camera-viewer/app/main.py

"""
Camera Viewer - Live camera grid with Frigate event-driven fullscreen
"""
import asyncio
import json
import logging
from contextlib import asynccontextmanager
from typing import AsyncGenerator

import aiomqtt
from fastapi import FastAPI, Request
from fastapi.responses import HTMLResponse, StreamingResponse
from fastapi.staticfiles import StaticFiles
from fastapi.templating import Jinja2Templates

from .config import settings

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

# Event queue for SSE clients
event_queues: list[asyncio.Queue] = []

async def mqtt_listener():
    """Subscribe to Frigate MQTT events and broadcast to SSE clients"""
    reconnect_interval = 5

    while True:
        try:
            async with aiomqtt.Client(
                hostname=settings.MQTT_HOST,
                port=settings.MQTT_PORT,
                username=settings.MQTT_USER,
                password=settings.MQTT_PASSWORD,
                identifier="camera-viewer"
            ) as client:
                logger.info(f"Connected to MQTT broker at {settings.MQTT_HOST}")

                # Subscribe to Frigate events
                await client.subscribe("frigate/events")
                await client.subscribe("frigate/+/person")  # Per-camera person topic

                async for message in client.messages:
                    try:
                        payload = json.loads(message.payload.decode())

                        # Handle frigate/events topic
                        if message.topic.matches("frigate/events"):
                            event_type = payload.get("type")
                            after = payload.get("after", {})
                            camera = after.get("camera")
                            label = after.get("label")

                            # Check for person on alert camera
                            if (event_type in ["new", "update"] and
                                camera == settings.ALERT_CAMERA and
                                label == "person"):

                                event = {
                                    "type": "person_detected",
                                    "camera": camera,
                                    "score": after.get("score", 0),
                                    "event_id": after.get("id")
                                }
                                logger.info(f"Person detected on {camera}")

                                # Broadcast to all SSE clients
                                for queue in event_queues:
                                    await queue.put(event)

                    except json.JSONDecodeError:
                        pass
                    except Exception as e:
                        logger.error(f"Error processing MQTT message: {e}")

        except aiomqtt.MqttError as e:
            logger.error(f"MQTT connection error: {e}. Reconnecting in {reconnect_interval}s...")
            await asyncio.sleep(reconnect_interval)
        except Exception as e:
            logger.error(f"Unexpected error in MQTT listener: {e}")
            await asyncio.sleep(reconnect_interval)

@asynccontextmanager
async def lifespan(app: FastAPI):
    """Start MQTT listener on startup"""
    mqtt_task = asyncio.create_task(mqtt_listener())
    logger.info("Camera Viewer started")
    yield
    mqtt_task.cancel()
    try:
        await mqtt_task
    except asyncio.CancelledError:
        pass

app = FastAPI(title="Camera Viewer", lifespan=lifespan)
app.mount("/static", StaticFiles(directory="app/static"), name="static")
templates = Jinja2Templates(directory="app/templates")


@app.get("/", response_class=HTMLResponse)
async def index(request: Request):
    """Main camera grid view"""
    return templates.TemplateResponse("viewer.html", {
        "request": request,
        "cameras": settings.CAMERAS,
        "go2rtc_host": settings.GO2RTC_HOST,
        "alert_camera": settings.ALERT_CAMERA,
        "auto_dismiss_seconds": settings.AUTO_DISMISS_SECONDS
    })


@app.get("/events")
async def events() -> StreamingResponse:
    """SSE endpoint for Frigate events"""
    queue: asyncio.Queue = asyncio.Queue()
    event_queues.append(queue)

    async def event_generator() -> AsyncGenerator[str, None]:
        try:
            # Send initial connection confirmation
            yield f"data: {json.dumps({'type': 'connected'})}\n\n"

            while True:
                event = await queue.get()
                yield f"data: {json.dumps(event)}\n\n"
        except asyncio.CancelledError:
            pass
        finally:
            event_queues.remove(queue)

    return StreamingResponse(
        event_generator(),
        media_type="text/event-stream",
        headers={
            "Cache-Control": "no-cache",
            "Connection": "keep-alive",
            "X-Accel-Buffering": "no"
        }
    )


@app.get("/health")
async def health():
    """Health check endpoint"""
    return {
        "status": "ok",
        "mqtt_clients": len(event_queues),
        "cameras": len(settings.CAMERAS)
    }