import json
import uuid
import logging
import asyncio

import websockets
from sanic import Blueprint

bp = Blueprint(__name__)
log = logging.getLogger(__name__)


class OP:
    UNSUBSCRIBE = -1
    SUBSCRIBE = 0
    SUBSCRIBED = 1
    UNSUBSCRIBED = 2
    DATA = 3

    # incident specific
    INCIDENT_NEW = 4
    INC_UPDATE = 5
    INCIDENT_CLOSE = 6


class ErrorCodes:
    INVALID_PAYLOAD = 4200
    TOO_MUCH = 4420


async def recv_msg(ws):
    opening_msg = await ws.recv()

    if len(opening_msg) > 256:
        await ws.close(code=ErrorCodes.TOO_MUCH, reason='Too much data')
        return

    try:
        return json.loads(opening_msg)
    except json.decoder.JSONDecodeError:
        await ws.close(code=ErrorCodes.INVALID_PAYLOAD,
                       reason='invalid json')
        return


async def recv_op(ws, op: int):
    payload = await recv_msg(ws)

    if not payload:
        return

    if payload.get('op') != op:
        await ws.close(code=ErrorCodes.INVALID_PAYLOAD,
                       reason='Invalid OP code')
        return

    return payload


async def _recv_payload_loop(ws, app):
    while True:
        try:
            payload = await recv_msg(ws)
        except websockets.exceptions.ConnectionClosed:
            break

        if not payload:
            continue

        op = payload.get('op')
        chans = payload.get('channels')

        if op == OP.SUBSCRIBE:
            subscribed = app.manager.subscribe(chans, ws)
            await ws.send(json.dumps({
                'op': OP.SUBSCRIBED,
                'channels': subscribed,
            }))
        elif op == OP.UNSUBSCRIBE:
            unsub = app.manager.unsubscribe(chans, ws)
            await ws.send(json.dumps({
                'op': OP.UNSUBSCRIBED,
                'channels': unsub,
            }))


@bp.websocket('/api/streaming')
async def streaming_ws(request, ws):
    hewwo_msg = await recv_op(ws, OP.SUBSCRIBE)

    # subscribe the websocket to all channels it wants
    ws.client_id = uuid.uuid4()

    channels = hewwo_msg['channels']
    subscribed = request.app.manager.subscribe(channels, ws)

    try:
        await ws.send(json.dumps({
            'op': OP.SUBSCRIBED,
            'channels': subscribed,
        }))

        request.app.loop.create_task(_recv_payload_loop(ws, request.app))

        # keep websocket alive
        while True:
            await ws.ping()
            await asyncio.sleep(1)
    except websockets.exceptions.ConnectionClosed as wc:
        log.warning(f'connection {ws.client_id} closed: {wc!r}')
        request.app.manager.unsub_all(ws)