bambuddy/backend/app/services/mqtt_smart_plug.py

"""MQTT Smart Plug Service for subscribing to external MQTT topics and extracting power/energy data.

This service enables integration with Shelly, Zigbee2MQTT, and other MQTT-based energy monitoring devices.
"""

import json
import logging
import threading
from dataclasses import dataclass, field
from datetime import datetime, timedelta
from typing import Any

import paho.mqtt.client as mqtt

logger = logging.getLogger(__name__)


@dataclass
class SmartPlugMQTTData:
    """Latest data received from an MQTT smart plug."""

    plug_id: int
    power: float | None = None  # Current power in watts
    energy: float | None = None  # Energy in kWh (today)
    state: str | None = None  # "ON" or "OFF"
    last_seen: datetime = field(default_factory=datetime.utcnow)


@dataclass
class MQTTDataSourceConfig:
    """Configuration for a single MQTT data source (power, energy, or state)."""

    topic: str
    path: str
    multiplier: float = 1.0  # For power/energy
    on_value: str | None = None  # For state (what value means "ON")


class MQTTSmartPlugService:
    """Subscribes to MQTT topics for smart plug energy monitoring."""

    # Consider plug unreachable if no message received in this time
    REACHABLE_TIMEOUT_MINUTES = 5

    def __init__(self):
        self.client: mqtt.Client | None = None
        self.connected = False
        self._lock = threading.Lock()
        # topic -> list of (plug_id, data_type) where data_type is "power", "energy", or "state"
        self.subscriptions: dict[str, list[tuple[int, str]]] = {}
        # plug_id -> {data_type: MQTTDataSourceConfig}
        self.plug_configs: dict[int, dict[str, MQTTDataSourceConfig]] = {}
        # plug_id -> latest data
        self.plug_data: dict[int, SmartPlugMQTTData] = {}
        self._configured = False
        self._broker = ""
        self._port = 1883
        self._username = ""
        self._password = ""
        self._use_tls = False

    def is_configured(self) -> bool:
        """Check if the MQTT service is configured and connected."""
        return self._configured and self.connected

    def has_broker_settings(self) -> bool:
        """Check if broker settings are available (even if not connected yet)."""
        return bool(self._broker)

    async def configure(self, settings: dict) -> bool:
        """Configure MQTT connection from settings.

        Uses the same broker settings as the MQTT relay service.
        Returns True if connection was successful or MQTT is disabled.
        """
        enabled = settings.get("mqtt_enabled", False)

        if not enabled:
            await self.disconnect()
            self._configured = False
            logger.debug("MQTT smart plug service disabled (MQTT relay not enabled)")
            return True

        broker = settings.get("mqtt_broker", "")
        port = settings.get("mqtt_port", 1883)
        username = settings.get("mqtt_username", "")
        password = settings.get("mqtt_password", "")
        use_tls = settings.get("mqtt_use_tls", False)

        if not broker:
            logger.warning("MQTT smart plug service: no broker configured")
            self._configured = False
            return False

        # Check if settings changed
        settings_changed = (
            self._broker != broker
            or self._port != port
            or self._username != username
            or self._password != password
            or self._use_tls != use_tls
        )

        self._broker = broker
        self._port = port
        self._username = username
        self._password = password
        self._use_tls = use_tls
        self._configured = True

        # Disconnect and reconnect if settings changed
        if settings_changed and self.client:
            await self.disconnect()

        # Connect if not already connected
        if not self.client or not self.connected:
            return await self._connect()

        return True

    async def _connect(self) -> bool:
        """Establish MQTT connection."""
        import asyncio
        import ssl

        try:
            # Create client with callback API version 2
            self.client = mqtt.Client(
                callback_api_version=mqtt.CallbackAPIVersion.VERSION2,
                client_id=f"bambuddy-smartplug-{id(self)}",
                protocol=mqtt.MQTTv311,
            )

            # Set up callbacks
            self.client.on_connect = self._on_connect
            self.client.on_disconnect = self._on_disconnect
            self.client.on_message = self._on_message

            # Configure authentication
            if self._username:
                self.client.username_pw_set(self._username, self._password)

            # Configure TLS
            if self._use_tls:
                self.client.tls_set(cert_reqs=ssl.CERT_NONE)
                self.client.tls_insecure_set(True)

            # Connect with timeout
            try:
                await asyncio.wait_for(
                    asyncio.to_thread(self.client.connect_async, self._broker, self._port, 60),
                    timeout=3.0,
                )
            except TimeoutError:
                logger.warning("MQTT smart plug connection to %s:%s timed out", self._broker, self._port)
                return False

            self.client.loop_start()

            # Wait briefly for connection
            await asyncio.sleep(1.0)

            if self.connected:
                logger.info("MQTT smart plug service connected to %s:%s", self._broker, self._port)
                # Resubscribe to all topics
                self._resubscribe_all()
                return True
            else:
                logger.warning("MQTT smart plug connection pending to %s:%s", self._broker, self._port)
                return True  # Connection is async

        except Exception as e:
            logger.error("MQTT smart plug connection failed: %s", e)
            self.connected = False
            return False

    def _on_connect(
        self,
        client: mqtt.Client,
        userdata: Any,
        flags: dict,
        reason_code: int | mqtt.ReasonCode,
        properties: mqtt.Properties | None = None,
    ):
        """Callback when connected to broker."""
        rc = reason_code if isinstance(reason_code, int) else reason_code.value
        if rc == 0:
            self.connected = True
            logger.info("MQTT smart plug service connected successfully")
            # Resubscribe to all topics
            self._resubscribe_all()
        else:
            self.connected = False
            logger.error("MQTT smart plug connection failed: %s", reason_code)

    def _on_disconnect(
        self,
        client: mqtt.Client,
        userdata: Any,
        flags_or_rc: dict | int | mqtt.ReasonCode,
        reason_code: int | mqtt.ReasonCode | None = None,
        properties: mqtt.Properties | None = None,
    ):
        """Callback when disconnected from broker."""
        self.connected = False
        rc = reason_code if reason_code is not None else flags_or_rc
        rc_val = rc if isinstance(rc, int) else getattr(rc, "value", 0)
        if rc_val != 0:
            logger.warning("MQTT smart plug service disconnected: %s", rc)
        else:
            logger.info("MQTT smart plug service disconnected cleanly")

    def _on_message(self, client: mqtt.Client, userdata: Any, msg: mqtt.MQTTMessage):
        """Handle incoming MQTT message, extract data using JSON path."""
        topic = msg.topic

        with self._lock:
            subscriptions = self.subscriptions.get(topic, [])
            if not subscriptions:
                return

            # Parse JSON payload (or treat as raw value)
            try:
                payload = json.loads(msg.payload.decode("utf-8"))
                is_json = True
            except (json.JSONDecodeError, UnicodeDecodeError):
                # Not JSON - treat the whole payload as a raw value
                payload = msg.payload.decode("utf-8").strip()
                is_json = False

            # Process for each subscribed (plug_id, data_type)
            for plug_id, data_type in subscriptions:
                configs = self.plug_configs.get(plug_id, {})
                config = configs.get(data_type)
                if not config:
                    continue

                # Extract value using path (or use raw payload if no path)
                if is_json and config.path:
                    raw_value = self._extract_json_path(payload, config.path)
                elif is_json and not config.path:
                    # JSON but no path - if it's a simple value use it, otherwise skip
                    if isinstance(payload, (int, float, str, bool)):
                        raw_value = payload
                    else:
                        # Can't use a dict/list as a value
                        logger.debug("MQTT plug %s: JSON payload is object/array but no path configured", plug_id)
                        continue
                else:
                    # Raw value (non-JSON)
                    raw_value = payload

                if raw_value is None:
                    continue

                # Initialize plug data if needed
                if plug_id not in self.plug_data:
                    self.plug_data[plug_id] = SmartPlugMQTTData(plug_id=plug_id)

                data = self.plug_data[plug_id]
                data.last_seen = datetime.utcnow()

                # Process based on data type
                if data_type == "power":
                    try:
                        data.power = float(raw_value) * config.multiplier
                        logger.debug("MQTT smart plug %s: power=%s", plug_id, data.power)
                    except (ValueError, TypeError):
                        pass  # Ignore unparseable power reading from MQTT

                elif data_type == "energy":
                    try:
                        data.energy = float(raw_value) * config.multiplier
                        logger.debug("MQTT smart plug %s: energy=%s", plug_id, data.energy)
                    except (ValueError, TypeError):
                        pass  # Ignore unparseable energy reading from MQTT

                elif data_type == "state":
                    state_str = str(raw_value)
                    # Check against configured ON value if set
                    if config.on_value:
                        # Case-insensitive comparison
                        if state_str.lower() == config.on_value.lower():
                            data.state = "ON"
                        else:
                            data.state = "OFF"
                    else:
                        # Default behavior: normalize common values
                        upper_state = state_str.upper()
                        if upper_state in ("ON", "1", "TRUE"):
                            data.state = "ON"
                        elif upper_state in ("OFF", "0", "FALSE"):
                            data.state = "OFF"
                        else:
                            data.state = state_str
                    logger.debug("MQTT smart plug %s: state=%s", plug_id, data.state)

    def _extract_json_path(self, data: dict, path: str) -> Any:
        """Extract value using dot notation (e.g., 'power_l1' or 'data.power').

        Supports simple dot notation for nested objects.
        """
        if not path:
            return None

        parts = path.split(".")
        current = data

        for part in parts:
            if isinstance(current, dict) and part in current:
                current = current[part]
            else:
                return None

        return current

    def _resubscribe_all(self):
        """Resubscribe to all registered topics after reconnection."""
        if not self.client or not self.connected:
            return

        with self._lock:
            for topic in self.subscriptions:
                if self.subscriptions[topic]:  # Only if there are subscribers
                    try:
                        self.client.subscribe(topic, qos=1)
                        logger.debug("MQTT smart plug: resubscribed to %s", topic)
                    except Exception as e:
                        logger.error("MQTT smart plug: failed to resubscribe to %s: %s", topic, e)

    def subscribe(
        self,
        plug_id: int,
        # Power source
        power_topic: str | None = None,
        power_path: str | None = None,
        power_multiplier: float = 1.0,
        # Energy source
        energy_topic: str | None = None,
        energy_path: str | None = None,
        energy_multiplier: float = 1.0,
        # State source
        state_topic: str | None = None,
        state_path: str | None = None,
        state_on_value: str | None = None,
        # Legacy: single topic/path/multiplier (for backward compatibility)
        topic: str | None = None,
        multiplier: float = 1.0,
    ):
        """Subscribe to MQTT topics for a plug.

        Each data type (power, energy, state) can have its own topic.
        For backward compatibility, if power_topic is not set but topic is,
        topic will be used for all data types that have paths configured.
        """
        with self._lock:
            # Initialize config for this plug
            self.plug_configs[plug_id] = {}

            # Determine topics (new fields take priority, fall back to legacy)
            effective_power_topic = power_topic or topic
            effective_energy_topic = energy_topic or topic
            effective_state_topic = state_topic or topic

            # Use new multipliers or fall back to legacy
            effective_power_mult = power_multiplier if power_multiplier != 1.0 else multiplier
            effective_energy_mult = energy_multiplier if energy_multiplier != 1.0 else multiplier

            # Configure power subscription (path is optional - empty means use raw payload)
            if effective_power_topic:
                config = MQTTDataSourceConfig(
                    topic=effective_power_topic,
                    path=power_path or "",
                    multiplier=effective_power_mult,
                )
                self.plug_configs[plug_id]["power"] = config
                self._add_subscription(plug_id, effective_power_topic, "power")

            # Configure energy subscription (path is optional - empty means use raw payload)
            if effective_energy_topic:
                config = MQTTDataSourceConfig(
                    topic=effective_energy_topic,
                    path=energy_path or "",
                    multiplier=effective_energy_mult,
                )
                self.plug_configs[plug_id]["energy"] = config
                self._add_subscription(plug_id, effective_energy_topic, "energy")

            # Configure state subscription (path is optional - empty means use raw payload)
            if effective_state_topic:
                config = MQTTDataSourceConfig(
                    topic=effective_state_topic,
                    path=state_path or "",
                    on_value=state_on_value,
                )
                self.plug_configs[plug_id]["state"] = config
                self._add_subscription(plug_id, effective_state_topic, "state")

            # Initialize data entry
            if plug_id not in self.plug_data:
                self.plug_data[plug_id] = SmartPlugMQTTData(plug_id=plug_id)

            logger.info(
                f"MQTT smart plug {plug_id}: configured with "
                f"power={effective_power_topic if power_path else None}, "
                f"energy={effective_energy_topic if energy_path else None}, "
                f"state={effective_state_topic if state_path else None}"
            )

    def _add_subscription(self, plug_id: int, topic: str, data_type: str):
        """Add a subscription for a plug/data_type to a topic."""
        if topic not in self.subscriptions:
            self.subscriptions[topic] = []
            # Actually subscribe if connected
            if self.client and self.connected:
                try:
                    self.client.subscribe(topic, qos=1)
                    logger.info("MQTT smart plug: subscribed to %s", topic)
                except Exception as e:
                    logger.error("MQTT smart plug: failed to subscribe to %s: %s", topic, e)

        entry = (plug_id, data_type)
        if entry not in self.subscriptions[topic]:
            self.subscriptions[topic].append(entry)

    def unsubscribe(self, plug_id: int):
        """Unsubscribe when plug is deleted/updated."""
        with self._lock:
            # Get all configs for this plug
            configs = self.plug_configs.pop(plug_id, {})
            if not configs:
                # Still clean up any stray subscriptions
                pass

            # Collect all topics this plug was subscribed to
            topics_to_check = set()
            for _data_type, config in configs.items():
                topics_to_check.add(config.topic)

            # Also scan subscriptions to remove any entries for this plug
            for topic in list(self.subscriptions.keys()):
                # Remove all entries for this plug_id
                self.subscriptions[topic] = [(pid, dtype) for pid, dtype in self.subscriptions[topic] if pid != plug_id]
                topics_to_check.add(topic)

            # Unsubscribe from topics with no more subscribers
            for topic in topics_to_check:
                if topic in self.subscriptions and not self.subscriptions[topic]:
                    del self.subscriptions[topic]
                    if self.client and self.connected:
                        try:
                            self.client.unsubscribe(topic)
                            logger.info("MQTT smart plug: unsubscribed from %s", topic)
                        except Exception as e:
                            logger.error("MQTT smart plug: failed to unsubscribe from %s: %s", topic, e)

            # Remove data
            self.plug_data.pop(plug_id, None)

    def get_plug_data(self, plug_id: int) -> SmartPlugMQTTData | None:
        """Get latest data for a plug (called by status endpoint)."""
        with self._lock:
            return self.plug_data.get(plug_id)

    def is_reachable(self, plug_id: int) -> bool:
        """Check if a plug has received data recently."""
        data = self.get_plug_data(plug_id)
        if not data:
            return False

        timeout = timedelta(minutes=self.REACHABLE_TIMEOUT_MINUTES)
        return datetime.utcnow() - data.last_seen < timeout

    async def disconnect(self):
        """Disconnect from MQTT broker."""
        if self.client:
            try:
                self.client.loop_stop()
                self.client.disconnect()
            except Exception as e:
                logger.debug("MQTT smart plug disconnect error (ignored): %s", e)
            finally:
                self.client = None
                self.connected = False


# Global instance
mqtt_smart_plug_service = MQTTSmartPlugService()