Add MatchOffer class

server/matchmaker/__init__.py

@@ -5,14 +5,17 @@
 games, currently just used for 1v1 ``ladder``.
 """
 from .map_pool import MapPool
+from .match_offer import MatchOffer, OfferTimeoutError
 from .matchmaker_queue import MatchmakerQueue
 from .pop_timer import PopTimer
 from .search import CombinedSearch, Search
 
 __all__ = (
     "CombinedSearch",
     "MapPool",
+    "MatchOffer",
     "MatchmakerQueue",
+    "OfferTimeoutError",
     "PopTimer",
     "Search",
 )

server/matchmaker/match_offer.py

@@ -0,0 +1,88 @@
+import asyncio
+from datetime import datetime
+from typing import Generator, Iterable
+
+from ..players import Player
+
+
+class OfferTimeoutError(asyncio.TimeoutError):
+    pass
+
+
+class MatchOffer(object):
+    """
+    Track which players are ready for a match to begin.
+
+    Once a player has become ready, they cannot become unready again. State
+    changes are eagerly broadcast to other players in the MatchOffer.
+    """
+
+    def __init__(self, players: Iterable[Player], expires_at: datetime):
+        self.expires_at = expires_at
+        self._players_ready = {player: False for player in players}
+        self.future = asyncio.Future()
+
+    def get_unready_players(self) -> Generator[Player, None, None]:
+        return (
+            player for player, ready in self._players_ready.items()
+            if not ready
+        )
+
+    def get_ready_players(self) -> Generator[Player, None, None]:
+        return (
+            player for player, ready in self._players_ready.items()
+            if ready
+        )
+
+    def ready_player(self, player: Player) -> None:
+        """
+        Mark a player as ready.
+
+        Broadcasts the state change to other players.
+        """
+        if player not in self._players_ready:
+            raise KeyError(player)
+
+        if self._players_ready[player]:
+            # This client's state is probably out of date
+            player.write_message({
+                "command": "match_info",
+                **self.to_dict(),
+                "ready": True
+            })
+        else:
+            self._players_ready[player] = True
+            self.write_broadcast_update()
+
+        if all(self._players_ready.values()) and not self.future.done():
+            self.future.set_result(True)
+
+    async def wait_ready(self) -> None:
+        """Wait for all players to have readied up."""
+        timeout = (self.expires_at - datetime.now()).total_seconds()
+        if timeout <= 0:
+            raise OfferTimeoutError()
+
+        try:
+            await asyncio.wait_for(self.future, timeout=timeout)
+        except asyncio.TimeoutError:
+            raise OfferTimeoutError()
+
+    def write_broadcast_update(self) -> None:
+        """Queue the `match_info` message to be sent to all players in the
+        MatchOffer."""
+        info = self.to_dict()
+        for player, ready in self._players_ready.items():
+            player.write_message({
+                "command": "match_info",
+                **info,
+                "ready": ready
+            })
+
+    def to_dict(self) -> dict:
+        return {
+            "expires_at": self.expires_at.isoformat(),
+            "players_total": len(self._players_ready),
+            # Works because `True` is counted as 1 and `False` as 0
+            "players_ready": sum(self._players_ready.values())
+        }

tests/unit_tests/test_match_offer.py

@@ -0,0 +1,72 @@
+from datetime import datetime, timedelta
+
+import mock
+import pytest
+
+from server.matchmaker import MatchOffer, OfferTimeoutError
+from tests.utils import fast_forward
+
+
+@pytest.fixture
+def offer(player_factory):
+    return MatchOffer(
+            [player_factory(player_id=i) for i in range(5)],
+            datetime(2020, 1, 31, 14, 30, 36)
+        )
+
+
+def test_match_offer_api(offer):
+
+    assert offer.to_dict() == {
+        "expires_at": "2020-01-31T14:30:36",
+        "players_total": 5,
+        "players_ready": 0
+    }
+
+    assert len(list(offer.get_ready_players())) == 0
+    assert len(list(offer.get_unready_players())) == 5
+
+
+def test_broadcast_called_on_ready(offer):
+    offer.write_broadcast_update = mock.Mock()
+    player = next(offer.get_unready_players())
+
+    offer.ready_player(player)
+
+    offer.write_broadcast_update.assert_called_once()
+
+
+def test_ready_player_bad_key(offer, player_factory):
+    with pytest.raises(KeyError):
+        offer.ready_player(player_factory(player_id=42))
+
+
+@pytest.mark.asyncio
+async def test_wait_ready_timeout(offer):
+    with pytest.raises(OfferTimeoutError):
+        await offer.wait_ready()
+
+
+@pytest.mark.asyncio
+@fast_forward(5)
+async def test_wait_ready_timeout_some_ready(offer):
+    offer.expires_at = datetime.now() + timedelta(seconds=5)
+
+    players = offer.get_unready_players()
+    p1, p2 = next(players), next(players)
+
+    offer.ready_player(p1)
+    offer.ready_player(p2)
+
+    with pytest.raises(OfferTimeoutError):
+        await offer.wait_ready()
+
+
+@pytest.mark.asyncio
+async def test_wait_ready(offer):
+    offer.expires_at = datetime.now() + timedelta(seconds=5)
+
+    for player in offer.get_unready_players():
+        offer.ready_player(player)
+
+    await offer.wait_ready()