bambuddy/backend/app/api/routes/printers.py

import asyncio
import logging
import re
import zipfile
from pathlib import Path

from fastapi import APIRouter, Depends, HTTPException, Query
from fastapi.responses import Response
from sqlalchemy import func, select
from sqlalchemy.ext.asyncio import AsyncSession

from backend.app.core import database
from backend.app.core.auth import (
    RequireCameraStreamTokenIfAuthEnabled,
    RequireOverlayTokenIfAuthEnabled,
    RequirePermissionIfAuthEnabled,
    is_auth_enabled,
)
from backend.app.core.config import settings
from backend.app.core.database import get_db
from backend.app.core.permissions import Permission
from backend.app.core.tasks import spawn_background_task
from backend.app.models.ams_label import AmsLabel
from backend.app.models.printer import Printer
from backend.app.models.slot_preset import SlotPresetMapping
from backend.app.models.user import User
from backend.app.schemas.printer import (
    AmsLabelBody,
    AMSTray,
    AMSUnit,
    DiagnosticRequest,
    FilaSwitchResponse,
    HmsActionBody,
    HMSErrorResponse,
    NozzleInfoResponse,
    NozzleRackSlot,
    PrinterCreate,
    PrinterDiagnosticResult,
    PrinterResponse,
    PrinterResponseWithSecret,
    PrinterStatus,
    PrinterUpdate,
    PrintOptionsResponse,
)
from backend.app.services import drying_preflight
from backend.app.services.bambu_ftp import (
    cache_3mf_download,
    delete_file_async,
    download_file_bytes_async,
    download_file_try_paths_async,
    ftps_handshake_blocked,
    get_cached_3mf,
    get_storage_info_async,
    list_files_async,
)
from backend.app.services.print_storage import ftp_probe_paths, print_file_reachable_over_ftp
from backend.app.services.printer_diagnostic import run_connection_diagnostic
from backend.app.services.printer_manager import (
    display_temperatures,
    drying_screen_only,
    get_derived_status_name,
    printer_manager,
    resolve_expected_tray,
    resolve_plate_id,
    supports_chamber_heater,
    supports_chamber_temp,
    supports_drying,
    supports_drying_while_printing,
    uniform_tray_filament_hint,
)
from backend.app.utils.filament_ids import filament_id_to_setting_id
from backend.app.utils.fts_routing import slot_extruder
from backend.app.utils.http import build_content_disposition
from backend.app.utils.printer_models import MAX_CHAMBER_TEMP_C, uses_exhaust_fan_label

logger = logging.getLogger(__name__)
router = APIRouter(prefix="/printers", tags=["printers"])

# Seconds the /hms/execute-action route waits for a printer status push
# confirming the command landed before reporting 502 to the UI. Module-level
# so tests can monkeypatch a near-zero value instead of mocking asyncio.sleep.
HMS_ACTION_ACK_WAIT_SECONDS = 2.5


async def _caller_can_view_printer_secrets(user: User | None, db: AsyncSession) -> bool:
    """Whether the caller is trusted enough to see ``access_code`` on a printer
    response. Fail-CLOSED: anything that isn't an authenticated user holding
    PRINTERS_UPDATE returns False.

    - Auth disabled  → True (single trust domain — same as today's local UI).
    - JWT user with PRINTERS_UPDATE → True (Admin or Operator; the same roles
      that already manage printers and the Virtual Printer card UX that
      surfaces a target's code for slicer configuration).
    - JWT Viewer → False (the bug fix: Viewers must not be able to read
      access_code via PRINTERS_READ and then go around Bambuddy to MQTT).
    - API-key principal (``user is None`` because the dep returns None for
      API keys) → False. PRINTERS_UPDATE is admin-only and absent from
      ``_APIKEY_SCOPE_BY_PERMISSION``, so no API key can hold it.
    """
    if not await is_auth_enabled(db):
        return True
    if user is None:
        return False
    return user.has_permission(Permission.PRINTERS_UPDATE.value)


def _serialize_printer(printer: Printer, *, include_secret: bool):
    """Build the response shape that matches the caller's authority."""
    if include_secret:
        return PrinterResponseWithSecret.model_validate(printer)
    return PrinterResponse.model_validate(printer)


@router.get("/")
async def list_printers(
    user: User | None = RequirePermissionIfAuthEnabled(Permission.PRINTERS_READ),
    db: AsyncSession = Depends(get_db),
):
    """List all configured printers.

    ``access_code`` is included in each item only when the caller is trusted
    to see it (Admin / Operator JWT, or auth-disabled mode). Viewers and
    API keys never receive it.
    """
    result = await db.execute(select(Printer).order_by(Printer.name))
    printers = list(result.scalars().all())
    include_secret = await _caller_can_view_printer_secrets(user, db)
    return [_serialize_printer(p, include_secret=include_secret) for p in printers]


@router.post("/", response_model=PrinterResponse)
async def create_printer(
    printer_data: PrinterCreate,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CREATE),
    db: AsyncSession = Depends(get_db),
):
    """Add a new printer.

    Verifies the MQTT connection succeeds before persisting. A wrong access
    code or unreachable IP would otherwise create a printer row that shows
    as an empty / never-connecting card on the dashboard — those reports
    were turning into support tickets that all traced back to a mistyped
    access code.
    """
    # Check if serial number already exists
    result = await db.execute(select(Printer).where(Printer.serial_number == printer_data.serial_number))
    if result.scalar_one_or_none():
        raise HTTPException(400, "Printer with this serial number already exists")

    test_result = await printer_manager.test_connection(
        ip_address=printer_data.ip_address,
        serial_number=printer_data.serial_number,
        access_code=printer_data.access_code,
    )
    if not test_result.get("success"):
        # The frontend renders the user-facing message via i18n on `code`;
        # `message` is an English fallback for non-UI clients (curl / scripts).
        raise HTTPException(
            status_code=400,
            detail={
                "code": "printer_connection_failed",
                "message": (
                    "Could not connect to the printer. Verify IP address, serial number, "
                    "and access code, and confirm LAN-only mode is enabled. "
                    "The printer was not added."
                ),
            },
        )

    printer = Printer(**printer_data.model_dump())
    db.add(printer)
    await db.commit()
    await db.refresh(printer)

    # Connect to the printer
    if printer.is_active:
        await printer_manager.connect_printer(printer)

    return printer


@router.get("/usb-cameras")
async def list_usb_cameras(
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_READ),
):
    """List available USB cameras connected to the system.

    Returns a list of detected V4L2 video devices with their info.
    Only works on Linux systems with V4L2 support.

    Returns:
        List of dicts with {device: str, name: str, capabilities: list, formats?: list}
    """
    from backend.app.services.external_camera import list_usb_cameras

    cameras = list_usb_cameras()
    return {"cameras": cameras}


@router.get("/available-filaments")
async def get_available_filaments(
    model: str = Query(..., description="Target printer model"),
    location: str | None = Query(None, description="Optional location filter"),
    _=RequirePermissionIfAuthEnabled(Permission.QUEUE_CREATE),
    db: AsyncSession = Depends(get_db),
):
    """Get deduplicated list of filaments loaded across all active printers of a given model.

    Used by the frontend to offer filament override options for model-based queue assignment.
    """
    from backend.app.utils.printer_models import normalize_printer_model, normalize_printer_model_id

    # Normalize model name
    normalized_model = normalize_printer_model(model) or normalize_printer_model_id(model) or model

    query = (
        select(Printer).where(func.lower(Printer.model) == normalized_model.lower()).where(Printer.is_active == True)  # noqa: E712
    )
    if location:
        query = query.where(Printer.location == location)

    result = await db.execute(query)
    printers_list = list(result.scalars().all())

    if not printers_list:
        return []

    # Collect filaments from all matching printers
    # Dedup key includes extruder_id and tray_sub_brands so "PLA Basic" and "PLA Matte" appear separately
    seen: set[tuple[str, str, str, int | None]] = set()  # (type_upper, color_normalized, sub_brands_upper, extruder_id)
    filaments = []

    for printer in printers_list:
        status = printer_manager.get_status(printer.id)
        if not status:
            continue

        # Get ams_extruder_map for dual-nozzle printers
        ams_extruder_map = status.raw_data.get("ams_extruder_map", {})

        # AMS trays
        for ams_unit in status.raw_data.get("ams", []):
            ams_id = str(ams_unit.get("id", 0))
            extruder_id = ams_extruder_map.get(ams_id)
            for tray in ams_unit.get("tray", []):
                tray_type = tray.get("tray_type")
                if not tray_type:
                    continue
                tray_color = tray.get("tray_color", "") or "808080"
                # Preserve the full RRGGBBAA so transparent filament (alpha=00)
                # reaches the frontend instead of collapsing to #000000 → black
                # (#1545). Opaque colours still round-trip as #RRGGBB. The
                # dedup key uses the 6-char RGB so two slots that share an RGB
                # but differ only in alpha still merge.
                stripped = tray_color.replace("#", "")
                rgb = stripped[:6].lower() or "808080"
                color = f"#{stripped}"
                tray_info_idx = tray.get("tray_info_idx", "")
                tray_sub_brands = tray.get("tray_sub_brands", "") or ""

                key = (tray_type.upper(), rgb, tray_sub_brands.upper(), extruder_id)
                if key not in seen:
                    seen.add(key)
                    filaments.append(
                        {
                            "type": tray_type,
                            "color": color,
                            "tray_info_idx": tray_info_idx,
                            "tray_sub_brands": tray_sub_brands,
                            "extruder_id": extruder_id,
                        }
                    )

        # External spools (vt_tray)
        for vt in status.raw_data.get("vt_tray") or []:
            vt_type = vt.get("tray_type")
            if not vt_type:
                continue
            vt_color = vt.get("tray_color", "") or "808080"
            # Same alpha-preserving handling as the AMS branch — see #1545.
            stripped = vt_color.replace("#", "")
            rgb = stripped[:6].lower() or "808080"
            color = f"#{stripped}"
            tray_info_idx = vt.get("tray_info_idx", "")
            tray_sub_brands = vt.get("tray_sub_brands", "") or ""
            vt_id = int(vt.get("id", 254))
            extruder_id = (255 - vt_id) if ams_extruder_map else None

            key = (vt_type.upper(), rgb, tray_sub_brands.upper(), extruder_id)
            if key not in seen:
                seen.add(key)
                filaments.append(
                    {
                        "type": vt_type,
                        "color": color,
                        "tray_info_idx": tray_info_idx,
                        "tray_sub_brands": tray_sub_brands,
                        "extruder_id": extruder_id,
                    }
                )

    return filaments


@router.get("/developer-mode-warnings")
async def get_developer_mode_warnings(
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_READ),
    db: AsyncSession = Depends(get_db),
):
    """Check if any connected printer lacks developer LAN mode."""
    result = await db.execute(select(Printer).where(Printer.is_active == True))  # noqa: E712
    printers = result.scalars().all()
    statuses = printer_manager.get_all_statuses()

    warnings = []
    for printer in printers:
        state = statuses.get(printer.id)
        if state and state.connected and state.developer_mode is False:
            warnings.append(
                {
                    "printer_id": printer.id,
                    "name": printer.name,
                }
            )
    return warnings


@router.get("/{printer_id}")
async def get_printer(
    printer_id: int,
    user: User | None = RequirePermissionIfAuthEnabled(Permission.PRINTERS_READ),
    db: AsyncSession = Depends(get_db),
):
    """Get a specific printer.

    ``access_code`` is included only when the caller is trusted to see it
    (Admin / Operator JWT, or auth-disabled mode). Viewers and API keys
    never receive it.
    """
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")
    include_secret = await _caller_can_view_printer_secrets(user, db)
    return _serialize_printer(printer, include_secret=include_secret)


@router.patch("/{printer_id}", response_model=PrinterResponse)
async def update_printer(
    printer_id: int,
    printer_data: PrinterUpdate,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_UPDATE),
    db: AsyncSession = Depends(get_db),
):
    """Update a printer."""
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    update_data = printer_data.model_dump(exclude_unset=True)

    # Handle nested ROI object - flatten to individual columns
    if "plate_detection_roi" in update_data:
        roi = update_data.pop("plate_detection_roi")
        if roi:
            update_data["plate_detection_roi_x"] = roi.get("x")
            update_data["plate_detection_roi_y"] = roi.get("y")
            update_data["plate_detection_roi_w"] = roi.get("w")
            update_data["plate_detection_roi_h"] = roi.get("h")
        else:
            # Clear ROI if set to null
            update_data["plate_detection_roi_x"] = None
            update_data["plate_detection_roi_y"] = None
            update_data["plate_detection_roi_w"] = None
            update_data["plate_detection_roi_h"] = None

    for field, value in update_data.items():
        setattr(printer, field, value)

    await db.commit()
    await db.refresh(printer)

    # Reconnect if connection settings changed
    if any(k in update_data for k in ["ip_address", "access_code", "is_active"]):
        printer_manager.disconnect_printer(printer_id)
        if printer.is_active:
            await printer_manager.connect_printer(printer)

    return printer


@router.delete("/{printer_id}")
async def delete_printer(
    printer_id: int,
    delete_archives: bool = True,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_DELETE),
    db: AsyncSession = Depends(get_db),
):
    """Delete a printer.

    Args:
        printer_id: ID of the printer to delete
        delete_archives: If True (default), delete all print archives for this printer.
                        If False, keep archives but remove their printer association.
    """
    from sqlalchemy import delete as sql_delete

    from backend.app.models.archive import PrintArchive
    from backend.app.models.maintenance import MaintenanceHistory, PrinterMaintenance
    from backend.app.models.scheduled_drying import ScheduledDrying
    from backend.app.models.spoolman_slot_assignment import SpoolmanSlotAssignment

    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    printer_manager.disconnect_printer(printer_id)

    if delete_archives:
        # Delete all archives for this printer
        await db.execute(sql_delete(PrintArchive).where(PrintArchive.printer_id == printer_id))
    else:
        # Orphan the archives instead of deleting them
        from sqlalchemy import update

        await db.execute(update(PrintArchive).where(PrintArchive.printer_id == printer_id).values(printer_id=None))

    # Delete slot assignments for this printer (SQLite doesn't enforce FK cascades)
    await db.execute(sql_delete(SpoolmanSlotAssignment).where(SpoolmanSlotAssignment.printer_id == printer_id))

    # Delete scheduled drying runs for this printer (SQLite doesn't enforce FK cascades)
    await db.execute(sql_delete(ScheduledDrying).where(ScheduledDrying.printer_id == printer_id))

    # Delete maintenance history and items for this printer
    # (SQLite doesn't enforce FK cascades, so do it explicitly)
    maintenance_ids = (
        (await db.execute(select(PrinterMaintenance.id).where(PrinterMaintenance.printer_id == printer_id)))
        .scalars()
        .all()
    )
    if maintenance_ids:
        await db.execute(
            sql_delete(MaintenanceHistory).where(MaintenanceHistory.printer_maintenance_id.in_(maintenance_ids))
        )
        await db.execute(sql_delete(PrinterMaintenance).where(PrinterMaintenance.printer_id == printer_id))

    await db.delete(printer)
    await db.commit()

    return {"status": "deleted", "archives_deleted": delete_archives}


@router.get("/{printer_id}/status", response_model=PrinterStatus)
async def get_printer_status(
    printer_id: int,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_READ),
    db: AsyncSession = Depends(get_db),
):
    """Get real-time status of a printer."""
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    state = printer_manager.get_status(printer_id)
    if not state:
        # No MQTT client state — the printer was never connected this run, or it
        # was disconnected manually. The plate-clear gate is Bambuddy-side and
        # persisted, so it still has a truthful value here (#2864); reporting the
        # schema default instead told clients the plate was clean and hid the
        # only control that can release the gate.
        return PrinterStatus(
            id=printer_id,
            name=printer.name,
            connected=False,
            awaiting_plate_clear=printer_manager.is_awaiting_plate_clear(printer_id),
        )

    # Determine cover URL if there's an active print (including paused)
    cover_url = None
    if state.state in ("RUNNING", "PAUSE") and state.gcode_file:
        cover_url = f"/api/v1/printers/{printer_id}/cover"

    # Convert HMS errors to response format
    hms_errors = [
        HMSErrorResponse(
            code=e.code,
            attr=e.attr,
            module=e.module,
            severity=e.severity,
            actions=e.actions,
            job_id=e.job_id,
            full_code=e.full_code,
        )
        for e in (state.hms_errors or [])
    ]

    # Parse AMS data from raw_data
    ams_units = []
    vt_tray = []
    ams_exists = False
    raw_data = state.raw_data or {}

    # Build K-profile lookup map: (extruder_id, cali_idx) -> k_value.
    #
    # Keyed on the pair, not on cali_idx alone: the printer numbers its
    # calibration table per nozzle, so entry 16 exists on both and means a
    # different profile on each. A cali_idx-only map let whichever profile the
    # printer happened to list last overwrite the other, and the slot then
    # displayed the wrong nozzle's K — on the maintainer's H2C, 0.018 and 0.020
    # for the same spool.
    kprofile_map: dict[tuple[int, int], float] = {}
    for kp in state.kprofiles or []:
        if kp.slot_id is not None and kp.k_value:
            try:
                kprofile_map[(int(kp.extruder_id or 0), kp.slot_id)] = float(kp.k_value)
            except (ValueError, TypeError):
                pass  # Skip K-profile entries with unparseable values

    def _kprofile_k(cali_idx: int | None, ams_id: int, tray_id: int) -> float | None:
        """K value for a slot's bound profile, resolved against its own nozzle."""
        if cali_idx is None:
            return None
        extruder = slot_extruder(ams_id, tray_id, state.ams_extruder_map, state.ams_switch_inlet)
        if extruder is not None:
            return kprofile_map.get((extruder, cali_idx))
        # Single-nozzle printers report everything under extruder 0.
        return kprofile_map.get((0, cali_idx))

    # Cached active-cycle drying params (filament + target temp) we sent
    # last; Bambu doesn't echo them on the per-tick AMS push, so the badge
    # needs the cache to render "<filament> @ <temp>°C".
    drying_targets = printer_manager.get_drying_targets(printer_id) or {}

    if "ams" in raw_data and isinstance(raw_data["ams"], list):
        ams_exists = True
        for ams_data in raw_data["ams"]:
            # Skip if ams_data is not a dict (defensive check)
            if not isinstance(ams_data, dict):
                continue
            trays = []
            for tray_data in ams_data.get("tray", []):
                # Filter out empty/invalid tag values
                tag_uid = tray_data.get("tag_uid", "")
                if tag_uid in ("", "0000000000000000"):
                    tag_uid = None
                tray_uuid = tray_data.get("tray_uuid", "")
                if tray_uuid in ("", "00000000000000000000000000000000"):
                    tray_uuid = None

                # Get K value: first try tray's k field, then lookup from K-profiles
                k_value = tray_data.get("k")
                cali_idx = tray_data.get("cali_idx")
                if k_value is None:
                    k_value = _kprofile_k(cali_idx, int(ams_data.get("id", 0)), int(tray_data.get("id", 0)))

                trays.append(
                    AMSTray(
                        id=tray_data.get("id", 0),
                        tray_color=tray_data.get("tray_color"),
                        tray_type=tray_data.get("tray_type"),
                        tray_sub_brands=tray_data.get("tray_sub_brands"),
                        tray_id_name=tray_data.get("tray_id_name"),
                        tray_info_idx=tray_data.get("tray_info_idx"),
                        remain=tray_data.get("remain", 0),
                        k=k_value,
                        cali_idx=cali_idx,
                        tag_uid=tag_uid,
                        tray_uuid=tray_uuid,
                        nozzle_temp_min=tray_data.get("nozzle_temp_min"),
                        nozzle_temp_max=tray_data.get("nozzle_temp_max"),
                        drying_temp=tray_data.get("drying_temp"),
                        drying_time=tray_data.get("drying_time"),
                        state=tray_data.get("state"),
                        exists=tray_data.get("exists"),
                    )
                )
            # Prefer humidity_raw (percentage) over humidity (index 1-5)
            # humidity_raw is the actual percentage value from the sensor
            humidity_raw = ams_data.get("humidity_raw")
            humidity_idx = ams_data.get("humidity")
            humidity_value = None

            if humidity_raw is not None:
                try:
                    humidity_value = int(humidity_raw)
                except (ValueError, TypeError):
                    pass  # Skip unparseable humidity; will try index fallback
            if humidity_value is None and humidity_idx is not None:
                try:
                    humidity_value = int(humidity_idx)
                except (ValueError, TypeError):
                    pass  # Skip unparseable humidity index; humidity remains None
            # AMS-HT has 1 tray, regular AMS has 4 trays
            is_ams_ht = len(trays) == 1

            ams_id_int = int(ams_data.get("id", 0))
            target = drying_targets.get(ams_id_int) or {}
            dry_target_temp: int | None = None
            dry_filament: str | None = None
            target_temp_val = target.get("temp")
            target_fil_val = target.get("filament") or ""
            if target_temp_val is not None:
                try:
                    dry_target_temp = int(target_temp_val)
                except (TypeError, ValueError):
                    dry_target_temp = None
            if target_fil_val:
                dry_filament = str(target_fil_val)
            # Fallback: name the filament from the loaded trays when there is no
            # cached target (drying started in a previous backend session, or
            # the cache wasn't seeded), and only when they agree. The
            # temperature has no fallback — see uniform_tray_filament_hint.
            if not dry_filament:
                dry_filament = uniform_tray_filament_hint([tray.tray_type or "" for tray in trays])

            ams_units.append(
                AMSUnit(
                    id=ams_id_int,
                    humidity=humidity_value,
                    temp=ams_data.get("temp"),
                    is_ams_ht=is_ams_ht,
                    tray=trays,
                    # Serial number: Bambu MQTT uses "sn" key on AMS unit objects
                    serial_number=str(ams_data.get("sn") or ams_data.get("serial_number") or ""),
                    # Firmware version: populated by _handle_version_info from info.module ams/* entries
                    sw_ver=str(ams_data.get("sw_ver") or ""),
                    # Drying: dry_time > 0 means drying is active (minutes remaining)
                    dry_time=int(ams_data.get("dry_time") or 0),
                    dry_target_temp=dry_target_temp,
                    dry_filament=dry_filament,
                    module_type=str(ams_data.get("module_type") or ""),
                )
            )

    # Virtual tray (external spool holder) - comes from vt_tray in raw_data (list)
    if "vt_tray" in raw_data:
        for vt_data in raw_data["vt_tray"]:
            # Filter out empty/invalid tag values for vt_tray
            vt_tag_uid = vt_data.get("tag_uid", "")
            if vt_tag_uid in ("", "0000000000000000"):
                vt_tag_uid = None
            vt_tray_uuid = vt_data.get("tray_uuid", "")
            if vt_tray_uuid in ("", "00000000000000000000000000000000"):
                vt_tray_uuid = None

            # Get K value: first try tray's k field, then lookup from K-profiles
            vt_k_value = vt_data.get("k")
            vt_cali_idx = vt_data.get("cali_idx")
            if vt_k_value is None:
                # External holder: id 254 is Ext-L, 255 is Ext-R. slot_extruder
                # takes the 0/1 tray index, so normalise before asking.
                vt_id = int(vt_data.get("id", 254))
                vt_k_value = _kprofile_k(vt_cali_idx, 255, vt_id - 254 if vt_id >= 254 else vt_id)

            tray_id = int(vt_data.get("id", 254))
            vt_tray.append(
                AMSTray(
                    id=tray_id,
                    tray_color=vt_data.get("tray_color"),
                    tray_type=vt_data.get("tray_type"),
                    tray_sub_brands=vt_data.get("tray_sub_brands"),
                    tray_id_name=vt_data.get("tray_id_name"),
                    tray_info_idx=vt_data.get("tray_info_idx"),
                    remain=vt_data.get("remain", 0),
                    k=vt_k_value,
                    cali_idx=vt_cali_idx,
                    tag_uid=vt_tag_uid,
                    tray_uuid=vt_tray_uuid,
                    nozzle_temp_min=vt_data.get("nozzle_temp_min"),
                    nozzle_temp_max=vt_data.get("nozzle_temp_max"),
                )
            )

    # Convert nozzle info to response format
    nozzles = [
        NozzleInfoResponse(
            nozzle_type=n.nozzle_type,
            nozzle_diameter=n.nozzle_diameter,
        )
        for n in (state.nozzles or [])
    ]

    # H2C nozzle rack (tool-changer dock positions)
    nozzle_rack = [
        NozzleRackSlot(
            id=n.get("id", 0),
            nozzle_type=n.get("type", ""),
            nozzle_diameter=n.get("diameter", ""),
            wear=n.get("wear"),
            stat=n.get("stat"),
            max_temp=n.get("max_temp", 0),
            serial_number=n.get("serial_number", ""),
            filament_color=n.get("filament_color", ""),
            filament_id=n.get("filament_id", ""),
            filament_type=n.get("filament_type", ""),
        )
        for n in (state.nozzle_rack or [])
    ]

    # Convert print options to response format
    print_options = PrintOptionsResponse(
        spaghetti_detector=state.print_options.spaghetti_detector,
        print_halt=state.print_options.print_halt,
        halt_print_sensitivity=state.print_options.halt_print_sensitivity,
        first_layer_inspector=state.print_options.first_layer_inspector,
        printing_monitor=state.print_options.printing_monitor,
        buildplate_marker_detector=state.print_options.buildplate_marker_detector,
        allow_skip_parts=state.print_options.allow_skip_parts,
        nozzle_clumping_detector=state.print_options.nozzle_clumping_detector,
        nozzle_clumping_sensitivity=state.print_options.nozzle_clumping_sensitivity,
        pileup_detector=state.print_options.pileup_detector,
        pileup_sensitivity=state.print_options.pileup_sensitivity,
        airprint_detector=state.print_options.airprint_detector,
        airprint_sensitivity=state.print_options.airprint_sensitivity,
        auto_recovery_step_loss=state.print_options.auto_recovery_step_loss,
        filament_tangle_detect=state.print_options.filament_tangle_detect,
    )

    # Get AMS mapping from raw_data (which AMS is connected to which nozzle)
    ams_mapping = raw_data.get("ams_mapping", [])
    # Get per-AMS extruder map from state attribute (not raw_data, to avoid race condition
    # where raw_data gets replaced during MQTT updates and ams_extruder_map is temporarily missing)
    ams_extruder_map = state.ams_extruder_map or {}
    logger.debug("API returning ams_mapping: %s, ams_extruder_map: %s", ams_mapping, ams_extruder_map)

    # tray_now from MQTT is already a global tray ID: (ams_id * 4) + slot_id
    # Per OpenBambuAPI docs: 254 = external spool, 255 = no filament, otherwise global tray ID
    # No conversion needed - just use the raw value directly
    tray_now = state.tray_now
    logger.debug("Using tray_now directly as global ID: %s", tray_now)

    # Filter out chamber temp for models that don't have a real sensor
    # P1P, P1S, A1, A1Mini report meaningless chamber_temper values
    temperatures = state.temperatures
    if not supports_chamber_temp(printer.model):
        temperatures = {
            k: v for k, v in temperatures.items() if k not in ("chamber", "chamber_target", "chamber_heating")
        }

    # Resolve the active print's archive + plate (#881 follow-up): lets the
    # printer card show the actual plate name for multi-plate 3MFs instead of
    # just the 3MF filename. Only attempted for active prints, since subtask_id
    # is only meaningful then.
    current_archive_id: int | None = None
    current_plate_id: int | None = None
    if state.state in ("RUNNING", "PAUSE"):
        current_plate_id = resolve_plate_id(state)
        if state.subtask_id:
            from backend.app.models.archive import PrintArchive

            archive_row = await db.execute(
                select(PrintArchive.id)
                .where(PrintArchive.subtask_id == state.subtask_id)
                .where(PrintArchive.printer_id == printer_id)
                .order_by(PrintArchive.created_at.desc())
                .limit(1)
            )
            current_archive_id = archive_row.scalar_one_or_none()

    return PrinterStatus(
        id=printer_id,
        name=printer.name,
        connected=state.connected,
        state=state.state,
        current_print=state.current_print,
        subtask_name=state.subtask_name,
        gcode_file=state.gcode_file,
        progress=state.progress,
        remaining_time=state.remaining_time,
        layer_num=state.layer_num,
        total_layers=state.total_layers,
        temperatures=temperatures,
        cover_url=cover_url,
        hms_errors=hms_errors,
        ams=ams_units,
        ams_exists=ams_exists,
        vt_tray=vt_tray,
        sdcard=state.sdcard,
        store_to_sdcard=state.store_to_sdcard,
        timelapse=state.timelapse,
        ipcam=state.ipcam,
        wifi_signal=state.wifi_signal,
        wired_network=state.wired_network,
        door_open=state.door_open,
        nozzles=nozzles,
        nozzle_rack=nozzle_rack,
        print_options=print_options,
        stg_cur=state.stg_cur,
        stg_cur_name=get_derived_status_name(state, printer.model),
        stg=state.stg,
        airduct_mode=state.airduct_mode,
        speed_level=state.speed_level,
        chamber_light=state.chamber_light,
        active_extruder=state.active_extruder,
        ams_mapping=ams_mapping,
        ams_extruder_map=ams_extruder_map,
        # Only meaningful alongside an installed switch; without one the map is
        # empty anyway, but gating it keeps a stale binding from outliving the
        # accessory being unplugged.
        ams_switch_inlet=(dict(state.ams_switch_inlet) if state.fila_switch and state.fila_switch.installed else {}),
        tray_now=tray_now,
        # Runout guidance (#2587): resolve the firmware's target/previous slot to a
        # global tray ID, but only while PAUSED — the moment the operator needs it.
        expected_tray=(
            resolve_expected_tray(
                state.tray_tar,
                [(u.id, u.is_ams_ht) for u in ams_units],
                raw_data.get("mapping"),
            )
            if state.state == "PAUSE"
            else None
        ),
        previous_tray=(
            resolve_expected_tray(
                state.tray_pre,
                [(u.id, u.is_ams_ht) for u in ams_units],
                raw_data.get("mapping"),
            )
            if state.state == "PAUSE"
            else None
        ),
        ams_status_main=state.ams_status_main,
        ams_status_sub=state.ams_status_sub,
        mc_print_sub_stage=state.mc_print_sub_stage,
        last_ams_update=state.last_ams_update,
        printable_objects_count=len(state.printable_objects),
        cooling_fan_speed=state.cooling_fan_speed,
        big_fan1_speed=state.big_fan1_speed,
        big_fan2_speed=state.big_fan2_speed,
        heatbreak_fan_speed=state.heatbreak_fan_speed,
        left_aux_fan_speed=state.left_aux_fan_speed,
        exhaust_fan_present=state.exhaust_fan_present,
        firmware_version=state.firmware_version,
        developer_mode=state.developer_mode if state else None,
        ams_filament_backup=state.ams_filament_backup if state else None,
        awaiting_plate_clear=printer_manager.is_awaiting_plate_clear(printer_id),
        supports_drying=supports_drying(printer.model, state.firmware_version),
        supports_drying_while_printing=supports_drying_while_printing(printer.model, state.firmware_version),
        drying_screen_only=drying_screen_only(printer.model),
        supports_chamber_heater=supports_chamber_heater(printer.model),
        current_archive_id=current_archive_id,
        current_plate_id=current_plate_id,
        fila_switch=(
            FilaSwitchResponse(
                installed=state.fila_switch.installed,
                in_slots=list(state.fila_switch.in_slots),
                out_extruders=list(state.fila_switch.out_extruders),
                stat=state.fila_switch.stat,
                info=state.fila_switch.info,
            )
            if state.fila_switch and state.fila_switch.installed
            else None
        ),
    )


@router.get("/{printer_id}/overlay-status")
async def get_overlay_status(
    printer_id: int,
    _: None = RequireOverlayTokenIfAuthEnabled,
    db: AsyncSession = Depends(get_db),
) -> dict:
    """Everything the streaming overlay (#2613) draws for one printer.

    A token-authenticated sibling of ``get_printer_status`` for embeds with no
    login session — OBS loads ``/overlay/{id}?token=...`` and this feeds it.
    Deliberately flat and minimal (name, camera rotation, live print state, and
    the one setting the overlay reads) rather than the full ``PrinterStatus``:
    a token holder gets exactly the fields the overlay renders, nothing more.

    Unlike the Cam Wall feed this *includes the print filename* — the overlay
    names the part on screen — which is why it sits behind its own ``overlay``
    scope rather than ``camwall``.
    """
    from backend.app.api.routes.settings import get_setting

    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    time_format = await get_setting(db, "time_format") or "system"
    state = printer_manager.get_status(printer_id)

    if not state:
        # Never connected this run — mirror get_printer_status()'s disconnected
        # shape so the overlay renders its offline state rather than erroring.
        return {
            "id": printer_id,
            "name": printer.name,
            "camera_rotation": printer.camera_rotation or 0,
            "connected": False,
            "state": None,
            "current_print": None,
            "gcode_file": None,
            "progress": None,
            "remaining_time": None,
            "layer_num": None,
            "total_layers": None,
            "stg_cur_name": None,
            "temperatures": {},
            "time_format": time_format,
        }

    return {
        "id": printer_id,
        "name": printer.name,
        "camera_rotation": printer.camera_rotation or 0,
        "connected": state.connected,
        "state": state.state,
        "current_print": state.current_print,
        "gcode_file": state.gcode_file,
        "progress": state.progress,
        "remaining_time": state.remaining_time,
        "layer_num": state.layer_num,
        "total_layers": state.total_layers,
        "stg_cur_name": get_derived_status_name(state, printer.model),
        # Nozzle / bed / chamber readings for the overlay's temperature fields
        # (#1422). Filtered rather than passed through: see display_temperatures.
        "temperatures": display_temperatures(state.temperatures, printer.model),
        "time_format": time_format,
    }


@router.get("/{printer_id}/current-print-user")
async def get_current_print_user(
    printer_id: int,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_READ),
    db: AsyncSession = Depends(get_db),
):
    """Get the user who started the current print (for reprint tracking).

    Returns user info if available, empty object otherwise.
    This tracks users for reprints (which bypass the queue).
    For queue-based prints, use the queue item's created_by field instead.
    """
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    user_info = printer_manager.get_current_print_user(printer_id)
    return user_info or {}


@router.post("/{printer_id}/refresh-status")
async def refresh_printer_status(
    printer_id: int,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_READ),
    db: AsyncSession = Depends(get_db),
):
    """Request a full status refresh from the printer (sends pushall command)."""
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    success = printer_manager.request_status_update(printer_id)
    if not success:
        raise HTTPException(400, "Printer not connected")

    return {"status": "refresh_requested"}


@router.post("/{printer_id}/connect")
async def connect_printer(
    printer_id: int,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Manually connect to a printer."""
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    success = await printer_manager.connect_printer(printer)
    return {"connected": success}


@router.post("/{printer_id}/disconnect")
async def disconnect_printer(
    printer_id: int,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Manually disconnect from a printer."""
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    printer_manager.disconnect_printer(printer_id)
    return {"connected": False}


@router.post("/test")
async def test_printer_connection(
    ip_address: str,
    serial_number: str,
    access_code: str,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CREATE),
):
    """Test connection to a printer without saving."""
    result = await printer_manager.test_connection(
        ip_address=ip_address,
        serial_number=serial_number,
        access_code=access_code,
    )
    return result


@router.post("/diagnostic", response_model=PrinterDiagnosticResult)
async def diagnose_connection(
    req: DiagnosticRequest,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CREATE),
):
    """Run connection diagnostics for the Add-Printer flow (printer not yet saved).

    When serial_number + access_code are supplied the MQTT credential check
    also runs; otherwise only the network-level checks are performed.
    """
    return await run_connection_diagnostic(
        req.ip_address,
        serial_number=req.serial_number or None,
        access_code=req.access_code or None,
    )


@router.get("/{printer_id}/diagnostic", response_model=PrinterDiagnosticResult)
async def diagnose_printer(
    printer_id: int,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_READ),
    db: AsyncSession = Depends(get_db),
):
    """Run connection diagnostics for an existing saved printer.

    On-demand run from the UI: wait up to PUBLISH_WAIT_DEFAULT seconds for the
    printer to publish a status report so a fresh reconnect (counter reset to
    0) isn't reported as `printer_publishing: fail` prematurely. The support
    package code path calls run_connection_diagnostic without the wait so
    bundling stays fast.
    """
    from backend.app.services.printer_diagnostic import PUBLISH_WAIT_DEFAULT

    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")
    return await run_connection_diagnostic(
        printer.ip_address,
        printer=printer,
        wait_for_publish_seconds=PUBLISH_WAIT_DEFAULT,
    )


# Cache for cover images (printer_id -> {(subtask_name, view_key) -> image_bytes}).
# Cleared on every print start by main.py::on_print_start, so re-dispatches with
# different plates always fetch a fresh thumbnail without needing plate in the key.
_cover_cache: dict[int, dict[tuple[str, str], bytes]] = {}

# Negative cache (#1420): when a cover lookup exhausts every FTP path with 550
# (file sliced on SD card, not on printer storage), remember the failure so the
# next request short-circuits to 404 instead of re-hammering FTP 8 paths deep.
# Cleared on print start alongside _cover_cache.
_cover_404_cache: dict[int, set[tuple[str, str]]] = {}

# In-flight cover downloads, keyed by (printer_id, subtask_name, view_key) (#2572).
# The farm dashboard mounts a cover tile per printer card, so several browsers
# request the same printer's cover in the same instant, all miss the cache, and
# each runs the full multi-path FTP lookup + 3MF extraction (one observed live
# transfer pulled an 81 MB 3MF while real print uploads were in flight). The
# first request to miss becomes the leader; concurrent requests await its future
# and then serve from the positive/negative cache it filled.
_cover_inflight: dict[tuple[int, str, str], asyncio.Future] = {}


def clear_cover_cache(printer_id: int) -> None:
    """Clear cached cover images for a printer. Call on print start to avoid stale thumbnails."""
    _cover_cache.pop(printer_id, None)
    _cover_404_cache.pop(printer_id, None)


async def _running_print_archive_file(printer_id: int, state) -> Path | None:
    """Path to the 3MF of the print this printer is running, if we have it.

    Bambuddy archives the sliced file when the print starts, so the copy the
    printer is executing is usually already on disk. Anchored on ``subtask_id``,
    which the firmware mints per print: a leftover ``status="printing"`` row from
    a completion that was never seen must not lend its file to another job.

    Opens its own short-lived session, like the caller does, so the pooled
    connection is not held across the FTP work that follows.
    """
    subtask_id = str(getattr(state, "subtask_id", "") or "").strip()
    if subtask_id in ("", "0"):
        return None

    from backend.app.models.archive import PrintArchive

    async with database.async_session() as db:
        archive = await db.scalar(
            select(PrintArchive)
            .where(
                PrintArchive.printer_id == printer_id,
                PrintArchive.status == "printing",
                PrintArchive.subtask_id == subtask_id,
            )
            .order_by(PrintArchive.created_at.desc())
            .limit(1)
        )
    if archive is None or not archive.file_path:
        return None

    path = settings.base_dir / archive.file_path
    return path if path.is_file() and str(path).endswith(".3mf") else None


@router.get("/{printer_id}/cover")
async def get_printer_cover(
    printer_id: int,
    view: str | None = None,
    _: None = RequireCameraStreamTokenIfAuthEnabled,
):
    """Get the cover image for the current print job.

    Args:
        view: Optional view type. Use "top" for the top-down build plate view or
              "pick" for the slicer's object-ID mask used by skip objects.
              Default returns angled 3D perspective view.
    """
    # Fetch the printer in a short-lived session and release the pooled DB
    # connection BEFORE the FTP download below. Previously this route took its
    # row via Depends(get_db), whose session stays open for the whole request —
    # so a 3MF cover download (up to 8 paths × 3 retries with backoff, minutes
    # under FTP contention) pinned one pooled connection idle-in-transaction the
    # entire time (issue #2572). db is used only for this one SELECT; everything
    # after reads already-loaded printer.* scalars (expire_on_commit=False keeps
    # them readable), printer_manager, and FTP/zip — no lazy loads.
    #
    # Reference async_session via the module so the maker is looked up at call
    # time — keeps it in sync with reinitialize_database() and lets the test
    # harness's patch of backend.app.core.database.async_session take effect.
    async with database.async_session() as db:
        result = await db.execute(select(Printer).where(Printer.id == printer_id))
        printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    state = printer_manager.get_status(printer_id)
    if not state:
        raise HTTPException(404, "Printer not connected")

    # Use subtask_name as the 3MF filename (gcode_file is the path inside the 3MF)
    subtask_name = state.subtask_name
    if not subtask_name:
        raise HTTPException(404, f"No subtask_name in printer state (state={state.state})")

    # Resolve the active plate. Precedence (#1166):
    #   1. The plate Bambuddy dispatched (authoritative when we sent the print)
    #   2. plate_(\d+)\.gcode regex on state.gcode_file (works on firmware that
    #      reflects the full path, e.g. some X1C builds)
    #   3. Scan the downloaded 3MF for a unique Metadata/plate_*.gcode (covers
    #      per-plate archives sliced separately in Bambu Studio, where the
    #      printer's gcode_file echo is just the .3mf filename)
    #   4. Fall back to plate 1
    # The 3MF-scan fallback runs later — after the file is on disk.
    plate_num = resolve_plate_id(state)
    if plate_num is not None:
        logger.info("Cover: resolved plate %s before download (subtask=%s)", plate_num, subtask_name)

    # Normalize view parameter
    view_key = view or "default"

    # Check cache. Cache by (subtask_name, view_key) only — clear_cover_cache()
    # runs on every print start, so a re-dispatch with a different plate gets
    # a fresh image regardless. Pre-#1166 the key included plate_num, but with
    # late plate resolution the cache check would always miss.
    cache_key = (subtask_name, view_key)
    if printer_id in _cover_cache and cache_key in _cover_cache[printer_id]:
        return Response(content=_cover_cache[printer_id][cache_key], media_type="image/png")

    # Negative-cache short-circuit (#1420): if a prior lookup for this same
    # subtask + view already failed, don't replay 8 FTP retries on every page
    # refresh. _cover_404_cache is cleared on print start.
    if printer_id in _cover_404_cache and cache_key in _cover_404_cache[printer_id]:
        raise HTTPException(404, f"No cover available for '{subtask_name}' (cached)")

    # Coalesce concurrent downloads for the same cover (#2572). The positive and
    # negative caches were just checked above; if another request is already
    # downloading this exact cover, wait for it and serve from the cache it fills
    # instead of launching a duplicate multi-path FTP + 3MF extraction.
    inflight_key = (printer_id, subtask_name, view_key)
    leader = _cover_inflight.get(inflight_key)
    if leader is not None:
        # shield() so our own cancellation can't cancel the shared leader.
        try:
            await asyncio.shield(leader)
        except Exception:
            pass
        if printer_id in _cover_cache and cache_key in _cover_cache[printer_id]:
            return Response(content=_cover_cache[printer_id][cache_key], media_type="image/png")
        if printer_id in _cover_404_cache and cache_key in _cover_404_cache[printer_id]:
            raise HTTPException(404, f"No cover available for '{subtask_name}' (cached)")
        # Leader finished without filling either cache (a transient 503) — fall
        # through and try the download ourselves.

    fut: asyncio.Future = asyncio.get_event_loop().create_future()
    _cover_inflight[inflight_key] = fut
    try:
        image_data = await _produce_cover_image(
            printer,
            printer_id,
            subtask_name,
            view,
            view_key,
            plate_num,
            cache_key,
            archive_path=await _running_print_archive_file(printer_id, state),
        )
        return Response(content=image_data, media_type="image/png")
    finally:
        if not fut.done():
            fut.set_result(None)
        _cover_inflight.pop(inflight_key, None)


async def _produce_cover_image(
    printer: Printer,
    printer_id: int,
    subtask_name: str,
    view: str | None,
    view_key: str,
    plate_num: int | None,
    cache_key: tuple[str, str],
    archive_path: Path | None = None,
) -> bytes:
    """Download the active-print 3MF and extract its cover thumbnail (#2572).

    Split out of ``get_printer_cover`` so concurrent requests for the same cover
    can single-flight through it (see ``_cover_inflight``). Returns the PNG bytes
    on success (also filling ``_cover_cache``) and raises ``HTTPException`` on
    failure (filling ``_cover_404_cache`` for the definitive 404s). Does no DB
    work — the caller already released the pooled connection before this runs,
    which is also why ``archive_path`` arrives resolved rather than looked up
    here.
    """
    # Build possible 3MF filenames from subtask_name
    # Bambu printers may store files as "name.gcode.3mf" (sliced via Bambu Studio)
    # or just "name.3mf" (uploaded directly)
    possible_filenames = []
    if subtask_name.endswith(".3mf"):
        possible_filenames.append(subtask_name)
    else:
        # Try both naming patterns
        possible_filenames.append(f"{subtask_name}.gcode.3mf")
        possible_filenames.append(f"{subtask_name}.3mf")

    # Also try with spaces converted to underscores (Bambu Studio may normalize filenames)
    if " " in subtask_name:
        normalized = subtask_name.replace(" ", "_")
        if normalized.endswith(".3mf"):
            possible_filenames.append(normalized)
        else:
            possible_filenames.append(f"{normalized}.gcode.3mf")
            possible_filenames.append(f"{normalized}.3mf")

    # Build list of all remote paths to try
    remote_paths = []
    for filename in possible_filenames:
        remote_paths.extend(
            [
                f"/{filename}",  # Root directory (most common)
                f"/cache/{filename}",
                f"/model/{filename}",
                f"/data/{filename}",
            ]
        )

    # Use first filename for temp path (will be reused)
    temp_filename = possible_filenames[0]
    temp_path = settings.archive_dir / "temp" / f"cover_{printer_id}_{temp_filename}"
    temp_path.parent.mkdir(parents=True, exist_ok=True)

    storage = print_file_reachable_over_ftp(printer_manager.get_status(printer_id))

    # Cache check (#972): the archive-metadata flow in main.py may have already
    # downloaded this 3MF during the print-start handler. Reusing that file
    # avoids a second 36MB transfer competing with the printer's single FTP
    # socket (which produces the 425 errors that feed the retry storm).
    #
    # The dispatch's own filename is a candidate too: it is what the archive
    # flow's probe cached the file under, and it does not always survive the
    # trip through subtask_name (#2856).
    downloaded = False
    using_cached = False
    for candidate_name in (*possible_filenames, storage.probe_filename):
        if not candidate_name:
            continue
        cached = get_cached_3mf(printer_id, candidate_name)
        if cached:
            logger.info("Cover using cached 3MF from %s (avoided duplicate FTP)", cached)
            temp_path = cached
            downloaded = True
            using_cached = True
            break

    if not downloaded:
        # Same idea, one step further back: that in-memory cache dies with the
        # process, but the archive of the print that is still running holds the
        # very 3MF on disk. Without this, reopening a card or the skip-objects
        # plate after a restart pulls the whole file back off a printer that is
        # mid-print — measured at three concurrent fan-outs, thirteen seconds
        # and a 0-byte read on the maintainer's H2C, which is exactly the
        # single-socket contention #972 was about.
        if archive_path is not None:
            logger.info("Cover using the running print's archived 3MF at %s (no FTP)", archive_path)
            temp_path = archive_path
            downloaded = True
            using_cached = True

    if not downloaded:
        # The cover lives inside the 3MF, so it is only reachable if the 3MF is.
        # When the printer kept the print on internal storage there is nothing
        # at any of these paths, and walking all sixteen of them just to end on
        # a 404 that reads as "this print has no cover" helps nobody (#2780).
        #
        # Unless the printer is wrong about that, which an H2D with a card in
        # routinely is (#2856). The dispatch names the file, so when it does,
        # trade the immediate 404 for a five-path probe of that one name — same
        # single connection, and it is the only way this endpoint ever recovers
        # a cover for a print the archive flow did not see start.
        max_retries = 2
        if not storage.reachable:
            if not storage.probe_filename:
                _cover_404_cache.setdefault(printer_id, set()).add(cache_key)
                raise HTTPException(
                    404,
                    f"The print file for '{subtask_name}' is not on storage Bambuddy can read over FTPS "
                    f"({storage.reason}), so it has no cover to extract.",
                )
            remote_paths = ftp_probe_paths(storage.probe_filename)
            # The dispatch's name is the authoritative one — a print whose
            # subtask_name has been normalized or truncated would otherwise be
            # cached under a key the archive flow never looks up.
            temp_filename = storage.probe_filename
            temp_path = settings.archive_dir / "temp" / f"cover_{printer_id}_{temp_filename}"
            # One look, not three: the printer has already said this file is not
            # here, so a retry storm on top of a hunch is exactly what #2780 was.
            max_retries = 0

        logger.info(
            f"Trying to download cover for '{subtask_name}' from {printer.ip_address} (trying {len(remote_paths)} paths)"
        )

        # Retry logic for transient FTP failures
        last_error = None

        for attempt in range(max_retries + 1):
            if ftps_handshake_blocked(printer.ip_address):
                # Nothing to retry: the printer is not completing a TLS
                # handshake on port 990, so no path and no attempt reaches it
                # (#2780). Report the real cause instead of the 404 below,
                # which would read as "this print has no cover".
                raise HTTPException(
                    503,
                    f"Printer {printer.ip_address} is not answering its file service over TLS. "
                    "Bambuddy will try again shortly.",
                )
            try:
                downloaded = await download_file_try_paths_async(
                    printer.ip_address,
                    printer.access_code,
                    remote_paths,
                    temp_path,
                    printer_model=printer.model,
                )
                if downloaded:
                    break
            except Exception as e:
                last_error = e
                if attempt < max_retries:
                    logger.warning("FTP download attempt %s failed: %s, retrying...", attempt + 1, e)
                    await asyncio.sleep(0.5 * (attempt + 1))  # Brief backoff
                else:
                    logger.error("FTP download failed after %s attempts: %s", max_retries + 1, e)

        if last_error and not downloaded:
            raise HTTPException(503, f"FTP download temporarily unavailable: {last_error}")

        if not downloaded:
            # Remember this failure so subsequent requests for the same print
            # skip the 8-path FTP fan-out (#1420).
            _cover_404_cache.setdefault(printer_id, set()).add(cache_key)
            if not storage.reachable:
                # The probe looked and found nothing, so the printer's own
                # account of where the file went is the answer after all —
                # keep saying so rather than reporting a generic miss (#2780).
                raise HTTPException(
                    404,
                    f"The print file for '{subtask_name}' is not on storage Bambuddy can read over FTPS "
                    f"({storage.reason}), so it has no cover to extract.",
                )
            raise HTTPException(
                404,
                f"Could not download 3MF file for '{subtask_name}' from printer {printer.ip_address}. Tried: {possible_filenames}",
            )

        # Share the fresh download with the archive flow.
        cache_3mf_download(printer_id, temp_filename, temp_path)

    # Verify file actually exists and has content
    if not temp_path.exists():
        raise HTTPException(500, f"Download reported success but file not found: {temp_path}")

    file_size = temp_path.stat().st_size
    logger.info("Downloaded file size: %s bytes", file_size)

    if file_size == 0:
        if not using_cached:
            temp_path.unlink()
        raise HTTPException(500, f"Downloaded file is empty for '{subtask_name}'")

    try:
        # Extract thumbnail from 3MF (which is a ZIP file)
        try:
            zf = zipfile.ZipFile(temp_path, "r")
        except zipfile.BadZipFile:
            raise HTTPException(500, "Downloaded file is not a valid 3MF/ZIP archive")
        except OSError as e:
            logger.error("Failed to open 3MF file: %s", e, exc_info=True)
            raise HTTPException(500, "Failed to open 3MF file. Check server logs for details.")

        try:
            # 3MF-scan fallback for plate detection (#1166). Per-plate archives
            # sliced separately in Bambu Studio contain a single
            # Metadata/plate_N.gcode for the active plate, even though
            # thumbnails for all plates are bundled. Using that gcode's plate
            # number prevents falling back to plate_1.png.
            if plate_num is None:
                plate_gcodes = [name for name in zf.namelist() if re.match(r"^Metadata/plate_\d+\.gcode$", name)]
                if len(plate_gcodes) == 1:
                    match = re.search(r"plate_(\d+)\.gcode", plate_gcodes[0])
                    if match:
                        plate_num = int(match.group(1))
                        logger.info("Cover: detected plate %s from 3MF contents", plate_num)
            if plate_num is None:
                plate_num = 1

            # Try common thumbnail paths in 3MF files
            # Use plate_num to get the correct plate's thumbnail for multi-plate projects
            # Use top-down view if requested (better for skip objects modal)
            if view == "pick":
                # Only the active plate's mask, with no fallback: every other view
                # falls back to plate 1 because a slightly wrong picture is better
                # than none, but a mask is coordinates, not decoration. Plate 1's
                # mask over plate 3's layout would resolve clicks to whichever
                # object happened to occupy that pixel on a different plate.
                thumbnail_paths = [f"Metadata/pick_{plate_num}.png"]
            elif view == "top":
                thumbnail_paths = [
                    f"Metadata/top_{plate_num}.png",
                    # Fall back to plate 1 if specific plate not found
                    "Metadata/top_1.png",
                    f"Metadata/plate_{plate_num}.png",
                    "Metadata/plate_1.png",
                    "Metadata/thumbnail.png",
                ]
            else:
                thumbnail_paths = [
                    f"Metadata/plate_{plate_num}.png",
                    # Fall back to plate 1 if specific plate not found
                    "Metadata/plate_1.png",
                    "Metadata/thumbnail.png",
                    f"Metadata/plate_{plate_num}_small.png",
                    "Metadata/plate_1_small.png",
                    "Thumbnails/thumbnail.png",
                    "thumbnail.png",
                ]

            for thumb_path in thumbnail_paths:
                try:
                    image_data = zf.read(thumb_path)
                    if printer_id not in _cover_cache:
                        _cover_cache[printer_id] = {}
                    _cover_cache[printer_id][(subtask_name, view_key)] = image_data
                    return image_data
                except KeyError:
                    continue

            # If no specific thumbnail found, try any PNG in Metadata. Never for
            # "pick": handing back a rendered thumbnail in place of the object-ID
            # mask is worse than nothing, because the caller can't tell the
            # difference and decodes the render's pixel colours as object IDs —
            # dark pixels yield small integers that collide with real IDs, so a
            # click would select an arbitrary object and skip it irreversibly.
            # A 404 is what tells the UI to fall back to the checklist.
            if view != "pick":
                for name in zf.namelist():
                    if name.startswith("Metadata/") and name.endswith(".png"):
                        image_data = zf.read(name)
                        if printer_id not in _cover_cache:
                            _cover_cache[printer_id] = {}
                        _cover_cache[printer_id][(subtask_name, view_key)] = image_data
                        return image_data

            _cover_404_cache.setdefault(printer_id, set()).add(cache_key)
            raise HTTPException(404, "No thumbnail found in 3MF file")
        finally:
            zf.close()

    finally:
        # Only delete when this invocation owns the file. A cached path is
        # shared with the archive flow — removing it would force a refetch
        # the next time either flow needs the 3MF.
        if not using_cached and temp_path.exists():
            temp_path.unlink()


# ============================================
# File Manager Endpoints
# ============================================


async def _load_printer_or_404(printer_id: int) -> Printer:
    """Load a printer in a short-lived session, releasing the pooled DB
    connection before the caller starts any FTP/network I/O (#2572).

    The file-manager and storage routes talk FTP to the printer, which can
    block for the full socket timeout — longer when a saturated FTP pool backs
    up. Holding the request's Depends(get_db) session across that FTP pinned one
    pooled connection idle-in-transaction per in-flight request, a top cause of
    pool exhaustion on large farms. The returned row's scalar columns stay
    readable after the session closes (expire_on_commit=False). Raises 404 when
    the printer doesn't exist.

    Reference async_session via the module so the maker is resolved at call time
    — keeps it in sync with reinitialize_database() and lets tests patch it.
    """
    async with database.async_session() as db:
        result = await db.execute(select(Printer).where(Printer.id == printer_id))
        printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")
    return printer


@router.get("/{printer_id}/files")
async def list_printer_files(
    printer_id: int,
    path: str = "/",
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_FILES),
):
    """List files on the printer at the specified path."""
    printer = await _load_printer_or_404(printer_id)

    files = await list_files_async(printer.ip_address, printer.access_code, path, printer_model=printer.model)

    # Add full path to each file
    for f in files:
        f["path"] = f"{path.rstrip('/')}/{f['name']}" if path != "/" else f"/{f['name']}"

    return {
        "path": path,
        "files": files,
    }


@router.get("/{printer_id}/files/download")
async def download_printer_file(
    printer_id: int,
    path: str,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_FILES),
):
    """Download a file from the printer."""
    printer = await _load_printer_or_404(printer_id)

    data = await download_file_bytes_async(printer.ip_address, printer.access_code, path, printer_model=printer.model)
    if data is None:
        raise HTTPException(404, f"File not found: {path}")

    # Determine content type based on extension
    filename = path.split("/")[-1]
    ext = filename.lower().split(".")[-1] if "." in filename else ""

    content_types = {
        "3mf": "application/vnd.ms-package.3dmanufacturing-3dmodel+xml",
        "gcode": "text/plain",
        "mp4": "video/mp4",
        "avi": "video/x-msvideo",
        "png": "image/png",
        "jpg": "image/jpeg",
        "jpeg": "image/jpeg",
        "json": "application/json",
        "txt": "text/plain",
    }
    content_type = content_types.get(ext, "application/octet-stream")

    return Response(
        content=data,
        media_type=content_type,
        headers={"Content-Disposition": build_content_disposition(filename)},
    )


@router.get("/{printer_id}/files/gcode")
async def get_printer_file_gcode(
    printer_id: int,
    path: str,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_FILES),
):
    """Get gcode for a file stored on a printer (for preview)."""
    import io

    printer = await _load_printer_or_404(printer_id)

    data = await download_file_bytes_async(printer.ip_address, printer.access_code, path, printer_model=printer.model)
    if data is None:
        raise HTTPException(404, f"File not found: {path}")

    filename = path.split("/")[-1]
    lower = filename.lower()

    if lower.endswith(".gcode"):
        return Response(content=data, media_type="text/plain")
    if lower.endswith(".3mf"):
        try:
            with zipfile.ZipFile(io.BytesIO(data), "r") as zf:
                gcode_files = [n for n in zf.namelist() if n.endswith(".gcode")]
                if not gcode_files:
                    raise HTTPException(status_code=404, detail="No gcode found in 3MF file")
                gcode_content = zf.read(gcode_files[0])
                return Response(content=gcode_content, media_type="text/plain")
        except zipfile.BadZipFile:
            raise HTTPException(status_code=400, detail="Invalid 3MF file")

    raise HTTPException(status_code=400, detail="Unsupported file type")


@router.get("/{printer_id}/files/plates")
async def get_printer_file_plates(
    printer_id: int,
    path: str = Query(..., description="Full path to the 3MF file on the printer"),
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_FILES),
):
    """Get available plates from a multi-plate 3MF file stored on a printer."""
    import io
    import json

    import defusedxml.ElementTree as ET

    printer = await _load_printer_or_404(printer_id)

    filename = path.split("/")[-1]
    if not filename.lower().endswith(".3mf"):
        return {
            "printer_id": printer_id,
            "path": path,
            "filename": filename,
            "plates": [],
            "is_multi_plate": False,
        }

    data = await download_file_bytes_async(printer.ip_address, printer.access_code, path, printer_model=printer.model)
    if data is None:
        raise HTTPException(404, f"File not found: {path}")

    plates = []

    try:
        with zipfile.ZipFile(io.BytesIO(data), "r") as zf:
            namelist = zf.namelist()

            # Find all plate gcode files to determine available plates
            gcode_files = [n for n in namelist if n.startswith("Metadata/plate_") and n.endswith(".gcode")]

            # If no gcode is present (source-only or unsliced), fall back to plate JSON/PNG
            plate_indices: list[int] = []
            if gcode_files:
                for gf in gcode_files:
                    try:
                        plate_str = gf[15:-6]  # Remove "Metadata/plate_" and ".gcode"
                        plate_indices.append(int(plate_str))
                    except ValueError:
                        pass  # Skip gcode files with non-numeric plate indices
            else:
                plate_json_files = [n for n in namelist if n.startswith("Metadata/plate_") and n.endswith(".json")]
                plate_png_files = [
                    n
                    for n in namelist
                    if n.startswith("Metadata/plate_")
                    and n.endswith(".png")
                    and "_small" not in n
                    and "no_light" not in n
                ]
                plate_name_candidates = plate_json_files + plate_png_files
                plate_re = re.compile(r"^Metadata/plate_(\d+)\.(json|png)$")
                seen_indices: set[int] = set()
                for name in plate_name_candidates:
                    match = plate_re.match(name)
                    if match:
                        try:
                            index = int(match.group(1))
                        except ValueError:
                            continue
                        if index in seen_indices:
                            continue
                        seen_indices.add(index)
                        plate_indices.append(index)

            if not plate_indices:
                return {
                    "printer_id": printer_id,
                    "path": path,
                    "filename": filename,
                    "plates": [],
                    "is_multi_plate": False,
                }

            plate_indices.sort()

            # Parse model_settings.config for plate names
            plate_names = {}
            if "Metadata/model_settings.config" in namelist:
                try:
                    model_content = zf.read("Metadata/model_settings.config").decode()
                    model_root = ET.fromstring(model_content)
                    for plate_elem in model_root.findall(".//plate"):
                        plater_id = None
                        plater_name = None
                        for meta in plate_elem.findall("metadata"):
                            key = meta.get("key")
                            value = meta.get("value")
                            if key == "plater_id" and value:
                                try:
                                    plater_id = int(value)
                                except ValueError:
                                    pass  # Skip plate with unparseable ID
                            elif key == "plater_name" and value:
                                plater_name = value.strip()
                        if plater_id is not None and plater_name:
                            plate_names[plater_id] = plater_name
                except Exception:
                    pass  # Plate names are optional; continue without them

            # Parse slice_info.config for plate metadata
            plate_metadata = {}
            if "Metadata/slice_info.config" in namelist:
                content = zf.read("Metadata/slice_info.config").decode()
                root = ET.fromstring(content)

                for plate_elem in root.findall(".//plate"):
                    plate_info = {"filaments": [], "prediction": None, "weight": None, "name": None, "objects": []}

                    plate_index = None
                    for meta in plate_elem.findall("metadata"):
                        key = meta.get("key")
                        value = meta.get("value")
                        if key == "index" and value:
                            try:
                                plate_index = int(value)
                            except ValueError:
                                pass  # Skip plate with unparseable index
                        elif key == "prediction" and value:
                            try:
                                plate_info["prediction"] = int(value)
                            except ValueError:
                                pass  # Skip unparseable prediction; leave as None
                        elif key == "weight" and value:
                            try:
                                plate_info["weight"] = float(value)
                            except ValueError:
                                pass  # Skip unparseable weight; leave as None

                    # Get filaments used in this plate
                    for filament_elem in plate_elem.findall("filament"):
                        filament_id = filament_elem.get("id")
                        filament_type = filament_elem.get("type", "")
                        filament_color = filament_elem.get("color", "")
                        used_g = filament_elem.get("used_g", "0")
                        used_m = filament_elem.get("used_m", "0")

                        try:
                            used_grams = float(used_g)
                        except (ValueError, TypeError):
                            used_grams = 0

                        if used_grams > 0 and filament_id:
                            plate_info["filaments"].append(
                                {
                                    "slot_id": int(filament_id),
                                    "type": filament_type,
                                    "color": filament_color,
                                    "used_grams": round(used_grams, 1),
                                    "used_meters": float(used_m) if used_m else 0,
                                }
                            )

                    plate_info["filaments"].sort(key=lambda x: x["slot_id"])

                    # Collect object names
                    for obj_elem in plate_elem.findall("object"):
                        obj_name = obj_elem.get("name")
                        if obj_name and obj_name not in plate_info["objects"]:
                            plate_info["objects"].append(obj_name)

                    # Set plate name
                    if plate_index is not None:
                        custom_name = plate_names.get(plate_index)
                        if custom_name:
                            plate_info["name"] = custom_name
                        elif plate_info["objects"]:
                            plate_info["name"] = plate_info["objects"][0]
                        plate_metadata[plate_index] = plate_info

            # Parse plate_*.json for object lists when slice_info is missing
            plate_json_objects: dict[int, list[str]] = {}
            for name in namelist:
                match = re.match(r"^Metadata/plate_(\d+)\.json$", name)
                if not match:
                    continue
                try:
                    plate_index = int(match.group(1))
                except ValueError:
                    continue
                try:
                    payload = json.loads(zf.read(name).decode())
                    bbox_objects = payload.get("bbox_objects", [])
                    names: list[str] = []
                    for obj in bbox_objects:
                        obj_name = obj.get("name") if isinstance(obj, dict) else None
                        if obj_name and obj_name not in names:
                            names.append(obj_name)
                    if names:
                        plate_json_objects[plate_index] = names
                except Exception:
                    continue

            # Build plate list
            for idx in plate_indices:
                meta = plate_metadata.get(idx, {})
                has_thumbnail = f"Metadata/plate_{idx}.png" in namelist
                objects = meta.get("objects", [])
                if not objects:
                    objects = plate_json_objects.get(idx, [])

                plate_name = meta.get("name")
                if not plate_name:
                    plate_name = plate_names.get(idx)
                if not plate_name and objects:
                    plate_name = objects[0]

                plates.append(
                    {
                        "index": idx,
                        "name": plate_name,
                        "objects": objects,
                        "object_count": len(objects),
                        "has_thumbnail": has_thumbnail,
                        "thumbnail_url": f"/api/v1/printers/{printer_id}/files/plate-thumbnail/{idx}?path={path}",
                        "print_time_seconds": meta.get("prediction"),
                        "filament_used_grams": meta.get("weight"),
                        "filaments": meta.get("filaments", []),
                    }
                )

    except Exception as e:
        logger.warning("Failed to parse plates from printer file %s: %s", path, e)

    return {
        "printer_id": printer_id,
        "path": path,
        "filename": filename,
        "plates": plates,
        "is_multi_plate": len(plates) > 1,
    }


@router.get("/{printer_id}/files/plate-thumbnail/{plate_index}")
async def get_printer_file_plate_thumbnail(
    printer_id: int,
    plate_index: int,
    path: str = Query(..., description="Full path to the 3MF file on the printer"),
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_FILES),
):
    """Get a plate thumbnail image from a printer-stored 3MF file."""
    import io

    printer = await _load_printer_or_404(printer_id)

    data = await download_file_bytes_async(printer.ip_address, printer.access_code, path, printer_model=printer.model)
    if data is None:
        raise HTTPException(404, f"File not found: {path}")

    try:
        with zipfile.ZipFile(io.BytesIO(data), "r") as zf:
            thumb_path = f"Metadata/plate_{plate_index}.png"
            if thumb_path in zf.namelist():
                image_data = zf.read(thumb_path)
                return Response(content=image_data, media_type="image/png")
    except Exception:
        pass  # Corrupt or unreadable 3MF; fall through to 404

    raise HTTPException(status_code=404, detail=f"Thumbnail for plate {plate_index} not found")


@router.post("/{printer_id}/files/download-zip")
async def download_printer_files_as_zip(
    printer_id: int,
    request: dict,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_FILES),
):
    """Download multiple files from the printer as a ZIP archive."""
    import io

    paths = request.get("paths", [])
    if not paths:
        raise HTTPException(400, "No files specified")

    printer = await _load_printer_or_404(printer_id)

    # Create ZIP in memory
    zip_buffer = io.BytesIO()
    with zipfile.ZipFile(zip_buffer, "w", zipfile.ZIP_DEFLATED) as zf:
        for path in paths:
            try:
                data = await download_file_bytes_async(
                    printer.ip_address, printer.access_code, path, printer_model=printer.model
                )
                if data:
                    filename = path.split("/")[-1]
                    zf.writestr(filename, data)
            except Exception as e:
                logging.warning("Failed to add %s to ZIP: %s", path, e)
                continue

    zip_buffer.seek(0)
    zip_data = zip_buffer.read()

    if len(zip_data) == 0:
        raise HTTPException(404, "No files could be downloaded")

    return Response(
        content=zip_data,
        media_type="application/zip",
        headers={"Content-Disposition": 'attachment; filename="printer-files.zip"'},
    )


@router.delete("/{printer_id}/files")
async def delete_printer_file(
    printer_id: int,
    path: str,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_FILES),
):
    """Delete a file from the printer."""
    printer = await _load_printer_or_404(printer_id)

    from backend.app.services.bambu_ftp import DeleteResult

    result = await delete_file_async(printer.ip_address, printer.access_code, path, printer_model=printer.model)
    if result == DeleteResult.NOT_FOUND:
        raise HTTPException(404, f"File not found on printer: {path}")
    if result == DeleteResult.FAILED:
        raise HTTPException(500, f"Failed to delete file: {path}")

    return {"status": "deleted", "path": path}


@router.get("/{printer_id}/storage")
async def get_printer_storage(
    printer_id: int,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_READ),
):
    """Get storage information from the printer."""
    printer = await _load_printer_or_404(printer_id)

    storage_info = await get_storage_info_async(printer.ip_address, printer.access_code, printer_model=printer.model)

    return storage_info or {"used_bytes": None, "free_bytes": None}


# ============================================
# MQTT Debug Logging Endpoints
# ============================================


@router.post("/{printer_id}/logging/enable")
async def enable_mqtt_logging(
    printer_id: int,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Enable MQTT message logging for a printer."""
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    success = printer_manager.enable_logging(printer_id, True)
    if not success:
        raise HTTPException(400, "Printer not connected")

    return {"logging_enabled": True}


@router.post("/{printer_id}/logging/disable")
async def disable_mqtt_logging(
    printer_id: int,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Disable MQTT message logging for a printer."""
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    success = printer_manager.enable_logging(printer_id, False)
    if not success:
        raise HTTPException(400, "Printer not connected")

    return {"logging_enabled": False}


@router.get("/{printer_id}/logging")
async def get_mqtt_logs(
    printer_id: int,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_READ),
    db: AsyncSession = Depends(get_db),
):
    """Get MQTT message logs for a printer."""
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    logs = printer_manager.get_logs(printer_id)
    return {
        "logging_enabled": printer_manager.is_logging_enabled(printer_id),
        "logs": [
            {
                "timestamp": log.timestamp,
                "topic": log.topic,
                "direction": log.direction,
                "payload": log.payload,
            }
            for log in logs
        ],
    }


@router.delete("/{printer_id}/logging")
async def clear_mqtt_logs(
    printer_id: int,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Clear MQTT message logs for a printer."""
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    printer_manager.clear_logs(printer_id)
    return {"status": "cleared"}


# ============================================
# AMS Drying Endpoints
# ============================================

# The P1 firmware acks `ams_filament_drying` with result: success and then ignores it
# — Bambu's own P1 manual says drying "may only be controlled from the P1S screen"
# (#2533). Refuse the command rather than let the caller believe it landed.
_DRYING_SCREEN_ONLY_DETAIL = drying_preflight.SCREEN_ONLY_DETAIL


@router.post("/{printer_id}/drying/start")
async def start_drying(
    printer_id: int,
    ams_id: int,
    temp: int = 45,
    duration: int = 4,
    filament: str = "",
    rotate_tray: bool = False,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Send AMS drying start command. temp=45-85, duration=hours."""
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    # Server-side guard: reject if this model/firmware doesn't support drying
    live_state = printer_manager.get_status(printer_id)
    firmware = live_state.firmware_version if live_state else None
    unsupported = drying_preflight.check_drying_supported(printer.model, firmware)
    if unsupported:
        raise HTTPException(400, unsupported)

    if temp < 45 or temp > 85:
        raise HTTPException(400, "Temperature must be 45-85°C")
    if duration < 1 or duration > 24:
        raise HTTPException(400, "Duration must be 1-24 hours")

    # Inspect the live AMS unit: surface blocking dry_sf_reasons (otherwise the
    # firmware silently ignores the command — #971) and backfill an empty
    # filament field from the first loaded tray so the printer doesn't reject
    # the payload.
    target_ams = drying_preflight.find_ams_unit(live_state, ams_id)
    blocking = drying_preflight.blocking_reason_codes(target_ams)
    if blocking:
        # Same pick the scheduled path makes, so both describe one blocked AMS
        # the same way rather than differing on which code the firmware listed
        # first.
        raise HTTPException(
            409, drying_preflight.DRY_SF_REASON_MESSAGES[drying_preflight.primary_reason_code(blocking)]
        )
    filament = drying_preflight.resolve_filament(target_ams, filament)

    success = printer_manager.send_drying_command(
        printer_id, ams_id, temp, duration, mode=1, filament=filament, rotate_tray=rotate_tray
    )
    if not success:
        raise HTTPException(400, "Printer not connected")
    return {"status": "drying_started", "ams_id": ams_id, "temp": temp, "duration": duration}


@router.post("/{printer_id}/drying/stop")
async def stop_drying(
    printer_id: int,
    ams_id: int,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Send AMS drying stop command."""
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    # Screen-only models ignore stop just as they ignore start — a cycle running on a
    # P1S was started at the printer and has to be ended there too (#2533).
    if drying_screen_only(printer.model):
        raise HTTPException(400, _DRYING_SCREEN_ONLY_DETAIL)

    success = printer_manager.send_drying_command(printer_id, ams_id, temp=0, duration=0, mode=0)
    if not success:
        raise HTTPException(400, "Printer not connected")

    # A cycle the user stopped by hand tells us nothing about whether drying can
    # move the humidity reading, so it must not count towards the auto-drying
    # suspension (#2770). Imported here rather than at module scope to keep the
    # existing routes/scheduler import direction.
    from backend.app.services.print_scheduler import scheduler as print_scheduler

    print_scheduler.forget_auto_dry_cycle(printer_id, ams_id)

    return {"status": "drying_stopped", "ams_id": ams_id}


# ============================================
# Print Options (AI Detection) Endpoints
# ============================================


@router.post("/{printer_id}/print-options")
async def set_print_option(
    printer_id: int,
    module_name: str,
    enabled: bool,
    print_halt: bool = True,
    sensitivity: str = "medium",
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Set an AI detection / print option on the printer.

    Valid module_name values:
    - spaghetti_detector: Spaghetti detection
    - first_layer_inspector: First layer inspection
    - printing_monitor: AI print quality monitoring
    - buildplate_marker_detector: Build plate marker detection
    - allow_skip_parts: Allow skipping failed parts
    """
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    client = printer_manager.get_client(printer_id)
    if not client or not client.state.connected:
        raise HTTPException(400, "Printer not connected")

    # Validate module_name
    valid_modules = [
        "spaghetti_detector",
        "first_layer_inspector",
        "printing_monitor",
        "buildplate_marker_detector",
        "allow_skip_parts",
        "pileup_detector",
        "clump_detector",
        "airprint_detector",
        "auto_recovery_step_loss",
    ]
    if module_name not in valid_modules:
        raise HTTPException(400, f"Invalid module_name. Must be one of: {valid_modules}")

    # Validate sensitivity
    valid_sensitivities = ["low", "medium", "high", "never_halt"]
    if sensitivity not in valid_sensitivities:
        raise HTTPException(400, f"Invalid sensitivity. Must be one of: {valid_sensitivities}")

    success = client.set_xcam_option(
        module_name=module_name,
        enabled=enabled,
        print_halt=print_halt,
        sensitivity=sensitivity,
    )

    if not success:
        raise HTTPException(500, "Failed to send command to printer")

    return {
        "success": True,
        "module_name": module_name,
        "enabled": enabled,
        "print_halt": print_halt,
        "sensitivity": sensitivity,
    }


@router.post("/{printer_id}/ams-backup")
async def set_ams_backup(
    printer_id: int,
    enabled: bool,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Toggle AMS Filament Backup (auto-switch to a backup spool when one runs out)."""
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    client = printer_manager.get_client(printer_id)
    if not client or not client.state.connected:
        raise HTTPException(400, "Printer not connected")

    success = client.set_ams_filament_backup(enabled)
    if not success:
        raise HTTPException(500, "Failed to send command to printer")

    return {"success": True, "ams_filament_backup": enabled}


@router.get("/{printer_id}/inventory-remain")
async def get_inventory_remain(
    printer_id: int,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_READ),
    db: AsyncSession = Depends(get_db),
):
    """Per-globalTrayId remaining grams for slots bound to an inventory spool.

    Mirrors `_build_inventory_remain_overrides` server-side so the PrintModal
    client can apply the same two-tier "Prefer Lowest Remaining Filament" sort
    the dispatcher uses (#1766). Works for both internal inventory and
    Spoolman; unbound slots are absent from the map (client falls back to the
    printer's MQTT `remain` for those).

    `slot_materials` carries the same bindings with their material identity and
    extruder side attached, which is what the modal's pre-flight filament check
    needs to pool spools under AMS Filament Backup the way the dispatcher does.
    It is deliberately server-computed: the identity rule lives in
    `filament_deficit`, and a client-side reimplementation of it is exactly how
    the modal came to block prints the dispatcher would have accepted. Unlike
    `inventory_remain_g` it covers every binding, not just currently-loaded
    slots — again matching what the dispatcher pools.
    """
    from backend.app.services.filament_deficit import build_slot_materials
    from backend.app.services.print_scheduler import PrintScheduler

    state = printer_manager.get_status(printer_id)
    if not state:
        return {"inventory_remain_g": {}, "slot_materials": []}

    scheduler = PrintScheduler()
    loaded = scheduler._build_loaded_filaments(state)
    overrides = await scheduler._build_inventory_remain_overrides(db, printer_id, loaded)
    slot_materials = await build_slot_materials(db, printer_id)
    return {
        "inventory_remain_g": {str(k): v for k, v in overrides.items()},
        "slot_materials": [s.to_dict() for s in slot_materials],
    }


# ============================================
# Calibration
# ============================================


@router.post("/{printer_id}/calibration")
async def start_calibration(
    printer_id: int,
    bed_leveling: bool = False,
    vibration: bool = False,
    motor_noise: bool = False,
    nozzle_offset: bool = False,
    high_temp_heatbed: bool = False,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Start printer calibration with selected options.

    At least one option must be selected.

    Options:
    - 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
    """
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    client = printer_manager.get_client(printer_id)
    if not client or not client.state.connected:
        raise HTTPException(400, "Printer not connected")

    # Check that at least one option is selected
    if not any([bed_leveling, vibration, motor_noise, nozzle_offset, high_temp_heatbed]):
        raise HTTPException(400, "At least one calibration option must be selected")

    success = client.start_calibration(
        bed_leveling=bed_leveling,
        vibration=vibration,
        motor_noise=motor_noise,
        nozzle_offset=nozzle_offset,
        high_temp_heatbed=high_temp_heatbed,
    )

    if not success:
        raise HTTPException(500, "Failed to send calibration command to printer")

    return {
        "success": True,
        "bed_leveling": bed_leveling,
        "vibration": vibration,
        "motor_noise": motor_noise,
        "nozzle_offset": nozzle_offset,
        "high_temp_heatbed": high_temp_heatbed,
    }


# ============================================================================
# Slot Preset Mapping Endpoints
# ============================================================================


def _slot_preset_key(ams_id: int, tray_id: int) -> int:
    # Mirrors frontend getGlobalTrayId (amsHelpers.ts): AMS-HT (128-135) is keyed
    # by ams_id since each unit has a single slot and shares its global ID with
    # the unit itself. Regular AMS and external (255) use ams_id*4+tray_id.
    if 128 <= ams_id <= 135:
        return ams_id
    return ams_id * 4 + tray_id


@router.get("/{printer_id}/slot-presets")
async def get_slot_presets(
    printer_id: int,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_READ),
    db: AsyncSession = Depends(get_db),
):
    """Get all saved slot-to-preset mappings for a printer."""
    result = await db.execute(select(SlotPresetMapping).where(SlotPresetMapping.printer_id == printer_id))
    mappings = result.scalars().all()

    return {
        _slot_preset_key(mapping.ams_id, mapping.tray_id): {
            "ams_id": mapping.ams_id,
            "tray_id": mapping.tray_id,
            "preset_id": mapping.preset_id,
            "preset_name": mapping.preset_name,
        }
        for mapping in mappings
    }


@router.get("/{printer_id}/slot-presets/{ams_id}/{tray_id}")
async def get_slot_preset(
    printer_id: int,
    ams_id: int,
    tray_id: int,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_READ),
    db: AsyncSession = Depends(get_db),
):
    """Get the saved preset for a specific slot."""
    result = await db.execute(
        select(SlotPresetMapping).where(
            SlotPresetMapping.printer_id == printer_id,
            SlotPresetMapping.ams_id == ams_id,
            SlotPresetMapping.tray_id == tray_id,
        )
    )
    mapping = result.scalar_one_or_none()

    if not mapping:
        return None

    return {
        "ams_id": mapping.ams_id,
        "tray_id": mapping.tray_id,
        "preset_id": mapping.preset_id,
        "preset_name": mapping.preset_name,
    }


@router.put("/{printer_id}/slot-presets/{ams_id}/{tray_id}")
async def save_slot_preset(
    printer_id: int,
    ams_id: int,
    tray_id: int,
    preset_id: str,
    preset_name: str,
    preset_source: str = "cloud",
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_UPDATE),
    db: AsyncSession = Depends(get_db),
):
    """Save a preset mapping for a specific slot."""
    # Check printer exists
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    if not result.scalar_one_or_none():
        raise HTTPException(404, "Printer not found")

    # Check for existing mapping
    result = await db.execute(
        select(SlotPresetMapping).where(
            SlotPresetMapping.printer_id == printer_id,
            SlotPresetMapping.ams_id == ams_id,
            SlotPresetMapping.tray_id == tray_id,
        )
    )
    mapping = result.scalar_one_or_none()

    if mapping:
        # Update existing
        mapping.preset_id = preset_id
        mapping.preset_name = preset_name
        mapping.preset_source = preset_source
    else:
        # Create new
        mapping = SlotPresetMapping(
            printer_id=printer_id,
            ams_id=ams_id,
            tray_id=tray_id,
            preset_id=preset_id,
            preset_name=preset_name,
            preset_source=preset_source,
        )
        db.add(mapping)

    await db.commit()
    await db.refresh(mapping)

    return {
        "ams_id": mapping.ams_id,
        "tray_id": mapping.tray_id,
        "preset_id": mapping.preset_id,
        "preset_name": mapping.preset_name,
        "preset_source": mapping.preset_source,
    }


@router.delete("/{printer_id}/slot-presets/{ams_id}/{tray_id}")
async def delete_slot_preset(
    printer_id: int,
    ams_id: int,
    tray_id: int,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_UPDATE),
    db: AsyncSession = Depends(get_db),
):
    """Delete a saved preset mapping for a slot."""
    result = await db.execute(
        select(SlotPresetMapping).where(
            SlotPresetMapping.printer_id == printer_id,
            SlotPresetMapping.ams_id == ams_id,
            SlotPresetMapping.tray_id == tray_id,
        )
    )
    mapping = result.scalar_one_or_none()

    if mapping:
        await db.delete(mapping)
        await db.commit()

    return {"success": True}


@router.post("/{printer_id}/slots/{ams_id}/{tray_id}/configure")
async def configure_ams_slot(
    printer_id: int,
    ams_id: int,
    tray_id: int,
    tray_info_idx: str = Query(...),
    tray_type: str = Query(...),
    tray_sub_brands: str = Query(...),
    tray_color: str = Query(...),
    nozzle_temp_min: int = Query(...),
    nozzle_temp_max: int = Query(...),
    cali_idx: int = Query(-1),
    nozzle_diameter: str = Query("0.4"),
    setting_id: str = Query(""),
    kprofile_filament_id: str = Query(""),
    kprofile_setting_id: str = Query(""),
    k_value: float = Query(0.0),
    db: AsyncSession = Depends(get_db),
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
):
    """Configure an AMS slot with a specific filament setting and K profile.

    This sends two commands to the printer:
    1. ams_filament_setting - sets filament type, color, temperature
    2. extrusion_cali_sel - sets the K profile (pressure advance value)

    Args:
        printer_id: Database ID of the printer
        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") or user preset ID
        tray_type: Filament type (e.g., "PLA", "PETG")
        tray_sub_brands: Sub-brand/profile 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
        cali_idx: K profile calibration index (-1 for default 0.020)
        nozzle_diameter: Nozzle diameter string (e.g., "0.4")
        setting_id: Full setting ID with version (e.g., "GFSL05_07") - optional
        kprofile_filament_id: K profile's filament_id for proper K profile linking
        k_value: Direct K value to set (0.0 to skip direct K value setting)
    """
    logger = logging.getLogger(__name__)
    logger.info("[configure_ams_slot] printer_id=%s, ams_id=%s, tray_id=%s", printer_id, ams_id, tray_id)
    logger.info(
        f"[configure_ams_slot] tray_info_idx={tray_info_idx!r}, tray_type={tray_type!r}, tray_sub_brands={tray_sub_brands!r}"
    )
    logger.info(
        f"[configure_ams_slot] setting_id={setting_id!r}, kprofile_filament_id={kprofile_filament_id!r}, kprofile_setting_id={kprofile_setting_id!r}"
    )

    # Get MQTT client for this printer
    client = printer_manager.get_client(printer_id)
    if not client:
        raise HTTPException(status_code=400, detail="Printer not connected")

    # Resolve tray_info_idx for the MQTT command.
    # Priority:
    #   1. Use the provided tray_info_idx if set (including cloud-synced
    #      custom presets like PFUS* / P*).
    #   2. Reuse the slot's existing tray_info_idx if it's a specific
    #      (non-generic) preset for the same material.
    #   3. Fall back to a generic Bambu filament ID.
    _GENERIC_FILAMENT_IDS = {
        "PLA": "GFL99",
        "PETG": "GFG99",
        "ABS": "GFB99",
        "ASA": "GFB98",
        "PC": "GFC99",
        "PA": "GFN99",
        "NYLON": "GFN99",
        "TPU": "GFU99",
        "PVA": "GFS99",
        "HIPS": "GFS98",
        "PLA-CF": "GFL98",
        "PETG-CF": "GFG98",
        "PA-CF": "GFN98",
        "PETG HF": "GFG96",
    }
    _GENERIC_ID_VALUES = set(_GENERIC_FILAMENT_IDS.values())
    effective_tray_info_idx = tray_info_idx

    if not tray_info_idx:
        # No preset provided — try slot reuse or generic fallback
        current_tray_info_idx = ""
        current_tray_type = ""
        state = printer_manager.get_status(printer_id)
        if state and state.raw_data:
            from backend.app.api.routes.inventory import _find_tray_in_ams_data

            if ams_id == 255:
                vt_tray = state.raw_data.get("vt_tray") or []
                ext_id = tray_id + 254
                for vt in vt_tray:
                    if isinstance(vt, dict) and int(vt.get("id", 254)) == ext_id:
                        current_tray_info_idx = vt.get("tray_info_idx", "")
                        current_tray_type = vt.get("tray_type", "")
                        break
            else:
                ams_data = state.raw_data.get("ams", {})
                ams_list = (
                    ams_data.get("ams", [])
                    if isinstance(ams_data, dict)
                    else ams_data
                    if isinstance(ams_data, list)
                    else []
                )
                cur_tray = _find_tray_in_ams_data(ams_list, ams_id, tray_id)
                if cur_tray:
                    current_tray_info_idx = cur_tray.get("tray_info_idx", "")
                    current_tray_type = cur_tray.get("tray_type", "")

        if (
            current_tray_info_idx
            and current_tray_info_idx not in _GENERIC_ID_VALUES
            and current_tray_type
            and current_tray_type.upper() == tray_type.upper()
        ):
            logger.info(
                "[configure_ams_slot] Reusing slot's existing tray_info_idx=%r (same material %r)",
                current_tray_info_idx,
                tray_type,
            )
            effective_tray_info_idx = current_tray_info_idx
        elif tray_type:
            material = tray_type.upper().strip()
            generic = (
                _GENERIC_FILAMENT_IDS.get(material)
                or _GENERIC_FILAMENT_IDS.get(material.split("-")[0].split(" ")[0])
                or ""
            )
            if generic:
                logger.info("[configure_ams_slot] Falling back to generic %r for material %r", generic, tray_type)
                effective_tray_info_idx = generic

    # Send filament setting + K-profile commands
    filament_id_for_kprofile = kprofile_filament_id if kprofile_filament_id else effective_tray_info_idx

    # Realign the slot's filament context to the K-profile's calibration
    # context. The printer's calibration table is keyed by (filament_id,
    # cali_idx) — so for the cali_idx selected via extrusion_cali_sel to
    # actually stick to the slot, ams_filament_setting must declare the
    # slot under the SAME filament_id.
    #
    # Without this, configure_ams_slot would send:
    #   ams_filament_setting → tray_info_idx=GFL99 (generic from material)
    #   extrusion_cali_sel    → filament_id=P4d64437 (kp's preset)
    # ...and the cali_idx would silently be dropped to default because the
    # slot's filament context (GFL99) doesn't match the kp's (P4d64437).
    #
    # This realignment fires only when the kp is targeted at a different
    # preset than the user's filament selection AND the kp's preset is a
    # valid tray_info_idx (GF* official, P* local — not PFUS* cloud-user
    # which the slicer rejects in tray_info_idx).
    effective_setting_id = setting_id
    if (
        kprofile_filament_id
        and kprofile_filament_id != effective_tray_info_idx
        and not kprofile_filament_id.startswith("PFUS")
    ):
        logger.info(
            "[configure_ams_slot] realigning slot filament context to kp: tray_info_idx %r → %r, setting_id %r → %r",
            effective_tray_info_idx,
            kprofile_filament_id,
            setting_id,
            kprofile_setting_id or setting_id,
        )
        effective_tray_info_idx = kprofile_filament_id
        if kprofile_setting_id:
            effective_setting_id = kprofile_setting_id

    # Back-fill setting_id from the resolved filament id when the client sent
    # none. Built-in / local / Orca-generic presets in the Configure AMS Slot
    # modal leave setting_id empty (they carry only a GF* tray_info_idx), and
    # the printer treats a filament-id-without-setting-id slot as half
    # configured: it shows the new material briefly, then reverts to its
    # previously stored profile (#2604). This mirrors the derivation the
    # inventory/assignment path already does (inventory.py). filament_id_to_
    # setting_id leaves P* user presets and already-GFS* values unchanged, so
    # only the empty-setting_id generic paths are affected.
    if effective_tray_info_idx and not effective_setting_id:
        effective_setting_id = filament_id_to_setting_id(effective_tray_info_idx)

    # Always send ams_set_filament_setting — the user explicitly clicked
    # "Configure Slot", so honor that.  Previous versions skipped this for
    # RFID-tagged slots to preserve the slicer eye icon, but printers cache
    # stale tag_uid/tray_uuid after a BL spool is removed, causing the check
    # to false-positive on non-RFID slots and silently drop the command.
    success = client.ams_set_filament_setting(
        ams_id=ams_id,
        tray_id=tray_id,
        tray_info_idx=effective_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,
        setting_id=effective_setting_id,
    )

    if not success:
        raise HTTPException(status_code=500, detail="Failed to send filament configuration command")

    # Method 1: Select existing calibration profile by cali_idx
    # Do NOT include setting_id — BambuStudio never sends it in extrusion_cali_sel,
    # and including it causes the firmware to mislink the profile on X1C/P1S.
    client.extrusion_cali_sel(
        ams_id=ams_id,
        tray_id=tray_id,
        cali_idx=cali_idx,
        filament_id=filament_id_for_kprofile,
        nozzle_diameter=nozzle_diameter,
    )

    # Method 2: Only send extrusion_cali_set when NO existing profile was selected
    # (cali_idx == -1). When cali_idx >= 0, extrusion_cali_sel already selected the
    # correct profile. Sending extrusion_cali_set with the same cali_idx would MODIFY
    # the existing profile's metadata (extruder_id, nozzle_id, name, setting_id),
    # corrupting it — e.g., overwriting a High Flow extruder 1 profile with
    # hardcoded extruder_id=0 and nozzle_id=HS00.
    if k_value > 0 and cali_idx < 0:
        # Calculate global tray ID for extrusion_cali_set
        if ams_id <= 3:
            global_tray_id = ams_id * 4 + tray_id
        elif ams_id >= 128 and ams_id <= 135:
            global_tray_id = (ams_id - 128) * 4 + tray_id
        else:
            global_tray_id = tray_id

        client.extrusion_cali_set(
            tray_id=global_tray_id,
            k_value=k_value,
            nozzle_diameter=nozzle_diameter,
            nozzle_temp=nozzle_temp_max,
            filament_id=filament_id_for_kprofile,
            setting_id=kprofile_setting_id or "",
            name=tray_sub_brands or "",
            cali_idx=cali_idx,
        )

    # Persist the user's K-profile choice so it survives RFID re-reads and
    # session restarts. Pre-Phase-13 this was ephemeral — the MQTT command
    # took effect on the printer but bambuddy never recorded it, so the next
    # `_apply_pa_after_refresh` cycle had no stored profile to re-assert.
    if cali_idx >= 0:
        try:
            from sqlalchemy.orm import selectinload

            from backend.app.models.spool_assignment import SpoolAssignment
            from backend.app.models.spool_k_profile import SpoolKProfile
            from backend.app.models.spoolman_k_profile import SpoolmanKProfile
            from backend.app.models.spoolman_slot_assignment import SpoolmanSlotAssignment

            # Resolve the slot's extruder for the K-profile match key. On a
            # Filament Track Switch machine this comes from the AMS's inlet
            # binding, because every unit reports extruder 0xE there — without
            # that, the `else 0` below filed every profile under the right-hand
            # nozzle and a left-nozzle calibration was stored as a right one.
            slot_state = printer_manager.get_status(printer_id)
            resolved_extruder = slot_extruder(
                ams_id,
                tray_id,
                slot_state.ams_extruder_map if slot_state else None,
                slot_state.ams_switch_inlet if slot_state else None,
            )
            # Still 0 when nothing is known, which is right for a single-nozzle
            # printer — the resolver only returns None when it genuinely cannot
            # tell, and on those machines extruder 0 is the only one there is.
            kp_extruder = resolved_extruder if resolved_extruder is not None else 0

            # Spoolman SlotAssignment first — has UniqueConstraint, idempotent.
            sm_result = await db.execute(
                select(SpoolmanSlotAssignment).where(
                    SpoolmanSlotAssignment.printer_id == printer_id,
                    SpoolmanSlotAssignment.ams_id == ams_id,
                    SpoolmanSlotAssignment.tray_id == tray_id,
                )
            )
            sm_assignment = sm_result.scalar_one_or_none()
            if sm_assignment:
                existing = await db.execute(
                    select(SpoolmanKProfile).where(
                        SpoolmanKProfile.spoolman_spool_id == sm_assignment.spoolman_spool_id,
                        SpoolmanKProfile.printer_id == printer_id,
                        SpoolmanKProfile.extruder == kp_extruder,
                        SpoolmanKProfile.nozzle_diameter == nozzle_diameter,
                    )
                )
                kp = existing.scalar_one_or_none()
                if kp:
                    kp.cali_idx = cali_idx
                    kp.k_value = k_value or 0.0
                    kp.setting_id = kprofile_setting_id or None
                    kp.name = tray_sub_brands or None
                else:
                    db.add(
                        SpoolmanKProfile(
                            spoolman_spool_id=sm_assignment.spoolman_spool_id,
                            printer_id=printer_id,
                            extruder=kp_extruder,
                            nozzle_diameter=nozzle_diameter,
                            k_value=k_value or 0.0,
                            name=tray_sub_brands or None,
                            cali_idx=cali_idx,
                            setting_id=kprofile_setting_id or None,
                        )
                    )
                await db.commit()
                logger.info(
                    "[configure_ams_slot] Persisted Spoolman K-profile spool=%d printer=%d ams=%d tray=%d cali_idx=%d",
                    sm_assignment.spoolman_spool_id,
                    printer_id,
                    ams_id,
                    tray_id,
                    cali_idx,
                )
            else:
                # Local SpoolAssignment + SpoolKProfile (no UNIQUE — use .first())
                local_result = await db.execute(
                    select(SpoolAssignment)
                    .options(selectinload(SpoolAssignment.spool))
                    .where(
                        SpoolAssignment.printer_id == printer_id,
                        SpoolAssignment.ams_id == ams_id,
                        SpoolAssignment.tray_id == tray_id,
                    )
                )
                local_assignment = local_result.scalar_one_or_none()
                if local_assignment and local_assignment.spool:
                    existing = await db.execute(
                        select(SpoolKProfile).where(
                            SpoolKProfile.spool_id == local_assignment.spool.id,
                            SpoolKProfile.printer_id == printer_id,
                            SpoolKProfile.extruder == kp_extruder,
                            SpoolKProfile.nozzle_diameter == nozzle_diameter,
                        )
                    )
                    # SpoolKProfile has no unique constraint on this tuple, so
                    # multiple rows could theoretically exist (shouldn't, but
                    # don't crash if they do). Update the first match, leave
                    # any duplicates alone.
                    kp = existing.scalars().first()
                    if kp:
                        kp.cali_idx = cali_idx
                        kp.k_value = k_value or 0.0
                        kp.setting_id = kprofile_setting_id or None
                        kp.name = tray_sub_brands or None
                    else:
                        db.add(
                            SpoolKProfile(
                                spool_id=local_assignment.spool.id,
                                printer_id=printer_id,
                                extruder=kp_extruder,
                                nozzle_diameter=nozzle_diameter,
                                k_value=k_value or 0.0,
                                name=tray_sub_brands or None,
                                cali_idx=cali_idx,
                                setting_id=kprofile_setting_id or None,
                            )
                        )
                    await db.commit()
                    logger.info(
                        "[configure_ams_slot] Persisted local K-profile spool=%d printer=%d ams=%d tray=%d cali_idx=%d",
                        local_assignment.spool.id,
                        printer_id,
                        ams_id,
                        tray_id,
                        cali_idx,
                    )
        except Exception:
            # MQTT command was already sent successfully — DB persist is best-effort.
            logger.exception(
                "[configure_ams_slot] Failed to persist K-profile (printer=%d ams=%d tray=%d cali_idx=%d)",
                printer_id,
                ams_id,
                tray_id,
                cali_idx,
            )
            try:
                await db.rollback()
            except Exception:
                pass

    # Register a read-back verification (#2582) so the tray telemetry that the
    # status push below returns can confirm the printer accepted this manual
    # slot configuration. Mirrors the inventory/assignment path.
    client.register_assignment_verification(
        ams_id=ams_id,
        tray_id=tray_id,
        tray_info_idx=effective_tray_info_idx,
        tray_color=tray_color,
        cali_idx=cali_idx,
    )

    # Request fresh status push from printer so frontend gets updated data via WebSocket
    logger.info("[configure_ams_slot] Requesting status update from printer")
    update_result = client.request_status_update()
    logger.info("[configure_ams_slot] Status update request result: %s", update_result)

    return {
        "success": True,
        "message": f"Configured AMS {ams_id} tray {tray_id} with {tray_sub_brands}",
    }


@router.post("/{printer_id}/ams/{ams_id}/tray/{tray_id}/reset")
async def reset_ams_slot(
    printer_id: int,
    ams_id: int,
    tray_id: int,
    db: AsyncSession = Depends(get_db),
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
):
    """Reset an AMS slot to empty/unconfigured state.

    This clears the filament configuration from the slot.
    """
    # Get MQTT client for this printer
    client = printer_manager.get_client(printer_id)
    if not client:
        raise HTTPException(status_code=400, detail="Printer not connected")

    # Reset the slot
    success = client.reset_ams_slot(ams_id=ams_id, tray_id=tray_id)

    if not success:
        raise HTTPException(status_code=500, detail="Failed to send reset command")

    # Also delete any saved slot preset mapping
    result = await db.execute(
        select(SlotPresetMapping).where(
            SlotPresetMapping.printer_id == printer_id,
            SlotPresetMapping.ams_id == ams_id,
            SlotPresetMapping.tray_id == tray_id,
        )
    )
    mapping = result.scalar_one_or_none()
    if mapping:
        await db.delete(mapping)
        await db.commit()

    # Request fresh status push from printer so frontend gets updated data via WebSocket
    client.request_status_update()

    return {
        "success": True,
        "message": f"Reset AMS {ams_id} tray {tray_id}",
    }


@router.get("/{printer_id}/ams-labels")
async def get_ams_labels(
    printer_id: int,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_READ),
    db: AsyncSession = Depends(get_db),
):
    """Get all user-defined AMS labels for a printer, keyed by AMS unit ID.

    Labels are stored by AMS serial number.  This endpoint resolves the current
    serial-to-ams_id mapping from the live printer state so the response is still
    keyed by ams_id for UI compatibility.
    """
    # Build serial -> ams_id map from live printer state
    serial_to_ams_id: dict[str, int] = {}
    state = printer_manager.get_status(printer_id)
    if state and state.raw_data:
        for ams_unit in state.raw_data.get("ams", []):
            sn = str(ams_unit.get("sn") or ams_unit.get("serial_number") or "")
            if sn:
                serial_to_ams_id[sn] = int(ams_unit.get("id", 0))

    # Collect all known serials for this printer (live + synthetic fallback keys)
    serials_to_query = set(serial_to_ams_id.keys())

    # Fetch labels for all known serials
    labels: dict[int, str] = {}
    if serials_to_query:
        result = await db.execute(select(AmsLabel).where(AmsLabel.ams_serial_number.in_(serials_to_query)))
        for lbl in result.scalars().all():
            aid = serial_to_ams_id.get(lbl.ams_serial_number)
            if aid is not None:
                labels[aid] = lbl.label

    # Also fetch labels stored under synthetic keys for this printer (backward compat)
    # Collect all synthetic keys first, then query with a single IN clause.
    if state and state.raw_data:
        synthetic_key_to_aid: dict[str, int] = {
            f"p{printer_id}a{int(ams_unit.get('id', 0))}": int(ams_unit.get("id", 0))
            for ams_unit in state.raw_data.get("ams", [])
            if int(ams_unit.get("id", 0)) not in labels
        }
        if synthetic_key_to_aid:
            result = await db.execute(
                select(AmsLabel).where(AmsLabel.ams_serial_number.in_(synthetic_key_to_aid.keys()))
            )
            for lbl in result.scalars().all():
                aid = synthetic_key_to_aid.get(lbl.ams_serial_number)
                if aid is not None:
                    labels[aid] = lbl.label

    return labels


@router.put("/{printer_id}/ams-labels/{ams_id}")
async def save_ams_label(
    printer_id: int,
    ams_id: int,
    body: AmsLabelBody,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_UPDATE),
    db: AsyncSession = Depends(get_db),
):
    """Create or update the friendly name for a specific AMS unit.

    When ``ams_serial`` is provided the label is stored under that serial number so
    it survives the AMS being moved to a different printer.  When it is absent (e.g.
    older firmware that does not report a serial) a synthetic key based on the
    printer_id and ams_id is used as a fallback.
    """
    # Verify printer exists
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    if not result.scalar_one_or_none():
        raise HTTPException(404, "Printer not found")

    # Determine the serial key to store under
    stripped = body.ams_serial.strip() if body.ams_serial else ""
    serial_key = stripped if stripped else f"p{printer_id}a{ams_id}"

    result = await db.execute(select(AmsLabel).where(AmsLabel.ams_serial_number == serial_key))
    existing = result.scalar_one_or_none()

    if existing:
        existing.label = body.label
        existing.ams_id = ams_id
    else:
        db.add(AmsLabel(ams_serial_number=serial_key, ams_id=ams_id, label=body.label))

    await db.commit()
    return {"ams_id": ams_id, "label": body.label}


@router.delete("/{printer_id}/ams-labels/{ams_id}")
async def delete_ams_label(
    printer_id: int,
    ams_id: int,
    ams_serial: str = Query(default="", max_length=50),
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_UPDATE),
    db: AsyncSession = Depends(get_db),
):
    """Delete the friendly name for a specific AMS unit, reverting to the auto label."""
    stripped = ams_serial.strip() if ams_serial else ""
    serial_key = stripped if stripped else f"p{printer_id}a{ams_id}"

    result = await db.execute(select(AmsLabel).where(AmsLabel.ams_serial_number == serial_key))
    existing = result.scalar_one_or_none()

    if existing:
        await db.delete(existing)
        await db.commit()

    return {"success": True}


@router.post("/{printer_id}/debug/simulate-print-complete")
async def debug_simulate_print_complete(
    printer_id: int,
    db: AsyncSession = Depends(get_db),
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
):
    """DEBUG: Simulate print completion to test freeze behavior.

    This triggers the same code path as a real print completion,
    without needing to wait for an actual print to finish.
    """
    from backend.app.main import _active_prints, on_print_complete
    from backend.app.models.archive import PrintArchive

    # Get the most recent archive for this printer
    result = await db.execute(
        select(PrintArchive)
        .where(PrintArchive.printer_id == printer_id)
        .order_by(PrintArchive.created_at.desc())
        .limit(1)
    )
    archive = result.scalar_one_or_none()

    if not archive:
        raise HTTPException(status_code=404, detail="No archives found for this printer")

    # Register this archive as "active" so on_print_complete can find it
    filename = archive.file_path.split("/")[-1] if archive.file_path else "test.3mf"
    subtask_name = archive.print_name or "Test Print"
    _active_prints[(printer_id, filename)] = archive.id
    _active_prints[(printer_id, subtask_name)] = archive.id

    # Simulate print completion data
    data = {
        "status": "completed",
        "filename": filename,
        "subtask_name": subtask_name,
        "timelapse_was_active": False,
    }

    logger.info("Simulating print complete for printer %s, archive %s", printer_id, archive.id)

    # Call the actual on_print_complete handler
    await on_print_complete(printer_id, data)

    return {"success": True, "archive_id": archive.id, "message": "Print completion simulated"}


# =============================================================================
# Print Control Endpoints
# =============================================================================


@router.post("/{printer_id}/print/stop")
async def stop_print(
    printer_id: int,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Stop/cancel the current print job."""
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    client = printer_manager.get_client(printer_id)
    if not client:
        raise HTTPException(400, "Printer not connected")

    success = client.stop_print()
    if not success:
        raise HTTPException(500, "Failed to stop print")

    # Mark this printer as user-stopped so on_print_complete reclassifies
    # the resulting "failed"/"aborted" MQTT status as "cancelled" — otherwise
    # the HMS heuristic in _dispatch_archive_update mislabels user-cancels
    # (e.g. the H2D's cancel-sequence module-0x0C HMS) as "Layer shift".
    try:
        from backend.app.main import mark_printer_stopped_by_user

        mark_printer_stopped_by_user(printer_id)
    except Exception as _mark_err:
        logger.warning("Failed to mark printer %s as user-stopped: %s", printer_id, _mark_err)

    return {"success": True, "message": "Print stop command sent"}


@router.post("/{printer_id}/clear-plate")
async def clear_plate(
    printer_id: int,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CLEAR_PLATE),
    db: AsyncSession = Depends(get_db),
):
    """Acknowledge that the build plate has been cleared after a finished/failed print.

    Sets a plate-cleared flag so the scheduler can start the next queued print.
    No MQTT command is sent to the printer — the scheduler's start_print command
    will override the FINISH/FAILED state when it sends the next job.
    """
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    # Deliberately NOT gated on the printer being connected. Acknowledging the plate
    # only mutates Bambuddy-side state — no MQTT command is sent — and with Auto Power
    # Off the normal end-of-print state is exactly this: gate up, printer powered down.
    # The guard this replaces was inherited from the sibling stop/pause/resume handlers,
    # where reaching the printer IS required, and left farms with no way to release the
    # gate short of powering each printer back on by hand (#2864).

    # Accept the acknowledgment whenever the printer is awaiting it — not only when the
    # reported state is FINISH/FAILED. After a power cycle the printer boots into IDLE
    # but the awaiting flag persists, and the user still needs a way to ack it (#961).
    state = printer_manager.get_status(printer_id)
    awaiting = printer_manager.is_awaiting_plate_clear(printer_id)
    if not awaiting and (not state or state.state not in ("FINISH", "FAILED")):
        raise HTTPException(
            400,
            f"Printer is not awaiting plate-clear acknowledgment (state={state.state if state else 'unknown'})",
        )

    printer_manager.set_awaiting_plate_clear(printer_id, False)

    return {"success": True, "message": "Plate cleared, next print will start shortly"}


@router.post("/{printer_id}/print/pause")
async def pause_print(
    printer_id: int,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Pause the current print job."""
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    client = printer_manager.get_client(printer_id)
    if not client:
        raise HTTPException(400, "Printer not connected")

    success = client.pause_print()
    if not success:
        raise HTTPException(500, "Failed to pause print")

    return {"success": True, "message": "Print pause command sent"}


@router.post("/{printer_id}/print/resume")
async def resume_print(
    printer_id: int,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Resume a paused print job."""
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    client = printer_manager.get_client(printer_id)
    if not client:
        raise HTTPException(400, "Printer not connected")

    success = client.resume_print()
    if not success:
        raise HTTPException(500, "Failed to resume print")

    return {"success": True, "message": "Print resume command sent"}


@router.post("/{printer_id}/print-speed")
async def set_print_speed(
    printer_id: int,
    mode: int = Query(..., description="Speed mode (1=silent, 2=standard, 3=sport, 4=ludicrous)"),
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Set the print speed mode."""
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    client = printer_manager.get_client(printer_id)
    if not client:
        raise HTTPException(400, "Printer not connected")

    success = client.set_print_speed(mode)
    if not success:
        raise HTTPException(500, "Failed to set print speed")

    speed_names = {1: "Silent", 2: "Standard", 3: "Sport", 4: "Ludicrous"}
    return {"success": True, "message": f"Print speed set to {speed_names.get(mode, 'Unknown')}"}


@router.post("/{printer_id}/temperature/nozzle")
async def set_nozzle_temperature(
    printer_id: int,
    target: int = Query(..., ge=0, le=320, description="Target nozzle temperature in Celsius; 0 turns heating off"),
    nozzle: int = Query(0, ge=0, le=1, description="Nozzle/extruder index (0=right/default, 1=left)"),
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Set a nozzle target temperature."""
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    client = printer_manager.get_client(printer_id)
    if not client:
        raise HTTPException(400, "Printer not connected")

    success = client.set_nozzle_temperature(target, nozzle)
    if not success:
        raise HTTPException(500, "Failed to set nozzle temperature")

    return {"success": True, "message": f"Nozzle temperature set to {target}°C"}


@router.post("/{printer_id}/temperature/bed")
async def set_bed_temperature(
    printer_id: int,
    target: int = Query(..., ge=0, le=140, description="Target bed temperature in Celsius; 0 turns heating off"),
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Set the bed target temperature."""
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    client = printer_manager.get_client(printer_id)
    if not client:
        raise HTTPException(400, "Printer not connected")

    success = client.set_bed_temperature(target)
    if not success:
        raise HTTPException(500, "Failed to set bed temperature")

    return {"success": True, "message": f"Bed temperature set to {target}°C"}


@router.post("/{printer_id}/temperature/chamber")
async def set_chamber_temperature(
    printer_id: int,
    target: int = Query(
        ...,
        ge=0,
        le=MAX_CHAMBER_TEMP_C,
        description="Target chamber temperature in Celsius; 0 turns heating off",
    ),
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Set the chamber target temperature.

    Gated on `supports_chamber_heater(model)`: only H2C, H2D, H2D Pro, H2S,
    and X2D have an active chamber heater. Sensor-only models (X1C, X1E,
    P2S) report chamber temp but silently swallow M141, so we 400 here
    rather than send a no-op.
    """
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    if not supports_chamber_heater(printer.model):
        raise HTTPException(400, f"Model {printer.model or 'unknown'} does not have an active chamber heater")

    client = printer_manager.get_client(printer_id)
    if not client:
        raise HTTPException(400, "Printer not connected")

    success = client.set_chamber_temperature(target)
    if not success:
        raise HTTPException(500, "Failed to set chamber temperature")

    return {"success": True, "message": f"Chamber temperature set to {target}°C"}


@router.post("/{printer_id}/fan-speed")
async def set_fan_speed(
    printer_id: int,
    fan: str = Query(..., description="Fan to control: part, aux, aux2 (left aux), or chamber"),
    speed: int = Query(..., ge=0, le=100, description="Fan speed percentage"),
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Set a fan speed by percentage.

    Fan index 10 ("aux2") is the optional left auxiliary part cooling fan on
    P2S/X2D — driven with "M106 P10" exactly like Bambu's official machine
    profile gcode does. It only exists when the printer reports airduct part 10,
    so the request is rejected rather than sending M106 P10 into the void on a
    machine that has no such fan.

    That gate also rejects for the short window between connecting and the
    first airduct push, when nothing is known about the fan yet. The card hides
    the badge over the same window, so there is no control to click; a direct
    API caller gets a 400 and should retry once the status reports the fan.
    """
    fan_ids = {"part": 1, "aux": 2, "chamber": 3, "aux2": 10}
    fan_id = fan_ids.get(fan)
    if fan_id is None:
        raise HTTPException(400, "fan must be 'part', 'aux', 'aux2', or 'chamber'")

    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    client = printer_manager.get_client(printer_id)
    if not client:
        raise HTTPException(400, "Printer not connected")

    # Presence gate for the accessory fan. Without this, aux2 is accepted for
    # every model and an A1 would be sent M106 P10 for a fan it does not have.
    # The UI already hides the badge; this closes the same hole on the API.
    if fan == "aux2" and getattr(client.state, "left_aux_fan_speed", None) is None:
        raise HTTPException(
            400,
            "This printer does not report a left auxiliary fan "
            "(no airduct part 10). The fan is an accessory kit on the P2S "
            "and factory-fitted on the X2D.",
        )

    pwm_speed = round(speed * 255 / 100)
    success = client.set_fan_speed(fan_id, pwm_speed)
    if not success:
        raise HTTPException(500, "Failed to set fan speed")

    # The enclosure fan is called "Exhaust" on P2S/X2D and "Chamber" elsewhere;
    # match whatever the printer card badge shows so the toast agrees with the
    # control the user just clicked.
    fan_names = {
        "part": "Part cooling fan",
        "aux": "Auxiliary fan",
        "aux2": "Left auxiliary fan",
        "chamber": "Exhaust fan" if uses_exhaust_fan_label(printer.model) else "Chamber fan",
    }
    return {"success": True, "message": f"{fan_names[fan]} set to {speed}%"}


@router.post("/{printer_id}/select-extruder")
async def select_extruder(
    printer_id: int,
    extruder: int = Query(..., ge=0, le=1, description="Extruder index (0=right, 1=left)"),
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Select the active extruder/nozzle on dual-nozzle printers."""
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    client = printer_manager.get_client(printer_id)
    if not client:
        raise HTTPException(400, "Printer not connected")

    success = client.select_extruder(extruder)
    if not success:
        raise HTTPException(500, "Failed to select nozzle")

    return {"success": True, "message": f"{'Left' if extruder == 1 else 'Right'} nozzle selected"}


@router.post("/{printer_id}/airduct-mode")
async def set_airduct_mode(
    printer_id: int,
    mode: str = Query(..., description="Airduct mode: 'cooling' or 'heating'"),
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Set the airduct mode (cooling/heating) on supported printers (P2S/H2*)."""
    if mode not in ("cooling", "heating"):
        raise HTTPException(400, "Mode must be 'cooling' or 'heating'")

    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    client = printer_manager.get_client(printer_id)
    if not client:
        raise HTTPException(400, "Printer not connected")

    success = client.set_airduct_mode(mode)
    if not success:
        raise HTTPException(500, "Failed to set airduct mode")

    return {"success": True, "message": f"Airduct mode set to {mode}"}


@router.post("/{printer_id}/chamber-light")
async def set_chamber_light(
    printer_id: int,
    on: bool = Query(..., description="True to turn on, False to turn off"),
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Turn the chamber light on or off."""
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    client = printer_manager.get_client(printer_id)
    if not client:
        raise HTTPException(400, "Printer not connected")

    success = client.set_chamber_light(on)
    if not success:
        raise HTTPException(500, "Failed to control chamber light")

    return {"success": True, "message": f"Chamber light {'on' if on else 'off'}"}


@router.post("/{printer_id}/bed-jog")
async def bed_jog(
    printer_id: int,
    distance: float = Query(
        ...,
        description=(
            "Signed nozzle-bed gap adjustment in mm. Negative = decrease gap "
            '("up" arrow in the UI: bed up on bed-on-Z models, toolhead down '
            "on A1 bed-slingers). Positive = increase gap. The backend "
            "translates this into the right G-code Z sign per printer model."
        ),
    ),
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Adjust the nozzle-bed gap by a relative distance.

    Emits a short G-code sequence via MQTT.

    Soft-endstop policy (#2579). The printer's software travel limits are the
    only thing between a jog button and a bed crash — on Bambu machines the
    physical endstops are homing-only (there is no runtime limit switch in the
    travel path), so once they are disabled nothing stops the move. The old
    code disabled them (``M211 S0``) around every forced jog, and the UI sent
    ``force`` on every jog, so the limits were off on every bed move — that is
    what let a jog drive the nozzle into the bed on all models (#2579). This
    endpoint now emits a **bare relative move and never touches ``M211`` at
    all** — byte-for-byte what the printer's own touchscreen jog sends, which
    stops at the travel limit. Bambuddy no longer disables the firmware's soft
    endstops, and it no longer sends ``M211 S1`` either: that was an unverified
    attempt to re-enable a printer left disabled by an older build, and on real
    hardware the jog moved past the limit *with* it. If a printer still jogs
    past its limits, its endstops were disabled at the firmware level by the old
    build — power-cycle it once to restore them; from then on Bambuddy leaves
    them alone.

    Direction handling: on bed-on-Z printers (X1 / P1 / H2 family) the bed
    is the Z-axis, and Bambu's home convention puts Z=0 at the top with
    Z+ moving the bed down — so a frontend "Up" (decrease gap) maps
    naturally to ``G1 Z-``. On bed-slingers (A1 / A1 Mini) the Z-axis is
    the *toolhead*, and ``G1 Z-`` instead drives the nozzle DOWN into the
    bed (#1334 reported exactly that crash). For those models we invert
    the sign before emitting the G-code, so the UI semantics stay the
    same regardless of which part physically moves.
    """
    if distance == 0 or abs(distance) > 200:
        raise HTTPException(400, "Distance must be non-zero and ≤ 200 mm")

    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    client = printer_manager.get_client(printer_id)
    if not client:
        raise HTTPException(400, "Printer not connected")

    from backend.app.services.printer_manager import is_bed_slinger

    gcode_distance = -distance if is_bed_slinger(printer.model) else distance

    # Bare relative move — exactly what the touchscreen sends. Never touch M211
    # (#2579): the firmware keeps its soft endstops on by default and clamps the
    # move at the travel limit.
    lines = ["G91", f"G1 Z{gcode_distance:.2f} F600", "G90"]

    if not client.send_gcode("\n".join(lines)):
        raise HTTPException(500, "Failed to send bed-jog command")

    return {"success": True, "message": f"Bed jog {distance:+.1f} mm sent"}


@router.post("/{printer_id}/xy-jog")
async def xy_jog(
    printer_id: int,
    x: float = Query(0, description="Signed relative X movement in mm"),
    y: float = Query(0, description="Signed relative Y movement in mm"),
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Move the toolhead by a relative X/Y distance."""
    if (x == 0 and y == 0) or abs(x) > 200 or abs(y) > 200:
        raise HTTPException(400, "X/Y movement must be non-zero and ≤ 200 mm per axis")

    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    client = printer_manager.get_client(printer_id)
    if not client:
        raise HTTPException(400, "Printer not connected")

    axes = []
    if x:
        axes.append(f"X{x:.2f}")
    if y:
        axes.append(f"Y{y:.2f}")

    # Bare relative move — never touch M211 (#2579). The firmware keeps its soft
    # endstops on by default and clamps the move at the travel limit; a printer
    # left disabled by an older build is recovered with a power cycle.
    if not client.send_gcode("\n".join(["G91", f"G1 {' '.join(axes)} F6000", "G90"])):
        raise HTTPException(500, "Failed to send XY jog command")

    return {"success": True, "message": f"XY jog X{x:+.1f} Y{y:+.1f} mm sent"}


@router.post("/{printer_id}/extruder-jog")
async def extruder_jog(
    printer_id: int,
    distance: float = Query(
        ..., description="Signed relative extrusion distance in mm. Positive extrudes, negative retracts."
    ),
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Extrude or retract filament by a relative distance.

    No client-side cold-extrude guard: Bambu firmware refuses extrusion
    below its min-extrude temperature, so a cold call is rejected at the
    printer, not silently damaging the extruder gear.
    """
    if distance == 0 or abs(distance) > 100:
        raise HTTPException(400, "Extruder movement must be non-zero and ≤ 100 mm")

    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    client = printer_manager.get_client(printer_id)
    if not client:
        raise HTTPException(400, "Printer not connected")

    if not client.send_gcode("\n".join(["M83", f"G1 E{distance:.2f} F300", "M82"])):
        raise HTTPException(500, "Failed to send extruder jog command")

    return {"success": True, "message": f"Extruder jog {distance:+.1f} mm sent"}


@router.post("/{printer_id}/home-axes")
async def home_axes(
    printer_id: int,
    axes: str = Query(
        "all",
        description="Legacy; accepted values are 'z' | 'xy' | 'all'. Always runs the printer's full auto-home sequence — see below.",
    ),
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Run the printer's full auto-home sequence via bare `G28`.

    Bambu printers (H2C / H2D / H2S / X1 family) home the Z axis by moving
    the BED UP toward an endstop at the top of travel. If the toolhead is
    not already parked out of the way, a bare `G28 Z` will crash the bed
    into the toolhead — #1052 reported exactly that on H2C: the bed rose
    without stopping at a safe height because `G28 Z` skipped the
    toolhead-park step that a full `G28` runs first.

    The endpoint therefore ignores the `axes` argument and always sends a
    bare `G28`, which the firmware expands into a safe multi-step sequence
    (park toolhead → home XY → home Z). The argument is kept only for
    backward-compat with existing clients; sending an invalid value still
    returns 400 so typos surface instead of silently proceeding.
    """
    axes = axes.lower()
    if axes not in ("z", "xy", "all"):
        raise HTTPException(400, "axes must be 'z', 'xy', or 'all'")

    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    client = printer_manager.get_client(printer_id)
    if not client:
        raise HTTPException(400, "Printer not connected")

    if not client.send_gcode("G28"):
        raise HTTPException(500, "Failed to send home command")

    return {"success": True, "message": "Full auto-home sequence sent"}


@router.post("/{printer_id}/hms/clear")
async def clear_hms_errors(
    printer_id: int,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Clear HMS/print errors on the printer."""
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    client = printer_manager.get_client(printer_id)
    if not client:
        raise HTTPException(400, "Printer not connected")

    success = client.clear_hms_errors()
    if not success:
        raise HTTPException(500, "Failed to clear HMS errors")

    return {"success": True, "message": "HMS errors cleared"}


@router.get("/{printer_id}/print/objects")
async def get_printable_objects(
    printer_id: int,
    reload: bool = False,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_READ),
    db: AsyncSession = Depends(get_db),
):
    """Get the list of printable objects for the current print.

    Returns a list of objects with id, name, position (if available), and skip status.
    Objects that have already been skipped are marked in the skipped_objects list.

    Args:
        reload: If True, reload objects from the archive file (useful after restart)
    """
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    client = printer_manager.get_client(printer_id)
    if not client:
        raise HTTPException(400, "Printer not connected")

    # Reload objects from 3MF if requested or no objects loaded
    if reload or not client.state.printable_objects:
        # The archive of a running print normally holds the very file the
        # printer is executing, so ask the disk before asking the printer:
        # the fan-out below pulls the whole 3MF over FTPS from a machine that
        # is mid-print — 15 MB on the print this was written for — and on a
        # printer that kept the file on internal storage it cannot succeed at
        # all. skipped_objects is deliberately left alone: a reload is
        # not a new print, and the list of what the user already skipped only
        # lives here.
        from backend.app.models.archive import PrintArchive
        from backend.app.services.archive import extract_printable_objects_from_archive

        subtask_id = str(getattr(client.state, "subtask_id", "") or "").strip()
        if subtask_id not in ("", "0"):
            archive = await db.scalar(
                select(PrintArchive)
                .where(
                    PrintArchive.printer_id == printer_id,
                    PrintArchive.status == "printing",
                    PrintArchive.subtask_id == subtask_id,
                )
                .order_by(PrintArchive.created_at.desc())
                .limit(1)
            )
            if archive is not None:
                objects, bbox_all = extract_printable_objects_from_archive(
                    settings.base_dir / archive.file_path,
                    plate_number=resolve_plate_id(client.state),
                )
                if objects:
                    client.state.printable_objects = objects
                    client.state.printable_objects_bbox_all = bbox_all
                    logger.info(
                        "Reloaded %s objects for printer %s from archive %s",
                        len(objects),
                        printer_id,
                        archive.id,
                    )

    # Only when the disk could not answer: a `reload=true` that the archive
    # satisfied has already refreshed from the file the printer is running.
    if not client.state.printable_objects:
        subtask_name = client.state.subtask_name
        if subtask_name:
            from backend.app.services.archive import extract_printable_objects_from_3mf
            from backend.app.services.bambu_ftp import download_file_try_paths_async

            # Build possible 3MF filenames (try both .gcode.3mf and .3mf)
            possible_filenames = []
            if subtask_name.endswith(".3mf"):
                possible_filenames.append(subtask_name)
            else:
                possible_filenames.append(f"{subtask_name}.gcode.3mf")
                possible_filenames.append(f"{subtask_name}.3mf")

            # Also try with spaces converted to underscores (Bambu Studio may normalize filenames)
            if " " in subtask_name:
                normalized = subtask_name.replace(" ", "_")
                if normalized.endswith(".3mf"):
                    possible_filenames.append(normalized)
                else:
                    possible_filenames.append(f"{normalized}.gcode.3mf")
                    possible_filenames.append(f"{normalized}.3mf")

            # Download 3MF from printer
            temp_path = settings.archive_dir / "temp" / f"objects_{printer_id}_{possible_filenames[0]}"
            temp_path.parent.mkdir(parents=True, exist_ok=True)

            # Build list of all remote paths to try
            remote_paths = []
            for filename in possible_filenames:
                remote_paths.extend([f"/{filename}", f"/cache/{filename}", f"/model/{filename}"])

            try:
                downloaded = await download_file_try_paths_async(
                    printer.ip_address,
                    printer.access_code,
                    remote_paths,
                    temp_path,
                    printer_model=printer.model,
                )
                if downloaded and temp_path.exists():
                    with open(temp_path, "rb") as f:
                        data = f.read()
                    # Scope to the running plate: an all-plates 3MF lists every
                    # plate's objects, and offering plate 1's while the printer
                    # runs plate 2 makes every skip a misfire (#2522).
                    objects, bbox_all = extract_printable_objects_from_3mf(
                        data,
                        plate_number=resolve_plate_id(client.state),
                        include_positions=True,
                    )
                    if objects:
                        client.state.printable_objects = objects
                        client.state.printable_objects_bbox_all = bbox_all
                        logger.info("Reloaded %s objects for printer %s", len(objects), printer_id)
            except Exception as e:
                logger.debug("Failed to reload objects from printer: %s", e)
            finally:
                if temp_path.exists():
                    temp_path.unlink()

    # Return objects with their skip status and position data
    objects = []
    for obj_id, obj_data in client.state.printable_objects.items():
        # Handle both old format (string name) and new format (dict with name, x, y)
        if isinstance(obj_data, dict):
            obj_entry = {
                "id": obj_id,
                "name": obj_data.get("name", f"Object {obj_id}"),
                "x": obj_data.get("x"),
                "y": obj_data.get("y"),
                "skipped": obj_id in client.state.skipped_objects,
            }
        else:
            # Legacy format: obj_data is just the name string
            obj_entry = {
                "id": obj_id,
                "name": obj_data,
                "x": None,
                "y": None,
                "skipped": obj_id in client.state.skipped_objects,
            }
        objects.append(obj_entry)

    return {
        "objects": objects,
        "total": len(objects),
        "skipped_count": len(client.state.skipped_objects),
        "is_printing": client.state.state in ("RUNNING", "PAUSE"),
        "bbox_all": getattr(client.state, "printable_objects_bbox_all", None),
    }


@router.post("/{printer_id}/print/skip-objects")
async def skip_objects(
    printer_id: int,
    object_ids: list[int],
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Skip specific objects during the current print.

    Args:
        object_ids: List of object identify_id values to skip
    """
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    client = printer_manager.get_client(printer_id)
    if not client:
        raise HTTPException(400, "Printer not connected")

    if not object_ids:
        raise HTTPException(400, "No object IDs provided")

    # Validate object IDs exist in printable_objects
    invalid_ids = [oid for oid in object_ids if oid not in client.state.printable_objects]
    if invalid_ids:
        raise HTTPException(400, f"Invalid object IDs: {invalid_ids}")

    success = client.skip_objects(object_ids)
    if not success:
        raise HTTPException(500, "Failed to skip objects")

    # Get names of skipped objects for response (handle both old and new format)
    skipped_names = []
    for oid in object_ids:
        obj_data = client.state.printable_objects.get(oid, str(oid))
        if isinstance(obj_data, dict):
            skipped_names.append(obj_data.get("name", str(oid)))
        else:
            skipped_names.append(obj_data)

    return {
        "success": True,
        "message": f"Skipped {len(object_ids)} object(s): {', '.join(skipped_names)}",
        "skipped_objects": object_ids,
    }


# =============================================================================
# AMS Control Endpoints
# =============================================================================


@router.post("/{printer_id}/ams/{ams_id}/slot/{slot_id}/refresh")
async def refresh_ams_slot(
    printer_id: int,
    ams_id: int,
    slot_id: int,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_AMS_RFID),
    db: AsyncSession = Depends(get_db),
):
    """Re-read RFID for an AMS slot (triggers filament info refresh)."""
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    client = printer_manager.get_client(printer_id)
    if not client:
        raise HTTPException(400, "Printer not connected")

    success, message = client.ams_refresh_tray(ams_id, slot_id)
    if not success:
        raise HTTPException(400, message)

    # Apply PA profile after delay (RFID re-read takes a few seconds)
    spawn_background_task(
        _apply_pa_after_refresh(printer_id, ams_id, slot_id),
        name=f"apply-pa-after-refresh-{printer_id}-{ams_id}-{slot_id}",
    )

    return {"success": True, "message": message}


async def _apply_pa_after_refresh(printer_id: int, ams_id: int, slot_id: int):
    """Apply PA profile after RFID re-read completes.

    Waits for the printer to finish processing the RFID data, then selects
    the K-profile via extrusion_cali_sel.  Does NOT re-send ams_set_filament_setting
    because that would overwrite the RFID-provided filament data.
    """
    await asyncio.sleep(5)
    try:
        from backend.app.api.routes.inventory import _find_tray_in_ams_data
        from backend.app.core.database import async_session
        from backend.app.models.spool import Spool
        from backend.app.models.spool_assignment import SpoolAssignment as SA
        from backend.app.models.spoolman_k_profile import SpoolmanKProfile
        from backend.app.models.spoolman_slot_assignment import SpoolmanSlotAssignment
        from backend.app.services.spool_tag_matcher import (
            ZERO_TAG_UID,
            ZERO_TRAY_UUID,
            is_bambu_tag,
        )
        from backend.app.utils.tag_normalization import (
            normalize_tag_uid,
            normalize_tray_uuid,
        )

        client = printer_manager.get_client(printer_id)
        if not client:
            return

        state = printer_manager.get_status(printer_id)
        if not state or not state.raw_data:
            return

        # Find current tray data (should have RFID data by now)
        ams_data = state.raw_data.get("ams", {})
        ams_list = (
            ams_data.get("ams", []) if isinstance(ams_data, dict) else ams_data if isinstance(ams_data, list) else []
        )
        tray = _find_tray_in_ams_data(ams_list, ams_id, slot_id)
        if not tray or not tray.get("tray_type"):
            logger.debug("PA re-apply: no tray data for AMS%d-T%d", ams_id, slot_id)
            return

        tag_uid = tray.get("tag_uid", "")
        tray_uuid = tray.get("tray_uuid", "")
        tray_info_idx = tray.get("tray_info_idx", "")
        if not is_bambu_tag(tag_uid, tray_uuid, tray_info_idx):
            return

        # Compute nozzle/extruder once — used by both local and Spoolman lookup.
        nozzle_diameter = "0.4"
        if state.nozzles:
            nd = state.nozzles[0].nozzle_diameter
            if nd:
                nozzle_diameter = nd

        resolved_extruder = slot_extruder(ams_id, slot_id, state.ams_extruder_map, state.ams_switch_inlet)

        # 3-stage K-profile cascade: local SpoolKProfile → Spoolman SpoolmanKProfile
        # → live tray.cali_idx fallback. Pre-Phase-13 only handled the local path
        # and exited silently if no SpoolKProfile match; Spoolman-assigned slots
        # were ignored entirely and live cali_idx was never re-asserted.
        matching_cali_idx: int | None = None
        matching_filament_id: str = tray_info_idx

        async with async_session() as db:
            from sqlalchemy import or_, select as sa_select
            from sqlalchemy.orm import selectinload

            # Stage 1: local SpoolAssignment + SpoolKProfile match
            result = await db.execute(
                sa_select(SA)
                .options(selectinload(SA.spool).selectinload(Spool.k_profiles))
                .where(SA.printer_id == printer_id, SA.ams_id == ams_id, SA.tray_id == slot_id)
            )
            assignment = result.scalar_one_or_none()
            spool: Spool | None = assignment.spool if assignment else None

            # Stage 1b: tag-based fallback. The slot may have just been reset
            # (SpoolAssignment row deleted) before the user triggered a re-read.
            # The live tray already carries the spool's tray_uuid/tag_uid from
            # the RFID re-read, but the SA row hasn't been re-created yet.
            # Without this fallback we miss the stored SpoolKProfile and Stage 3
            # ends up re-asserting whatever cali_idx the firmware reset to
            # (typically the default profile).
            if spool is None:
                norm_uuid = normalize_tray_uuid(tray_uuid) if tray_uuid else ""
                norm_tag = normalize_tag_uid(tag_uid) if tag_uid else ""
                tag_filters = []
                if norm_uuid and norm_uuid != ZERO_TRAY_UUID:
                    tag_filters.append(Spool.tray_uuid == norm_uuid)
                if norm_tag and norm_tag != ZERO_TAG_UID:
                    tag_filters.append(Spool.tag_uid == norm_tag)
                if tag_filters:
                    tag_lookup = await db.execute(
                        sa_select(Spool).options(selectinload(Spool.k_profiles)).where(or_(*tag_filters)).limit(1)
                    )
                    spool = tag_lookup.scalar_one_or_none()
                    if spool is not None:
                        logger.info(
                            "PA re-apply AMS%d-T%d: matched spool %d via tag fallback "
                            "(SpoolAssignment row missing, likely after slot reset)",
                            ams_id,
                            slot_id,
                            spool.id,
                        )

            if spool is not None and spool.k_profiles:
                # Prefer exact extruder match, fall back to extruder-agnostic kp
                # for the same printer + nozzle. Hard-skipping on extruder
                # mismatch made the cascade refuse perfectly valid stored
                # profiles whenever the AMS-extruder mapping had shifted since
                # calibration time, falling all the way through to Stage 3 and
                # re-asserting the firmware default.
                exact_kp = None
                fallback_kp = None
                for kp in spool.k_profiles:
                    if kp.printer_id != printer_id or kp.nozzle_diameter != nozzle_diameter or kp.cali_idx is None:
                        continue
                    if resolved_extruder is not None and kp.extruder is not None and kp.extruder == resolved_extruder:
                        exact_kp = kp
                        break
                    if fallback_kp is None:
                        fallback_kp = kp
                chosen_kp = exact_kp or fallback_kp
                if chosen_kp is not None:
                    matching_cali_idx = chosen_kp.cali_idx
                    # The filament_id in extrusion_cali_sel must match the preset
                    # under which the K-profile was calibrated. Prefer the spool's
                    # slicer_filament setting, falling back to the tray's RFID value.
                    matching_filament_id = spool.slicer_filament or tray_info_idx

            # Stage 2: Spoolman SpoolmanSlotAssignment + SpoolmanKProfile match
            # (only when no local spool was matched — local takes priority,
            # including the tag-based fallback above)
            if matching_cali_idx is None and spool is None:
                sm_result = await db.execute(
                    sa_select(SpoolmanSlotAssignment).where(
                        SpoolmanSlotAssignment.printer_id == printer_id,
                        SpoolmanSlotAssignment.ams_id == ams_id,
                        SpoolmanSlotAssignment.tray_id == slot_id,
                    )
                )
                sm_assignment = sm_result.scalar_one_or_none()
                if sm_assignment:
                    kp_result = await db.execute(
                        sa_select(SpoolmanKProfile).where(
                            SpoolmanKProfile.spoolman_spool_id == sm_assignment.spoolman_spool_id,
                            SpoolmanKProfile.printer_id == printer_id,
                        )
                    )
                    for kp in kp_result.scalars().all():
                        if kp.nozzle_diameter == nozzle_diameter:
                            if (
                                resolved_extruder is not None
                                and kp.extruder is not None
                                and kp.extruder != resolved_extruder
                            ):
                                continue
                            if kp.cali_idx is not None:
                                matching_cali_idx = kp.cali_idx
                                # Spoolman has no slicer_filament — use the tray's RFID value
                                matching_filament_id = tray_info_idx
                            break

        # Stage 3: live tray.cali_idx fallback. Re-asserts the printer's current
        # selection so the value sticks across the RFID re-read (otherwise some
        # firmwares clear cali_idx back to -1 mid-cycle).
        if matching_cali_idx is None:
            live_cali_idx = tray.get("cali_idx")
            if live_cali_idx is not None and live_cali_idx >= 0:
                matching_cali_idx = live_cali_idx

        if matching_cali_idx is None:
            logger.debug(
                "PA re-apply AMS%d-T%d: no stored or live cali_idx — skipping MQTT",
                ams_id,
                slot_id,
            )
            return

        logger.info(
            "PA re-apply AMS%d-T%d: cali_idx=%d, filament_id=%s",
            ams_id,
            slot_id,
            matching_cali_idx,
            matching_filament_id,
        )

        # NOTE: Do NOT send ams_set_filament_setting here — it tells the firmware
        # "this is a manual config" which destroys the RFID-detected spool state
        # (changes eye icon to pen icon in slicer).
        client.extrusion_cali_sel(
            ams_id=ams_id,
            tray_id=slot_id,
            cali_idx=matching_cali_idx,
            filament_id=matching_filament_id,
            nozzle_diameter=nozzle_diameter,
        )

        # NOTE: Do NOT send extrusion_cali_set here. extrusion_cali_sel already
        # selected the correct profile by cali_idx. Sending extrusion_cali_set with
        # the same cali_idx would MODIFY the existing profile's metadata (extruder_id,
        # nozzle_id, name), corrupting it.

        logger.info(
            "Applied PA profile cali_idx=%d to printer %d AMS%d-T%d",
            matching_cali_idx,
            printer_id,
            ams_id,
            slot_id,
        )
    except Exception as e:
        logger.warning("Failed to apply PA profile after RFID re-read: %s", e)


@router.post("/{printer_id}/ams/load")
async def ams_load(
    printer_id: int,
    tray_id: int = Query(..., description="Tray ID: 0-15 for AMS slots (ams_id*4+slot_id), 254 for external spool"),
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Load filament from a specific AMS slot or external spool.

    Tray ID encoding (matches Bambu firmware convention):
    - 0..15: AMS slot, computed as ams_id * 4 + slot_id
    - 254: external spool (single-external printers, or Ext-L on dual-nozzle H2D)
    - 255: Ext-R on dual-nozzle H2D
    """
    # 24-27 are the A2L AMS-Lite slots (normalised unit 6 = 6*4+slot); see
    # a2l-am-unit-16. They are valid global tray ids alongside the regular 0-15.
    if tray_id not in range(16) and tray_id not in range(24, 28) and tray_id not in (254, 255):
        raise HTTPException(
            400, "tray_id must be 0..15 (AMS slot), 24..27 (A2L AMS-Lite), 254 (external / Ext-L), or 255 (Ext-R)"
        )

    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    client = printer_manager.get_client(printer_id)
    if not client:
        raise HTTPException(400, "Printer not connected")

    success = client.ams_load_filament(tray_id)
    if not success:
        raise HTTPException(500, "Failed to send load command")

    if tray_id == 254:
        target = "external spool"
    elif tray_id == 255:
        target = "Ext-R"
    else:
        target = f"AMS {tray_id // 4} slot {tray_id % 4 + 1}"
    return {"success": True, "message": f"Loading filament from {target}"}


@router.post("/{printer_id}/ams/unload")
async def ams_unload(
    printer_id: int,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Unload the currently loaded filament."""
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    client = printer_manager.get_client(printer_id)
    if not client:
        raise HTTPException(400, "Printer not connected")

    success = client.ams_unload_filament()
    if not success:
        raise HTTPException(500, "Failed to send unload command")

    return {"success": True, "message": "Unloading filament"}


@router.get("/{printer_id}/runtime-debug")
async def get_runtime_debug(
    printer_id: int,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_READ),
    db: AsyncSession = Depends(get_db),
):
    """Debug endpoint: Get runtime tracking status for a printer."""
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    state = printer_manager.get_status(printer_id)

    return {
        "printer_name": printer.name,
        "runtime_seconds": printer.runtime_seconds,
        "runtime_hours": printer.runtime_seconds / 3600.0 if printer.runtime_seconds else 0,
        "print_hours_offset": printer.print_hours_offset,
        "total_hours": (printer.runtime_seconds / 3600.0 if printer.runtime_seconds else 0)
        + (printer.print_hours_offset or 0),
        "last_runtime_update": printer.last_runtime_update.isoformat() if printer.last_runtime_update else None,
        "mqtt_state": {
            "connected": state.connected if state else False,
            "state": state.state if state else None,
            "progress": state.progress if state else None,
            "gcode_file": state.gcode_file if state else None,
        }
        if state
        else None,
        "is_active": printer.is_active,
    }


@router.post("/{printer_id}/hms/execute-action")
async def execute_hms_action(
    printer_id: int,
    body: HmsActionBody,
    _=RequirePermissionIfAuthEnabled(Permission.PRINTERS_CONTROL),
    db: AsyncSession = Depends(get_db),
):
    """Execute an HMS action on the printer."""
    result = await db.execute(select(Printer).where(Printer.id == printer_id))
    printer = result.scalar_one_or_none()
    if not printer:
        raise HTTPException(404, "Printer not found")

    client = printer_manager.get_client(printer_id)
    if not client:
        raise HTTPException(400, "Printer not connected")

    # Snapshot pre-state so we can verify the printer actually acted on the
    # command. publish() success is NOT the same as printer-ack: Bambu's
    # firmware silently rejects malformed HMS commands at QoS 1 (the broker
    # ACKs the publish, but the printer drops it). Verified end-to-end against
    # a live H2D — see #1830 §(3).
    #
    # We probe `_last_message_time` (bumped on every MQTT push) rather than a
    # (gcode_state, hms_errors-length) diff. The old diff missed the
    # wrong-plate IGNORE_RESUME case where the printer briefly resumes and
    # re-pauses with the same fault inside the 2.5s window: both fields
    # round-trip to their pre-publish values → false 502 even though the
    # firmware fully ack'd the resume. Every accepted command triggers a
    # pushall response within ~100-500ms, so a fresh inbound message after
    # the publish is the robust ack signal.
    pre_last_message = client._last_message_time

    success = client.execute_hms_action(body.print_error, body.action, body.job_id)
    if not success:
        raise HTTPException(400, "Failed to execute HMS action")

    # Give the printer time to push a state update. The dispatch helper already
    # publishes a pushall after every command, so a fresh status should arrive
    # within ~1s; the default 2.5s covers slower firmware variants without
    # making the UI feel hung. Plain sleep is fine — paho's MQTT callback
    # runs in its own thread and updates state regardless of whether this
    # coroutine is awaiting.
    await asyncio.sleep(HMS_ACTION_ACK_WAIT_SECONDS)

    acked = client._last_message_time > pre_last_message
    if not acked:
        # Publish succeeded but the printer sent nothing back. Almost always
        # firmware-side silent rejection (err mismatch, command/state mismatch)
        # or a dropped MQTT route. 502 makes it visible at the UI instead of
        # the 200-but-broken loop #1830 reported.
        raise HTTPException(502, "Printer did not acknowledge HMS action within 2.5s")

    return {"success": True, "message": "HMS action executed"}