Server/src/main/java/de/towerdefence/server/match/queue/MatchQueueService.java

package de.towerdefence.server.match.queue;

import de.towerdefence.server.match.confirmation.*;
import de.towerdefence.server.player.Player;
import lombok.AllArgsConstructor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@Service
@AllArgsConstructor
public class MatchQueueService {
    private final static int REQUIRED_PLAYER_COUNT = 2;

    @Autowired
    private final MatchConfirmationService matchConfirmationService;

    private final List<Player> queue = new ArrayList<>();
    private final Map<Player, ConfirmationCallbacks> confirmationCallbacks = new HashMap<>();

    public void queuePlayer(
            Player player,
            FoundCallback foundCallback,
            QueuedCallback queuedCallback,
            AbortCallback abortCallback,
            EstablishedCallback establishedCallback) {
        queue.add(player);
        confirmationCallbacks.put(player, new ConfirmationCallbacks(
                foundCallback,
                queuedCallback,
                abortCallback,
                establishedCallback,
                this::onRequeue));
        tryMatching();
    }

    public void onRequeue(
            Player player,
            String matchId,
            FoundCallback foundCallback,
            QueuedCallback queuedCallback,
            AbortCallback abortCallback,
            EstablishedCallback establishedCallback) {
        abortCallback.call(player, matchId);
        try {
            queuedCallback.call(player);
        } catch (IOException ignored) {
            return;
        }
        queuePlayer(player, foundCallback, queuedCallback, abortCallback, establishedCallback);
    }

    public void unQueuePlayer(Player player) {
        queue.remove(player);
        confirmationCallbacks.remove(player);
    }

    private void tryMatching() {
        if (queue.size() < REQUIRED_PLAYER_COUNT) {
            return;
        }

        List<Player> loopQueue = new ArrayList<>(queue);
        for (int i = 0; i < loopQueue.size() / REQUIRED_PLAYER_COUNT; i++) {
            Player player1 = loopQueue.get(REQUIRED_PLAYER_COUNT * i);
            Player player2 = loopQueue.get(REQUIRED_PLAYER_COUNT * i + 1);

            ConfirmationCallbacks player1Callbacks = confirmationCallbacks.get(player1);
            ConfirmationCallbacks player2Callbacks = confirmationCallbacks.get(player2);

            UnconfirmedMatch match = this.matchConfirmationService.createMatch(
                    player1,
                    player2,
                    player1Callbacks,
                    player2Callbacks);
            sentMatchFound(
                    match,
                    player1,
                    player2,
                    player1Callbacks,
                    player2Callbacks);

        }
        if (queue.size() > REQUIRED_PLAYER_COUNT) {
            tryMatching();
        }
    }

    private void sentMatchFound(
            UnconfirmedMatch match,
            Player player1,
            Player player2,
            ConfirmationCallbacks player1Callbacks,
            ConfirmationCallbacks player2Callbacks) {
        boolean player1disconnected = setMatchFoundToPlayer(player1, player1Callbacks.getFoundCallback(), match);
        boolean player2disconnected = setMatchFoundToPlayer(player2, player2Callbacks.getFoundCallback(), match);

        queue.remove(player1);
        queue.remove(player2);

        if (!player1disconnected && !player2disconnected) {
            return;
        }

        if (player1disconnected && match.getPlayer2State() != PlayerMatchConfirmState.ABORTED) {
            player2Callbacks.getRequeueCallback().call(
                    player2,
                    match.getMatchId(),
                    player2Callbacks.getFoundCallback(),
                    player2Callbacks.getQueuedCallback(),
                    player2Callbacks.getAbortCallback(),
                    player2Callbacks.getEstablishedCallback());
        }

        if (player2disconnected && match.getPlayer1State() != PlayerMatchConfirmState.ABORTED) {
            player1Callbacks.getRequeueCallback().call(
                    player1,
                    match.getMatchId(),
                    player1Callbacks.getFoundCallback(),
                    player1Callbacks.getQueuedCallback(),
                    player1Callbacks.getAbortCallback(),
                    player1Callbacks.getEstablishedCallback());
        }
    }

    private boolean setMatchFoundToPlayer(Player player, FoundCallback callback, UnconfirmedMatch match) {
        try {
            callback.call(
                    player,
                    match.getMatchId(),
                    match.getCreated(),
                    UnconfirmedMatch.TTL);
        } catch (IOException e) {
            return true;
        }
        return false;
    }
}