[Server] Implement Swiss tournament engine for lobby games

Adds the server-side tournament mode driven through the strategy and
factory interfaces from #7132:
- Server_Tournament runs greedy Swiss pairing with rematch avoidance,
  byes, ceil(log2(n)) rounds, and best-of-N series via gamesPerMatch;
  match sub-games are spawned through the parent game's
  Server_MatchGameFactory implementation with players auto-joined and
  their submitted decks installed
- Tournament lifecycle strategy gates the hub game start until all
  decks are submitted; match result strategy reports sub-game outcomes
  back to the parent tournament
- Server_Game gains tournament state (isTournament flag, settings,
  parent link), protocol fields in getInfo/game state events, a
  full-lobby bypass for tournament hubs, and disconnectRemovesPlayer
  plumbing for upcoming draft modes
- Match-game creation is deferred to the owning thread's event loop so
  room registration never nests lock orders; shared state is guarded by
  the tournament mutex

libcockatrice_network/libcockatrice/network/server/remote/CMakeLists.txt

@@ -14,9 +14,12 @@ set(HEADERS
     game/server_deck_validation_strategy.h
     game/server_game.h
     game/server_game_lifecycle_strategy.h
-    game/server_match_result_strategy.h
     game/server_match_game_factory.h
+    game/server_match_result_strategy.h
     game/server_player.h
+    game/server_tournament.h
+    game/server_tournament_lifecycle_strategy.h
+    game/server_tournament_match_result_strategy.h
     game/server_spectator.h
     server.h
     server_abstractuserinterface.h
@@ -43,6 +46,9 @@ add_library(
   game/server_game.cpp
   game/server_player.cpp
   game/server_spectator.cpp
+  game/server_tournament.cpp
+  game/server_tournament_lifecycle_strategy.cpp
+  game/server_tournament_match_result_strategy.cpp
   server.cpp
   server_abstractuserinterface.cpp
   server_database_interface.cpp

libcockatrice_network/libcockatrice/network/server/remote/game/server_abstract_participant.cpp

@@ -580,7 +580,7 @@ void Server_AbstractParticipant::setUserInterface(Server_AbstractUserInterface *
 void Server_AbstractParticipant::disconnectClient()
 {
     bool isRegistered = userInfo->user_level() & ServerInfo_User::IsRegistered;
-    if (!isRegistered || spectator) {
+    if (!isRegistered || spectator || game->getDisconnectRemovesPlayer()) {
         game->removeParticipant(this, Event_Leave::USER_DISCONNECTED);
     } else {
         setUserInterface(nullptr);

libcockatrice_network/libcockatrice/network/server/remote/game/server_game.cpp

@@ -30,10 +30,14 @@
 #include "server_cardzone.h"
 #include "server_player.h"
 #include "server_spectator.h"
+#include "server_tournament.h"
+#include "server_tournament_lifecycle_strategy.h"
+#include "server_tournament_match_result_strategy.h"
 
 #include <QDebug>
 #include <QRegularExpression>
 #include <QTimer>
+#include <algorithm>
 #include <google/protobuf/descriptor.h>
 #include <libcockatrice/deck_list/deck_list.h>
 #include <libcockatrice/protocol/pb/context_connection_state_changed.pb.h>
@@ -62,8 +66,9 @@ Server_Game::Server_Game(const GameConfig &config, Server_Room *_room)
       spectatorsCanTalk(config.spectatorsCanTalk), spectatorsSeeEverything(config.spectatorsSeeEverything),
       startingLifeTotal(config.startingLifeTotal), shareDecklistsOnLoad(config.shareDecklistsOnLoad),
       inactivityCounter(0), startTimeOfThisGame(0), secondsElapsed(0), firstGameStarted(false),
-      turnOrderReversed(false), startTime(QDateTime::currentDateTime()), pingClock(nullptr),
-      deckValidationStrategy(new Server_DefaultDeckValidationStrategy),
+      turnOrderReversed(false), startTime(QDateTime::currentDateTime()), pingClock(nullptr), isTournament(false),
+      tournament(nullptr), tournamentParentGame(nullptr), tournamentMatchPlayer1Id(-1), tournamentMatchPlayer2Id(-1),
+      disconnectRemovesPlayer(false), deckValidationStrategy(new Server_DefaultDeckValidationStrategy),
       lifecycleStrategy(new Server_DefaultLifecycleStrategy), matchResultStrategy(new Server_NullMatchResultStrategy),
       gameMutex()
 {
@@ -265,6 +270,12 @@ void Server_Game::createGameStateChangedEvent(Event_GameStateChanged *event,
         event->set_game_started(false);
     }
 
+    event->set_is_tournament(isTournament);
+
+    if (tournamentParentGame) {
+        event->set_parent_game_id(tournamentParentGame->getGameId());
+    }
+
     for (Server_AbstractParticipant *participant : participants.values()) {
         participant->getInfo(event->add_player_list(), recipient, omniscient, withUserInfo);
     }
@@ -313,7 +324,7 @@ void Server_Game::doStartGameIfReady(bool forceStartGame)
     Server_DatabaseInterface *databaseInterface = room->getServer()->getDatabaseInterface();
     QMutexLocker locker(&gameMutex);
 
-    if (getPlayerCount() < maxPlayers && !forceStartGame) {
+    if (!isTournament && getPlayerCount() < maxPlayers && !forceStartGame) {
         return;
     }
 
@@ -861,6 +872,7 @@ void Server_Game::getInfo(ServerInfo_Game &result) const
         result.set_share_decklists_on_load(shareDecklistsOnLoad);
         result.set_spectators_count(getSpectatorCount());
         result.set_start_time(startTime.toSecsSinceEpoch());
+        result.set_is_tournament(isTournament);
     }
 }
 
@@ -911,3 +923,86 @@ void Server_Game::setDeckValidationStrategy(Server_DeckValidationStrategy *strat
 {
     deckValidationStrategy.reset(strategy);
 }
+
+void Server_Game::setMatchResultStrategy(Server_MatchResultStrategy *strategy)
+{
+    matchResultStrategy.reset(strategy);
+}
+
+void Server_Game::setIsTournamentGame(bool _isTournament)
+{
+    isTournament = _isTournament;
+    if (isTournament) {
+        tournament = new Server_Tournament(this, this, this);
+        lifecycleStrategy.reset(new Server_TournamentLifecycleStrategy);
+        matchResultStrategy.reset(new Server_TournamentMatchResultStrategy);
+    } else if (tournament) {
+        delete tournament;
+        tournament = nullptr;
+        lifecycleStrategy.reset(new Server_DefaultLifecycleStrategy);
+        matchResultStrategy.reset(new Server_NullMatchResultStrategy);
+    }
+}
+
+void Server_Game::startTournament()
+{
+    if (!tournament) {
+        tournament = new Server_Tournament(this, this, this);
+    }
+
+    if (!tournament->isStarted()) {
+        // Add all current players to the tournament
+        auto players = getPlayers();
+        for (auto *player : players.values()) {
+            tournament->addPlayer(player->getPlayerId(), QString::fromStdString(player->getUserInfo()->name()));
+        }
+
+        tournament->startTournament();
+    }
+
+    GameEventStorage ges;
+    tournament->broadcastTournamentState(ges);
+    ges.sendToGame(this);
+}
+
+void Server_Game::setPlayerTournamentDeck(int playerId, DeckList *deck)
+{
+    if (tournament) {
+        tournament->setPlayerDeck(playerId, deck);
+    }
+}
+
+void Server_Game::setTournamentMatchInfo(Server_Game *parentGame, int p1Id, int p2Id)
+{
+    tournamentParentGame = parentGame;
+    tournamentMatchPlayer1Id = p1Id;
+    tournamentMatchPlayer2Id = p2Id;
+}
+
+Server_Game *Server_Game::createMatchGame(const GameConfig &config, int &outGameId)
+{
+    Server_DatabaseInterface *databaseInterface = room->getServer()->getDatabaseInterface();
+    outGameId = databaseInterface->getNextGameId();
+    if (outGameId == -1) {
+        return nullptr;
+    }
+
+    GameConfig matchConfig = config;
+    matchConfig.gameId = outGameId;
+    auto *game = new Server_Game(matchConfig, room);
+    // Sub-games carry the tournament flag (for protocol fields) but keep the default
+    // strategies; the parent tournament drives them through the match result strategy
+    // installed by Server_Tournament::createMatchGame.
+    game->isTournament = true;
+    return game;
+}
+
+Server_AbstractUserInterface *Server_Game::getUserInterface(const QString &playerName)
+{
+    return room->getUserInterfaceByName(playerName);
+}
+
+void Server_Game::addGameToRoom(Server_Game *game)
+{
+    room->addGame(game);
+}

libcockatrice_network/libcockatrice/network/server/remote/game/server_game.h

@@ -24,6 +24,7 @@
 #include "game_config.h"
 #include "server_deck_validation_strategy.h"
 #include "server_game_lifecycle_strategy.h"
+#include "server_match_game_factory.h"
 #include "server_match_result_strategy.h"
 
 #include <QDateTime>
@@ -34,21 +35,26 @@
 #include <QSet>
 #include <QStringList>
 #include <libcockatrice/protocol/pb/event_leave.pb.h>
+#include <libcockatrice/protocol/pb/event_tournament_state.pb.h>
 #include <libcockatrice/protocol/pb/response.pb.h>
 #include <libcockatrice/protocol/pb/serverinfo_game.pb.h>
 
 class QTimer;
+class DeckList;
 class GameEventContainer;
+class GameEventStorage;
 class GameReplay;
 class Server_Room;
 class Server_AbstractPlayer;
 class Server_AbstractParticipant;
+class Server_Card;
+class Server_Tournament;
 class ServerInfo_User;
 class ServerInfo_Game;
 class Server_AbstractUserInterface;
 class Event_GameStateChanged;
 
-class Server_Game : public QObject
+class Server_Game : public QObject, public Server_MatchGameFactory
 {
     Q_OBJECT
 private:
@@ -83,6 +89,14 @@ private:
     QList<GameReplay *> replayList;
     GameReplay *currentReplay;
 
+    bool isTournament;
+    TournamentSettings tournamentSettings;
+    Server_Tournament *tournament;
+    Server_Game *tournamentParentGame;
+    int tournamentMatchPlayer1Id;
+    int tournamentMatchPlayer2Id;
+    bool disconnectRemovesPlayer;
+
     QScopedPointer<Server_DeckValidationStrategy> deckValidationStrategy;
 
     QScopedPointer<Server_GameLifecycleStrategy> lifecycleStrategy;
@@ -220,6 +234,45 @@ public:
     void returnCardsFromPlayer(GameEventStorage &ges, Server_AbstractPlayer *player);
 
     /** @brief Get the current deck validation strategy (non-owning). */
+    bool getIsTournamentGame() const
+    {
+        return isTournament;
+    }
+    void setIsTournamentGame(bool _isTournament);
+    bool getIsTournament() const
+    {
+        return tournament != nullptr;
+    }
+    Server_Tournament *getTournament() const
+    {
+        return tournament;
+    }
+    void startTournament();
+    void setPlayerTournamentDeck(int playerId, DeckList *deck);
+    void setTournamentMatchInfo(Server_Game *parentGame, int p1Id, int p2Id);
+    Server_Game *getTournamentParentGame() const
+    {
+        return tournamentParentGame;
+    }
+    bool getDisconnectRemovesPlayer() const
+    {
+        return disconnectRemovesPlayer;
+    }
+
+    // Server_MatchGameFactory implementation
+    Server_Game *createMatchGame(const GameConfig &config, int &outGameId) override;
+    Server_AbstractUserInterface *getUserInterface(const QString &playerName) override;
+    void addGameToRoom(Server_Game *game) override;
+
+    const TournamentSettings &getTournamentSettings() const
+    {
+        return tournamentSettings;
+    }
+    void setTournamentSettings(const TournamentSettings &settings)
+    {
+        tournamentSettings = settings;
+    }
+
     Server_DeckValidationStrategy *getDeckValidationStrategy() const
     {
         return deckValidationStrategy.data();
@@ -232,6 +285,8 @@ public:
     {
         return lifecycleStrategy.data();
     }
+    /** @brief Replace the match result strategy; takes ownership of @p strategy. */
+    void setMatchResultStrategy(Server_MatchResultStrategy *strategy);
 };
 
 #endif

libcockatrice_network/libcockatrice/network/server/remote/game/server_tournament.cpp

@@ -0,0 +1,556 @@
+#include "server_tournament.h"
+
+#include "../server_abstractuserinterface.h"
+#include "../server_response_containers.h"
+#include "../serverinfo_user_container.h"
+#include "game_config.h"
+#include "server_abstract_player.h"
+#include "server_game.h"
+#include "server_match_game_factory.h"
+#include "server_player.h"
+#include "server_tournament_match_result_strategy.h"
+
+#include <QLoggingCategory>
+#include <algorithm>
+#include <libcockatrice/deck_list/deck_list.h>
+#include <libcockatrice/protocol/pb/event_tournament_state.pb.h>
+#include <libcockatrice/protocol/pb/game_event_container.pb.h>
+
+inline Q_LOGGING_CATEGORY(TournamentLog, "tournament");
+
+Server_Tournament::Server_Tournament(Server_Game *_parentGame, Server_MatchGameFactory *_factory, QObject *parent)
+    : QObject(parent), parentGame(_parentGame), matchGameFactory(_factory), currentRound(0), totalRounds(0),
+      started(false)
+{
+}
+
+Server_Tournament::~Server_Tournament()
+{
+    qDeleteAll(submittedDecks);
+}
+
+void Server_Tournament::addPlayer(int playerId, const QString &playerName)
+{
+    TournamentPlayerData data;
+    data.playerId = playerId;
+    data.playerName = playerName;
+    players[playerId] = data;
+}
+
+void Server_Tournament::setPlayerDeck(int playerId, DeckList *deck)
+{
+    QMutexLocker locker(&tournamentMutex);
+    delete submittedDecks.value(playerId, nullptr);
+    submittedDecks[playerId] = deck;
+    if (players.contains(playerId)) {
+        players[playerId].deckSubmitted = true;
+    }
+}
+
+void Server_Tournament::removePlayer(int playerId)
+{
+    QMutexLocker locker(&tournamentMutex);
+    players.remove(playerId);
+}
+
+void Server_Tournament::startTournament()
+{
+    {
+        QMutexLocker locker(&tournamentMutex);
+        if (started) {
+            return;
+        }
+        totalRounds = calculateTotalRounds();
+        started = true;
+        currentRound = 0;
+        generateSwissPairings();
+    }
+
+    // Spawn the first round's match games
+    enqueueMatchGameCreation();
+}
+
+bool Server_Tournament::isAllDecksSubmitted() const
+{
+    QMutexLocker locker(&tournamentMutex);
+    for (auto it = players.constBegin(); it != players.constEnd(); ++it) {
+        if (!it->deckSubmitted) {
+            return false;
+        }
+    }
+    return true;
+}
+
+int Server_Tournament::getTournamentPlayerIdByName(const QString &name) const
+{
+    QMutexLocker locker(&tournamentMutex);
+    for (auto it = players.constBegin(); it != players.constEnd(); ++it) {
+        if (it->playerName == name) {
+            return it->playerId;
+        }
+    }
+    return -1;
+}
+
+void Server_Tournament::generateSwissPairings()
+{
+    currentPairings.clear();
+    QList<int> available;
+    for (auto it = players.constBegin(); it != players.constEnd(); ++it) {
+        available.append(it->playerId);
+    }
+
+    // Sort by wins descending (and by record for tie-breaking)
+    std::sort(available.begin(), available.end(), [this](int a, int b) {
+        const auto &pa = players[a];
+        const auto &pb = players[b];
+        if (pa.wins != pb.wins) {
+            return pa.wins > pb.wins;
+        }
+        if (pa.losses != pb.losses) {
+            return pa.losses < pb.losses;
+        }
+        return a < b;
+    });
+
+    // Simple greedy Swiss pairing
+    QSet<int> paired;
+    for (int i = 0; i < available.size(); ++i) {
+        if (paired.contains(available[i])) {
+            continue;
+        }
+        for (int j = i + 1; j < available.size(); ++j) {
+            if (paired.contains(available[j])) {
+                continue;
+            }
+            if (!havePlayed(available[i], available[j])) {
+                TournamentPairingData pairing;
+                pairing.player1Id = available[i];
+                pairing.player2Id = available[j];
+                currentPairings.append(pairing);
+                paired.insert(available[i]);
+                paired.insert(available[j]);
+                break;
+            }
+        }
+    }
+
+    // Bye for unpaired player if odd count
+    for (int i = 0; i < available.size(); ++i) {
+        if (!paired.contains(available[i])) {
+            // Player gets a bye (auto-win)
+            TournamentPairingData bye;
+            bye.player1Id = available[i];
+            bye.player2Id = -1;
+            bye.winnerId = available[i];
+            bye.player1MatchWins = gamesPerMatch; // Match immediately decided
+            currentPairings.append(bye);
+            players[available[i]].wins += 1;
+            allPreviousPairings.append(qMakePair(available[i], -1));
+            break;
+        }
+    }
+}
+
+int Server_Tournament::calculateTotalRounds() const
+{
+    int n = players.size();
+    if (n <= 1) {
+        return 0;
+    }
+    // Standard Swiss rounds: ceil(log2(n))
+    int rounds = 0;
+    while ((1 << rounds) < n) {
+        ++rounds;
+    }
+    return rounds;
+}
+
+bool Server_Tournament::havePlayed(int p1, int p2) const
+{
+    for (const auto &pair : allPreviousPairings) {
+        if ((pair.first == p1 && pair.second == p2) || (pair.first == p2 && pair.second == p1)) {
+            return true;
+        }
+    }
+    return false;
+}
+
+void Server_Tournament::advanceRound(GameEventStorage &ges)
+{
+    {
+        QMutexLocker locker(&tournamentMutex);
+        ++currentRound;
+        if (currentRound >= totalRounds) {
+            broadcastTournamentState(ges);
+            return;
+        }
+        generateSwissPairings();
+    }
+
+    enqueueMatchGameCreation();
+    broadcastTournamentState(ges);
+}
+
+bool Server_Tournament::allPairingsDecided() const
+{
+    for (const auto &pairing : currentPairings) {
+        if (pairing.winnerId == -2) {
+            return false;
+        }
+    }
+    return true;
+}
+
+void Server_Tournament::enqueueMatchGameCreation()
+{
+    QList<QPair<int, int>> planned;
+    {
+        QMutexLocker locker(&tournamentMutex);
+        for (const auto &pairing : currentPairings) {
+            if (pairing.player2Id != -1 && pairing.winnerId == -2 &&
+                pairing.matchGameIds.size() < static_cast<int>(gamesPerMatch)) {
+                planned.append(qMakePair(pairing.player1Id, pairing.player2Id));
+            }
+        }
+    }
+    if (planned.isEmpty()) {
+        return;
+    }
+
+    // Create the games from the event loop instead of the caller's stack: command
+    // processing holds game mutexes, and room registration takes gamesLock, so spawning
+    // synchronously would nest lock orders. The queued job runs once this object's
+    // owning thread returns to its event loop with no locks held; it is dropped if this
+    // tournament is destroyed first.
+    QMetaObject::invokeMethod(
+        this,
+        [this, planned] {
+            for (const auto &pair : planned) {
+                createMatchGame(pair.first, pair.second);
+            }
+
+            GameEventStorage ges;
+            broadcastTournamentState(ges);
+            ges.sendToGame(parentGame);
+        },
+        Qt::QueuedConnection);
+}
+
+void Server_Tournament::createMatchGame(int player1Id, int player2Id)
+{
+    if (!matchGameFactory || player2Id == -1) {
+        return;
+    }
+
+    QString player1Name;
+    QString player2Name;
+    QString deck1Native;
+    QString deck2Native;
+    int round = 0;
+    int gameNumber = 1;
+    {
+        QMutexLocker locker(&tournamentMutex);
+        player1Name = players.value(player1Id).playerName;
+        player2Name = players.value(player2Id).playerName;
+
+        if (submittedDecks.contains(player1Id)) {
+            deck1Native = submittedDecks.value(player1Id)->writeToString_Native();
+        }
+        if (submittedDecks.contains(player2Id)) {
+            deck2Native = submittedDecks.value(player2Id)->writeToString_Native();
+        }
+
+        round = currentRound;
+        for (const auto &pairing : currentPairings) {
+            if (pairing.player1Id == player1Id && pairing.player2Id == player2Id) {
+                gameNumber = pairing.matchGameIds.size() + 1;
+                break;
+            }
+        }
+
+        // Defense in depth: never exceed the configured series length
+        for (const auto &pairing : currentPairings) {
+            if (pairing.player1Id == player1Id && pairing.player2Id == player2Id &&
+                pairing.matchGameIds.size() >= static_cast<int>(gamesPerMatch)) {
+                qCWarning(TournamentLog) << "Refusing to exceed series length for pairing" << player1Id << player2Id;
+                return;
+            }
+        }
+    }
+
+    // Create a sub-game for this match via the factory
+    ServerInfo_User creatorInfo;
+    creatorInfo.set_name(player1Name.toStdString());
+    creatorInfo.set_user_level(ServerInfo_User::IsAdmin | ServerInfo_User::IsRegistered);
+
+    QString gameDesc = gamesPerMatch > 1 ? QString("R%1 Match - Game %2 of %3").arg(round).arg(gameNumber).arg(gamesPerMatch)
+                                         : QString("Tournament Round %1").arg(round);
+
+    GameConfig matchConfig;
+    matchConfig.creatorInfo = creatorInfo;
+    matchConfig.description = gameDesc;
+    matchConfig.maxPlayers = 2;
+    matchConfig.startingLifeTotal = parentGame->getStartingLifeTotal();
+
+    int matchGameId = -1;
+    auto *matchGame = matchGameFactory->createMatchGame(matchConfig, matchGameId);
+    if (!matchGame || matchGameId == -1) {
+        return;
+    }
+
+    matchGame->setTournamentMatchInfo(parentGame, player1Id, player2Id);
+    matchGame->setMatchResultStrategy(new Server_TournamentMatchResultStrategy);
+    matchGameFactory->addGameToRoom(matchGame);
+
+    // Store the game ID in the pairing
+    {
+        QMutexLocker locker(&tournamentMutex);
+        for (auto &pairing : currentPairings) {
+            if (pairing.player1Id == player1Id && pairing.player2Id == player2Id) {
+                pairing.gameId = matchGameId;
+                pairing.matchGameIds.append(matchGameId);
+                break;
+            }
+        }
+    }
+
+    // Auto-join both players, sending the join event directly through their UIs.
+    QMap<int, QPair<Server_AbstractUserInterface *, ResponseContainer *>> joiners;
+
+    auto joinAndSetupPlayer = [&](int pid, const QString &name) {
+        Server_AbstractUserInterface *ui = matchGameFactory->getUserInterface(name);
+        if (ui) {
+            auto *rc = new ResponseContainer(0);
+            matchGame->addPlayer(ui, *rc, false, false, false);
+            joiners[pid] = qMakePair(ui, rc);
+        }
+    };
+
+    joinAndSetupPlayer(player1Id, player1Name);
+    joinAndSetupPlayer(player2Id, player2Name);
+
+    // Now send the enqueued GameJoined + GameStateChanged events to each player's client.
+    for (auto it = joiners.constBegin(); it != joiners.constEnd(); ++it) {
+        it.value().first->sendResponseContainer(*it.value().second, Response::RespNothing);
+        delete it.value().second;
+    }
+    joiners.clear();
+
+    // Set decks and mark players as ready in the match game
+    auto matchPlayers = matchGame->getPlayers();
+    for (auto *matchPlayer : matchPlayers) {
+        const QString name = QString::fromStdString(matchPlayer->getUserInfo()->name());
+        QString deckNative;
+        if (name == player1Name) {
+            deckNative = deck1Native;
+        } else if (name == player2Name) {
+            deckNative = deck2Native;
+        }
+
+        if (!deckNative.isEmpty()) {
+            matchPlayer->setDeck(new DeckList(deckNative));
+            matchPlayer->setReadyStart(true);
+        }
+    }
+
+    // Start the match game
+    matchGame->startGameIfReady(true);
+}
+
+void Server_Tournament::recordMatchResult(int playerId1, int playerId2, int winnerId, GameEventStorage &ges)
+{
+    QMutexLocker locker(&tournamentMutex);
+
+    // Find the pairing and set the winner
+    for (auto &pairing : currentPairings) {
+        if ((pairing.player1Id == playerId1 && pairing.player2Id == playerId2) ||
+            (pairing.player1Id == playerId2 && pairing.player2Id == playerId1)) {
+            if (pairing.winnerId != -2) {
+                return; // Already recorded — defense in depth against double-call
+            }
+            pairing.winnerId = winnerId;
+            break;
+        }
+    }
+
+    // Update player records
+    if (winnerId == -1) {
+        // Draw
+        players[playerId1].draws += 1;
+        players[playerId2].draws += 1;
+    } else if (winnerId == playerId1) {
+        players[playerId1].wins += 1;
+        players[playerId2].losses += 1;
+    } else if (winnerId == playerId2) {
+        players[playerId2].wins += 1;
+        players[playerId1].losses += 1;
+    }
+
+    // Store for future pairing avoidance
+    allPreviousPairings.append(qMakePair(playerId1, playerId2));
+
+    // Check if all pairings in current round have results
+    bool allDecided = true;
+    for (const auto &pairing : currentPairings) {
+        if (pairing.winnerId == -2) {
+            allDecided = false;
+            break;
+        }
+    }
+
+    broadcastTournamentState(ges);
+
+    if (allDecided) {
+        advanceRound(ges);
+    }
+}
+
+bool Server_Tournament::recordMatchResultByGameId(int gameId, int winnerId, GameEventStorage &ges)
+{
+    bool matchDecided = false;
+    bool seriesContinues = false;
+    int p1 = -1;
+    int p2 = -1;
+    {
+        QMutexLocker locker(&tournamentMutex);
+
+        // Find the pairing that owns this game
+        TournamentPairingData *pairingPtr = nullptr;
+        for (auto &pairing : currentPairings) {
+            if (pairing.matchGameIds.contains(gameId)) {
+                pairingPtr = &pairing;
+                break;
+            }
+        }
+
+        if (!pairingPtr) {
+            return false;
+        }
+
+        // If the match is already decided, ignore further sub-game results
+        if (pairingPtr->winnerId != -2) {
+            return true;
+        }
+
+        // Increment per-match wins
+        if (winnerId == pairingPtr->player1Id) {
+            pairingPtr->player1MatchWins += 1;
+        } else if (winnerId == pairingPtr->player2Id) {
+            pairingPtr->player2MatchWins += 1;
+        }
+        // Draw (winnerId == -1): no match wins incremented
+
+        // Check if match is decided
+        const int gamesNeeded = static_cast<int>(gamesPerMatch);
+        matchDecided =
+            (pairingPtr->player1MatchWins >= gamesNeeded) || (pairingPtr->player2MatchWins >= gamesNeeded);
+
+        if (matchDecided) {
+            // Determine match winner
+            int matchWinnerId;
+            if (pairingPtr->player1MatchWins >= gamesNeeded) {
+                matchWinnerId = pairingPtr->player1Id;
+            } else {
+                matchWinnerId = pairingPtr->player2Id;
+            }
+
+            // Set the match winner on the pairing
+            pairingPtr->winnerId = matchWinnerId;
+
+            // Update tournament-level player records
+            if (matchWinnerId == pairingPtr->player1Id) {
+                players[pairingPtr->player1Id].wins += 1;
+                players[pairingPtr->player2Id].losses += 1;
+            } else {
+                players[pairingPtr->player2Id].wins += 1;
+                players[pairingPtr->player1Id].losses += 1;
+            }
+
+            // Store for future pairing avoidance
+            allPreviousPairings.append(qMakePair(pairingPtr->player1Id, pairingPtr->player2Id));
+        } else {
+            // Match not decided — spawn the next sub-game outside all locks
+            seriesContinues = true;
+            p1 = pairingPtr->player1Id;
+            p2 = pairingPtr->player2Id;
+        }
+
+        broadcastTournamentState(ges);
+    }
+
+    if (seriesContinues) {
+        QMetaObject::invokeMethod(
+            this,
+            [this, p1, p2] {
+                createMatchGame(p1, p2);
+
+                GameEventStorage nextGes;
+                broadcastTournamentState(nextGes);
+                nextGes.sendToGame(parentGame);
+            },
+            Qt::QueuedConnection);
+    }
+
+    checkAndAdvanceRound(ges);
+
+    return matchDecided;
+}
+
+void Server_Tournament::checkAndAdvanceRound(GameEventStorage &ges)
+{
+    bool roundComplete = false;
+    {
+        QMutexLocker locker(&tournamentMutex);
+        roundComplete = allPairingsDecided();
+    }
+
+    if (roundComplete) {
+        advanceRound(ges);
+    }
+}
+
+void Server_Tournament::broadcastTournamentState(GameEventStorage &ges)
+{
+    QMutexLocker locker(&tournamentMutex);
+
+    Event_TournamentState state;
+
+    if (started && currentRound >= totalRounds) {
+        state.set_phase(Event_TournamentState::PHASE_FINISHED);
+    } else if (started) {
+        state.set_phase(Event_TournamentState::PHASE_PLAYING);
+    } else {
+        state.set_phase(Event_TournamentState::PHASE_DECK_BUILDING);
+    }
+
+    state.set_current_round(currentRound);
+    state.set_total_rounds(totalRounds);
+
+    // Settings
+    TournamentSettings *settings = state.mutable_settings();
+    settings->set_games_per_match(gamesPerMatch);
+
+    for (auto it = players.constBegin(); it != players.constEnd(); ++it) {
+        TournamentPlayer *p = state.add_players();
+        p->set_player_id(it->playerId);
+        p->set_player_name(it->playerName.toStdString());
+        p->set_wins(it->wins);
+        p->set_losses(it->losses);
+        p->set_draws(it->draws);
+        p->set_deck_submitted(it->deckSubmitted);
+    }
+
+    for (const auto &pairing : currentPairings) {
+        TournamentPairing *p = state.add_pairings();
+        p->set_player1_id(pairing.player1Id);
+        p->set_player2_id(pairing.player2Id);
+        p->set_game_id(pairing.gameId);
+        // Map internal sentinel: -2 (undecided) -> -1 (no winner yet in proto)
+        p->set_winner_id(pairing.winnerId == -2 ? -1 : pairing.winnerId);
+        p->set_player1_match_wins(pairing.player1MatchWins);
+        p->set_player2_match_wins(pairing.player2MatchWins);
+    }
+
+    ges.enqueueGameEvent(state, -1);
+}

libcockatrice_network/libcockatrice/network/server/remote/game/server_tournament.h

@@ -0,0 +1,106 @@
+#ifndef SERVER_TOURNAMENT_H
+#define SERVER_TOURNAMENT_H
+
+#include <QList>
+#include <QMap>
+#include <QObject>
+#include <QRecursiveMutex>
+#include <QSet>
+#include <libcockatrice/protocol/pb/event_tournament_state.pb.h>
+
+class DeckList;
+class Server_Game;
+class Server_MatchGameFactory;
+class Server_AbstractParticipant;
+class Server_AbstractUserInterface;
+class GameEventStorage;
+
+/** @brief Maximum number of games per match a tournament can be configured with. */
+constexpr int MAX_GAMES_PER_MATCH = 5;
+
+class Server_Tournament : public QObject
+{
+    Q_OBJECT
+public:
+    explicit Server_Tournament(Server_Game *_parentGame, Server_MatchGameFactory *_factory, QObject *parent = nullptr);
+    ~Server_Tournament() override;
+
+    void addPlayer(int playerId, const QString &playerName);
+    void removePlayer(int playerId);
+    void startTournament();
+    void advanceRound(GameEventStorage &ges);
+    void recordMatchResult(int playerId1, int playerId2, int winnerId, GameEventStorage &ges);
+    bool recordMatchResultByGameId(int gameId, int winnerId, GameEventStorage &ges);
+    void broadcastTournamentState(GameEventStorage &ges);
+
+    bool isStarted() const
+    {
+        return started;
+    }
+    bool isAllDecksSubmitted() const;
+    int getPlayerCount() const
+    {
+        return players.size();
+    }
+    int getTournamentPlayerIdByName(const QString &name) const;
+    void setPlayerDeckSubmitted(int playerId)
+    {
+        if (players.contains(playerId)) {
+            players[playerId].deckSubmitted = true;
+        }
+    }
+    void setPlayerDeck(int playerId, DeckList *deck);
+
+    void setGamesPerMatch(uint32_t n)
+    {
+        gamesPerMatch = n;
+    }
+    uint32_t getGamesPerMatch() const
+    {
+        return gamesPerMatch;
+    }
+
+    struct TournamentPlayerData
+    {
+        int playerId;
+        QString playerName;
+        int wins = 0;
+        int losses = 0;
+        int draws = 0;
+        bool deckSubmitted = false;
+    };
+
+    struct TournamentPairingData
+    {
+        int player1Id;
+        int player2Id;
+        int gameId = -1;
+        int winnerId = -2; // -2 = undecided, -1 = draw, >= 0 = winner player id
+        int player1MatchWins = 0;
+        int player2MatchWins = 0;
+        QList<int> matchGameIds;
+    };
+
+private:
+    Server_Game *parentGame;
+    Server_MatchGameFactory *matchGameFactory;
+    mutable QRecursiveMutex tournamentMutex;
+    QMap<int, TournamentPlayerData> players;
+    QMap<int, DeckList *> submittedDecks;
+    QList<TournamentPairingData> currentPairings;
+    QList<QPair<int, int>> allPreviousPairings;
+    int currentRound;
+    int totalRounds;
+    bool started;
+    uint32_t gamesPerMatch = 1;
+
+    void generateSwissPairings();
+    int calculateTotalRounds() const;
+    bool havePlayed(int p1, int p2) const;
+    bool allPairingsDecided() const;
+    void createMatchGame(int player1Id, int player2Id);
+    void enqueueMatchGameCreation();
+    void checkAndAdvanceRound(GameEventStorage &ges);
+};
+
+#endif // SERVER_TOURNAMENT_H

libcockatrice_network/libcockatrice/network/server/remote/game/server_tournament_lifecycle_strategy.cpp

@@ -0,0 +1,33 @@
+#include "server_tournament_lifecycle_strategy.h"
+
+#include "server_abstract_player.h"
+#include "server_game.h"
+
+#include <QLoggingCategory>
+
+inline Q_LOGGING_CATEGORY(TournamentLifecycleLog, "tournament_lifecycle");
+
+Server_GameLifecycleStrategy::StartAction Server_TournamentLifecycleStrategy::onGameStarting(Server_Game *game)
+{
+    // Match sub-games start through the normal flow; only the tournament hub game is
+    // managed by this lifecycle.
+    if (game->getTournamentParentGame() != nullptr) {
+        return StartAction::ProceedNormal;
+    }
+
+    for (auto *player : game->getPlayers().values()) {
+        if (!player->getDeckList()) {
+            qCWarning(TournamentLifecycleLog)
+                << "Tournament cannot start: player" << player->getUserInfo()->name().c_str() << "has no deck";
+            return StartAction::Handled;
+        }
+    }
+
+    if (!game->getIsTournamentGame()) {
+        qCWarning(TournamentLifecycleLog) << "Tournament lifecycle used for non-tournament game — falling back";
+        return StartAction::ProceedNormal;
+    }
+
+    game->startTournament();
+    return StartAction::Handled;
+}

libcockatrice_network/libcockatrice/network/server/remote/game/server_tournament_lifecycle_strategy.h

@@ -0,0 +1,12 @@
+#ifndef SERVER_TOURNAMENT_LIFECYCLE_STRATEGY_H
+#define SERVER_TOURNAMENT_LIFECYCLE_STRATEGY_H
+
+#include "server_game_lifecycle_strategy.h"
+
+class Server_TournamentLifecycleStrategy : public Server_GameLifecycleStrategy
+{
+public:
+    StartAction onGameStarting(Server_Game *game) override;
+};
+
+#endif

libcockatrice_network/libcockatrice/network/server/remote/game/server_tournament_match_result_strategy.cpp

@@ -0,0 +1,34 @@
+#include "server_tournament_match_result_strategy.h"
+
+#include "../server_response_containers.h"
+#include "server_abstract_player.h"
+#include "server_game.h"
+#include "server_tournament.h"
+
+#include <libcockatrice/protocol/pb/event_game_closed.pb.h>
+#include <libcockatrice/protocol/pb/event_tournament_state.pb.h>
+
+bool Server_TournamentMatchResultStrategy::onGameFinished(Server_Game *game,
+                                                          int playing,
+                                                          Server_AbstractPlayer *lastPlayer)
+{
+    auto *parentGame = game->getTournamentParentGame();
+    if (!parentGame || !parentGame->getTournament()) {
+        return false;
+    }
+
+    int winnerId;
+    if (playing == 0) {
+        winnerId = -1;
+    } else {
+        QString winnerName = QString::fromStdString(lastPlayer->getUserInfo()->name());
+        auto *tournament = parentGame->getTournament();
+        winnerId = tournament->getTournamentPlayerIdByName(winnerName);
+    }
+
+    GameEventStorage parentGes;
+    bool matchDecided = parentGame->getTournament()->recordMatchResultByGameId(game->getGameId(), winnerId, parentGes);
+    parentGes.sendToGame(parentGame);
+
+    return matchDecided;
+}

libcockatrice_network/libcockatrice/network/server/remote/game/server_tournament_match_result_strategy.h

@@ -0,0 +1,12 @@
+#ifndef SERVER_TOURNAMENT_MATCH_RESULT_STRATEGY_H
+#define SERVER_TOURNAMENT_MATCH_RESULT_STRATEGY_H
+
+#include "server_match_result_strategy.h"
+
+class Server_TournamentMatchResultStrategy : public Server_MatchResultStrategy
+{
+public:
+    bool onGameFinished(Server_Game *game, int playing, Server_AbstractPlayer *lastPlayer) override;
+};
+
+#endif

libcockatrice_network/libcockatrice/network/server/remote/server_protocolhandler.cpp

@@ -3,6 +3,7 @@
 #include "game/game_config.h"
 #include "game/server_game.h"
 #include "game/server_player.h"
+#include "game/server_tournament.h"
 #include "server_database_interface.h"
 #include "server_room.h"
 
@@ -916,6 +917,8 @@ Server_ProtocolHandler::cmdCreateGame(const Command_CreateGame &cmd, Server_Room
     int startingLifeTotal = cmd.has_starting_life_total() ? cmd.starting_life_total() : 20;
 
     bool shareDecklistsOnLoad = cmd.has_share_decklists_on_load() ? cmd.share_decklists_on_load() : false;
+    bool isTournament = cmd.has_is_tournament() ? cmd.is_tournament() : false;
+    int gamesPerMatch = cmd.has_games_per_match() ? static_cast<int>(cmd.games_per_match()) : 1;
 
     const int gameId = databaseInterface->getNextGameId();
     if (gameId == -1) {
@@ -940,6 +943,11 @@ Server_ProtocolHandler::cmdCreateGame(const Command_CreateGame &cmd, Server_Room
                       .shareDecklistsOnLoad = shareDecklistsOnLoad};
 
     auto *game = new Server_Game(config, room);
+    game->setIsTournamentGame(isTournament);
+    if (isTournament && game->getTournament()) {
+        game->getTournament()->setGamesPerMatch(
+            static_cast<uint32_t>(qBound(1, gamesPerMatch, MAX_GAMES_PER_MATCH)));
+    }
 
     game->addPlayer(this, rc, asSpectator, asJudge, false);
     room->addGame(game);