from fastapi import APIRouter, Depends, Query, WebSocket, WebSocketDisconnect
from typing import Optional
from auth.models import TokenPayload
from auth.dependencies import require_permission
from mqtt.models import (
    MqttCommandRequest, CommandSendResponse, MqttStatusResponse,
    DeviceMqttStatus, LogListResponse, HeartbeatListResponse,
    CommandListResponse, HeartbeatEntry,
)
from mqtt.client import mqtt_manager
from mqtt import database as db
from datetime import datetime, timezone

router = APIRouter(prefix="/api/mqtt", tags=["mqtt"])


@router.get("/status", response_model=MqttStatusResponse)
async def get_all_device_status(
    _user: TokenPayload = Depends(require_permission("mqtt", "view")),
):
    heartbeats = await db.get_latest_heartbeats()
    now = datetime.now(timezone.utc)
    devices = []
    for hb in heartbeats:
        received_str = hb["received_at"]
        try:
            received = datetime.fromisoformat(received_str)
            if received.tzinfo is None:
                received = received.replace(tzinfo=timezone.utc)
            seconds_ago = int((now - received).total_seconds())
        except (ValueError, TypeError):
            seconds_ago = 9999

        devices.append(DeviceMqttStatus(
            device_serial=hb["device_serial"],
            online=seconds_ago < 90,
            last_heartbeat=HeartbeatEntry(**hb),
            seconds_since_heartbeat=seconds_ago,
        ))
    return MqttStatusResponse(
        devices=devices,
        broker_connected=mqtt_manager.connected,
    )


@router.post("/command/{device_serial}", response_model=CommandSendResponse)
async def send_command(
    device_serial: str,
    body: MqttCommandRequest,
    _user: TokenPayload = Depends(require_permission("mqtt", "view")),
):
    command_id = await db.insert_command(
        device_serial=device_serial,
        command_name=body.cmd,
        command_payload={"cmd": body.cmd, "contents": body.contents},
    )

    success = mqtt_manager.publish_command(
        device_serial=device_serial,
        cmd=body.cmd,
        contents=body.contents,
    )

    if not success:
        await db.update_command_response(
            command_id, "error",
            {"error": "MQTT broker not connected"},
        )
        return CommandSendResponse(
            success=False, command_id=command_id,
            message="MQTT broker not connected",
        )

    return CommandSendResponse(
        success=True, command_id=command_id,
        message=f"Command '{body.cmd}' sent to {device_serial}",
    )


@router.get("/logs/{device_serial}", response_model=LogListResponse)
async def get_device_logs(
    device_serial: str,
    level: Optional[str] = Query(None, description="Filter: INFO, WARN, ERROR"),
    search: Optional[str] = Query(None),
    limit: int = Query(100, ge=1, le=1000),
    offset: int = Query(0, ge=0),
    _user: TokenPayload = Depends(require_permission("mqtt", "view")),
):
    logs, total = await db.get_logs(
        device_serial, level=level, search=search,
        limit=limit, offset=offset,
    )
    return LogListResponse(logs=logs, total=total)


@router.get("/heartbeats/{device_serial}", response_model=HeartbeatListResponse)
async def get_device_heartbeats(
    device_serial: str,
    limit: int = Query(100, ge=1, le=1000),
    offset: int = Query(0, ge=0),
    _user: TokenPayload = Depends(require_permission("mqtt", "view")),
):
    heartbeats, total = await db.get_heartbeats(
        device_serial, limit=limit, offset=offset,
    )
    return HeartbeatListResponse(heartbeats=heartbeats, total=total)


@router.get("/commands/{device_serial}", response_model=CommandListResponse)
async def get_device_commands(
    device_serial: str,
    limit: int = Query(100, ge=1, le=1000),
    offset: int = Query(0, ge=0),
    _user: TokenPayload = Depends(require_permission("mqtt", "view")),
):
    commands, total = await db.get_commands(
        device_serial, limit=limit, offset=offset,
    )
    return CommandListResponse(commands=commands, total=total)


@router.websocket("/ws")
async def mqtt_websocket(websocket: WebSocket):
    """Live MQTT data stream. Auth via query param: ?token=JWT"""
    token = websocket.query_params.get("token")
    if not token:
        await websocket.close(code=4001, reason="Missing token")
        return

    try:
        from auth.utils import decode_access_token
        from shared.firebase import get_db
        payload = decode_access_token(token)
        role = payload.get("role", "")

        # sysadmin and admin always have MQTT access
        if role not in ("sysadmin", "admin"):
            # Check MQTT permission for editor/user
            user_sub = payload.get("sub", "")
            db_inst = get_db()
            if db_inst:
                doc = db_inst.collection("admin_users").document(user_sub).get()
                if doc.exists:
                    perms = doc.to_dict().get("permissions", {})
                    if not perms.get("mqtt", False):
                        await websocket.close(code=4003, reason="MQTT access denied")
                        return
                else:
                    await websocket.close(code=4003, reason="User not found")
                    return
            else:
                await websocket.close(code=4003, reason="Service unavailable")
                return
    except Exception:
        await websocket.close(code=4001, reason="Invalid token")
        return

    await websocket.accept()
    mqtt_manager.add_ws_subscriber(websocket)

    try:
        while True:
            await websocket.receive_text()
    except WebSocketDisconnect:
        pass
    finally:
        mqtt_manager.remove_ws_subscriber(websocket)