import asyncio
import websockets
import json
import queue # refer to https://docs.python.org/3/library/queue.html for cross threading communication
import uuid
from typing import Dict
from threading import Thread

class MultiplayerService():
    _thread = None
    _receive_piece_queue = queue.Queue()
    _send_piece_queue = queue.Queue()
    _current_game_id = None
    _client_id = str(uuid.uuid4())

    @classmethod
    def init(cls) -> None:
        thread = Thread(target=asyncio.get_event_loop().run_until_complete,\
                        args=(_NetworkConnectionService.init(),))
        thread.start()

    @classmethod
    def enter_game(cls, game_id: str) -> None:
        cls._current_game_id = game_id
        _NetworkConnectionService._join_game = True # TODO: change this to a function

    @classmethod
    def send_piece(cls, piece: "PieceDto") -> None:
        cls._send_piece_queue.put(piece)

    @classmethod
    def try_receive_piece(cls) -> "PieceDto":
        result = cls._receive_piece_queue.get()
        cls._receive_piece_queue.task_done()
        return result

    @classmethod
    def quit(cls) -> None:
        _NetworkConnectionService.close_connection()

class _NetworkConnectionService():
    _URI = "ws://localhost:5001" # TODO get from config file
    _websocket = None
    _is_closed = False
    _join_game = False
    _pending_receive_task = None

    @classmethod
    async def init(cls) -> None:
        await cls._connect_to_server()
        await cls._run_network_loop()
            
    @classmethod
    def close_connection(cls) -> None:
        cls._is_closed = True

    @classmethod
    async def _run_network_loop(cls) -> None:
        while True:
            await asyncio.sleep(16e-3) # TODO add clock tick instead 

            await cls._try_enter_game()
            await cls._try_send_piece()
            await cls._try_receive_message()

            # if conection is closed, exit loop
            if cls._is_closed:
                await cls._websocket.close()
                break

    @classmethod
    async def _try_enter_game(cls) -> None:
        if not cls._join_game:
            return
        
        json_message = json.dumps({"action": "enter_game",\
                                   "clientId": MultiplayerService._client_id,\
                                   "gameId": MultiplayerService._current_game_id})
        await cls._websocket.send(json_message)
        cls._join_game = False

    @classmethod
    async def _try_send_piece(cls) -> None:
        # if no messages to proccess, return
        if MultiplayerService._send_piece_queue.empty():
            return
        
        # get next piece to send and send to server
        piece = MultiplayerService._send_piece_queue.get()

        # construct json message
        json_message = json.dumps({"action": "send_piece",\
                                   "clientId": MultiplayerService._client_id,\
                                   "gameId": MultiplayerService._current_game_id,\
                                   "piece": piece.__dict__})

        await cls._websocket.send(json_message)
        MultiplayerService._send_piece_queue.task_done()

    @classmethod
    async def _try_receive_message(cls) -> None:
        try:
            task = cls._pending_receive_task if cls._pending_receive_task else asyncio.create_task(cls._websocket.recv())
            done, pending = await asyncio.wait({task}, timeout=8e-3) # TODO experiment with the timeout

            if task in done:
                data = json.loads(await task)
                print(data)

                if data["type"] == "wait_for_opponent":
                    print("Wait for my opponent!")
                if data["type"] == "start_game":
                    print("Start the game!")
                if data["type"] == "receive_piece":
                    print("Receive a piece!")
                    MultiplayerService._receive_piece_queue.put(PieceDto.create(data["piece"]))
                if data["type"] == "exit_game":
                    print("Exit the game!")
                    cls.close_connection()

                cls._pending_receive_task = None
            elif len(pending):
                cls._pending_receive_task = pending.pop()
        finally:
            pass # TODO handle connection closed exception

    @classmethod
    async def _connect_to_server(cls) -> None:
        print("Connecting to server...") # TODO replace with logging
        cls._websocket = await websockets.connect(cls._URI, ping_interval=None)
        # ping_interval=None is important, otherwise the server will disconnect us
        # https://stackoverflow.com/a/58993145/11512104
        print("Connected to server...") # TODO replace with logging

# DTOs

class PieceDto():
    def __init__(self, x: int, y: int, type_: str) -> None:
        self.x = x
        self.y = y
        self.type = type_
        pass

    @staticmethod
    def create(data: Dict) -> "PieceDto": 
        return PieceDto(data["x"], data["y"], data["type"])