import asyncio
import json
import time
import paho.mqtt.client as mqtt
from asgiref.sync import sync_to_async
from asyncio_mqtt import Client

from django.conf import settings
from django.core.management.base import BaseCommand
from api.models import Device
from telemetry.models import Telemetry

MQTT_HOST = settings.MQTT_BROKER['HOST']
MQTT_PORT = int(settings.MQTT_BROKER['PORT'])


class Command(BaseCommand):
    help = 'MQTT to DB deamon'

    @sync_to_async
    def get_device(self, serial):
        return Device.objects.get(serial=serial)

    @sync_to_async
    def store_telemetry(self, device, payload):
        Telemetry.objects.create(
            device=device,
            transport='mqtt',
            clock=payload['clock'],
            payload=payload['payload']
        )

    async def mqtt_broker(self):
        async with Client(MQTT_HOST, port=MQTT_PORT) as client:
            # use shared subscription for HA/balancing
            await client.subscribe("$share/telemetry/#")
            async with client.unfiltered_messages() as messages:
                async for message in messages:
                    payload = json.loads(message.payload.decode('utf-8'))
                    device = await self.get_device(message.topic)
                    await self.store_telemetry(device, payload)

    def handle(self, *args, **options):
        client = mqtt.Client()
        while True:
            try:
                client.connect(MQTT_HOST, MQTT_PORT)
                break
            except ConnectionRefusedError:
                self.stdout.write('WARNING: Broker not available')
                time.sleep(5)
        client.disconnect()
        asyncio.run(self.mqtt_broker())