState(
                    installed=True,
                    in_slots=list(in_raw) if isinstance(in_raw, list) else [],
                    out_extruders=list(out_raw) if isinstance(out_raw, list) else [],
                    stat=int(fs_data.get("stat", 0) or 0),
                    info=int(fs_data.get("info", 0) or 0),
                )

        if "bed_temper" in data:
            temps["bed"] = float(data["bed_temper"])
        if "bed_target_temper" in data:
            temps["bed_target"] = float(data["bed_target_temper"])
        # Check if this is H2D (has device.extruder.info with 2 extruders)
        has_h2d_extruder_info = (
            "device" in data
            and isinstance(data.get("device"), dict)
            and "extruder" in data["device"]
            and isinstance(data["device"]["extruder"].get("info"), list)
            and len(data["device"]["extruder"]["info"]) >= 2
        )

        # Standard nozzle fields: these are for the RIGHT/default nozzle on H2D
        # For H2D, we use these for nozzle_2 (RIGHT), for others use as nozzle (primary)
        # NOTE: On H2D, nozzle_temper seems to mirror left nozzle - we override with extruder_info[0] later
        if "nozzle_temper" in data:
            if has_h2d_extruder_info:
                temps["nozzle_2"] = float(data["nozzle_temper"])  # Will be overridden by extruder_info[0]
            else:
                temps["nozzle"] = float(data["nozzle_temper"])
        if "nozzle_target_temper" in data:
            if has_h2d_extruder_info:
                temps["nozzle_2_target"] = float(data["nozzle_target_temper"])  # RIGHT target on H2D
            else:
                temps["nozzle_target"] = float(data["nozzle_target_temper"])
        # Second nozzle for dual-extruder printers - skip for H2D (uses device.extruder.info instead)
        if not has_h2d_extruder_info:
            # Try multiple possible field names used by different firmware versions
            if "nozzle_temper_2" in data:
                val = float(data["nozzle_temper_2"])
                if -50 < val < 500:  # Valid temp range
                    temps["nozzle_2"] = val
                else:
                    logger.debug("[%s] nozzle_temper_2=%s out of range", self.serial_number, val)
            elif "right_nozzle_temper" in data:
                val = float(data["right_nozzle_temper"])
                if -50 < val < 500:  # Valid temp range
                    temps["nozzle_2"] = val
                else:
                    logger.debug("[%s] right_nozzle_temper=%s out of range", self.serial_number, val)
            if "nozzle_target_temper_2" in data:
                val = float(data["nozzle_target_temper_2"])
                if 0 <= val < 500:  # Valid temp range
                    temps["nozzle_2_target"] = val
                else:
                    logger.debug("[%s] nozzle_target_temper_2=%s out of range", self.serial_number, val)
            elif "right_nozzle_target_temper" in data:
                val = float(data["right_nozzle_target_temper"])
                if 0 <= val < 500:  # Valid temp range
                    temps["nozzle_2_target"] = val
                else:
                    logger.debug("[%s] right_nozzle_target_temper=%s out of range", self.serial_number, val)
            # Also check for left nozzle as primary (some H2 models)
            if "left_nozzle_temper" in data and "nozzle" not in temps:
                temps["nozzle"] = float(data["left_nozzle_temper"])
            if "left_nozzle_target_temper" in data and "nozzle_target" not in temps:
                temps["nozzle_target"] = float(data["left_nozzle_target_temper"])
        if "chamber_temper" in data:
            chamber_val = float(data["chamber_temper"])
            logger.debug("[%s] chamber_temper raw value: %s", self.serial_number, chamber_val)
            # Check if we recently set the target locally (within 5 seconds)
            local_set_time = self.state.temperatures.get("_chamber_target_set_time", 0)
            respect_local = (time.time() - local_set_time) < 5.0
            # H2D protocol: chamber_temper encoding indicates heater state
            # - When > 500: encoded as (target * 65536 + current) - heater is ON
            # - When < 500: direct Celsius current temp only - heater is OFF
            if -50 < chamber_val < 100:
                # Direct value = heater is OFF
                temps["chamber"] = chamber_val
                if not respect_local:
                    temps["chamber_target"] = 0.0  # Heater off means target = 0
                    logger.debug("[%s] chamber_temper direct value: %s°C (heater OFF)", self.serial_number, chamber_val)
            else:
                logger.debug("[%s] chamber_temper %s out of direct range", self.serial_number, chamber_val)
                # Try to decode if it looks like an encoded value
                if chamber_val > 500:
                    mqtt_target = int(chamber_val) // 65536
                    current = int(chamber_val) % 65536
                    logger.debug(
                        f"[{self.serial_number}] chamber_temper decoded: mqtt_target={mqtt_target}, current={current}, respect_local={respect_local}"
                    )
                    if -50 < current < 100:
                        temps["chamber"] = float(current)
                    # Store decoded target for later use, but DON'T set chamber_heating here!
                    # Heating state will be calculated later after parsing ctc.info.target (explicit target)
                    # which is the authoritative source the slicer uses.
                    if not respect_local:
                        if 0 <= mqtt_target <= 60:
                            # Store as "decoded" target - may be overridden by explicit target fields
                            temps["_chamber_decoded_target"] = float(mqtt_target)
        # Chamber target temperature (set by print file or display)
        if "mc_target_cham" in data:
            mc_target = float(data["mc_target_cham"])
            logger.debug("[%s] mc_target_cham raw value: %s", self.serial_number, mc_target)
            # Filter out encoded/invalid values - valid chamber target is 0-60°C
            if 0 <= mc_target <= 60:
                temps["chamber_target"] = mc_target
        # H2D series: Chamber temp is in info.temp (may be encoded or direct °C)
        # NOTE: Don't set chamber_heating here - let ctc.info.target or fallback logic handle it
        # The encoded target in info.temp may be stale (slicer uses ctc.info.target as source of truth)
        try:
            if "info" in data and isinstance(data["info"], dict):
                info_temp = data["info"].get("temp")
                if info_temp is not None and "chamber" not in temps:
                    # Check for encoded value (target * 65536 + current)
                    if info_temp > 500:
                        # Decode: extract current temperature and target
                        target = info_temp // 65536
                        current = info_temp % 65536
                        temps["chamber"] = float(current)
                        # Store decoded target as fallback (may be overridden by ctc.info.target)
                        if "_chamber_decoded_target" not in temps:
                            temps["_chamber_decoded_target"] = float(target)
                        logger.debug(
                            f"[{self.serial_number}] info.temp encoded: {info_temp} -> current={current}, decoded_target={target}"
                        )
                    elif -50 < info_temp < 100:
                        # Valid direct temperature - heater is OFF
                        temps["chamber"] = float(info_temp)
                        temps["chamber_target"] = 0.0  # Direct value means heater off
                        logger.debug("[%s] info.temp direct: %s°C (heater OFF)", self.serial_number, info_temp)
            # H2D series: Dual extruder temps are in device.extruder.info array
            # Temperature values are encoded as fixed-point (value / 65536 = °C)
            if "device" in data and isinstance(data["device"], dict):
                device = data["device"]
                # Parse dual extruder temperatures
                extruder_data = device.get("extruder", {})
                extruder_info = extruder_data.get("info", [])
                if isinstance(extruder_info, list) and len(extruder_info) >= 1:
                    # H2D nozzle mapping: id=0 is RIGHT nozzle (default), id=1 is LEFT nozzle
                    # Only parse dual nozzle temps if this is actually a dual nozzle printer (H2D)
                    # has_h2d_extruder_info requires len(extruder_info) >= 2
                    if has_h2d_extruder_info:
                        # Right nozzle (extruder 0) - use extruder_info for actual temp, not nozzle_temper
                        # nozzle_temper field seems to mirror left nozzle on H2D, so use extruder_info[0]
                        if "temp" in extruder_info[0]:
                            temp_val = extruder_info[0]["temp"]
                            if temp_val > 500:
                                # Encoded format: temp = target * 65536 + current
                                target = temp_val // 65536
                                current = temp_val % 65536
                                if -50 < current < 500:
                                    temps["nozzle_2"] = float(current)
                                if 0 < target < 500:
                                    temps["nozzle_2_target"] = float(target)
                                temps["nozzle_2_heating"] = target > 0 and current < target
                            elif -50 < temp_val < 500:
                                # Direct Celsius value = heater is OFF
                                temps["nozzle_2"] = float(temp_val)
                                temps["nozzle_2_target"] = 0.0
                                temps["nozzle_2_heating"] = False
                    # Left nozzle (extruder 1) - only for dual nozzle printers
                    # H2D protocol: temp field encoding depends on value
                    # - When > 500: encoded as (target * 65536 + current) - heater is ON
                    # - When < 500: direct Celsius current temp only - heater is OFF
                    if len(extruder_info) >= 2 and "temp" in extruder_info[1]:
                        ext1 = extruder_info[1]
                        temp_val = ext1["temp"]

                        # Check if we recently set the target locally (within 5 seconds)
                        # If so, don't let MQTT data overwrite it
                        local_set_time = self.state.temperatures.get("_nozzle_target_set_time", 0)
                        respect_local_target = (time.time() - local_set_time) < 5.0

                        if temp_val > 500:
                            # Encoded format: temp = target * 65536 + current
                            target = temp_val // 65536
                            current = temp_val % 65536
                            if 0 < target < 500 and not respect_local_target:
                                temps["nozzle_target"] = float(target)
                            if -50 < current < 500:
                                temps["nozzle"] = float(current)
                            # Heating = encoded AND we're using the MQTT target (not local override)
                            # If local target is being respected, use local target to determine heating
                            if respect_local_target:
                                local_target = self.state.temperatures.get("nozzle_target", 0)
                                temps["nozzle_heating"] = local_target > 0 and current < local_target
                            else:
                                temps["nozzle_heating"] = target > 0 and current < target
                        elif -50 < temp_val < 500:
                            # Direct Celsius = heater is OFF (or at target with heater off)
                            temps["nozzle"] = float(temp_val)
                            if not respect_local_target:
                                temps["nozzle_target"] = 0.0
                            temps["nozzle_heating"] = False  # Direct = not heating
                    # Parse H2D snow field (slot now) for accurate tray_now disambiguation
                    # snow encodes AMS ID in high byte: ams_id = snow >> 8, slot = snow & 0xFF
                    if has_h2d_extruder_info:
                        for ext_info in extruder_info:
                            ext_id = ext_info.get("id")
                            snow = ext_info.get("snow")
                            if ext_id is not None and snow is not None and ext_id <= 1:
                                # Normalize H2D snow value to global tray ID
                                ams_id = snow >> 8
                                slot = snow & 0xFF
                                if 0 <= ams_id <= 3:
                                    # Regular AMS slot
                                    global_tray = ams_id * 4 + (slot & 0x03)
                                    old_val = self.state.h2d_extruder_snow.get(ext_id)
                                    if old_val != global_tray:
                                        logger.debug(
                                            f"[{self.serial_number}] H2D extruder[{ext_id}] snow: "
                                            f"raw={snow} (AMS {ams_id} slot {slot}) -> global tray {global_tray}"
                                        )
                                    self.state.h2d_extruder_snow[ext_id] = global_tray
                                elif ams_id == 254 or ams_id == 255:
                                    # External spool or unloaded
                                    normalized = 254 if slot != 255 else 255
                                    old_val = self.state.h2d_extruder_snow.get(ext_id)
                                    if old_val != normalized:
                                        logger.debug(
                                            f"[{self.serial_number}] H2D extruder[{ext_id}] snow: "
                                            f"raw={snow} -> {'external' if normalized == 254 else 'unloaded'}"
                                        )
                                    self.state.h2d_extruder_snow[ext_id] = normalized
                                elif 128 <= ams_id <= 135:
                                    # External spool with hub mapping
                                    old_val = self.state.h2d_extruder_snow.get(ext_id)
                                    if old_val != ams_id:
                                        logger.debug(
                                            f"[{self.serial_number}] H2D extruder[{ext_id}] snow: "
                                            f"raw={snow} -> external hub {ams_id}"
                                        )
                                    self.state.h2d_extruder_snow[ext_id] = ams_id
                # Parse bed heating state from device.bed.info.temp encoding
                # temp > 500 means encoded (target*65536+current), heating = target > 0 AND current < target
                bed_data = device.get("bed", {})
                bed_info = bed_data.get("info", {})
                if "temp" in bed_info:
                    temp_val = bed_info["temp"]
                    if temp_val > 500:
                        target = temp_val // 65536
                        current = temp_val % 65536
                        temps["bed_heating"] = target > 0 and current < target
                    else:
                        temps["bed_heating"] = False
                # Parse chamber temp from device.ctc.info.temp if not already set
                ctc_data = device.get("ctc", {})
                ctc_info = ctc_data.get("info", {})
                # Parse airduct mode (0=cooling, 1=heating)
                airduct_data = device.get("airduct", {})
                if "modeCur" in airduct_data:
                    new_mode = airduct_data["modeCur"]
                    if new_mode != self.state.airduct_mode:
                        logger.debug(
                            f"[{self.serial_number}] airduct_mode changed: {self.state.airduct_mode} -> {new_mode}"
                        )
                    self.state.airduct_mode = new_mode
                # Parse chamber temp - may be encoded as (target*65536+current) when > 500
                # Check if we recently set the target locally (within 5 seconds)
                local_set_time = self.state.temperatures.get("_chamber_target_set_time", 0)
                respect_local_target = (time.time() - local_set_time) < 5.0

                # Log ctc_info contents for debugging
                if ctc_info:
                    logger.debug("[%s] ctc_info keys: %s", self.serial_number, list(ctc_info.keys()))

                # FIRST: Parse explicit ctc.info.target if available - this is the authoritative target
                # (what the slicer shows). This OVERRIDES any previously decoded target.
                explicit_target = None
                if "target" in ctc_info:
                    target_val = ctc_info["target"]
                    logger.debug(
                        f"[{self.serial_number}] ctc_info.target explicit value: {target_val}, respect_local={respect_local_target}"
                    )
                    # Filter out invalid values (valid chamber target is 0-60°C)
                    if 0 <= target_val <= 60 and not respect_local_target:
                        explicit_target = float(target_val)
                        temps["chamber_target"] = explicit_target  # Override any previous value
                        logger.debug(
                            f"[{self.serial_number}] Setting chamber_target from ctc_info.target: {explicit_target}"
                        )

                # Parse chamber temp from ctc.info.temp - may be encoded
                if "temp" in ctc_info and "chamber" not in temps:
                    temp_val = ctc_info["temp"]
                    logger.debug("[%s] ctc_info.temp raw value: %s", self.serial_number, temp_val)
                    if temp_val > 500:
                        # Encoded value: decode target and current
                        decoded_target = temp_val // 65536
                        current = temp_val % 65536
                        temps["chamber"] = float(current)
                        logger.debug(
                            f"[{self.serial_number}] ctc_info.temp decoded: target={decoded_target}, current={current}, explicit_target={explicit_target}"
                        )

                        # Determine which target to use for heating state:
                        # Priority: local target > explicit target > decoded target
                        if respect_local_target:
                            local_target = self.state.temperatures.get("chamber_target", 0)
                            temps["chamber_heating"] = local_target > 0 and current < local_target
                        elif explicit_target is not None:
                            # Use explicit ctc.info.target - this is what slicer sees
                            temps["chamber_heating"] = explicit_target > 0 and current < explicit_target
                        else:
                            # Fallback to decoded target only if no explicit target available
                            if not respect_local_target and "chamber_target" not in temps:
                                temps["chamber_target"] = float(decoded_target)
                            temps["chamber_heating"] = decoded_target > 0 and current < decoded_target
                    else:
                        # Direct value (not encoded) - heater is OFF
                        temps["chamber"] = float(temp_val)
                        temps["chamber_heating"] = False
        except Exception as e:
            logger.warning("[%s] Error parsing H2D temperatures: %s", self.serial_number, e)
        if temps:
            # Handle chamber_target: prefer explicit over decoded
            if "_chamber_decoded_target" in temps and "chamber_target" not in temps:
                # No explicit target available, use decoded target from chamber_temper
                temps["chamber_target"] = temps["_chamber_decoded_target"]
            # Remove internal temp key before merging
            temps.pop("_chamber_decoded_target", None)

            # Merge new temps into existing, preserving valid values when new ones are filtered out
            for key, value in temps.items():
                self.state.temperatures[key] = value

            # Notify bed temperature updates (used by event-driven bed cooldown monitor)
            if "bed" in temps and self.on_bed_temp_update:
                self.on_bed_temp_update(temps["bed"])

            # Calculate chamber_heating after all targets are known
            # Priority: local target (if recent) > explicit target (chamber_target) > 0
            if "chamber" in temps and "chamber_heating" not in temps:
                current = self.state.temperatures.get("chamber", 0)
                local_set_time = self.state.temperatures.get("_chamber_target_set_time", 0)
                respect_local = (time.time() - local_set_time) < 5.0

                if respect_local:
                    # Use locally-set target
                    target = self.state.temperatures.get("chamber_target", 0)
                else:
                    # Use explicit/decoded target from MQTT
                    target = self.state.temperatures.get("chamber_target", 0)

                self.state.temperatures["chamber_heating"] = target > 0 and current < target
                logger.debug(
                    f"[{self.serial_number}] Chamber heating calculated: target={target}, current={current}, heating={self.state.temperatures['chamber_heating']}, respect_local={respect_local}"
                )

            # Debug: log chamber value if it was updated
            if "chamber" in temps:
                logger.debug(
                    f"[{self.serial_number}] Chamber temp updated to: {self.state.temperatures.get('chamber')}, target: {self.state.temperatures.get('chamber_target')}, heating: {self.state.temperatures.get('chamber_heating')}"
                )

            # Calculate nozzle_heating for single nozzle printers (not set by H2D parsing)
            # For H2D, nozzle_heating is set in temps dict; for single nozzle, calculate here
            if "nozzle" in temps and "nozzle_heating" not in temps:
                current = self.state.temperatures.get("nozzle", 0)
                target = self.state.temperatures.get("nozzle_target", 0)
                self.state.temperatures["nozzle_heating"] = target > 0 and current < target

        # Parse HMS (Health Management System) errors
        if "hms" in data:
            hms_list = data["hms"]
            logger.debug("[%s] HMS data received: %s", self.serial_number, hms_list)
            self.state.hms_errors = []
            if isinstance(hms_list, list):
                for hms in hms_list:
                    if isinstance(hms, dict):
                        # HMS format: {"attr": attribute_code, "code": error_code}
                        # attr contains module/severity info, code contains error number
                        # Both are needed to construct the wiki URL
                        attr = hms.get("attr", 0)
                        code = hms.get("code", 0)
                        if isinstance(attr, str):
                            attr = int(attr.replace("0x", ""), 16) if attr else 0
                        if isinstance(code, str):
                            code = int(code.replace("0x", ""), 16) if code else 0
                        # Severity is in attr byte 1 (bits 8-15)
                        severity = (attr >> 8) & 0xF
                        # Module is in attr byte 3 (bits 24-31)
                        module = (attr >> 24) & 0xFF
                        # Skip non-error status codes — all real HMS errors
                        # have code >= 0x4000. Lower values are status/phase
                        # indicators that some firmware sends during normal printing.
                        if code < 0x4000:
                            continue
                        # Skip user-action echoes — the printer firmware emits these
                        # as part of normal user-cancel sequences. They're not faults
                        # and shouldn't count toward "X problem" badges or surface as
                        # red pips on the printer card. Backend's notification path
                        # already suppresses 0500_400E for the same reason.
                        short_code = f"{(attr >> 16) & 0xFFFF:04X}_{code & 0xFFFF:04X}"
                        if short_code in _HMS_USER_ACTION_CODES:
                            continue
                        self.state.hms_errors.append(
                            HMSError(
                                code=f"0x{code:x}" if code else "0x0",
                                attr=attr,
                                module=module,
                                severity=severity if severity > 0 else 2,
                            )
                        )

        # Parse print_error - this is a different error format than HMS
        # print_error is a 32-bit integer where:
        #   - High 16 bits contain module info (e.g., 0x0500)
        #   - Low 16 bits contain error code (e.g., 0x8061)
        # Format on printer screen: [0500-8061] -> short code: 0500_8061
        if "print_error" in data:
            print_error = data["print_error"]
            if print_error and print_error != 0:
                # Extract components: MMMMEEEE -> MMMM_EEEE
                module = (print_error >> 16) & 0xFFFF  # High 16 bits (e.g., 0x0500)
                error = print_error & 0xFFFF  # Low 16 bits (e.g., 0x8061)

                # Values below 0x4000 are status/phase indicators, not real errors.
                # All known HMS errors use 0x4xxx (fatal), 0x8xxx (warning), 0xCxxx (prompt).
                # Some firmware sends low values like 0x0002 during normal printing.
                if error < 0x4000:
                    pass  # Skip — not a real error
                else:
                    # Store in a format that matches the community error database
                    # attr stores the full 32-bit value for reconstruction
                    # code stores the short format string for lookup
                    short_code = f"{module:04X}_{error:04X}"

                    logger.debug(
                        f"[{self.serial_number}] print_error: {print_error} (0x{print_error:08x}) -> short_code={short_code}"
                    )

                    # Same user-action filter as the hms[] branch above — print_error
                    # carries the same cancel echoes (e.g. 0500_400E) and they must
                    # not surface as faults on the printer card.
                    if short_code in _HMS_USER_ACTION_CODES:
                        pass  # cancel echo — silently drop
                    else:
                        # Only add if not already in HMS errors (avoid duplicates)
                        existing_short_codes = set()
                        for e in self.state.hms_errors:
                            # Extract short code from existing errors
                            e_module = (e.attr >> 16) & 0xFFFF
                            e_error = int(e.code.replace("0x", ""), 16) if e.code else 0
                            existing_short_codes.add(f"{e_module:04X}_{e_error:04X}")

                        if short_code not in existing_short_codes:
                            self.state.hms_errors.append(
                                HMSError(
                                    code=f"0x{error:x}",
                                    attr=print_error,  # Store full value for display
                                    module=module >> 8,  # High byte of module (e.g., 0x05)
                                    severity=3,  # Warning level for print_error
                                )
                            )

        # Parse home_flag first so SD-card detection below can prefer it.
        # Bit 8 = HAS_SDCARD_NORMAL, bit 9 = HAS_SDCARD_ABNORMAL, bit 11 = store-to-SD,
        # bit 23 = door-open (X1 family only).
        home_flag = None
        if "home_flag" in data:
            home_flag = data["home_flag"]
            if home_flag < 0:
                home_flag = home_flag & 0xFFFFFFFF

        # SD card presence: the only remaining consumer is the firmware-update
        # precondition check (firmware_update.py). Use the top-level `sdcard`
        # field when present with a permissive truthy check covering the
        # bool/int/"HAS_SDCARD_NORMAL" variants real firmware emits. We do NOT
        # derive this from home_flag — heartbeat pushes clear bits 8-9 even
        # when a card is inserted, which caused the badge to flap before the
        # badge was removed entirely.
        if "sdcard" in data:
            raw_sdcard = data["sdcard"]
            if isinstance(raw_sdcard, str):
                self.state.sdcard = "HAS_SDCARD" in raw_sdcard.upper() or raw_sdcard.lower() in ("true", "normal", "1")
            else:
                self.state.sdcard = bool(raw_sdcard)

        if home_flag is not None:
            store_to_sdcard = bool((home_flag >> 11) & 1)
            if store_to_sdcard != self.state.store_to_sdcard:
                logger.debug(
                    f"[{self.serial_number}] store_to_sdcard changed: {self.state.store_to_sdcard} -> {store_to_sdcard}"
                )
            self.state.store_to_sdcard = store_to_sdcard

        # Door open detection — source depends on printer family:
        #   X1 series (X1, X1C, X1E): home_flag bit 23
        #   All others (P1/P2/H2/A1/N-series): top-level `stat` field (hex string), bit 23
        # Both share the same bitmask (0x00800000) but live in different fields.
        model_upper = (self.model or "").upper().strip()
        is_x1_family = model_upper in ("X1", "X1C", "X1E")
        if is_x1_family and home_flag is not None:
            door_open = (home_flag & 0x00800000) != 0
            if door_open != self.state.door_open:
                logger.debug(
                    "[%s] door_open changed: %s -> %s (home_flag=0x%08X)",
                    self.serial_number,
                    self.state.door_open,
                    door_open,
                    home_flag,
                )
            self.state.door_open = door_open
        elif not is_x1_family and "stat" in data:
            try:
                stat_value = int(data["stat"], 16) if isinstance(data["stat"], str) else int(data["stat"])
                door_open = (stat_value & 0x00800000) != 0
                if door_open != self.state.door_open:
                    logger.debug(
                        "[%s] door_open changed: %s -> %s (stat=0x%08X)",
                        self.serial_number,
                        self.state.door_open,
                        door_open,
                        stat_value,
                    )
                self.state.door_open = door_open
            except (ValueError, TypeError):
                logger.debug("[%s] could not parse stat field: %r", self.serial_number, data["stat"])

        # Parse timelapse status (recording active during print)
        if "timelapse" in data:
            logger.debug("[%s] timelapse field: %s", self.serial_number, data["timelapse"])
            self.state.timelapse = data["timelapse"] is True
            # Track if timelapse was ever active during this print
            if self.state.timelapse and self._was_running:
                self._timelapse_during_print = True

        # Parse ipcam/live view status
        if "ipcam" in data:
            ipcam_data = data["ipcam"]
            logger.debug("[%s] ipcam field: %s", self.serial_number, ipcam_data)
            if isinstance(ipcam_data, dict):
                # Check ipcam_record field for live view status
                self.state.ipcam = ipcam_data.get("ipcam_record") == "enable"
                # Check timelapse field (H2D sends it here, not in xcam)
                if "timelapse" in ipcam_data:
                    timelapse_enabled = ipcam_data.get("timelapse") == "enable"
                    if timelapse_enabled != self.state.timelapse:
                        logger.debug(
                            f"[{self.serial_number}] timelapse changed (from ipcam): {self.state.timelapse} -> {timelapse_enabled}"
                        )
                    self.state.timelapse = timelapse_enabled
                    # Track if timelapse was ever active during this print
                    if self.state.timelapse and self._was_running:
                        self._timelapse_during_print = True
                        logger.debug("[%s] Timelapse detected during print (from ipcam)", self.serial_number)
            else:
                self.state.ipcam = ipcam_data is True

        # Parse WiFi signal strength (dBm)
        if "wifi_signal" in data:
            wifi_signal = data["wifi_signal"]
            logger.debug("[%s] wifi_signal received: %s", self.serial_number, wifi_signal)
            if isinstance(wifi_signal, (int, float)):
                self.state.wifi_signal = int(wifi_signal)
            elif isinstance(wifi_signal, str):
                # Handle string format like "-52dBm"
                try:
                    self.state.wifi_signal = int(wifi_signal.replace("dBm", "").strip())
                except ValueError:
                    pass  # Ignore unparseable wifi_signal strings; field is non-critical

            # Detect ethernet connection: printers on ethernet with WiFi disabled
            # report a hardcoded wifi_signal of -90 dBm. Real WiFi signals vary
            # (typically -30 to -80 dBm). Only check models with an ethernet port.
            from backend.app.utils.printer_models import has_ethernet

            if has_ethernet(self.model):
                self.state.wired_network = self.state.wifi_signal == -90

        # Parse print speed level (1=silent, 2=standard, 3=sport, 4=ludicrous)
        if "spd_lvl" in data:
            new_speed = data["spd_lvl"]
            if new_speed != self.state.speed_level:
                logger.debug(
                    "[%s] speed_level changed: %s -> %s", self.serial_number, self.state.speed_level, new_speed
                )
            self.state.speed_level = new_speed

        # Parse skipped objects from printer status (s_obj field)
        # This allows us to restore skipped objects state after reconnection
        if "s_obj" in data:
            s_obj = data["s_obj"]
            if isinstance(s_obj, list):
                # Update skipped objects from printer's list
                new_skipped = [int(oid) for oid in s_obj if isinstance(oid, (int, str))]
                if new_skipped != self.state.skipped_objects:
                    logger.debug("[%s] skipped_objects updated from printer: %s", self.serial_number, new_skipped)
                    self.state.skipped_objects = new_skipped

        # Parse chamber light status from lights_report
        if "lights_report" in data:
            lights = data["lights_report"]
            logger.debug("[%s] lights_report: %s", self.serial_number, lights)
            if isinstance(lights, list):
                for light in lights:
                    if isinstance(light, dict) and light.get("node") == "chamber_light":
                        new_light_state = light.get("mode") == "on"
                        if new_light_state != self.state.chamber_light:
                            logger.debug(
                                f"[{self.serial_number}] chamber_light changed: {self.state.chamber_light} -> {new_light_state}"
                            )
                        self.state.chamber_light = new_light_state
                        break

        # Parse nozzle hardware info (single nozzle printers)
        if "nozzle_type" in data:
            self.state.nozzles[0].nozzle_type = str(data["nozzle_type"])
        if "nozzle_diameter" in data:
            self.state.nozzles[0].nozzle_diameter = str(data["nozzle_diameter"])

        # Parse nozzle hardware info (dual nozzle printers - H2D series)
        # Left nozzle
        if "left_nozzle_type" in data:
            self.state.nozzles[0].nozzle_type = str(data["left_nozzle_type"])
        if "left_nozzle_diameter" in data:
            self.state.nozzles[0].nozzle_diameter = str(data["left_nozzle_diameter"])
        # Right nozzle
        if "right_nozzle_type" in data:
            self.state.nozzles[1].nozzle_type = str(data["right_nozzle_type"])
        if "right_nozzle_diameter" in data:
            self.state.nozzles[1].nozzle_diameter = str(data["right_nozzle_diameter"])

        # Alternative format for dual nozzle (nozzle_type_2, etc.)
        if "nozzle_type_2" in data:
            self.state.nozzles[1].nozzle_type = str(data["nozzle_type_2"])
        if "nozzle_diameter_2" in data:
            self.state.nozzles[1].nozzle_diameter = str(data["nozzle_diameter_2"])

        # H2D/H2C series: Nozzle hardware info is in device.nozzle.info array
        if "device" in data and isinstance(data["device"], dict):
            device = data["device"]
            nozzle_data = device.get("nozzle", {})
            nozzle_info = nozzle_data.get("info", [])
            if isinstance(nozzle_info, list):
                # H2 series: nozzle_info contains extended nozzle data (wear, serial,
                # max_temp, etc.) for all nozzles: L/R hotend (IDs 0,1) and rack slots
                # (IDs 16-21 on H2C). Store ALL entries so the frontend can use them
                # for hover cards on both the L/R indicator and the nozzle rack card.
                if nozzle_info:
                    self.state.nozzle_rack = sorted(
                        [
                            {
                                "id": n.get("id", i),
                                "type": str(n.get("type", "")),
                                "diameter": str(n.get("diameter", "")),
                                "wear": n.get("wear"),
                                "stat": n.get("stat"),
                                # H2C uses "tm", H2D uses "max_temp"
                                "max_temp": n.get("max_temp") or n.get("tm", 0),
                                # H2C uses "sn", H2D uses "serial_number"
                                "serial_number": str(n.get("serial_number") or n.get("sn", "")),
                                # H2C uses "color_m", H2D uses "filament_colour"
                                "filament_color": str(n.get("filament_colour") or n.get("color_m", "")),
                                # H2C uses "fila_id", H2D uses "filament_id"
                                "filament_id": str(n.get("filament_id") or n.get("fila_id", "")),
                                "filament_type": str(n.get("tray_type", "") or n.get("filament_type", "")),
                            }
                            for i, n in enumerate(nozzle_info)
                        ],
                        key=lambda x: x["id"],
                    )
                    if not hasattr(self, "_nozzle_rack_logged") and nozzle_info:
                        self._nozzle_rack_logged = True
                        logger.debug(
                            "[%s] Nozzle info: %d entries, IDs: %s",
                            self.serial_number,
                            len(nozzle_info),
                            [n.get("id") for n in nozzle_info],
                        )
                for nozzle in nozzle_info:
                    idx = nozzle.get("id", 0)
                    if idx < len(self.state.nozzles):
                        if "type" in nozzle and nozzle["type"]:
                            self.state.nozzles[idx].nozzle_type = str(nozzle["type"])
                        if "diameter" in nozzle:
                            self.state.nozzles[idx].nozzle_diameter = str(nozzle["diameter"])

        # Preserve AMS, vt_tray, ams_extruder_map, and mapping data when updating raw_data
        # (these fields aren't sent in every MQTT push, only when changed)
        ams_data = self.state.raw_data.get("ams")
        vt_tray_data = self.state.raw_data.get("vt_tray")
        ams_extruder_map_data = self.state.raw_data.get("ams_extruder_map")
        mapping_data = self.state.raw_data.get("mapping")

        # Normalize vt_tray in data before assigning to raw_data: MQTT sends it
        # as a dict but consumers expect a list.  Without this, the dev mode probe
        # below can release the GIL (via publish), letting the event-loop thread
        # read raw_data["vt_tray"] as a dict and crash iterating over string keys.
        if "vt_tray" in data and isinstance(data["vt_tray"], dict):
            data["vt_tray"] = [data["vt_tray"]]

        self.state.raw_data = data

        # Restore preserved fields BEFORE any work that may release the GIL
        # (e.g. _probe_developer_mode publishes an MQTT message).
        if ams_data is not None:
            self.state.raw_data["ams"] = ams_data
        if vt_tray_data is not None:
            self.state.raw_data["vt_tray"] = vt_tray_data
        if ams_extruder_map_data is not None:
            self.state.raw_data["ams_extruder_map"] = ams_extruder_map_data
        if mapping_data is not None and "mapping" not in data:
            self.state.raw_data["mapping"] = mapping_data

        # Parse developer LAN mode from "fun" field
        if "fun" in data:
            try:
                fun_val = data["fun"]
                fun_int = fun_val if isinstance(fun_val, int) else int(fun_val, 16)
                self.state.developer_mode = (fun_int & 0x20000000) == 0
            except (ValueError, TypeError):
                pass
        elif self.state.developer_mode is None and not self._dev_mode_probed:
            # No "fun" field — A1/P1 series never send it, so we need to probe.
            # Two gates: (1) wait for a full pushall (30+ keys) so we don't probe
            # before a pushall that might contain "fun" arrives, and (2) delay 5s
            # after connect to let the MQTT session stabilize — probing too early
            # can destabilize some firmware MQTT brokers (#887).
            if not self._dev_mode_needs_probe and len(data) > 30:
                # First full status without "fun" — mark that probe is needed
                self._dev_mode_needs_probe = True
            if self._dev_mode_needs_probe and time.monotonic() - self._connect_time >= 5.0:
                self._probe_developer_mode()
            elif self._dev_mode_needs_probe:
                logger.debug(
                    "[%s] Deferring developer mode probe (%.1fs since connect, need 5s)",
                    self.serial_number,
                    time.monotonic() - self._connect_time,
                )
        elif self._dev_mode_probed and self._dev_mode_probe_seq is not None:
            # Probe was sent but no response yet — check for timeout.
            # A half-broken MQTT session (e.g. after keep-alive timeout reconnect)
            # may deliver status pushes but silently drop commands (#887).
            elapsed = time.monotonic() - self._dev_mode_probe_time
            if elapsed > 10.0:
                self._dev_mode_probe_failures += 1
                logger.warning(
                    "[%s] Developer mode probe timed out after %.0fs (attempt %d)",
                    self.serial_number,
                    elapsed,
                    self._dev_mode_probe_failures,
                )
                self._dev_mode_probe_seq = None
                if self._dev_mode_probe_failures >= 2:
                    self.force_reconnect_stale_session("developer mode probe unanswered 2×")
                else:
                    # Allow retry on next full status message
                    self._dev_mode_probed = False

        # Zombie session detection: if an ams_filament_setting command has been
        # pending for >10s with no response, the publish path is likely dead (#887).
        if self._last_ams_cmd_time > 0:
            elapsed = time.monotonic() - self._last_ams_cmd_time
            if elapsed > 10.0:
                self._ams_cmd_unanswered += 1
                logger.warning(
                    "[%s] ams_filament_setting unanswered for %.0fs (count=%d)",
                    self.serial_number,
                    elapsed,
                    self._ams_cmd_unanswered,
                )
                self._last_ams_cmd_time = 0.0  # don't re-trigger on next push_status
                if self._ams_cmd_unanswered >= 2:
                    self.force_reconnect_stale_session("ams_filament_setting unanswered 2\u00d7")
                    self._ams_cmd_unanswered = 0

        # Log mapping data when received (for usage tracking debugging)
        if "mapping" in data:
            logger.debug("[%s] MQTT mapping field: %s", self.serial_number, data["mapping"])

        # Log state transitions for debugging
        if "gcode_state" in data:
            logger.debug(
                f"[{self.serial_number}] gcode_state: {self._previous_gcode_state} -> {self.state.state}, "
                f"file: {self.state.gcode_file}, subtask: {self.state.subtask_name}"
            )

        # Detect print start (state changes TO RUNNING with a file)
        current_file = self.state.gcode_file or self.state.current_print
        is_new_print = (
            self.state.state == "RUNNING"
            and self._previous_gcode_state is not None  # #1304: skip on first push after Bambuddy startup
            and self._previous_gcode_state != "RUNNING"
            and current_file
            and not self._was_running  # Prevent duplicates when resuming from PAUSE
        )
        # Also detect if file changed while running (new print started)
        is_file_change = (
            self.state.state == "RUNNING"
            and current_file
            and current_file != self._previous_gcode_file
            and self._previous_gcode_file is not None
        )

        # Track RUNNING state for more robust completion detection
        running_first_observed = False
        if self.state.state == "RUNNING" and current_file:
            if not self._was_running:
                logger.debug("[%s] Now tracking RUNNING state for %s", self.serial_number, current_file)
                # Check if timelapse was enabled in the same message (xcam parsed before this)
                if self.state.timelapse:
                    self._timelapse_during_print = True
                    logger.debug("[%s] Timelapse detected when entering RUNNING state", self.serial_number)
                # Mark this as the first RUNNING observation of the session.
                # If is_new_print also fires below, on_print_start handles
                # baseline capture and we suppress on_print_running_observed
                # to avoid double-capture. If is_new_print does NOT fire
                # (Bambuddy started mid-print — the #1304 guard suppressed
                # it), main.py needs this hook to catch the restart-recovery
                # case (#1485 follow-up).
                running_first_observed = True
            self._was_running = True
            self._completion_triggered = False

        if is_new_print or is_file_change:
            # Clear any old HMS errors when a new print starts
            self.state.hms_errors = []
            # Reset layer tracking for new print (needed for layer-based timelapse)
            self.state.layer_num = 0
            # Reset completion tracking for new print
            self._was_running = True
            self._completion_triggered = False
            # Reset last valid progress/layer for usage tracking
            self._last_valid_progress = 0.0
            self._last_valid_layer_num = 0
            # Clear and seed tray change log for mid-print usage splitting
            self.state.tray_change_log.clear()
            tn = self.state.tray_now
            if (0 <= tn <= 15) or (128 <= tn <= 135) or tn == 254:
                self.state.tray_change_log.append((tn, 0))
            # Initialize timelapse tracking based on current state
            # NOTE: xcam data is parsed BEFORE this code runs in _process_message,
            # so self.state.timelapse may already be set from this message.
            # We preserve that value instead of blindly resetting to False.
            if self.state.timelapse:
                self._timelapse_during_print = True
                logger.debug("[%s] Timelapse detected at print start", self.serial_number)
            else:
                self._timelapse_during_print = False

        if (is_new_print or is_file_change) and self.on_print_start:
            logger.info(
                f"[{self.serial_number}] PRINT START detected - file: {current_file}, "
                f"subtask: {self.state.subtask_name}, is_new: {is_new_print}, is_file_change: {is_file_change}"
            )
            self.on_print_start(
                {
                    "filename": current_file,
                    "subtask_name": self.state.subtask_name,
                    "remaining_time": self.state.remaining_time * 60
                    if self.state.remaining_time > 0
                    else None,  # Convert minutes to seconds
                    "raw_data": data,
                    "ams_mapping": self._captured_ams_mapping,
                }
            )
        elif running_first_observed and self.on_print_running_observed:
            # Restart-recovery hook (#1485 follow-up): Bambuddy started mid-
            # print, so the #1304 first-push guard suppressed on_print_start,
            # but we still need main.py to capture a fresh timelapse baseline
            # before the printer uploads the in-flight MP4. Same payload
            # shape as on_print_start so the consumer can reuse fields.
            logger.info(
                f"[{self.serial_number}] RUNNING observed without PRINT START "
                f"(restart-recovery) - file: {current_file}, subtask: {self.state.subtask_name}"
            )
            self.on_print_running_observed(
                {
                    "filename": current_file,
                    "subtask_name": self.state.subtask_name,
                    "remaining_time": self.state.remaining_time * 60 if self.state.remaining_time > 0 else None,
                    "raw_data": data,
                    "ams_mapping": self._captured_ams_mapping,
                }
            )

        # Detect print completion (FINISH = success, FAILED = error, IDLE = aborted)
        # Use _was_running flag in addition to _previous_gcode_state for more robust detection
        # This handles cases where server restarts during a print
        should_trigger_completion = (
            self.state.state in ("FINISH", "FAILED")
            and not self._completion_triggered
            and self.on_print_complete
            and (
                self._previous_gcode_state == "RUNNING"  # Normal transition
                or (self._was_running and self._previous_gcode_state != self.state.state)  # After server restart
                # Pre-print failure (#1111): printer rejected the job during setup
                # — wrong nozzle size, AMS error, etc. The print never reaches
                # RUNNING, so without this branch neither the RUNNING check nor
                # _was_running match and the queue item stays stuck at "printing".
                # Restricted to FAILED from pre-print states so a stale FAILED on
                # first connection (prev=None) still can't accidentally fire.
                or (self.state.state == "FAILED" and self._previous_gcode_state in ("PREPARE", "SLICING"))
            )
        )
        # For IDLE, only trigger if we just came from RUNNING (explicit abort/cancel)
        if (
            self.state.state == "IDLE"
            and self._previous_gcode_state == "RUNNING"
            and not self._completion_triggered
            and self.on_print_complete
        ):
            should_trigger_completion = True

        # Log when we FIRST see a terminal state but DON'T trigger completion (diagnostics)
        # Only log on the transition (prev != current) to avoid flooding logs every MQTT update
        if (
            not should_trigger_completion
            and self.state.state in ("FINISH", "FAILED")
            and self._previous_gcode_state != self.state.state
        ):
            logger.info(
                f"[{self.serial_number}] State is {self.state.state} but completion NOT triggered: "
                f"prev={self._previous_gcode_state}, was_running={self._was_running}, "
                f"already_triggered={self._completion_triggered}, has_callback={bool(self.on_print_complete)}"
            )
            # Mark as triggered so state is clean for the next print cycle
            self._completion_triggered = True

        if should_trigger_completion:
            if self.state.state == "FINISH":
                status = "completed"
            elif self.state.state == "FAILED":
                status = "failed"
            else:
                status = "aborted"
            logger.info(
                f"[{self.serial_number}] PRINT COMPLETE detected - state: {self.state.state}, "
                f"status: {status}, file: {self._previous_gcode_file or current_file}, "
                f"subtask: {self.state.subtask_name}, was_running: {self._was_running}, "
                f"timelapse_during_print: {self._timelapse_during_print}"
            )
            timelapse_was_active = self._timelapse_during_print
            self._completion_triggered = True
            self._was_running = False
            self._timelapse_during_print = False  # Reset for next print
            # Include HMS errors for failure reason detection
            hms_errors_data = (
                [
                    {"code": e.code, "attr": e.attr, "module": e.module, "severity": e.severity}
                    for e in self.state.hms_errors
                ]
                if self.state.hms_errors
                else []
            )
            self.on_print_complete(
                {
                    "status": status,
                    "filename": self._previous_gcode_file or current_file,
                    "subtask_name": self.state.subtask_name,
                    "raw_data": data,
                    "timelapse_was_active": timelapse_was_active,
                    "hms_errors": hms_errors_data,
                    "ams_mapping": self._captured_ams_mapping,
                    # Last valid progress/layer before firmware reset (for partial usage tracking)
                    "last_progress": self._last_valid_progress,
                    "last_layer_num": self._last_valid_layer_num,
                }
            )
            self._captured_ams_mapping = None

        self._previous_gcode_state = self.state.state
        if current_file:
            self._previous_gcode_file = current_file

        if self.on_state_change:
            self.on_state_change(self.state)

    def _request_push_all(self):
        """Request full status update from printer."""
        if self._client:
            message = {"pushing": {"command": "pushall"}}
            self._client.publish(self.topic_publish, json.dumps(message), qos=1)

    def _probe_developer_mode(self):
        """Probe developer mode by sending an ams_filament_setting for the external slot.

        Some printers (A1/P1 series) never send the "fun" field in MQTT status.
        For these, we detect developer mode by sending a harmless command and
        checking whether the printer accepts or rejects it:
        - result="success" → developer mode ON (commands accepted)
        - result="failed", reason="mqtt message verify failed" → developer mode OFF

        The probe re-sends the current external slot configuration so it's a no-op
        when the command succeeds. If there's no external slot data yet, we send a
        reset (empty filament) which is also safe.
        """
        if not self._client or not self.state.connected:
            return
        self._dev_mode_probed = True
        self._dev_mode_probe_time = time.monotonic()
        self._sequence_id += 1
        seq = str(self._sequence_id)
        self._dev_mode_probe_seq = seq

        # Build probe command: re-send current external slot config (no-op on success)
        vt_tray = self.state.raw_data.get("vt_tray", []) if self.state.raw_data else []
        current = vt_tray[0] if vt_tray else {}

        command = {
            "print": {
                "command": "ams_filament_setting",
                "ams_id": 255,
                "tray_id": 0,
                "slot_id": 0,
                "tray_info_idx": current.get("tray_info_idx", ""),
                "tray_type": current.get("tray_type", ""),
                "tray_sub_brands": current.get("tray_sub_brands", ""),
                "tray_color": current.get("tray_color", "00000000"),
                "nozzle_temp_min": current.get("nozzle_temp_min", 0),
                "nozzle_temp_max": current.get("nozzle_temp_max", 0),
                "sequence_id": seq,
            }
        }
        setting_id = current.get("setting_id")
        if setting_id:
            command["print"]["setting_id"] = setting_id

        logger.info("[%s] Probing developer mode via ams_filament_setting (seq=%s)", self.serial_number, seq)
        self._client.publish(self.topic_publish, json.dumps(command), qos=1)

    def _handle_dev_mode_probe_response(self, data: dict):
        """Handle response to the developer mode probe command.

        Sets developer_mode based on whether the printer accepted or rejected the command.
        """
        self._dev_mode_probe_seq = None  # One-shot: don't match future responses
        self._dev_mode_probe_failures = 0  # Reset on any response
        result = data.get("result", "")
        reason = data.get("reason", "")

        if result == "failed" and "verify failed" in reason:
            self.state.developer_mode = False
            logger.info("[%s] Developer mode probe: DISABLED (reason=%r)", self.serial_number, reason)
        else:
            # Success or any other response — commands are accepted
            self.state.developer_mode = True
            logger.info("[%s] Developer mode probe: ENABLED (result=%r)", self.serial_number, result)

        if self.on_state_change:
            self.on_state_change(self.state)

    def _request_version(self):
        """Request firmware version info from printer."""
        if self._client:
            self._sequence_id += 1
            message = {
                "info": {
                    "sequence_id": str(self._sequence_id),
                    "command": "get_version",
                }
            }
            logger.debug("[%s] Requesting firmware version info", self.serial_number)
            self._client.publish(self.topic_publish, json.dumps(message), qos=1)

    def request_status_update(self) -> bool:
        """Request a full status update from the printer (public API).

        Sends both pushall and get_accessories commands to refresh all data
        including nozzle hardware info.

        Returns:
            True if the request was sent, False if not connected.
        """
        if not self._client or not self.state.connected:
            logger.warning("[%s] request_status_update: not connected", self.serial_number)
            return False
        logger.debug("[%s] Requesting status update (pushall)", self.serial_number)
        self._request_push_all()
        # Note: get_accessories returns stale nozzle data on H2D.
        # The correct nozzle data comes from push_status response.
        return True

    def _request_accessories(self):
        """Request accessories info (nozzle type, etc.) from printer."""
        if self._client:
            self._sequence_id += 1
            message = {
                "system": {
                    "sequence_id": str(self._sequence_id),
                    "command": "get_accessories",
                    "accessory_type": "none",
                }
            }
            logger.debug("[%s] Requesting accessories info", self.serial_number)
            self._client.publish(self.topic_publish, json.dumps(message), qos=1)

    def _prime_kprofile_request(self):
        """Send a priming K-profile request on connect.

        Bambu printers often ignore the first K-profile request after connection,
        so we send a dummy request on connect to 'prime' the system.
        """
        if self._client:
            self._sequence_id += 1
            command = {
                "print": {
                    "command": "extrusion_cali_get",
                    "filament_id": "",
                    "nozzle_diameter": "0.4",
                    "sequence_id": str(self._sequence_id),
                }
            }
            logger.debug("[%s] Sending K-profile priming request", self.serial_number)
            self._client.publish(self.topic_publish, json.dumps(command), qos=1)

    def connect(self, loop: asyncio.AbstractEventLoop | None = None):
        """Connect to the printer MQTT broker.

        Args:
            loop: The asyncio event loop to use for thread-safe callbacks.
                  If not provided, will try to get the running loop.
        """
        self._loop = loop
        BambuMQTTClient._client_instance_counter += 1
        client_id = f"bambuddy_{self.serial_number}_{os.getpid()}_{BambuMQTTClient._client_instance_counter}"
        self._client = mqtt.Client(
            callback_api_version=mqtt.CallbackAPIVersion.VERSION2,
            client_id=client_id,
            protocol=mqtt.MQTTv311,
        )

        # Bambu's broker has racy PUBACK matching with paho's QoS=1 inflight
        # tracking (#1164). The default ceiling of 20 wedges sessions after
        # ~16-20 cumulative commands; lifting it well above any realistic
        # session count keeps QoS=1 working without changing wire-protocol
        # behaviour across printer models.
        self._client.max_inflight_messages_set(1000)

        self._client.username_pw_set("bblp", self.access_code)
        self._client.on_connect = self._on_connect
        self._client.on_disconnect = self._on_disconnect
        self._client.on_subscribe = self._on_subscribe
        self._client.on_message = self._on_message

        # TLS setup - Bambu uses self-signed certs
        ssl_context = ssl.create_default_context()
        ssl_context.check_hostname = False
        ssl_context.verify_mode = ssl.CERT_NONE
        self._client.tls_set_context(ssl_context)

        # Backoff reconnects to avoid tight reconnect loops on unstable brokers.
        self._client.reconnect_delay_set(min_delay=1, max_delay=30)

        # Keepalive: paho sends PINGREQs at this interval, broker considers
        # client dead at 1.5x.  30s is a good balance — fast enough to detect
        # real network loss (45s), not so aggressive that transient hiccups
        # trigger false disconnects.  Stale detection (60s no messages) handles
        # the P1S/P1P firmware bug where the broker stops publishing but the
        # TCP connection stays alive.
        self._client.connect_async(self.ip_address, self.MQTT_PORT, keepalive=30)
        self._client.loop_start()

    def start_print(
        self,
        filename: str,
        plate_id: int = 1,
        ams_mapping: list[int] | None = None,
        bed_levelling: bool = True,
        flow_cali: bool = False,
        vibration_cali: bool = True,
        layer_inspect: bool = False,
        timelapse: bool = False,
        use_ams: bool = True,
        nozzle_offset_cali: bool = False,
    ):
        """Start a print job on the printer.

        The file should already be uploaded to the printer's root directory via FTP.

        Args:
            filename: Name of the uploaded file
            plate_id: Plate number to print (default 1)
            ams_mapping: List of tray IDs for each filament slot in the 3MF.
                         Global tray ID = (ams_id * 4) + slot_id, external = 254
            timelapse: Record timelapse video
            bed_levelling: Auto bed levelling before print
            flow_cali: Flow/pressure advance calibration
            vibration_cali: Vibration compensation calibration
            layer_inspect: First layer AI inspection
            use_ams: Use AMS for automatic filament changes
            nozzle_offset_cali: Run nozzle offset calibration before print
                (dual-nozzle printers only — silently ignored on single-nozzle).
        """
        if self._client and self.state.connected:
            # Bambu print command format — matches Bambu Studio's format.
            # The calibration/leveling fields (timelapse, bed_leveling,
            # flow_cali, vibration_cali, layer_inspect) are JSON booleans for
            # every model. An earlier revision integer-encoded them for the H2
            # family (H2D/H2S/H2C/X2D) on the belief that H2 firmware required
            # 0/1 — but a BambuStudio request-topic capture from a real H2D
            # sends plain booleans, and the integer encoding made the H2S
            # silently skip flow-dynamics calibration (#1478). use_ams is the
            # one field that genuinely must stay boolean: H2D Pro firmware
            # reads an integer use_ams as a nozzle index (1 = deputy), which is
            # what actually caused the wrong-extruder routing behind #1386.
            # Dual-nozzle routing for external spool (254 = deputy/left,
            # 255 = main/right) and the use_ams=False fallback. H2S is in the
            # H2 firmware family but is single-nozzle, despite sharing serial
            # prefix "094" with H2D. Prefer runtime detection from
            # device.extruder.info (set in _handle_push_status); fall back to
            # model name for the brief window after connect before push data
            # arrives. _is_dual_nozzle only ever flips False→True, so it's safe
            # as the primary signal.
            from backend.app.utils.printer_models import is_dual_nozzle_model

            is_dual_nozzle = self._is_dual_nozzle or is_dual_nozzle_model(self.model)

            # Build ams_mapping2 from ams_mapping (detailed format with ams_id/slot_id)
            ams_mapping2 = []
            # BambuStudio converts virtual tray IDs (254/255) to -1 in the flat
            # ams_mapping and relies on ams_mapping2 for external spool details.
            # Passing raw 254/255 in the flat array causes H2D firmware to fail
            # with 0700_8012 "Failed to get AMS mapping table".
            flat_ams_mapping = []
            if ams_mapping is not None:
                for tray_id in ams_mapping:
                    # Ensure tray_id is an integer (may be string from JSON)
                    tray_id = int(tray_id) if tray_id is not None else -1
                    if tray_id == -1:
                        # Unmapped filament slot
                        flat_ams_mapping.append(-1)
                        ams_mapping2.append({"ams_id": 255, "slot_id": 255})
                    elif tray_id >= 254:
                        # External/virtual spool. BambuStudio convention:
                        #   255 = VIRTUAL_TRAY_MAIN_ID (main/right nozzle)
                        #   254 = VIRTUAL_TRAY_DEPUTY_ID (deputy/left nozzle)
                        # Flat mapping must use -1 (firmware doesn't accept raw 254/255).
                        # Single-nozzle printers (X1C, P1S, A1, etc.) report tray_now=254
                        # for external spool, but BambuStudio always sends ams_id=255
                        # (VIRTUAL_TRAY_MAIN_ID) in ams_mapping2. Sending 254 causes the
                        # firmware to target AMS tray 0 instead of external spool, leading
                        # to 07FF_8012 "Failed to get AMS mapping table" or stuck prints.
                        # Only H2D dual-nozzle printers use 254 (deputy/left nozzle).
                        flat_ams_mapping.append(-1)
                        ext_ams_id = tray_id if is_dual_nozzle else 255
                        ams_mapping2.append({"ams_id": ext_ams_id, "slot_id": 0})
                    elif tray_id >= 128:
                        # AMS-HT: global tray ID IS the ams_id (single tray per unit)
                        flat_ams_mapping.append(tray_id)
                        ams_mapping2.append({"ams_id": tray_id, "slot_id": 0})
                    else:
                        # Regular AMS tray: Global tray ID = (ams_id * 4) + slot_id
                        ams_id = tray_id // 4
                        slot_id = tray_id % 4
                        flat_ams_mapping.append(tray_id)
                        ams_mapping2.append({"ams_id": ams_id, "slot_id": slot_id})

            # If all mapped slots are external spool (no real AMS trays), force use_ams=False.
            # P1S/P1P with no AMS rejects use_ams=True with "Failed to get AMS mapping table".
            # Skip for dual-nozzle printers — use_ams controls nozzle routing there.
            # H2S falls through this gate now (#1386): it is single-nozzle and was
            # hitting the dual-nozzle bypass, which caused 07FF_8012 when printing
            # without an AMS attached.
            if ams_mapping and use_ams and not is_dual_nozzle:
                if all(t is None or int(t) < 0 or int(t) >= 254 for t in ams_mapping):
                    use_ams = False
                    logger.info(
                        "[%s] All filament slots use external spool — setting use_ams=False",
                        self.serial_number,
                    )

            # Unique per-submission identity fields. Hardcoded "0" values caused
            # third-party MQTT observers (OctoEverywhere, etc.) to see reprints as
            # continuations of the same job: the printer reuses gcode_start_time
            # from the prior print with task_id=0, so observers latch onto a stale
            # timestamp and report compounding durations on repeat replays (#1011).
            # BambuStudio mints fresh IDs per submission; matching that behavior
            # makes the printer emit a clean state-transition for each job.
            # md5 is left empty — firmware historically accepts "" as "skip
            # validation" (unlike Studio, we don't have the file's real md5 here
            # without re-reading the upload, and sending a synthetic wrong digest
            # risks activation of md5 verification on some firmwares).
            # Cap at signed int32 max: P1S firmware (01.10.00.00) clamps oversized
            # task identity fields to 2**31-1, so raw epoch-ms (13 digits, ~1.7e12)
            # overflows and every submission ends up with the same task_id from
            # the printer's perspective — the printer then treats a fresh dispatch
            # as a continuation of the last FAILED job and never leaves IDLE (#1042).
            # Modulo keeps uniqueness within a ~24-day wrap window; `or 1` guards
            # the (astronomically unlikely) zero case since task_id=0 is rejected.
            submission_id = str(int(time.time() * 1000) % 2_147_483_647 or 1)
            # Remember it so on_print_start can persist a restart-stable id on
            # the archive even before the printer echoes subtask_id back (#1485).
            self.last_dispatch_subtask_id = submission_id

            command = {
                "print": {
                    "sequence_id": "20000",
                    "command": "project_file",
                    "param": f"Metadata/plate_{plate_id}.gcode",
                    "url": f"ftp://{filename}",
                    "file": filename,
                    "md5": "",
                    "bed_type": "auto",
                    "timelapse": timelapse,
                    "bed_leveling": bed_levelling,
                    "auto_bed_leveling": 1 if bed_levelling else 0,
                    "flow_cali": flow_cali,
                    "vibration_cali": vibration_cali,
                    "layer_inspect": layer_inspect,
                    "use_ams": use_ams,
                    "cfg": "0",
                    # extrude_cali_flag gates flow-dynamics calibration:
                    # 1 = run it, 2 = skip and reuse the stored PA value.
                    # BambuStudio always pairs this with flow_cali and never
                    # sends 0; a hardcoded 0 made the printer skip calibration
                    # regardless of the flow_cali toggle (#1478).
                    "extrude_cali_flag": 1 if flow_cali else 2,
                    "extrude_cali_manual_mode": 0,
                    # 1 = run, 2 = skip. BambuStudio exposes the toggle only for
                    # dual-nozzle machines (H2D/H2D Pro/H2C/X2D); on single-nozzle
                    # printers we always send 2 so firmware never wastes cycles
                    # on a calibration their head doesn't support (#1682).
                    "nozzle_offset_cali": 1 if (nozzle_offset_cali and is_dual_nozzle) else 2,
                    "subtask_name": filename.replace(".3mf", "").replace(".gcode", ""),
                    "profile_id": "0",
                    "project_id": submission_id,
                    "subtask_id": submission_id,
                    "task_id": submission_id,
                }
            }

            # P2S-specific parameter adjustments
            # P2S printer doesn't support vibration calibration like X1/P1 series
            if self.model and self.model.upper().strip() in ("P2S", "N7"):
                command["print"]["vibration_cali"] = False
                logger.debug("[%s] P2S detected: disabling vibration_cali", self.serial_number)

            # Add AMS mapping if provided
            if ams_mapping is not None:
                command["print"]["ams_mapping"] = flat_ams_mapping
                command["print"]["ams_mapping2"] = ams_mapping2

            logger.info("[%s] Sending print command: %s", self.serial_number, json.dumps(command))
            self._client.publish(self.topic_publish, json.dumps(command), qos=1)
            # Record what we dispatched so /cover can pick the right plate
            # thumbnail even when the printer's gcode_file echo is just the
            # 3MF filename without a plate path (#1166). Match the same
            # subtask_name shape we send so the comparison in the cover route
            # works against state.subtask_name reflected back via MQTT.
            self.state.dispatched_plate_id = plate_id
            self.state.dispatched_subtask = command["print"]["subtask_name"]
            return True
        else:
            # Log why we couldn't send the command
            if not self._client:
                logger.error("[%s] Cannot start print: MQTT client not initialized", self.serial_number)
            elif not self.state.connected:
                logger.error(
                    f"[{self.serial_number}] Cannot start print: Printer not connected (client exists but disconnected). "
                    f"Connection state: {self.state.connected}, Last message: {self._last_message_time}"
                )
            return False

    def stop_print(self) -> bool:
        """Stop the current print job."""
        if self._client and self.state.connected:
            command = {"print": {"command": "stop", "sequence_id": "0"}}
            self._client.publish(self.topic_publish, json.dumps(command), qos=1)
            logger.info("[%s] Sent stop print command", self.serial_number)
            return True
        return False

    def set_xcam_option(
        self, module_name: str, enabled: bool, print_halt: bool = True, sensitivity: str = "medium"
    ) -> bool:
        """Set an xcam (AI detection) option on the printer.

        Args:
            module_name: The xcam module to control (e.g., "spaghetti_detector",
                        "first_layer_inspector", "printing_monitor", "buildplate_marker_detector")
            enabled: Whether to enable or disable the feature
            print_halt: Whether to halt print on detection (only applies to some detectors)
            sensitivity: Sensitivity level ("low", "medium", "high", or "never_halt")

        Returns:
            True if command was sent, False if not connected
        """
        if not self._client or not self.state.connected:
            return False

        # auto_recovery_step_loss uses a different command format (print.print_option)
        if module_name == "auto_recovery_step_loss":
            return self._set_print_option("auto_recovery", enabled)

        self._sequence_id += 1

        # Build the xcam control command (exact OrcaSlicer format)
        # Key findings from OrcaSlicer source:
        # - Uses "xcam" wrapper (not "print")
        # - print_halt is ALWAYS true (legacy protocol requirement)
        # - Both "control" and "enable" are set to the same value
        # - halt_print_sensitivity controls actual halt behavior
        command = {
            "xcam": {
                "command": "xcam_control_set",
                "sequence_id": str(self._sequence_id),
                "module_name": module_name,
                "control": enabled,
                "enable": enabled,  # old protocol compatibility
                "print_halt": True,  # ALWAYS true per OrcaSlicer
            }
        }

        # Only add sensitivity if not "never_halt"
        # OrcaSlicer uses halt_print_sensitivity for ALL detectors
        # The module_name field determines which detector's sensitivity is being set
        if sensitivity and sensitivity != "never_halt":
            command["xcam"]["halt_print_sensitivity"] = sensitivity

        command_json = json.dumps(command)
        self._client.publish(self.topic_publish, command_json, qos=1)
        logger.debug(
            "[%s] Set xcam option: %s=%s, sensitivity=%s", self.serial_number, module_name, enabled, sensitivity
        )
        logger.debug("[%s] MQTT command sent: %s", self.serial_number, command_json)

        # OrcaSlicer pattern: Set hold timer to ignore incoming data for 3 seconds
        # This prevents stale MQTT data from immediately overwriting our change
        self._xcam_hold_start[module_name] = time.time()

        # Update local state immediately for responsive UI
        # NOTE: Spaghetti and Pileup sensitivities are linked in firmware
        # When spaghetti_detector sensitivity is changed, pileup also changes
        if module_name == "spaghetti_detector":
            self.state.print_options.spaghetti_detector = enabled
            self.state.print_options.print_halt = print_halt
            if sensitivity and sensitivity != "never_halt":
                # spaghetti_detector controls BOTH spaghetti and pileup sensitivities
                self.state.print_options.halt_print_sensitivity = sensitivity
                self.state.print_options.pileup_sensitivity = sensitivity
                self._xcam_hold_start["halt_print_sensitivity"] = time.time()
                self._xcam_hold_start["pileup_sensitivity"] = time.time()
        elif module_name == "first_layer_inspector":
            self.state.print_options.first_layer_inspector = enabled
        elif module_name == "printing_monitor":
            self.state.print_options.printing_monitor = enabled
        elif module_name == "buildplate_marker_detector":
            self.state.print_options.buildplate_marker_detector = enabled
        elif module_name == "allow_skip_parts":
            self.state.print_options.allow_skip_parts = enabled
        elif module_name == "pileup_detector":
            self.state.print_options.pileup_detector = enabled
            # Pileup sensitivity is linked to spaghetti - both are set via spaghetti_detector
        elif module_name == "clump_detector":
            self.state.print_options.nozzle_clumping_detector = enabled
            if sensitivity and sensitivity != "never_halt":
                self.state.print_options.nozzle_clumping_sensitivity = sensitivity
                self._xcam_hold_start["nozzle_clumping_sensitivity"] = time.time()
        elif module_name == "airprint_detector":
            self.state.print_options.airprint_detector = enabled
            if sensitivity and sensitivity != "never_halt":
                self.state.print_options.airprint_sensitivity = sensitivity
                self._xcam_hold_start["airprint_sensitivity"] = time.time()
        elif module_name == "auto_recovery_step_loss":
            self.state.print_options.auto_recovery_step_loss = enabled

        return True

    def _set_print_option(self, option_name: str, enabled: bool) -> bool:
        """Set a print option using the print.print_option command.

        This is different from xcam_control_set and is used for options like:
        - auto_recovery
        - air_print_detect
        - filament_tangle_detect
        - nozzle_blob_detect
        - sound_enable

        Args:
            option_name: The option to control (e.g., "auto_recovery")
            enabled: Whether to enable or disable the option

        Returns:
            True if command was sent, False if not connected
        """
        if not self._client or not self.state.connected:
            return False

        self._sequence_id += 1

        command = {
            "print": {
                "command": "print_option",
                "sequence_id": str(self._sequence_id),
                option_name: enabled,
            }
        }

        command_json = json.dumps(command)
        self._client.publish(self.topic_publish, command_json, qos=1)
        logger.debug("[%s] Set print option: %s=%s", self.serial_number, option_name, enabled)

        # Set hold timer
        hold_key = f"print_option_{option_name}"
        self._xcam_hold_start[hold_key] = time.time()

        # Update local state immediately
        if option_name == "auto_recovery":
            self.state.print_options.auto_recovery_step_loss = enabled

        return True

    def start_calibration(
        self,
        bed_leveling: bool = False,
        vibration: bool = False,
        motor_noise: bool = False,
        nozzle_offset: bool = False,
        high_temp_heatbed: bool = False,
    ) -> bool:
        """Start printer calibration with selected options.

        Args:
            bed_leveling: Run bed leveling calibration
            vibration: Run vibration compensation calibration
            motor_noise: Run motor noise cancellation calibration
            nozzle_offset: Run nozzle offset calibration (dual nozzle printers)
            high_temp_heatbed: Run high-temperature heatbed calibration

        Returns:
            True if command was sent, False if not connected
        """
        if not self._client or not self.state.connected:
            return False

        # Build calibration bitmask based on OrcaSlicer DeviceManager.cpp
        # Bit 0: xcam_cali (not exposed in UI)
        # Bit 1: bed_leveling
        # Bit 2: vibration
        # Bit 3: motor_noise
        # Bit 4: nozzle_cali
        # Bit 5: bed_cali (high-temp heatbed)
        # Bit 6: clumppos_cali (not exposed in UI)
        option = 0
        if bed_leveling:
            option |= 1 << 1
        if vibration:
            option |= 1 << 2
        if motor_noise:
            option |= 1 << 3
        if nozzle_offset:
            option |= 1 << 4
        if high_temp_heatbed:
            option |= 1 << 5

        if option == 0:
            logger.warning("[%s] No calibration options selected", self.serial_number)
            return False

        self._sequence_id += 1

        command = {
            "print": {
                "command": "calibration",
                "sequence_id": str(self._sequence_id),
                "option": option,
            }
        }

        command_json = json.dumps(command)
        self._client.publish(self.topic_publish, command_json, qos=1)
        logger.info(
            f"[{self.serial_number}] Starting calibration: "
            f"bed_leveling={bed_leveling}, vibration={vibration}, "
            f"motor_noise={motor_noise}, nozzle_offset={nozzle_offset}, "
            f"high_temp_heatbed={high_temp_heatbed} (option={option})"
        )

        return True

    def disconnect(self, timeout: float = 0):
        """Disconnect from the printer."""
        if self._client:
            self._disconnection_event = threading.Event()
            self._client.disconnect()
            self._disconnection_event.wait(timeout=timeout)
            self._client.loop_stop()
            self._client = None
            self.state.connected = False

    def send_command(self, command: dict):
        """Send a command to the printer."""
        if self._client and self.state.connected:
            # Log outgoing message if logging is enabled
            if self._logging_enabled:
                self._message_log.append(
                    MQTTLogEntry(
                        timestamp=datetime.now(timezone.utc).isoformat(),
                        topic=self.topic_publish,
                        direction="out",
                        payload=command,
                    )
                )
            self._client.publish(self.topic_publish, json.dumps(command), qos=1)

    def enable_logging(self, enabled: bool = True):
        """Enable or disable MQTT message logging."""
        self._logging_enabled = enabled
        # Don't clear logs when stopping - user can manually clear with clear_logs()

    def get_logs(self) -> list[MQTTLogEntry]:
        """Get all logged MQTT messages."""
        return list(self._message_log)

    def clear_logs(self):
        """Clear the message log."""
        self._message_log.clear()

    @property
    def logging_enabled(self) -> bool:
        """Check if logging is enabled."""
        return self._logging_enabled

    def register_raw_message_handler(self, handler: Callable[[str, bytes], None]) -> None:
        """Register a handler invoked for every incoming MQTT message.

        Used by the VP MQTT bridge to republish the printer's report pushes to
        slicers connected to a virtual printer in non-proxy mode. Handlers run
        on paho's network thread and must not block; exceptions are caught.
        """
        if handler not in self._raw_message_handlers:
            self._raw_message_handlers.append(handler)

    def unregister_raw_message_handler(self, handler: Callable[[str, bytes], None]) -> None:
        """Unregister a previously-registered raw-message handler."""
        try:
            self._raw_message_handlers.remove(handler)
        except ValueError:
            pass

    def publish_raw(self, topic: str, payload: bytes | str, qos: int = 1) -> bool:
        """Publish a pre-formed payload directly to the printer's MQTT broker.

        Used by the VP MQTT bridge to forward slicer-originated commands without
        going through send_command's sequence-id mangling. Returns False if the
        underlying paho client isn't ready.
        """
        if self._client is None:
            return False
        try:
            info = self._client.publish(topic, payload, qos=qos)
            return info.rc == mqtt.MQTT_ERR_SUCCESS
        except Exception:
            logger.exception("[%s] publish_raw failed for topic=%s", self.serial_number, topic)
            return False

    def send_drying_command(
        self, ams_id: int, temp: int, duration: int, mode: int = 1, filament: str = "", rotate_tray: bool = False
    ):
        """Send AMS drying start/stop command.

        Args:
            ams_id: AMS unit ID (0-3 for AMS 2 Pro, 128-135 for AMS-HT)
            temp: Target drying temperature (45-65 for AMS 2 Pro, 45-85 for AMS-HT)
            duration: Drying duration in hours
            mode: 1=start, 0=stop
            filament: Filament type string (e.g. "PLA", "PETG")
            rotate_tray: Whether to rotate the spool during drying for even heat
        """
        if not self._client:
            return False
        self._sequence_id += 1
        command = {
            "print": {
                "sequence_id": str(self._sequence_id),
                "command": "ams_filament_drying",
                "ams_id": ams_id,
                "temp": temp,
                "cooling_temp": 20 if mode == 1 else 0,
                "duration": duration,
                "humidity": 0,
                "mode": mode,
                "rotate_tray": rotate_tray,
                "filament": filament,
                "close_power_conflict": False,
            }
        }
        # Log the full wire JSON at INFO so support bundles capture exactly
        # what we sent — needed to diagnose silent rejections (#1447) where
        # the printer ACKs the command but never starts/stops drying.
        # Paired with the ams_filament_drying response-payload INFO log so
        # both halves of the conversation land in the bundle by default.
        wire_json = json.dumps(command)
        self._client.publish(self.topic_publish, wire_json, qos=1)
        logger.info(
            "[%s] Sent ams_filament_drying: %s",
            self.serial_number,
            wire_json,
        )
        return True

    def _handle_kprofile_response(self, data: dict):
        """Handle K-profile response from printer."""
        response_nozzle = data.get("nozzle_diameter")
        response_seq_id = data.get("sequence_id", "?")
        filaments = data.get("filaments", [])
        expected_nozzle = getattr(self, "_expected_kprofile_nozzle", None)
        has_pending_request = self._pending_kprofile_response is not None

        # Log all incoming responses when we have a pending request (for debugging)
        if has_pending_request:
            logger.info(
                f"[{self.serial_number}] K-profile response: nozzle={response_nozzle}, "
                f"seq_id={response_seq_id}, {len(filaments)} profiles, expected={expected_nozzle}"
            )

        # If we have a pending request, only accept responses with matching nozzle_diameter
        # The printer broadcasts 0.4mm profiles constantly - we need to wait for the actual response
        if has_pending_request and expected_nozzle and response_nozzle != expected_nozzle:
            # Ignore this broadcast, keep waiting for matching response
            logger.debug(
                f"[{self.serial_number}] Ignoring broadcast: got nozzle={response_nozzle}, waiting for {expected_nozzle}"
            )
            return

        # If no pending request, this is just a broadcast - update state silently and return early
        if not has_pending_request:
            # Still parse profiles to keep state updated, but don't log
            profiles = []
            for f in filaments:
                if isinstance(f, dict):
                    try:
                        cali_idx = f.get("cali_idx", 0)
                        profiles.append(
                            KProfile(
                                slot_id=cali_idx,
                                extruder_id=int(f.get("extruder_id", 0)),
                                nozzle_id=str(f.get("nozzle_id", "")),
                                nozzle_diameter=str(f.get("nozzle_diameter", "0.4")),
                                filament_id=str(f.get("filament_id", "")),
                                name=str(f.get("name", "")),
                                k_value=str(f.get("k_value", "0.000000")),
                                n_coef=str(f.get("n_coef", "0.000000")),
                                ams_id=int(f.get("ams_id", 0)),
                                tray_id=int(f.get("tray_id", -1)),
                                setting_id=f.get("setting_id"),
                            )
                        )
                    except (ValueError, TypeError):
                        pass  # Skip malformed K-profile entries; remaining profiles still usable
            self.state.kprofiles = profiles
            return

        profiles = []

        for i, f in enumerate(filaments):
            if isinstance(f, dict):
                try:
                    # cali_idx is the actual slot/calibration index from the printer
                    cali_idx = f.get("cali_idx", i)
                    profiles.append(
                        KProfile(
                            slot_id=cali_idx,
                            extruder_id=int(f.get("extruder_id", 0)),
                            nozzle_id=str(f.get("nozzle_id", "")),
                            nozzle_diameter=str(f.get("nozzle_diameter", "0.4")),
                            filament_id=str(f.get("filament_id", "")),
                            name=str(f.get("name", "")),
                            k_value=str(f.get("k_value", "0.000000")),
                            n_coef=str(f.get("n_coef", "0.000000")),
                            ams_id=int(f.get("ams_id", 0)),
                            tray_id=int(f.get("tray_id", -1)),
                            setting_id=f.get("setting_id"),
                        )
                    )
                except (ValueError, TypeError) as e:
                    logger.warning("Failed to parse K-profile: %s", e)

        self.state.kprofiles = profiles
        self._kprofile_response_data = profiles

        # Signal that we received the response (only if we were waiting for one)
        # Use thread-safe method since MQTT callbacks run in a different thread
        # Capture in local var to avoid TOCTOU race: asyncio thread can clear
        # self._pending_kprofile_response between the check and the .set() call
        event = self._pending_kprofile_response
        if event:
            logger.info("[%s] Got %s K-profiles for nozzle=%s", self.serial_number, len(profiles), response_nozzle)
            if self._loop and self._loop.is_running():
                self._loop.call_soon_threadsafe(event.set)
            else:
                # Fallback for when loop is not available
                event.set()

    async def get_kprofiles(
        self, nozzle_diameter: str = "0.4", timeout: float = 5.0, max_retries: int = 3
    ) -> list[KProfile]:
        """Request K-profiles from the printer with retry logic.

        Bambu printers sometimes ignore the first K-profile request, so we
        implement retry logic to ensure reliable retrieval.

        Args:
            nozzle_diameter: Filter by nozzle diameter (e.g., "0.4")
            timeout: Timeout in seconds to wait for each response attempt
            max_retries: Maximum number of retry attempts

        Returns:
            List of KProfile objects
        """
        if not self._client or not self.state.connected:
            logger.warning("[%s] Cannot get K-profiles: not connected", self.serial_number)
            return []

        # Capture current event loop for thread-safe callback
        try:
            self._loop = asyncio.get_running_loop()
        except RuntimeError:
            logger.warning("[%s] No running event loop", self.serial_number)
            return []

        for attempt in range(max_retries):
            # Set up response event for this attempt
            self._sequence_id += 1
            self._pending_kprofile_response = asyncio.Event()
            self._kprofile_response_data = None
            self._expected_kprofile_nozzle = nozzle_diameter  # Track which nozzle response we expect

            # Send the command with nozzle_diameter filter
            command = {
                "print": {
                    "command": "extrusion_cali_get",
                    "filament_id": "",
                    "nozzle_diameter": nozzle_diameter,
                    "sequence_id": str(self._sequence_id),
                }
            }

            logger.info(
                f"[{self.serial_number}] Requesting K-profiles for nozzle_diameter={nozzle_diameter} (attempt {attempt + 1}/{max_retries})"
            )
            logger.debug("[%s] K-profile request JSON: %s", self.serial_number, json.dumps(command))
            self._client.publish(self.topic_publish, json.dumps(command), qos=1)

            # Wait for response (response handler already filters by nozzle_diameter)
            try:
                await asyncio.wait_for(self._pending_kprofile_response.wait(), timeout=timeout)
                profiles = self._kprofile_response_data or []
                logger.info(
                    f"[{self.serial_number}] Got {len(profiles)} K-profiles for nozzle={nozzle_diameter} on attempt {attempt + 1}"
                )
                return profiles
            except TimeoutError:
                logger.warning(
                    f"[{self.serial_number}] Timeout on K-profiles request attempt {attempt + 1}/{max_retries}"
                )
                if attempt < max_retries - 1:
                    # Brief delay before retry
                    await asyncio.sleep(0.5)
            finally:
                self._pending_kprofile_response = None
                self._expected_kprofile_nozzle = None

        logger.error("[%s] Failed to get K-profiles after %s attempts", self.serial_number, max_retries)
        return []

    def set_kprofile(
        self,
        filament_id: str,
        name: str,
        k_value: str,
        nozzle_diameter: str = "0.4",
        nozzle_id: str = "HS00-0.4",
        extruder_id: int = 0,
        setting_id: str | None = None,
        slot_id: int = 0,
        cali_idx: int | None = None,
    ) -> bool:
        """Set/update a K-profile on the printer.

        Args:
            filament_id: Bambu filament identifier
            name: Profile name
            k_value: Pressure advance value (e.g., "0.020000")
            nozzle_diameter: Nozzle diameter (e.g., "0.4")
            nozzle_id: Nozzle identifier (e.g., "HS00-0.4")
            extruder_id: Extruder ID (0 or 1 for dual nozzle)
            setting_id: Existing setting ID for updates, None for new
            slot_id: Calibration index (cali_idx) for the profile
            cali_idx: For edits, the existing slot being edited (enables in-place edit)

        Returns:
            True if command was sent, False otherwise
        """
        if not self._client or not self.state.connected:
            logger.warning("[%s] Cannot set K-profile: not connected", self.serial_number)
            return False

        self._sequence_id += 1

        # Build the filament entry - printer uses cali_idx for profile identification
        # For new profiles (slot_id=0), use cali_idx=-1 to tell printer to create new slot
        # For edits, use the provided cali_idx or slot_id
        if cali_idx is not None:
            effective_cali_idx = cali_idx
        else:
            effective_cali_idx = -1 if slot_id == 0 else slot_id

        # Generate a setting_id for new profiles (required by printer)
        # Format: "PF" + 17 random digits
        import random

        if not setting_id and slot_id == 0:
            setting_id = f"PF{random.randint(10000000000000000, 99999999999999999)}"

        filament_entry = {
            "ams_id": 0,
            "cali_idx": effective_cali_idx,
            "extruder_id": extruder_id,
            "filament_id": filament_id,
            "k_value": k_value,
            "n_coef": "0.000000",
            "name": name,
            "nozzle_diameter": nozzle_diameter,
            "nozzle_id": nozzle_id,
            "setting_id": setting_id if setting_id else "",
            "tray_id": -1,
        }

        command = {
            "print": {
                "command": "extrusion_cali_set",
                "filaments": [filament_entry],
                "nozzle_diameter": nozzle_diameter,
                "sequence_id": str(self._sequence_id),
            }
        }

        command_json = json.dumps(command)
        logger.info(
            f"[{self.serial_number}] Setting K-profile: {name} = {k_value} (cali_idx={effective_cali_idx}, new={slot_id == 0})"
        )
        logger.debug("[%s] K-profile SET command: %s", self.serial_number, command_json)
        self._client.publish(self.topic_publish, command_json, qos=1)
        return True

    def set_kprofiles_batch(
        self,
        profiles: list[dict],
        nozzle_diameter: str = "0.4",
    ) -> bool:
        """Set multiple K-profiles in a single command (for dual-nozzle).

        Args:
            profiles: List of profile dicts, each with:
                - filament_id, name, k_value, nozzle_id, extruder_id, setting_id (optional), slot_id
            nozzle_diameter: Common nozzle diameter for all profiles

        Returns:
            True if command was sent, False otherwise
        """
        if not self._client or not self.state.connected:
            logger.warning("[%s] Cannot set K-profiles batch: not connected", self.serial_number)
            return False

        import random

        self._sequence_id += 1

        filament_entries = []
        for p in profiles:
            slot_id = p.get("slot_id", 0)
            cali_idx = p.get("cali_idx")

            if cali_idx is not None:
                effective_cali_idx = cali_idx
            else:
                effective_cali_idx = -1 if slot_id == 0 else slot_id

            setting_id = p.get("setting_id")
            if not setting_id and slot_id == 0:
                setting_id = f"PF{random.randint(10000000000000000, 99999999999999999)}"

            filament_entries.append(
                {
                    "ams_id": 0,
                    "cali_idx": effective_cali_idx,
                    "extruder_id": p.get("extruder_id", 0),
                    "filament_id": p.get("filament_id", ""),
                    "k_value": p.get("k_value", "0.020000"),
                    "n_coef": "0.000000",
                    "name": p.get("name", ""),
                    "nozzle_diameter": nozzle_diameter,
                    "nozzle_id": p.get("nozzle_id", f"HS00-{nozzle_diameter}"),
                    "setting_id": setting_id if setting_id else "",
                    "tray_id": -1,
                }
            )

        command = {
            "print": {
                "command": "extrusion_cali_set",
                "filaments": filament_entries,
                "nozzle_diameter": nozzle_diameter,
                "sequence_id": str(self._sequence_id),
            }
        }

        command_json = json.dumps(command)
        logger.info("[%s] Setting %s K-profiles in batch", self.serial_number, len(filament_entries))
        logger.debug("[%s] K-profile SET batch command: %s", self.serial_number, command_json)
        self._client.publish(self.topic_publish, command_json, qos=1)
        return True

    def delete_kprofile(
        self,
        cali_idx: int,
        filament_id: str,
        nozzle_id: str,
        nozzle_diameter: str = "0.4",
        extruder_id: int = 0,
        setting_id: str | None = None,
    ) -> bool:
        """Delete a K-profile from the printer.

        Args:
            cali_idx: The calibration index (slot_id) of the profile to delete
            filament_id: Bambu filament identifier
            nozzle_id: Nozzle identifier (e.g., "HH00-0.4")
            nozzle_diameter: Nozzle diameter (e.g., "0.4")
            extruder_id: Extruder ID (0 or 1 for dual nozzle)
            setting_id: Unique setting identifier (for X1C series)

        Returns:
            True if command was sent, False otherwise
        """
        if not self._client or not self.state.connected:
            logger.warning("[%s] Cannot delete K-profile: not connected", self.serial_number)
            return False

        self._sequence_id += 1

        # Dual-nozzle K-profile delete uses the extruder_id/nozzle_id format;
        # single-nozzle printers (X1C/P1/A1/P2S/H2S) need the setting_id form.
        # Prefer runtime detection from device.extruder.info; fall back to
        # model name. H2S is single-nozzle but shares serial prefix "094" with
        # H2D, so a prefix-only check misclassified it (#1386).
        from backend.app.utils.printer_models import is_dual_nozzle_model

        is_dual_nozzle = self._is_dual_nozzle or is_dual_nozzle_model(self.model)

        if is_dual_nozzle:
            # H2D format: uses extruder_id, nozzle_id, nozzle_diameter
            command = {
                "print": {
                    "command": "extrusion_cali_del",
                    "sequence_id": str(self._sequence_id),
                    "extruder_id": extruder_id,
                    "nozzle_id": nozzle_id,
                    "filament_id": filament_id,
                    "cali_idx": cali_idx,
                    "nozzle_diameter": nozzle_diameter,
                }
            }
        else:
            # X1C/P1/A1 format: include all fields like the set command
            # The delete command structure should match what set uses
            command = {
                "print": {
                    "command": "extrusion_cali_del",
                    "sequence_id": str(self._sequence_id),
                    "filament_id": filament_id,
                    "cali_idx": cali_idx,
                    "setting_id": setting_id if setting_id else "",
                    "nozzle_diameter": nozzle_diameter,
                    "nozzle_id": nozzle_id,
                    "extruder_id": extruder_id,
                }
            }

        command_json = json.dumps(command)
        logger.info(
            f"[{self.serial_number}] Deleting K-profile: cali_idx={cali_idx}, filament={filament_id}, setting_id={setting_id}, dual={is_dual_nozzle}"
        )
        logger.debug("[%s] K-profile DELETE command: %s", self.serial_number, command_json)
        # Use QoS 1 for reliable delivery (at least once)
        self._client.publish(self.topic_publish, command_json, qos=1)
        return True

    # =========================================================================
    # Printer Control Commands
    # =========================================================================

    def pause_print(self) -> bool:
        """Pause the current print job."""
        if not self._client or not self.state.connected:
            logger.warning("[%s] Cannot pause print: not connected", self.serial_number)
            return False

        command = {"print": {"command": "pause", "sequence_id": "0"}}
        self._client.publish(self.topic_publish, json.dumps(command), qos=1)
        logger.info("[%s] Sent pause print command", self.serial_number)
        return True

    def resume_print(self) -> bool:
        """Resume a paused print job."""
        if not self._client or not self.state.connected:
            logger.warning("[%s] Cannot resume print: not connected", self.serial_number)
            return False

        command = {"print": {"command": "resume", "sequence_id": "0"}}
        self._client.publish(self.topic_publish, json.dumps(command), qos=1)
        logger.info("[%s] Sent resume print command", self.serial_number)
        return True

    def clear_hms_errors(self) -> bool:
        """Clear HMS/print errors on the printer and locally."""
        if not self._client or not self.state.connected:
            logger.warning("[%s] Cannot clear HMS errors: not connected", self.serial_number)
            return False

        command = {"print": {"command": "clean_print_error", "sequence_id": "0"}}
        self._client.publish(self.topic_publish, json.dumps(command), qos=1)
        self.state.hms_errors = []
        logger.info("[%s] Sent clear HMS errors command", self.serial_number)
        return True

    def skip_objects(self, object_ids: list[int]) -> bool:
        """Skip specific objects during a print.

        This command tells the printer to skip printing the specified objects.
        The object IDs come from the slice_info.config file in the 3MF.

        Args:
            object_ids: List of identify_id values from slice_info.config

        Returns:
            True if command was sent, False otherwise
        """
        if not self._client or not self.state.connected:
            logger.warning("[%s] Cannot skip objects: not connected", self.serial_number)
            return False

        if self.state.state != "RUNNING" and self.state.state != "PAUSE":
            logger.warning(
                f"[{self.serial_number}] Cannot skip objects: printer not printing (state={self.state.state})"
            )
            return False

        if not object_ids:
            logger.warning("[%s] Cannot skip objects: no object IDs provided", self.serial_number)
            return False

        # Validate all IDs are integers
        try:
            obj_list = [int(oid) for oid in object_ids]
        except (ValueError, TypeError) as e:
            logger.warning("[%s] Invalid object IDs: %s", self.serial_number, e)
            return False

        self._sequence_id += 1
        command = {"print": {"sequence_id": str(self._sequence_id), "command": "skip_objects", "obj_list": obj_list}}
        self._client.publish(self.topic_publish, json.dumps(command), qos=1)
        logger.info("[%s] Sent skip_objects command: %s", self.serial_number, obj_list)

        # Track skipped objects in state
        for oid in obj_list:
            if oid not in self.state.skipped_objects:
                self.state.skipped_objects.append(oid)

        return True

    def send_gcode(self, gcode: str) -> bool:
        """Send G-code command(s) to the printer.

        Multiple commands can be separated by newlines.

        Args:
            gcode: G-code command(s) to send

        Returns:
            True if command was sent, False otherwise
        """
        if not self._client or not self.state.connected:
            logger.warning("[%s] Cannot send G-code: not connected", self.serial_number)
            return False

        self._sequence_id += 1
        command = {"print": {"command": "gcode_line", "param": gcode, "sequence_id": str(self._sequence_id)}}
        # Use QoS 1 for reliable delivery (at least once)
        self._client.publish(self.topic_publish, json.dumps(command), qos=1)
        logger.debug("[%s] Sent G-code: %s...", self.serial_number, gcode[:50])
        return True

    def set_bed_temperature(self, target: int) -> bool:
        """Set the bed target temperature.

        Args:
            target: Target temperature in Celsius (0 to turn off)

        Returns:
            True if command was sent, False otherwise
        """
        return self.send_gcode(f"M140 S{target}")

    def set_nozzle_temperature(self, target: int, nozzle: int = 0) -> bool:
        """Set the nozzle target temperature.

        Args:
            target: Target temperature in Celsius (0 to turn off)
            nozzle: Nozzle index (0 for right/default, 1 for left on H2D)

        Returns:
            True if command was sent, False otherwise
        """
        # Use M104 for non-blocking
        # Always use T parameter for H2D compatibility
        result = self.send_gcode(f"M104 T{nozzle} S{target}")
        # H2D quirk: left nozzle (nozzle=1) target isn't reported in MQTT
        # Track it locally so we can display it correctly
        if result and nozzle == 1:
            self.state.temperatures["nozzle_target"] = float(target)
            self.state.temperatures["_nozzle_target_set_time"] = time.time()
            logger.info("[%s] Tracking LEFT nozzle target locally: %s°C", self.serial_number, target)
        return result

    def set_chamber_temperature(self, target: int) -> bool:
        """Set the chamber target temperature.

        Args:
            target: Target temperature in Celsius (0 to turn off heating)

        Returns:
            True if command was sent, False otherwise
        """
        # M141 sets chamber temperature
        result = self.send_gcode(f"M141 S{target}")
        # Track chamber target locally (MQTT reports encoded values that need filtering)
        if result:
            self.state.temperatures["chamber_target"] = float(target)
            self.state.temperatures["_chamber_target_set_time"] = time.time()
            # Update heating state immediately based on new target
            current_temp = self.state.temperatures.get("chamber", 0)
            self.state.temperatures["chamber_heating"] = target > 0 and current_temp < target
            logger.info(
                f"[{self.serial_number}] Tracking chamber target locally: {target}°C (heating={self.state.temperatures['chamber_heating']})"
            )
        return result

    def set_print_speed(self, mode: int) -> bool:
        """Set the print speed mode.

        Args:
            mode: Speed mode (1=silent, 2=standard, 3=sport, 4=ludicrous)

        Returns:
            True if command was sent, False otherwise
        """
        if not self._client or not self.state.connected:
            logger.warning("[%s] Cannot set print speed: not connected", self.serial_number)
            return False

        if mode not in (1, 2, 3, 4):
            logger.warning("[%s] Invalid speed mode: %s", self.serial_number, mode)
            return False

        command = {"print": {"command": "print_speed", "param": str(mode), "sequence_id": "0"}}
        self._client.publish(self.topic_publish, json.dumps(command), qos=1)
        logger.info("[%s] Set print speed mode to %s", self.serial_number, mode)
        return True

    def set_fan_speed(self, fan: int, speed: int) -> bool:
        """Set fan speed.

        Args:
            fan: Fan index (1=part cooling, 2=auxiliary, 3=chamber)
            speed: Speed 0-255 (0=off, 255=full)

        Returns:
            True if command was sent, False otherwise
        """
        if fan not in (1, 2, 3):
            logger.warning("[%s] Invalid fan index: %s", self.serial_number, fan)
            return False

        speed = max(0, min(255, speed))  # Clamp to 0-255
        return self.send_gcode(f"M106 P{fan} S{speed}")

    def set_part_fan(self, speed: int) -> bool:
        """Set part cooling fan speed (0-255)."""
        return self.set_fan_speed(1, speed)

    def set_aux_fan(self, speed: int) -> bool:
        """Set auxiliary fan speed (0-255)."""
        return self.set_fan_speed(2, speed)

    def set_chamber_fan(self, speed: int) -> bool:
        """Set chamber fan speed (0-255)."""
        return self.set_fan_speed(3, speed)

    def set_airduct_mode(self, mode: str) -> bool:
        """Set air conditioning mode (cooling or heating).

        Args:
            mode: "cooling" (modeId=0) or "heating" (modeId=1)
                - Cooling: Suitable for PLA/PETG/TPU, filters and cools chamber air
                - Heating: Suitable for ABS/ASA/PC/PA, circulates and heats chamber air,
                           closes top exhaust flap

        Returns:
            True if command was sent, False otherwise
        """
        if not self._client or not self.state.connected:
            logger.warning("[%s] Cannot set airduct mode: not connected", self.serial_number)
            return False

        self._sequence_id += 1
        mode_id = 0 if mode == "cooling" else 1
        command = {
            "print": {"command": "set_airduct", "modeId": mode_id, "sequence_id": str(self._sequence_id), "submode": -1}
        }
        # Use QoS 1 for reliable delivery
        self._client.publish(self.topic_publish, json.dumps(command), qos=1)
        logger.info(
            "[%s] Set airduct mode to %s (modeId=%s, seq=%s)", self.serial_number, mode, mode_id, self._sequence_id
        )
        return True

    def set_chamber_light(self, on: bool) -> bool:
        """Turn chamber light on or off.

        Args:
            on: True to turn on, False to turn off

        Returns:
            True if command was sent, False otherwise
        """
        if not self._client or not self.state.connected:
            logger.warning("[%s] Cannot set chamber light: not connected", self.serial_number)
            return False

        mode = "on" if on else "off"
        # Control both chamber lights (some printers like H2D have two)
        for led_node in ["chamber_light", "chamber_light2"]:
            self._sequence_id += 1
            command = {
                "system": {
                    "command": "ledctrl",
                    "led_node": led_node,
                    "led_mode": mode,
                    "led_on_time": 500,
                    "led_off_time": 500,
                    "loop_times": 0,
                    "interval_time": 0,
                    "sequence_id": str(self._sequence_id),
                }
            }
            self._client.publish(self.topic_publish, json.dumps(command), qos=1)
        logger.info("[%s] Set chamber lights %s (seq=%s)", self.serial_number, "on" if on else "off", self._sequence_id)
        return True

    def select_extruder(self, extruder: int) -> bool:
        """Select the active extruder for dual-nozzle printers (H2D).

        Args:
            extruder: Extruder index (0=right, 1=left for H2D)

        Returns:
            True if command was sent, False otherwise
        """
        if extruder not in (0, 1):
            logger.warning("[%s] Invalid extruder: %s", self.serial_number, extruder)
            return False

        if not self._client or not self.state.connected:
            logger.warning("[%s] Cannot switch extruder: not connected", self.serial_number)
            return False

        # H2D extruder switching via select_extruder command
        # Command format captured from OrcaSlicer:
        # {"print": {"command": "select_extruder", "extruder_index": 0, "sequence_id": "..."}}
        # extruder_index: 0 = RIGHT, 1 = LEFT
        self._sequence_id += 1
        command = {
            "print": {"command": "select_extruder", "extruder_index": extruder, "sequence_id": str(self._sequence_id)}
        }
        self._client.publish(self.topic_publish, json.dumps(command), qos=1)
        logger.info(
            "[%s] Sent select_extruder command: extruder_index=%s (0=right, 1=left)", self.serial_number, extruder
        )
        return True

    def home_axes(self, axes: str = "XYZ") -> bool:
        """Run the printer's full auto-home sequence.

        The ``axes`` argument is ignored: a bare ``G28`` is always sent so
        Bambu firmware runs its safe multi-step routine (park toolhead →
        home XY → home Z). Partial-axis variants like ``G28 Z`` skip the
        toolhead-park step and can crash the bed into the toolhead on H2C
        / H2D / H2S / X1 where Z-home moves the bed UP — see #1052.
        """
        return self.send_gcode("G28")

    def move_axis(self, axis: str, distance: float, speed: int = 3000) -> bool:
        """Move an axis by a relative distance.

        Args:
            axis: Axis to move ("X", "Y", or "Z")
            distance: Distance to move in mm (positive or negative)
            speed: Movement speed in mm/min

        Returns:
            True if command was sent, False otherwise
        """
        axis = axis.upper()
        if axis not in ("X", "Y", "Z"):
            logger.warning("[%s] Invalid axis: %s", self.serial_number, axis)
            return False

        # G91 = relative mode, G0 = rapid move, G90 = back to absolute
        gcode = f"G91\nG0 {axis}{distance:.2f} F{speed}\nG90"
        return self.send_gcode(gcode)

    def disable_motors(self) -> bool:
        """Disable all stepper motors.

        Warning: This will cause the printer to lose its position.
        A homing operation will be required before printing.

        Returns:
            True if command was sent, False otherwise
        """
        return self.send_gcode("M18")

    def enable_motors(self) -> bool:
        """Enable all stepper motors.

        Returns:
            True if command was sent, False otherwise
        """
        return self.send_gcode("M17")

    def ams_load_filament(self, tray_id: int, extruder_id: int | None = None) -> bool:
        """Load filament from a specific AMS tray.

        Args:
            tray_id: Global tray ID — 0..15 for AMS slots, 254 for external spool
                (single-external printers and Ext-L on dual-nozzle H2D),
                255 for Ext-R on dual-nozzle H2D.
            extruder_id: Unused - kept for API compatibility

        Returns:
            True if command was sent, False otherwise
        """
        if not self._client or not self.state.connected:
            logger.warning("[%s] Cannot load filament: not connected", self.serial_number)
            return False

        # Build the ams_change_filament command. Encoding differs by target type:
        #   - AMS slots (0..15): slot_id is the local slot, curr/tar_temp = -1.
        #   - External spool (tray_id=254): legacy capture from a single-extruder
        #     printer used slot_id=254, curr/tar_temp=-1; preserved here.
        #   - Ext-R on dual-nozzle H2D (tray_id=255): captured shape from
        #     BambuStudio uses slot_id=0 (extruder index, 0=right), and
        #     curr_temp/tar_temp = the actual right-nozzle temp.  See #891.
        self._sequence_id += 1
        if tray_id == 255:
            ams_id = 255
            slot_id = 0  # extruder index for the right nozzle
            right_temp = int(self.state.temperatures.get("nozzle_2", 0) or 0)
            if right_temp < 180:
                right_temp = 215  # Reasonable default if right nozzle is cold/unknown
            curr_temp = right_temp
            tar_temp = right_temp
        elif tray_id == 254:
            ams_id = 255
            slot_id = 254
            curr_temp = -1
            tar_temp = -1
        else:
            ams_id = tray_id // 4
            slot_id = tray_id % 4
            curr_temp = -1
            tar_temp = -1

        command = {
            "print": {
                "command": "ams_change_filament",
                "sequence_id": str(self._sequence_id),
                "ams_id": ams_id,
                "slot_id": slot_id,
                "target": tray_id,
                "curr_temp": curr_temp,
                "tar_temp": tar_temp,
            }
        }

        command_json = json.dumps(command)
        logger.info("[%s] Publishing ams_change_filament command: %s", self.serial_number, command_json)
        self._client.publish(self.topic_publish, command_json, qos=1)
        logger.info("[%s] Loading filament from tray %s (AMS %s slot %s)", self.serial_number, tray_id, ams_id, slot_id)

        # Track this load request for H2D dual-nozzle disambiguation
        # H2D reports only slot number (0-3) in tray_now, so we use our tracked value
        self._last_load_tray_id = tray_id
        self.state.pending_tray_target = tray_id
        logger.info("[%s] Set pending_tray_target=%s for H2D disambiguation", self.serial_number, tray_id)

        return True

    def ams_unload_filament(self) -> bool:
        """Unload the currently loaded filament.

        Returns:
            True if command was sent, False otherwise
        """
        if not self._client or not self.state.connected:
            logger.warning("[%s] Cannot unload filament: not connected", self.serial_number)
            return False

        # Get the currently loaded tray info
        tray_now = self.state.tray_now
        logger.info("[%s] Unload requested, tray_now=%s", self.serial_number, tray_now)

        # Determine source ams_id for the unload command
        if tray_now == 255 or tray_now == 254:
            ams_id = 255  # No filament or external spool
        else:
            ams_id = tray_now // 4  # Source AMS

        # Command format from BambuStudio traffic capture:
        # - No extruder_id field
        # - For UNLOAD: curr_temp and tar_temp are the actual nozzle temp (e.g., 210)
        # - slot_id=255 and target=255 for unload
        # Get current nozzle temperature for the unload command
        nozzle_temp = int(self.state.temperatures.get("nozzle", 210))
        if nozzle_temp < 180:
            nozzle_temp = 210  # Default to PLA temp if nozzle is cold

        self._sequence_id += 1
        command = {
            "print": {
                "command": "ams_change_filament",
                "sequence_id": str(self._sequence_id),
                "ams_id": ams_id,
                "slot_id": 255,  # 255 = unload marker
                "target": 255,  # 255 = unload destination
                "curr_temp": nozzle_temp,
                "tar_temp": nozzle_temp,
            }
        }

        command_json = json.dumps(command)
        logger.info("[%s] Publishing ams_change_filament (unload) command: %s", self.serial_number, command_json)
        self._client.publish(self.topic_publish, command_json, qos=1)
        logger.info("[%s] Unloading filament (tray_now was %s)", self.serial_number, tray_now)

        # Clear tracked load request since we're unloading
        self._last_load_tray_id = None
        self.state.pending_tray_target = None
        logger.info("[%s] Cleared pending_tray_target (unload)", self.serial_number)

        return True

    def ams_control(self, action: str) -> bool:
        """Control AMS operations.

        Args:
            action: "resume", "reset", or "pause"

        Returns:
            True if command was sent, False otherwise
        """
        if not self._client or not self.state.connected:
            logger.warning("[%s] Cannot control AMS: not connected", self.serial_number)
            return False

        if action not in ("resume", "reset", "pause"):
            logger.warning("[%s] Invalid AMS action: %s", self.serial_number, action)
            return False

        command = {"print": {"command": "ams_control", "param": action, "sequence_id": "0"}}
        self._client.publish(self.topic_publish, json.dumps(command), qos=1)
        logger.info("[%s] AMS control: %s", self.serial_number, action)
        return True

    def ams_refresh_tray(self, ams_id: int, tray_id: int) -> tuple[bool, str]:
        """Trigger RFID re-read for a specific AMS tray.

        Args:
            ams_id: AMS unit ID (0-3, or 128 for H2D external tray)
            tray_id: Tray ID within the AMS (0-3)

        Returns:
            Tuple of (success, message)
        """
        if not self._client or not self.state.connected:
            logger.warning("[%s] Cannot refresh AMS tray: not connected", self.serial_number)
            return False, "Printer not connected"

        # Check if filament is currently loaded (tray_now != 255)
        # RFID refresh requires the AMS to move filament, which can't happen if one is loaded
        tray_now = self.state.tray_now
        if tray_now != 255:
            # Decode which tray is loaded for the message
            if tray_now == 254:
                loaded_tray = "external spool"
            elif tray_now >= 0 and tray_now < 128:
                loaded_ams = tray_now // 4
                loaded_slot = tray_now % 4
                loaded_tray = f"AMS {loaded_ams + 1} slot {loaded_slot + 1}"
            else:
                loaded_tray = f"tray {tray_now}"
            logger.warning("[%s] Cannot refresh AMS tray: filament loaded from %s", self.serial_number, loaded_tray)
            return False, f"Please unload filament first. Currently loaded: {loaded_tray}"

        # Use ams_get_rfid command to trigger RFID re-read
        # This command is used by Bambu Studio to re-read the RFID tag
        command = {"print": {"command": "ams_get_rfid", "ams_id": ams_id, "slot_id": tray_id, "sequence_id": "0"}}
        self._client.publish(self.topic_publish, json.dumps(command), qos=1)
        logger.info("[%s] Triggering RFID re-read: AMS %s, slot %s", self.serial_number, ams_id, tray_id)

        return True, f"Refreshing AMS {ams_id} tray {tray_id}"

    def ams_set_filament_setting(
        self,
        ams_id: int,
        tray_id: int,
        tray_info_idx: str,
        tray_type: str,
        tray_sub_brands: str,
        tray_color: str,
        nozzle_temp_min: int,
        nozzle_temp_max: int,
        setting_id: str = "",
    ) -> bool:
        """Set AMS tray filament settings (type, color, temperature).

        Note: K value is set separately via extrusion_cali_sel command.

        Args:
            ams_id: AMS unit ID (0-3 for regular AMS, 128-135 for HT AMS)
            tray_id: Tray ID within the AMS (0-3)
            tray_info_idx: Filament ID short format (e.g., "GFL05")
            tray_type: Filament type (e.g., "PLA", "PETG")
            tray_sub_brands: Sub-brand name (e.g., "PLA Basic", "PETG HF")
            tray_color: Color in RRGGBBAA hex format (e.g., "FFFF00FF")
            nozzle_temp_min: Minimum nozzle temperature
            nozzle_temp_max: Maximum nozzle temperature
            setting_id: Full setting ID with version (e.g., "GFSL05_07") - optional

        Returns:
            True if command was sent, False otherwise
        """
        if not self._client or not self.state.connected:
            logger.warning("[%s] Cannot set AMS filament setting: not connected", self.serial_number)
            return False

        # Calculate mqtt IDs based on AMS type.
        # External-spool convention verified against a BambuStudio→X1C packet capture
        # (issue #1279, May 2026): for `ams_filament_setting` Studio sends the
        # *global* tray index in `tray_id`, not a local position within the virtual
        # unit. The printer's response echoes `tray_id: 0` (slot position), which
        # is what the original code was matching — but the request and response
        # use different semantics for that field. Sending `tray_id: 0` is what
        # the P1S in #1279 rejected with `result: "fail"`.
        if ams_id == 255:
            vt_tray = self.state.raw_data.get("vt_tray", []) if self.state.raw_data else []
            if len(vt_tray) > 1:
                # Dual external slots (H2D): each ext slot is its own virtual AMS unit
                # (254=ext-L / slot 0, 255=ext-R / slot 1). The dual case is NOT
                # covered by the X1C capture — left at `mqtt_tray_id = 0` until a
                # captured Studio→H2D exchange confirms the correct value.
                mqtt_ams_id = 254 + tray_id
                mqtt_tray_id = 0
            else:
                # Single external slot (X1C, P1S, A1): global tray_id=254.
                mqtt_ams_id = 255
                mqtt_tray_id = 254
            slot_id = 0
        elif ams_id <= 3:
            mqtt_ams_id = ams_id
            mqtt_tray_id = tray_id
            slot_id = tray_id
        else:
            # AMS-HT: single tray per unit
            mqtt_ams_id = ams_id
            mqtt_tray_id = tray_id
            slot_id = 0

        command = {
            "print": {
                "command": "ams_filament_setting",
                "ams_id": mqtt_ams_id,
                "tray_id": mqtt_tray_id,
                "slot_id": slot_id,
                "tray_info_idx": tray_info_idx,
                "tray_type": tray_type,
                "tray_sub_brands": tray_sub_brands,
                "tray_color": tray_color,
                "nozzle_temp_min": nozzle_temp_min,
                "nozzle_temp_max": nozzle_temp_max,
                "sequence_id": "0",
            }
        }

        # Include setting_id if provided (helps slicer show correct profile)
        if setting_id:
            command["print"]["setting_id"] = setting_id

        command_json = json.dumps(command)
        logger.info(
            f"[{self.serial_number}] Publishing ams_filament_setting: AMS {ams_id}, tray {tray_id}, tray_info_idx={tray_info_idx}, setting_id={setting_id}"
        )
        logger.debug("[%s] ams_filament_setting command: %s", self.serial_number, command_json)
        self._client.publish(self.topic_publish, command_json, qos=1)
        self._last_ams_cmd_time = time.monotonic()
        return True

    def reset_ams_slot(self, ams_id: int, tray_id: int) -> bool:
        """Reset an AMS slot to empty/unconfigured state.

        Args:
            ams_id: AMS unit ID (0-3 for regular AMS, 128-135 for HT AMS)
            tray_id: Tray ID within the AMS (0-3)

        Returns:
            True if command was sent, False otherwise
        """
        if not self._client or not self.state.connected:
            logger.warning("[%s] Cannot reset AMS slot: not connected", self.serial_number)
            return False

        # Calculate mqtt IDs based on AMS type — same convention as
        # ams_set_filament_setting above. See its comment for the #1279 capture rationale.
        if ams_id == 255:
            vt_tray = self.state.raw_data.get("vt_tray", []) if self.state.raw_data else []
            if len(vt_tray) > 1:
                # Dual external slots (H2D): each ext slot is its own virtual AMS unit
                mqtt_ams_id = 254 + tray_id
                mqtt_tray_id = 0
            else:
                # Single external slot (X1C, P1S, A1): global tray_id=254.
                mqtt_ams_id = 255
                mqtt_tray_id = 254
            slot_id = 0
        elif ams_id <= 3:
            mqtt_ams_id = ams_id
            mqtt_tray_id = tray_id
            slot_id = tray_id
        else:
            # AMS-HT: single tray per unit
            mqtt_ams_id = ams_id
            mqtt_tray_id = tray_id
            slot_id = 0

        command = {
            "print": {
                "command": "ams_filament_setting",
                "ams_id": mqtt_ams_id,
                "tray_id": mqtt_tray_id,
                "slot_id": slot_id,
                "tray_info_idx": "",
                "tray_type": "",
                "tray_sub_brands": "",
                "tray_color": "00000000",
                "nozzle_temp_min": 0,
                "nozzle_temp_max": 0,
                "sequence_id": "0",
            }
        }

        command_json = json.dumps(command)
        logger.info("[%s] Resetting AMS slot: AMS %s, tray %s", self.serial_number, ams_id, tray_id)
        logger.debug("[%s] reset_ams_slot command: %s", self.serial_number, command_json)
        self._client.publish(self.topic_publish, command_json, qos=1)
        self._last_ams_cmd_time = time.monotonic()
        return True

    def extrusion_cali_sel(
        self,
        ams_id: int,
        tray_id: int,
        cali_idx: int,
        filament_id: str,
        nozzle_diameter: str = "0.4",
    ) -> bool:
        """Set calibration profile (K value) for an AMS slot.

        This command selects a K profile from the printer's calibration list.
        Use cali_idx=-1 to use the default K value (0.020).

        Note: Do NOT send setting_id in this command — BambuStudio never includes
        it, and adding it causes the firmware to mislink the profile on X1C/P1S.

        Args:
            ams_id: AMS unit ID (0-3 for regular AMS, 128-135 for HT AMS)
            tray_id: Tray ID within the AMS (0-3)
            cali_idx: Calibration profile index (-1 for default)
            filament_id: Filament preset ID (same as tray_info_idx)
            nozzle_diameter: Nozzle diameter string (e.g., "0.4")

        Returns:
            True if command was sent, False otherwise
        """
        if not self._client or not self.state.connected:
            logger.warning("[%s] Cannot set calibration: not connected", self.serial_number)
            return False

        # Calculate mqtt IDs based on AMS type.
        # IMPORTANT: extrusion_cali_sel uses GLOBAL tray_id (unlike ams_filament_setting
        # which uses LOCAL).  BambuStudio confirms: tray_id = ams_id * 4 + slot.
        if ams_id == 255:
            # External spool: extrusion_cali_sel uses GLOBAL tray_id (unlike
            # ams_filament_setting which uses LOCAL tray_id=0).
            vt_tray = self.state.raw_data.get("vt_tray", []) if self.state.raw_data else []
            if len(vt_tray) > 1:
                # Dual external slots (H2D): each ext slot is its own virtual AMS unit
                # Confirmed from BambuStudio logs: ext-R sends ams_id=255, tray_id=255
                mqtt_ams_id = 254 + tray_id
                mqtt_tray_id = 254 + tray_id
            else:
                # Single external slot (X1C, P1S, A1): global tray_id=254
                mqtt_ams_id = 254
                mqtt_tray_id = 254
            slot_id = 0
        elif ams_id <= 3:
            mqtt_ams_id = ams_id
            mqtt_tray_id = ams_id * 4 + tray_id
            slot_id = tray_id
        elif ams_id >= 128 and ams_id <= 135:
            mqtt_ams_id = ams_id
            mqtt_tray_id = tray_id
            slot_id = 0
        else:
            mqtt_ams_id = ams_id
            mqtt_tray_id = tray_id
            slot_id = 0

        command = {
            "print": {
                "command": "extrusion_cali_sel",
                "cali_idx": cali_idx,
                "filament_id": filament_id,
                "nozzle_diameter": nozzle_diameter,
                "ams_id": mqtt_ams_id,
                "tray_id": mqtt_tray_id,
                "slot_id": slot_id,
                "sequence_id": "0",
            }
        }

        command_json = json.dumps(command)
        logger.info(
            f"[{self.serial_number}] Publishing extrusion_cali_sel: AMS {ams_id}, tray {tray_id}, cali_idx={cali_idx}"
        )
        logger.debug("[%s] extrusion_cali_sel command: %s", self.serial_number, command_json)
        self._client.publish(self.topic_publish, command_json, qos=1)
        return True

    def extrusion_cali_set(
        self,
        tray_id: int,
        k_value: float,
        nozzle_diameter: str = "0.4",
        nozzle_temp: int = 220,
        filament_id: str = "",
        setting_id: str = "",
        name: str = "",
        cali_idx: int = -1,
    ) -> bool:
        """Directly set K value (pressure advance) for a tray.

        Uses the filaments array format required by current firmware.

        Args:
            tray_id: Global tray ID (ams_id * 4 + slot)
            k_value: Pressure advance K value (e.g., 0.020)
            nozzle_diameter: Nozzle diameter string (e.g., "0.4")
            nozzle_temp: Nozzle temperature for calibration reference
            filament_id: Filament preset ID (e.g., "GFA02")
            setting_id: Setting ID (e.g., "GFSA02_07")
            name: Profile display name
            cali_idx: Calibration index (-1 for new)

        Returns:
            True if command was sent, False otherwise
        """
        if not self._client or not self.state.connected:
            logger.warning("[%s] Cannot set K value: not connected", self.serial_number)
            return False

        nozzle_id = f"HS00-{nozzle_diameter}"

        filament_entry = {
            "ams_id": 0,
            "cali_idx": cali_idx,
            "extruder_id": 0,
            "filament_id": filament_id,
            "k_value": f"{k_value:.6f}",
            "n_coef": "1.400000",
            "name": name,
            "nozzle_diameter": nozzle_diameter,
            "nozzle_id": nozzle_id,
            "setting_id": setting_id,
            "tray_id": tray_id,
        }

        command = {
            "print": {
                "command": "extrusion_cali_set",
                "filaments": [filament_entry],
                "nozzle_diameter": nozzle_diameter,
                "sequence_id": str(self._sequence_id),
            }
        }

        command_json = json.dumps(command)
        logger.info("[%s] Publishing extrusion_cali_set: tray %s, k_value=%s", self.serial_number, tray_id, k_value)
        logger.debug("[%s] extrusion_cali_set command: %s", self.serial_number, command_json)
        self._client.publish(self.topic_publish, command_json, qos=1)
        return True

    def set_timelapse(self, enable: bool) -> bool:
        """Enable or disable timelapse recording.

        Args:
            enable: True to enable, False to disable

        Returns:
            True if command was sent, False otherwise
        """
        if not self._client or not self.state.connected:
            logger.warning("[%s] Cannot set timelapse: not connected", self.serial_number)
            return False

        command = {"pushing": {"command": "pushall", "sequence_id": "0"}}
        # First send the timelapse setting
        timelapse_cmd = {
            "print": {"command": "gcode_line", "param": f"M981 S{1 if enable else 0} P20000", "sequence_id": "0"}
        }
        self._client.publish(self.topic_publish, json.dumps(timelapse_cmd), qos=1)
        # Request status update
        self._client.publish(self.topic_publish, json.dumps(command), qos=1)
        logger.info("[%s] Set timelapse %s", self.serial_number, "enabled" if enable else "disabled")
        return True

    def set_liveview(self, enable: bool) -> bool:
        """Enable or disable live view / camera streaming.

        Args:
            enable: True to enable, False to disable

        Returns:
            True if command was sent, False otherwise
        """
        if not self._client or not self.state.connected:
            logger.warning("[%s] Cannot set liveview: not connected", self.serial_number)
            return False

        command = {
            "xcam": {"command": "ipcam_record_set", "control": "enable" if enable else "disable", "sequence_id": "0"}
        }
        self._client.publish(self.topic_publish, json.dumps(command), qos=1)
        # Request status update
        pushall = {"pushing": {"command": "pushall", "sequence_id": "0"}}
        self._client.publish(self.topic_publish, json.dumps(pushall), qos=1)
        logger.info("[%s] Set liveview %s", self.serial_number, "enabled" if enable else "disabled")
        return True