from __future__ import annotations

import threading
from collections import deque
from typing import Deque, Optional, Tuple

from .net import ServerClient


class Matchmaker:
    def __init__(self) -> None:
        self._queue: Deque[ServerClient] = deque()
        self._lock = threading.Lock()

    def enqueue(self, client: ServerClient) -> None:
        with self._lock:
            # Avoid duplicates
            if client in self._queue:
                return
            self._queue.append(client)

    def dequeue_pair(self) -> Optional[Tuple[ServerClient, ServerClient]]:
        with self._lock:
            if len(self._queue) >= 2:
                c1 = self._queue.popleft()
                c2 = self._queue.popleft()
                return c1, c2
            return None

    def remove(self, client: ServerClient) -> None:
        with self._lock:
            try:
                self._queue.remove(client)
            except ValueError:
                pass