[Replay] Show the history sidebar in replay tabs

Add the Game History dock to the left of replay tabs, wire it to the replay timeline, and register it with the View menu and layout reset.

cockatrice/CMakeLists.txt

@@ -249,6 +249,8 @@ set(cockatrice_SOURCES
     src/interface/widgets/playmat/playmat_settings_dialog.cpp
     src/interface/widgets/quick_settings/settings_button_widget.cpp
     src/interface/widgets/quick_settings/settings_popup_widget.cpp
+    src/interface/widgets/replay/replay_event_index.cpp
+    src/interface/widgets/replay/replay_event_sidebar.cpp
     src/interface/widgets/replay/replay_manager.cpp
     src/interface/widgets/replay/replay_quick_settings_widget.cpp
     src/interface/widgets/replay/replay_timeline_widget.cpp

cockatrice/src/interface/widgets/replay/replay_event_index.cpp

@@ -0,0 +1,876 @@
+#include "replay_event_index.h"
+
+#include "libcockatrice/protocol/get_pb_extension.h"
+#include "libcockatrice/protocol/pb/card_attributes.pb.h"
+#include "libcockatrice/protocol/pb/context_concede.pb.h"
+#include "libcockatrice/protocol/pb/context_connection_state_changed.pb.h"
+#include "libcockatrice/protocol/pb/context_deck_select.pb.h"
+#include "libcockatrice/protocol/pb/context_mulligan.pb.h"
+#include "libcockatrice/protocol/pb/context_ready_start.pb.h"
+#include "libcockatrice/protocol/pb/context_set_sideboard_lock.pb.h"
+#include "libcockatrice/protocol/pb/context_undo_draw.pb.h"
+#include "libcockatrice/protocol/pb/event_attach_card.pb.h"
+#include "libcockatrice/protocol/pb/event_change_zone_properties.pb.h"
+#include "libcockatrice/protocol/pb/event_create_counter.pb.h"
+#include "libcockatrice/protocol/pb/event_create_token.pb.h"
+#include "libcockatrice/protocol/pb/event_del_counter.pb.h"
+#include "libcockatrice/protocol/pb/event_destroy_card.pb.h"
+#include "libcockatrice/protocol/pb/event_draw_cards.pb.h"
+#include "libcockatrice/protocol/pb/event_dump_zone.pb.h"
+#include "libcockatrice/protocol/pb/event_flip_card.pb.h"
+#include "libcockatrice/protocol/pb/event_game_closed.pb.h"
+#include "libcockatrice/protocol/pb/event_game_host_changed.pb.h"
+#include "libcockatrice/protocol/pb/event_game_log_notice.pb.h"
+#include "libcockatrice/protocol/pb/event_game_say.pb.h"
+#include "libcockatrice/protocol/pb/event_game_state_changed.pb.h"
+#include "libcockatrice/protocol/pb/event_join.pb.h"
+#include "libcockatrice/protocol/pb/event_kicked.pb.h"
+#include "libcockatrice/protocol/pb/event_leave.pb.h"
+#include "libcockatrice/protocol/pb/event_move_card.pb.h"
+#include "libcockatrice/protocol/pb/event_player_properties_changed.pb.h"
+#include "libcockatrice/protocol/pb/event_reveal_cards.pb.h"
+#include "libcockatrice/protocol/pb/event_reverse_turn.pb.h"
+#include "libcockatrice/protocol/pb/event_roll_die.pb.h"
+#include "libcockatrice/protocol/pb/event_set_active_phase.pb.h"
+#include "libcockatrice/protocol/pb/event_set_active_player.pb.h"
+#include "libcockatrice/protocol/pb/event_set_card_attr.pb.h"
+#include "libcockatrice/protocol/pb/event_set_card_counter.pb.h"
+#include "libcockatrice/protocol/pb/event_set_counter.pb.h"
+#include "libcockatrice/protocol/pb/event_shuffle.pb.h"
+#include "libcockatrice/protocol/pb/game_event.pb.h"
+#include "libcockatrice/protocol/pb/game_event_container.pb.h"
+#include "libcockatrice/protocol/pb/game_event_context.pb.h"
+#include "libcockatrice/protocol/pb/game_replay.pb.h"
+#include "libcockatrice/protocol/pb/serverinfo_card.pb.h"
+#include "libcockatrice/protocol/pb/serverinfo_counter.pb.h"
+#include "libcockatrice/protocol/pb/serverinfo_player.pb.h"
+#include "libcockatrice/protocol/pb/serverinfo_playerproperties.pb.h"
+#include "libcockatrice/protocol/pb/serverinfo_zone.pb.h"
+#include "libcockatrice/utility/zone_names.h"
+
+#include <QCoreApplication>
+#include <QHash>
+#include <QStringList>
+#include <QtGlobal>
+#include <algorithm>
+#include <libcockatrice/game/phase.h>
+
+namespace
+{
+struct PendingDetail
+{
+    QString text;
+    QString badge;
+    ReplayEventKind kind = ReplayEventKind::Action;
+    QString actor;
+};
+
+QString formatTime(int timeMs)
+{
+    const int totalSeconds = qMax(0, timeMs) / 1000;
+    const int hours = totalSeconds / 3600;
+    const int minutes = (totalSeconds / 60) % 60;
+    const int seconds = totalSeconds % 60;
+
+    if (hours > 0) {
+        return QStringLiteral("%1:%2:%3")
+            .arg(hours)
+            .arg(minutes, 2, 10, QLatin1Char('0'))
+            .arg(seconds, 2, 10, QLatin1Char('0'));
+    }
+
+    return QStringLiteral("%1:%2").arg(minutes, 2, 10, QLatin1Char('0')).arg(seconds, 2, 10, QLatin1Char('0'));
+}
+
+class ReplayEventIndexBuilder
+{
+    Q_DECLARE_TR_FUNCTIONS(ReplayEventIndex)
+
+public:
+    ReplayEventIndexBuilder(const GameReplay *replay, const QList<int> &timeline) : replay(replay), timeline(timeline)
+    {
+    }
+
+    QList<ReplayEventEntry> build()
+    {
+        QList<ReplayEventEntry> entries;
+
+        for (int i = 0; i < replay->event_list_size(); ++i) {
+            const GameEventContainer &container = replay->event_list(i);
+            const QList<PendingDetail> details = describeContainer(container);
+            if (details.isEmpty()) {
+                continue;
+            }
+
+            ReplayEventEntry entry;
+            entry.eventIndex = i;
+            entry.timeMs = timeline.value(i, static_cast<int>(container.seconds_elapsed()) * 1000);
+            entry.timeLabel = formatTime(entry.timeMs);
+            entry.kind = details.first().kind;
+            entry.badge = details.first().badge;
+            if (details.size() > 1) {
+                entry.badge += QStringLiteral(" +%1").arg(details.size() - 1);
+            }
+
+            const QString sharedActor = details.first().actor;
+            const bool mixedActors = std::any_of(details.cbegin(), details.cend(), [&sharedActor](const auto &detail) {
+                return detail.actor != sharedActor;
+            });
+
+            QStringList detailTexts;
+            for (const PendingDetail &detail : details) {
+                if (mixedActors && !detail.actor.isEmpty()) {
+                    detailTexts.append(tr("%1: %2").arg(detail.actor, detail.text));
+                } else {
+                    detailTexts.append(detail.text);
+                }
+            }
+            entry.actor = mixedActors ? QString() : sharedActor;
+            entry.detail = detailTexts.join(QStringLiteral("  •  "));
+
+            entries.append(entry);
+        }
+
+        return entries;
+    }
+
+private:
+    const GameReplay *replay;
+    const QList<int> &timeline;
+
+    QHash<int, QString> playerNames;
+    QHash<int, bool> spectators;
+    QHash<QString, QString> cardNames;
+    QHash<QString, QString> counterNames;
+
+    int activePlayerId = -1;
+    bool gameStarted = false;
+    bool sawGameState = false;
+
+    static QString cardKey(int playerId, const QString &zone, int cardId)
+    {
+        return QStringLiteral("%1/%2/%3").arg(playerId).arg(zone).arg(cardId);
+    }
+
+    static QString counterKey(int playerId, int counterId)
+    {
+        return QStringLiteral("%1/%2").arg(playerId).arg(counterId);
+    }
+
+    QString playerName(int playerId) const
+    {
+        if (playerId < 0) {
+            return tr("Game");
+        }
+        return playerNames.value(playerId, tr("Player %1").arg(playerId));
+    }
+
+    QString actorName(int playerId) const
+    {
+        if (playerId < 0) {
+            return QString();
+        }
+        return playerNames.value(playerId, tr("Player %1").arg(playerId));
+    }
+
+    bool isSpectator(int playerId) const
+    {
+        return spectators.value(playerId, false);
+    }
+
+    void rememberPlayer(const ServerInfo_PlayerProperties &properties)
+    {
+        const int playerId = properties.player_id();
+        if (playerId < 0) {
+            return;
+        }
+
+        const QString name = QString::fromStdString(properties.user_info().name());
+        if (!name.isEmpty()) {
+            playerNames.insert(playerId, name);
+        }
+        spectators.insert(playerId, properties.spectator());
+    }
+
+    void rememberCard(int playerId, const QString &zone, int cardId, const QString &name)
+    {
+        if (cardId >= 0 && !name.isEmpty()) {
+            cardNames.insert(cardKey(playerId, zone, cardId), name);
+        }
+    }
+
+    void forgetCard(int playerId, const QString &zone, int cardId)
+    {
+        if (cardId >= 0) {
+            cardNames.remove(cardKey(playerId, zone, cardId));
+        }
+    }
+
+    QString cardName(int playerId, const QString &zone, int cardId) const
+    {
+        if (cardId < 0) {
+            return QString();
+        }
+        return cardNames.value(cardKey(playerId, zone, cardId));
+    }
+
+    void rememberCounter(int playerId, const ServerInfo_Counter &counter)
+    {
+        const QString name = QString::fromStdString(counter.name());
+        if (!name.isEmpty()) {
+            counterNames.insert(counterKey(playerId, counter.id()), name);
+        }
+    }
+
+    QString counterName(int playerId, int counterId) const
+    {
+        return counterNames.value(counterKey(playerId, counterId));
+    }
+
+    QString zoneName(const QString &zone) const
+    {
+        if (zone == ZoneNames::TABLE) {
+            return tr("battlefield");
+        }
+        if (zone == ZoneNames::GRAVE) {
+            return tr("graveyard");
+        }
+        if (zone == ZoneNames::EXILE) {
+            return tr("exile");
+        }
+        if (zone == ZoneNames::HAND) {
+            return tr("hand");
+        }
+        if (zone == ZoneNames::DECK) {
+            return tr("library");
+        }
+        if (zone == ZoneNames::SIDEBOARD) {
+            return tr("sideboard");
+        }
+        if (zone == ZoneNames::STACK) {
+            return tr("stack");
+        }
+        return zone;
+    }
+
+    QString zonePhrase(int playerId, const QString &zone, int actorId) const
+    {
+        if (zone == ZoneNames::TABLE) {
+            return tr("the battlefield");
+        }
+        if (zone == ZoneNames::EXILE) {
+            return tr("exile");
+        }
+        if (zone == ZoneNames::STACK) {
+            return tr("the stack");
+        }
+
+        const QString name = zoneName(zone);
+        if (playerId < 0 || playerId == actorId) {
+            return tr("their %1").arg(name);
+        }
+        return tr("%1's %2").arg(playerName(playerId), name);
+    }
+
+    QString formatCardList(const QStringList &names, int total) const
+    {
+        // Keep repeats: each entry is a drawn/revealed card, so the list length must agree with the count.
+        QStringList listedNames;
+        for (const QString &name : names) {
+            if (!name.isEmpty()) {
+                listedNames.append(name);
+            }
+        }
+
+        if (listedNames.isEmpty()) {
+            if (total <= 0) {
+                return tr("no cards");
+            }
+            return total == 1 ? tr("1 card") : tr("%1 cards").arg(total);
+        }
+
+        if (total < listedNames.size()) {
+            total = listedNames.size();
+        }
+
+        if (listedNames.size() > 3) {
+            return tr("%1 and %2 more").arg(listedNames.mid(0, 3).join(QStringLiteral(", "))).arg(total - 3);
+        }
+        if (total > listedNames.size()) {
+            return tr("%1 and %2 more").arg(listedNames.join(QStringLiteral(", "))).arg(total - listedNames.size());
+        }
+
+        return listedNames.join(QStringLiteral(", "));
+    }
+
+    void updateGameState(const Event_GameStateChanged &event)
+    {
+        for (int i = 0; i < event.player_list_size(); ++i) {
+            const ServerInfo_Player &player = event.player_list(i);
+            const int playerId = player.properties().player_id();
+            rememberPlayer(player.properties());
+
+            for (int j = 0; j < player.zone_list_size(); ++j) {
+                const ServerInfo_Zone &zone = player.zone_list(j);
+                for (int k = 0; k < zone.card_list_size(); ++k) {
+                    const ServerInfo_Card &card = zone.card_list(k);
+                    rememberCard(playerId, QString::fromStdString(zone.name()), card.id(),
+                                 QString::fromStdString(card.name()));
+                }
+            }
+
+            for (int j = 0; j < player.counter_list_size(); ++j) {
+                rememberCounter(playerId, player.counter_list(j));
+            }
+        }
+
+        if (event.has_active_player_id()) {
+            activePlayerId = event.active_player_id();
+        }
+        if (event.has_game_started()) {
+            gameStarted = event.game_started();
+        }
+    }
+
+    QString describeMoveCard(const Event_MoveCard &event, int actorId, const GameEventContext &context)
+    {
+        const int startPlayerId = event.start_player_id() >= 0 ? event.start_player_id() : actorId;
+        const int targetPlayerId = event.target_player_id() >= 0 ? event.target_player_id() : startPlayerId;
+        const QString startZone = QString::fromStdString(event.start_zone());
+        const QString targetZone = event.has_target_zone() ? QString::fromStdString(event.target_zone()) : startZone;
+
+        QString name;
+        if (event.has_card_name()) {
+            name = QString::fromStdString(event.card_name());
+        }
+        if (name.isEmpty()) {
+            name = cardName(startPlayerId, startZone, event.card_id());
+        }
+
+        const bool knownName = !name.isEmpty();
+        if (name.isEmpty()) {
+            name = event.face_down() ? tr("a face-down card") : tr("a card");
+        }
+
+        const int newCardId = event.has_new_card_id() ? event.new_card_id() : event.card_id();
+        forgetCard(startPlayerId, startZone, event.card_id());
+        if (knownName) {
+            rememberCard(targetPlayerId, targetZone, newCardId, name);
+        }
+
+        if (startZone == targetZone) {
+            return tr("moved %1 within %2.").arg(name, zonePhrase(targetPlayerId, targetZone, actorId));
+        }
+        if (context.HasExtension(Context_UndoDraw::ext)) {
+            return tr("returned %1 to %2.").arg(name, zonePhrase(targetPlayerId, targetZone, actorId));
+        }
+
+        return tr("moved %1 from %2 to %3.")
+            .arg(name, zonePhrase(startPlayerId, startZone, actorId), zonePhrase(targetPlayerId, targetZone, actorId));
+    }
+
+    QString describeSetCardAttribute(const Event_SetCardAttr &event, int actorId)
+    {
+        const QString zone = QString::fromStdString(event.zone_name());
+        QString name;
+        if (event.has_card_id()) {
+            name = cardName(actorId, zone, event.card_id());
+        }
+        if (name.isEmpty()) {
+            name = event.has_card_id() ? tr("a card") : tr("all cards");
+        }
+
+        const QString value = QString::fromStdString(event.attr_value());
+        switch (event.attribute()) {
+            case AttrTapped:
+                return value == QLatin1String("1") ? tr("tapped %1.").arg(name) : tr("untapped %1.").arg(name);
+            case AttrAttacking:
+                return value == QLatin1String("1") ? tr("%1 is now attacking.").arg(name)
+                                                   : tr("%1 is no longer attacking.").arg(name);
+            case AttrFaceDown:
+                return value == QLatin1String("1") ? tr("turned %1 face down.").arg(name)
+                                                   : tr("turned %1 face up.").arg(name);
+            case AttrColor:
+                return tr("changed %1's color to %2.").arg(name, value);
+            case AttrPT:
+                return tr("set %1's power/toughness to %2.").arg(name, value);
+            case AttrAnnotation:
+                return value.isEmpty() ? tr("cleared %1's annotation.").arg(name)
+                                       : tr("annotated %1: %2").arg(name, value);
+            case AttrDoesntUntap:
+                return value == QLatin1String("1") ? tr("%1 will no longer untap.").arg(name)
+                                                   : tr("%1 will untap normally again.").arg(name);
+        }
+
+        return tr("changed %1.").arg(name);
+    }
+
+    QString badgeForCardAttribute(CardAttribute attribute) const
+    {
+        switch (attribute) {
+            case AttrTapped:
+                return tr("TAP");
+            case AttrAttacking:
+                return tr("ATTACK");
+            case AttrFaceDown:
+                return tr("FLIP");
+            case AttrColor:
+                return tr("COLOR");
+            case AttrPT:
+                return tr("PT");
+            case AttrAnnotation:
+                return tr("NOTE");
+            case AttrDoesntUntap:
+                return tr("TAP");
+        }
+        return tr("CARD");
+    }
+
+    QString describeLeaveReason(Event_Leave::LeaveReason reason) const
+    {
+        switch (reason) {
+            case Event_Leave::USER_KICKED:
+                return tr("kicked by game host or moderator");
+            case Event_Leave::USER_LEFT:
+                return tr("left the game");
+            case Event_Leave::USER_DISCONNECTED:
+                return tr("disconnected");
+            case Event_Leave::OTHER:
+            default:
+                return tr("reason unknown");
+        }
+    }
+
+    void addDetail(QList<PendingDetail> &details,
+                   const QString &text,
+                   const QString &badge,
+                   ReplayEventKind kind,
+                   int actorId,
+                   bool forcedByJudge) const
+    {
+        if (text.isEmpty()) {
+            return;
+        }
+
+        const QString finalText = forcedByJudge ? tr("%1 (judge)").arg(text) : text;
+        details.append(PendingDetail{.text = finalText, .badge = badge, .kind = kind, .actor = actorName(actorId)});
+    }
+
+    QList<PendingDetail> describeContainer(const GameEventContainer &container)
+    {
+        QList<PendingDetail> details;
+        const GameEventContext &context = container.context();
+        const bool forcedByJudge = container.has_forced_by_judge();
+        const auto contextType = static_cast<GameEventContext::ContextType>(getPbExtension(context));
+
+        for (int i = 0; i < container.event_list_size(); ++i) {
+            const GameEvent &event = container.event_list(i);
+            const int eventPlayerId = event.player_id();
+            const auto eventType = static_cast<GameEvent::GameEventType>(getPbExtension(event));
+
+            switch (eventType) {
+                case GameEvent::GAME_STATE_CHANGED: {
+                    const Event_GameStateChanged &state = event.GetExtension(Event_GameStateChanged::ext);
+                    const bool wasStarted = gameStarted;
+                    updateGameState(state);
+                    if (state.game_started() && !wasStarted) {
+                        addDetail(details, tr("Game started."), tr("GAME"), ReplayEventKind::System, -1, forcedByJudge);
+                    } else if (!sawGameState) {
+                        addDetail(details, tr("Game state loaded."), tr("GAME"), ReplayEventKind::System, -1,
+                                  forcedByJudge);
+                    }
+                    sawGameState = true;
+                    break;
+                }
+                case GameEvent::PLAYER_PROPERTIES_CHANGED: {
+                    const Event_PlayerPropertiesChanged &propertiesEvent =
+                        event.GetExtension(Event_PlayerPropertiesChanged::ext);
+                    const bool hasProperties = propertiesEvent.has_player_properties();
+                    const ServerInfo_PlayerProperties &properties = propertiesEvent.player_properties();
+                    // The server only fills in the field that changed, so player_id is absent from these events
+                    // unless they are about a specific player; fall back to the event's own player id.
+                    const bool describesPlayer = hasProperties && properties.has_player_id();
+                    const int playerId = describesPlayer ? properties.player_id() : eventPlayerId;
+                    if (describesPlayer) {
+                        rememberPlayer(properties);
+                    }
+
+                    switch (contextType) {
+                        case GameEventContext::READY_START:
+                            addDetail(details,
+                                      properties.ready_start() ? tr("is ready to start.") : tr("is no longer ready."),
+                                      tr("READY"), ReplayEventKind::System, playerId, forcedByJudge);
+                            break;
+                        case GameEventContext::CONCEDE:
+                            addDetail(details, tr("conceded the game."), tr("CONCEDE"), ReplayEventKind::System,
+                                      playerId, forcedByJudge);
+                            break;
+                        case GameEventContext::UNCONCEDE:
+                            addDetail(details, tr("unconceded the game."), tr("CONCEDE"), ReplayEventKind::System,
+                                      playerId, forcedByJudge);
+                            break;
+                        case GameEventContext::DECK_SELECT: {
+                            const Context_DeckSelect &deckSelect = context.GetExtension(Context_DeckSelect::ext);
+                            const int sideboardSize = deckSelect.sideboard_size();
+                            addDetail(details,
+                                      sideboardSize >= 0
+                                          ? tr("selected a deck with %1 sideboard cards.").arg(sideboardSize)
+                                          : tr("selected a deck."),
+                                      tr("DECK"), ReplayEventKind::System, playerId, forcedByJudge);
+                            break;
+                        }
+                        case GameEventContext::MULLIGAN: {
+                            const Context_Mulligan &mulligan = context.GetExtension(Context_Mulligan::ext);
+                            addDetail(details,
+                                      mulligan.number() > 0 ? tr("took a mulligan (%1).").arg(mulligan.number())
+                                                            : tr("took a mulligan."),
+                                      tr("MULLIGAN"), ReplayEventKind::System, playerId, forcedByJudge);
+                            break;
+                        }
+                        case GameEventContext::SET_SIDEBOARD_LOCK:
+                            addDetail(details,
+                                      properties.sideboard_locked() ? tr("locked their sideboard.")
+                                                                    : tr("unlocked their sideboard."),
+                                      tr("SIDEBOARD"), ReplayEventKind::System, playerId, forcedByJudge);
+                            break;
+                        case GameEventContext::CONNECTION_STATE_CHANGED:
+                            addDetail(details,
+                                      properties.ping_seconds() != -1 ? tr("reconnected to the game.")
+                                                                      : tr("lost connection to the game."),
+                                      tr("CONNECTION"), ReplayEventKind::System, playerId, forcedByJudge);
+                            break;
+                        default:
+                            break;
+                    }
+                    break;
+                }
+                case GameEvent::JOIN: {
+                    const Event_Join &join = event.GetExtension(Event_Join::ext);
+                    if (join.has_player_properties()) {
+                        rememberPlayer(join.player_properties());
+                    }
+                    const int playerId = join.player_properties().player_id() >= 0
+                                             ? join.player_properties().player_id()
+                                             : eventPlayerId;
+                    addDetail(details, isSpectator(playerId) ? tr("joined as a spectator.") : tr("joined the game."),
+                              tr("JOIN"), ReplayEventKind::System, playerId, forcedByJudge);
+                    break;
+                }
+                case GameEvent::LEAVE: {
+                    const Event_Leave &leave = event.GetExtension(Event_Leave::ext);
+                    const QString reason = describeLeaveReason(leave.reason());
+                    if (eventPlayerId < 0) {
+                        addDetail(details, tr("A player left the game (%1).").arg(reason), tr("LEAVE"),
+                                  ReplayEventKind::System, -1, forcedByJudge);
+                    } else {
+                        addDetail(details,
+                                  isSpectator(eventPlayerId) ? tr("stopped spectating (%1).").arg(reason)
+                                                             : tr("left the game (%1).").arg(reason),
+                                  tr("LEAVE"), ReplayEventKind::System, eventPlayerId, forcedByJudge);
+                    }
+                    break;
+                }
+                case GameEvent::KICKED:
+                    addDetail(details,
+                              eventPlayerId >= 0 ? tr("was kicked from the game.")
+                                                 : tr("A player was kicked from the game."),
+                              tr("KICK"), ReplayEventKind::System, eventPlayerId, forcedByJudge);
+                    break;
+                case GameEvent::GAME_CLOSED:
+                    addDetail(details, tr("Game closed."), tr("GAME"), ReplayEventKind::System, -1, forcedByJudge);
+                    break;
+                case GameEvent::GAME_HOST_CHANGED:
+                    addDetail(details, eventPlayerId >= 0 ? tr("is now the game host.") : tr("The game host changed."),
+                              tr("HOST"), ReplayEventKind::System, eventPlayerId, forcedByJudge);
+                    break;
+                case GameEvent::GAME_SAY: {
+                    const Event_GameSay &say = event.GetExtension(Event_GameSay::ext);
+                    addDetail(details, QString::fromStdString(say.message()), tr("CHAT"), ReplayEventKind::Chat,
+                              eventPlayerId, forcedByJudge);
+                    break;
+                }
+                case GameEvent::SET_ACTIVE_PLAYER: {
+                    const Event_SetActivePlayer &setActivePlayer = event.GetExtension(Event_SetActivePlayer::ext);
+                    activePlayerId = setActivePlayer.active_player_id();
+                    if (activePlayerId >= 0) {
+                        addDetail(details, tr("begins their turn."), tr("TURN"), ReplayEventKind::Turn, activePlayerId,
+                                  forcedByJudge);
+                    }
+                    break;
+                }
+                case GameEvent::SET_ACTIVE_PHASE: {
+                    const Event_SetActivePhase &setActivePhase = event.GetExtension(Event_SetActivePhase::ext);
+                    if (setActivePhase.phase() >= 0) {
+                        const QString phaseName = Phases::getPhase(setActivePhase.phase()).getName();
+                        addDetail(details, tr("entered the %1 phase.").arg(phaseName), tr("PHASE"),
+                                  ReplayEventKind::Phase, activePlayerId >= 0 ? activePlayerId : eventPlayerId,
+                                  forcedByJudge);
+                    }
+                    break;
+                }
+                case GameEvent::REVERSE_TURN: {
+                    const Event_ReverseTurn &reverseTurn = event.GetExtension(Event_ReverseTurn::ext);
+                    addDetail(details,
+                              reverseTurn.reversed() ? tr("reversed the turn order.") : tr("restored the turn order."),
+                              tr("TURN"), ReplayEventKind::Turn, eventPlayerId, forcedByJudge);
+                    break;
+                }
+                case GameEvent::MOVE_CARD: {
+                    const Event_MoveCard &moveCard = event.GetExtension(Event_MoveCard::ext);
+                    const QString text = describeMoveCard(moveCard, eventPlayerId, context);
+                    const QString startZone = QString::fromStdString(moveCard.start_zone());
+                    const QString targetZone = QString::fromStdString(moveCard.target_zone());
+                    QString badge = tr("MOVE");
+                    if (context.HasExtension(Context_UndoDraw::ext)) {
+                        badge = tr("UNDO");
+                    } else if (startZone == ZoneNames::STACK) {
+                        badge = tr("RESOLVE");
+                    } else if (startZone == ZoneNames::HAND && targetZone == ZoneNames::TABLE) {
+                        badge = tr("PLAY");
+                    }
+                    addDetail(details, text, badge, ReplayEventKind::Action, eventPlayerId, forcedByJudge);
+                    break;
+                }
+                case GameEvent::DRAW_CARDS: {
+                    const Event_DrawCards &drawCards = event.GetExtension(Event_DrawCards::ext);
+                    QStringList names;
+                    for (int j = 0; j < drawCards.cards_size(); ++j) {
+                        const ServerInfo_Card &card = drawCards.cards(j);
+                        const QString name = QString::fromStdString(card.name());
+                        names.append(name);
+                        rememberCard(eventPlayerId, ZoneNames::HAND, card.id(), name);
+                    }
+                    if (drawCards.number() > 0) {
+                        addDetail(details, tr("drew %1.").arg(formatCardList(names, drawCards.number())), tr("DRAW"),
+                                  ReplayEventKind::Action, eventPlayerId, forcedByJudge);
+                    }
+                    break;
+                }
+                case GameEvent::REVEAL_CARDS: {
+                    const Event_RevealCards &revealCards = event.GetExtension(Event_RevealCards::ext);
+                    const QString zone = QString::fromStdString(revealCards.zone_name());
+                    QStringList names;
+                    for (int j = 0; j < revealCards.cards_size(); ++j) {
+                        const ServerInfo_Card &card = revealCards.cards(j);
+                        const QString name = QString::fromStdString(card.name());
+                        names.append(name);
+                        rememberCard(eventPlayerId, zone, card.id(), name);
+                    }
+                    const int total =
+                        revealCards.number_of_cards() > 0 ? revealCards.number_of_cards() : revealCards.cards_size();
+                    QString text =
+                        tr("revealed %1 from %2.")
+                            .arg(formatCardList(names, total), zonePhrase(eventPlayerId, zone, eventPlayerId));
+                    if (revealCards.other_player_id() >= 0 && revealCards.other_player_id() != eventPlayerId) {
+                        text = tr("revealed %1 from %2 to %3.")
+                                   .arg(formatCardList(names, total), zonePhrase(eventPlayerId, zone, eventPlayerId),
+                                        playerName(revealCards.other_player_id()));
+                    }
+                    addDetail(details, text, tr("REVEAL"), ReplayEventKind::Action, eventPlayerId, forcedByJudge);
+                    break;
+                }
+                case GameEvent::SHUFFLE: {
+                    const Event_Shuffle &shuffle = event.GetExtension(Event_Shuffle::ext);
+                    addDetail(
+                        details,
+                        tr("shuffled %1.")
+                            .arg(zonePhrase(eventPlayerId, QString::fromStdString(shuffle.zone_name()), eventPlayerId)),
+                        tr("SHUFFLE"), ReplayEventKind::Action, eventPlayerId, forcedByJudge);
+                    break;
+                }
+                case GameEvent::ROLL_DIE: {
+                    const Event_RollDie &rollDie = event.GetExtension(Event_RollDie::ext);
+                    QStringList rolls;
+                    for (int j = 0; j < rollDie.values_size(); ++j) {
+                        rolls.append(QString::number(rollDie.values(j)));
+                    }
+                    if (rolls.isEmpty() && rollDie.value() > 0) {
+                        rolls.append(QString::number(rollDie.value()));
+                    }
+                    const QString sides = rollDie.sides() > 0 ? QString::number(rollDie.sides()) : QStringLiteral("?");
+                    addDetail(details, tr("rolled a d%1: %2.").arg(sides, rolls.join(QStringLiteral(", "))), tr("DICE"),
+                              ReplayEventKind::Action, eventPlayerId, forcedByJudge);
+                    break;
+                }
+                case GameEvent::FLIP_CARD: {
+                    const Event_FlipCard &flipCard = event.GetExtension(Event_FlipCard::ext);
+                    const QString zone = QString::fromStdString(flipCard.zone_name());
+                    if (flipCard.has_card_name()) {
+                        rememberCard(eventPlayerId, zone, flipCard.card_id(),
+                                     QString::fromStdString(flipCard.card_name()));
+                    }
+                    QString name = flipCard.has_card_name() ? QString::fromStdString(flipCard.card_name())
+                                                            : cardName(eventPlayerId, zone, flipCard.card_id());
+                    if (name.isEmpty()) {
+                        name = tr("a card");
+                    }
+                    addDetail(details,
+                              flipCard.face_down() ? tr("flipped %1 face down.").arg(name)
+                                                   : tr("flipped %1 face up.").arg(name),
+                              tr("FLIP"), ReplayEventKind::Action, eventPlayerId, forcedByJudge);
+                    break;
+                }
+                case GameEvent::DESTROY_CARD: {
+                    const Event_DestroyCard &destroyCard = event.GetExtension(Event_DestroyCard::ext);
+                    const QString zone = QString::fromStdString(destroyCard.zone_name());
+                    const QString name = cardName(eventPlayerId, zone, destroyCard.card_id());
+                    forgetCard(eventPlayerId, zone, destroyCard.card_id());
+                    addDetail(details, tr("destroyed %1.").arg(name.isEmpty() ? tr("a card") : name), tr("DESTROY"),
+                              ReplayEventKind::Action, eventPlayerId, forcedByJudge);
+                    break;
+                }
+                case GameEvent::ATTACH_CARD: {
+                    const Event_AttachCard &attachCard = event.GetExtension(Event_AttachCard::ext);
+                    const QString startZone = QString::fromStdString(attachCard.start_zone());
+                    const QString source = cardName(eventPlayerId, startZone, attachCard.card_id());
+                    const QString sourceText = source.isEmpty() ? tr("a card") : source;
+                    // An unattach event carries no target at all, so the target fields default to player 0 / no zone
+                    // / card 0; only a present target_player_id means the card was attached to something.
+                    if (!attachCard.has_target_player_id()) {
+                        addDetail(details, tr("unattached %1.").arg(sourceText), tr("ATTACH"), ReplayEventKind::Action,
+                                  eventPlayerId, forcedByJudge);
+                        break;
+                    }
+                    const QString targetZone = QString::fromStdString(attachCard.target_zone());
+                    const int targetPlayerId =
+                        attachCard.target_player_id() >= 0 ? attachCard.target_player_id() : eventPlayerId;
+                    const QString target = cardName(targetPlayerId, targetZone, attachCard.target_card_id());
+                    addDetail(details,
+                              tr("attached %1 to %2.").arg(sourceText, target.isEmpty() ? tr("a card") : target),
+                              tr("ATTACH"), ReplayEventKind::Action, eventPlayerId, forcedByJudge);
+                    break;
+                }
+                case GameEvent::CREATE_TOKEN: {
+                    const Event_CreateToken &createToken = event.GetExtension(Event_CreateToken::ext);
+                    const QString name = QString::fromStdString(createToken.card_name());
+                    rememberCard(eventPlayerId, QString::fromStdString(createToken.zone_name()), createToken.card_id(),
+                                 name);
+                    const QString pt = QString::fromStdString(createToken.pt());
+                    addDetail(
+                        details,
+                        tr("created a token: %1%2.")
+                            .arg(name.isEmpty() ? tr("token") : name, pt.isEmpty() ? QString() : tr(" (%1)").arg(pt)),
+                        tr("TOKEN"), ReplayEventKind::Action, eventPlayerId, forcedByJudge);
+                    break;
+                }
+                case GameEvent::SET_CARD_ATTR: {
+                    const Event_SetCardAttr &setCardAttr = event.GetExtension(Event_SetCardAttr::ext);
+                    addDetail(details, describeSetCardAttribute(setCardAttr, eventPlayerId),
+                              badgeForCardAttribute(setCardAttr.attribute()), ReplayEventKind::Action, eventPlayerId,
+                              forcedByJudge);
+                    break;
+                }
+                case GameEvent::SET_CARD_COUNTER: {
+                    const Event_SetCardCounter &setCardCounter = event.GetExtension(Event_SetCardCounter::ext);
+                    const QString name = cardName(eventPlayerId, QString::fromStdString(setCardCounter.zone_name()),
+                                                  setCardCounter.card_id());
+                    addDetail(
+                        details,
+                        tr("set a counter on %1 to %2.")
+                            .arg(name.isEmpty() ? tr("a card") : name, QString::number(setCardCounter.counter_value())),
+                        tr("COUNTER"), ReplayEventKind::Action, eventPlayerId, forcedByJudge);
+                    break;
+                }
+                case GameEvent::CREATE_COUNTER: {
+                    const Event_CreateCounter &createCounter = event.GetExtension(Event_CreateCounter::ext);
+                    const ServerInfo_Counter &counter = createCounter.counter_info();
+                    rememberCounter(eventPlayerId, counter);
+                    const QString name = QString::fromStdString(counter.name());
+                    addDetail(details,
+                              tr("created the %1 counter (%2).")
+                                  .arg(name.isEmpty() ? tr("new") : name, QString::number(counter.count())),
+                              tr("COUNTER"), ReplayEventKind::Action, eventPlayerId, forcedByJudge);
+                    break;
+                }
+                case GameEvent::SET_COUNTER: {
+                    const Event_SetCounter &setCounter = event.GetExtension(Event_SetCounter::ext);
+                    const QString name = counterName(eventPlayerId, setCounter.counter_id());
+                    addDetail(details,
+                              tr("set %1 to %2.")
+                                  .arg(name.isEmpty() ? tr("a counter") : tr("the %1 counter").arg(name),
+                                       QString::number(setCounter.value())),
+                              tr("COUNTER"), ReplayEventKind::Action, eventPlayerId, forcedByJudge);
+                    break;
+                }
+                case GameEvent::DEL_COUNTER: {
+                    const Event_DelCounter &delCounter = event.GetExtension(Event_DelCounter::ext);
+                    const QString name = counterName(eventPlayerId, delCounter.counter_id());
+                    counterNames.remove(counterKey(eventPlayerId, delCounter.counter_id()));
+                    addDetail(details,
+                              tr("removed %1.").arg(name.isEmpty() ? tr("a counter") : tr("the %1 counter").arg(name)),
+                              tr("COUNTER"), ReplayEventKind::Action, eventPlayerId, forcedByJudge);
+                    break;
+                }
+                case GameEvent::DUMP_ZONE: {
+                    const Event_DumpZone &dumpZone = event.GetExtension(Event_DumpZone::ext);
+                    const QString zoneOwnerPhrase = zonePhrase(
+                        dumpZone.zone_owner_id(), QString::fromStdString(dumpZone.zone_name()), eventPlayerId);
+                    if (dumpZone.number_cards() < 0) {
+                        addDetail(details, tr("looked at %1.").arg(zoneOwnerPhrase), tr("LOOK"),
+                                  ReplayEventKind::Action, eventPlayerId, forcedByJudge);
+                    } else {
+                        addDetail(details,
+                                  tr("looked at %1 from %2.")
+                                      .arg(formatCardList(QStringList(), dumpZone.number_cards()), zoneOwnerPhrase),
+                                  tr("LOOK"), ReplayEventKind::Action, eventPlayerId, forcedByJudge);
+                    }
+                    break;
+                }
+                case GameEvent::CHANGE_ZONE_PROPERTIES: {
+                    const Event_ChangeZoneProperties &changeZone = event.GetExtension(Event_ChangeZoneProperties::ext);
+                    const QString zone = QString::fromStdString(changeZone.zone_name());
+                    QStringList changes;
+                    if (changeZone.always_reveal_top_card()) {
+                        changes.append(tr("top card revealed to all"));
+                    }
+                    if (changeZone.always_look_at_top_card()) {
+                        changes.append(tr("top card visible to its owner"));
+                    }
+                    addDetail(
+                        details,
+                        changes.isEmpty()
+                            ? tr("changed the properties of %1.").arg(zonePhrase(eventPlayerId, zone, eventPlayerId))
+                            : tr("changed %1: %2.")
+                                  .arg(zonePhrase(eventPlayerId, zone, eventPlayerId),
+                                       changes.join(QStringLiteral(", "))),
+                        tr("ZONE"), ReplayEventKind::Action, eventPlayerId, forcedByJudge);
+                    break;
+                }
+                case GameEvent::GAME_LOG_NOTICE: {
+                    const Event_GameLogNotice &notice = event.GetExtension(Event_GameLogNotice::ext);
+                    switch (notice.notice_type()) {
+                        case Event_GameLogNotice::UNDO_DRAW_FAILED:
+                            addDetail(details, tr("failed to undo a draw."), tr("NOTICE"), ReplayEventKind::System,
+                                      eventPlayerId, forcedByJudge);
+                            break;
+                        default:
+                            addDetail(details, tr("A game notice was logged."), tr("NOTICE"), ReplayEventKind::System,
+                                      -1, forcedByJudge);
+                            break;
+                    }
+                    break;
+                }
+                case GameEvent::CREATE_ARROW:
+                case GameEvent::DELETE_ARROW:
+                    // Arrows are transient visual annotations and would make the history very noisy.
+                    break;
+                default:
+                    addDetail(details, tr("Unrecognized game event."), tr("EVENT"), ReplayEventKind::Action,
+                              eventPlayerId, forcedByJudge);
+                    break;
+            }
+        }
+
+        return details;
+    }
+};
+} // namespace
+
+QList<ReplayEventEntry> buildReplayEventEntries(const GameReplay *replay, const QList<int> &timeline)
+{
+    if (!replay) {
+        return {};
+    }
+
+    return ReplayEventIndexBuilder(replay, timeline).build();
+}

cockatrice/src/interface/widgets/replay/replay_event_index.h

@@ -0,0 +1,43 @@
+#ifndef COCKATRICE_REPLAY_EVENT_INDEX_H
+#define COCKATRICE_REPLAY_EVENT_INDEX_H
+
+#include <QList>
+#include <QString>
+
+class GameReplay;
+
+enum class ReplayEventKind
+{
+    Action,
+    Turn,
+    Phase,
+    Chat,
+    System
+};
+
+/**
+ * @brief One user-visible entry in the replay history sidebar.
+ *
+ * The event index refers to the corresponding GameEventContainer in the replay. It is used to seek the replay to that
+ * container.
+ */
+struct ReplayEventEntry
+{
+    int eventIndex = -1;
+    int timeMs = 0;
+    QString timeLabel;
+    QString actor;
+    QString badge;
+    QString detail;
+    ReplayEventKind kind = ReplayEventKind::Action;
+};
+
+/**
+ * @brief Builds a compact, human-readable index of the events in a replay.
+ *
+ * The returned entries copy all the data they need, so the caller does not need to keep the replay object alive after
+ * this function returns.
+ */
+QList<ReplayEventEntry> buildReplayEventEntries(const GameReplay *replay, const QList<int> &timeline);
+
+#endif // COCKATRICE_REPLAY_EVENT_INDEX_H

cockatrice/src/interface/widgets/replay/replay_event_sidebar.cpp

@@ -0,0 +1,284 @@
+#include "replay_event_sidebar.h"
+
+#include "replay_event_index.h"
+
+#include <QAbstractItemView>
+#include <QFontMetrics>
+#include <QFrame>
+#include <QLabel>
+#include <QListWidget>
+#include <QListWidgetItem>
+#include <QPainter>
+#include <QPalette>
+#include <QStyle>
+#include <QStyledItemDelegate>
+#include <QVBoxLayout>
+#include <algorithm>
+#include <libcockatrice/utility/qt_utils.h>
+
+namespace
+{
+enum ItemDataRole
+{
+    EventIndexRole = Qt::UserRole + 1,
+    TimeLabelRole,
+    KindRole,
+    ActorRole,
+    BadgeRole,
+    DetailRole
+};
+
+QColor accentForKind(ReplayEventKind kind, const QPalette &palette)
+{
+    switch (kind) {
+        case ReplayEventKind::Turn:
+            return QColor(0x4c, 0xaf, 0x50);
+        case ReplayEventKind::Phase:
+            return QColor(0x42, 0xa5, 0xf5);
+        case ReplayEventKind::Chat:
+            return QColor(0xff, 0xb3, 0x00);
+        case ReplayEventKind::System:
+            return palette.mid().color();
+        case ReplayEventKind::Action:
+        default:
+            return palette.highlight().color();
+    }
+}
+
+class ReplayEventDelegate : public QStyledItemDelegate
+{
+public:
+    explicit ReplayEventDelegate(QObject *parent) : QStyledItemDelegate(parent)
+    {
+    }
+
+    void paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const override
+    {
+        painter->save();
+        painter->setRenderHint(QPainter::Antialiasing, true);
+
+        const QPalette &palette = option.palette;
+        const bool selected = option.state.testFlag(QStyle::State_Selected);
+        const bool hovered = option.state.testFlag(QStyle::State_MouseOver);
+        const auto kind = static_cast<ReplayEventKind>(index.data(KindRole).toInt());
+        const QColor accent = accentForKind(kind, palette);
+
+        const QRect card = option.rect.adjusted(4, 2, -4, -2);
+        QColor cardBackground = selected ? palette.highlight().color() : palette.base().color();
+        if (!selected && hovered) {
+            cardBackground = palette.alternateBase().color();
+        }
+
+        painter->setPen(Qt::NoPen);
+        painter->setBrush(cardBackground);
+        painter->drawRoundedRect(card, 6, 6);
+
+        QColor borderColor = selected ? palette.highlightedText().color() : palette.mid().color();
+        borderColor.setAlpha(selected ? 100 : 130);
+        painter->setBrush(Qt::NoBrush);
+        painter->setPen(QPen(borderColor, 1));
+        painter->drawRoundedRect(card.adjusted(0, 0, -1, -1), 6, 6);
+
+        QColor accentColor = accent;
+        if (selected) {
+            accentColor = palette.highlightedText().color();
+            accentColor.setAlpha(210);
+        }
+        painter->setPen(Qt::NoPen);
+        painter->setBrush(accentColor);
+        painter->drawRoundedRect(QRect(card.left() + 7, card.top() + 7, 3, card.height() - 14), 1.5, 1.5);
+
+        const QColor textColor = selected ? palette.highlightedText().color() : palette.text().color();
+        QColor mutedColor = textColor;
+        mutedColor.setAlpha(170);
+
+        QFont timeFont = option.font;
+        timeFont.setBold(true);
+        timeFont.setPointSizeF(qMax(7.0, timeFont.pointSizeF() * 0.9));
+
+        QFont actorFont = option.font;
+        actorFont.setBold(true);
+
+        QFont badgeFont = option.font;
+        badgeFont.setBold(true);
+        badgeFont.setPointSizeF(qMax(6.5, badgeFont.pointSizeF() * 0.72));
+
+        QFont detailFont = option.font;
+        detailFont.setPointSizeF(qMax(7.0, detailFont.pointSizeF() * 0.95));
+
+        const QFontMetrics timeMetrics(timeFont);
+        const QFontMetrics actorMetrics(actorFont);
+        const QFontMetrics badgeMetrics(badgeFont);
+        const QFontMetrics detailMetrics(detailFont);
+
+        const int contentLeft = card.left() + 15;
+        const int contentRight = card.right() - 10;
+        const int topRowTop = card.top() + 6;
+        const int topRowHeight = qMax(timeMetrics.height(), badgeMetrics.height()) + 2;
+
+        const QString timeText = index.data(TimeLabelRole).toString();
+        const QString actorText = index.data(ActorRole).toString();
+        const QString badgeText = index.data(BadgeRole).toString();
+        const QString detailText = index.data(DetailRole).toString();
+
+        const int timeWidth = timeMetrics.horizontalAdvance(timeText);
+        painter->setFont(timeFont);
+        painter->setPen(mutedColor);
+        painter->drawText(QRect(contentLeft, topRowTop, timeWidth + 2, topRowHeight), Qt::AlignLeft | Qt::AlignVCenter,
+                          timeText);
+
+        int actorRight = contentRight;
+        if (!badgeText.isEmpty()) {
+            const int badgeWidth = badgeMetrics.horizontalAdvance(badgeText) + 10;
+            const int badgeHeight = badgeMetrics.height() + 2;
+            const QRect badgeRect(contentRight - badgeWidth, topRowTop + (topRowHeight - badgeHeight) / 2, badgeWidth,
+                                  badgeHeight);
+
+            QColor badgeBackground = accentColor;
+            badgeBackground.setAlpha(selected ? 45 : 32);
+            painter->setPen(Qt::NoPen);
+            painter->setBrush(badgeBackground);
+            painter->drawRoundedRect(badgeRect, 3, 3);
+
+            painter->setFont(badgeFont);
+            painter->setPen(accentColor);
+            painter->drawText(badgeRect, Qt::AlignCenter, badgeText);
+
+            actorRight = badgeRect.left() - 8;
+        }
+
+        const int actorLeft = contentLeft + timeWidth + 10;
+        if (actorRight > actorLeft) {
+            const QString elidedActor =
+                actorMetrics.elidedText(actorText, Qt::ElideRight, qMax(0, actorRight - actorLeft));
+            painter->setFont(actorFont);
+            painter->setPen(textColor);
+            painter->drawText(QRect(actorLeft, topRowTop, actorRight - actorLeft, topRowHeight),
+                              Qt::AlignLeft | Qt::AlignVCenter, elidedActor);
+        }
+
+        const int detailTop = topRowTop + topRowHeight + 2;
+        const int detailHeight = qMax(detailMetrics.height(), card.bottom() - detailTop);
+        const QString elidedDetail =
+            detailMetrics.elidedText(detailText, Qt::ElideRight, qMax(0, contentRight - contentLeft));
+        painter->setFont(detailFont);
+        painter->setPen(textColor);
+        painter->drawText(QRect(contentLeft, detailTop, contentRight - contentLeft, detailHeight),
+                          Qt::AlignLeft | Qt::AlignVCenter, elidedDetail);
+
+        painter->restore();
+    }
+
+    QSize sizeHint(const QStyleOptionViewItem &option, const QModelIndex & /*index*/) const override
+    {
+        const QFontMetrics metrics(option.font);
+        return {0, qMax(58, metrics.height() * 3 + 10)};
+    }
+};
+} // namespace
+
+ReplayEventSidebar::ReplayEventSidebar(QWidget *parent, const GameReplay *replay, const QList<int> &timeline)
+    : QWidget(parent), eventList(new QListWidget(this)), emptyLabel(new QLabel(this))
+{
+    setObjectName("replayEventSidebar");
+
+    eventList->setObjectName("replayEventList");
+    eventList->setItemDelegate(new ReplayEventDelegate(eventList));
+    eventList->setFrameShape(QFrame::NoFrame);
+    eventList->setFocusPolicy(Qt::NoFocus);
+    eventList->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
+    eventList->setSelectionMode(QAbstractItemView::SingleSelection);
+    eventList->setMouseTracking(true);
+    eventList->setUniformItemSizes(true);
+    eventList->setVerticalScrollMode(QAbstractItemView::ScrollPerPixel);
+
+    emptyLabel->setAlignment(Qt::AlignCenter);
+    emptyLabel->setWordWrap(true);
+    emptyLabel->setMargin(16);
+    emptyLabel->setForegroundRole(QPalette::PlaceholderText);
+
+    auto *layout = QtUtils::makeLayout<QVBoxLayout>(this);
+    layout->addWidget(eventList);
+    layout->addWidget(emptyLabel);
+
+    const QList<ReplayEventEntry> entries = buildReplayEventEntries(replay, timeline);
+    eventIndices.reserve(entries.size());
+
+    for (const ReplayEventEntry &entry : entries) {
+        auto *item = new QListWidgetItem(eventList);
+        item->setData(EventIndexRole, entry.eventIndex);
+        item->setData(TimeLabelRole, entry.timeLabel);
+        item->setData(KindRole, static_cast<int>(entry.kind));
+        item->setData(ActorRole, entry.actor);
+        item->setData(BadgeRole, entry.badge);
+        item->setData(DetailRole, entry.detail);
+        const QString tooltip = entry.actor.isEmpty()
+                                    ? tr("%1\n%2").arg(entry.timeLabel, entry.detail)
+                                    : tr("%1 · %2\n%3").arg(entry.timeLabel, entry.actor, entry.detail);
+        item->setToolTip(tooltip);
+        item->setData(Qt::AccessibleTextRole, entry.actor.isEmpty()
+                                                  ? tr("%1: %2").arg(entry.timeLabel, entry.detail)
+                                                  : tr("%1, %2: %3").arg(entry.timeLabel, entry.actor, entry.detail));
+        eventIndices.append(entry.eventIndex);
+    }
+
+    const bool hasEvents = !entries.isEmpty();
+    eventList->setVisible(hasEvents);
+    emptyLabel->setVisible(!hasEvents);
+    emptyLabel->setText(tr("No game events in this replay."));
+
+    connect(eventList, &QListWidget::itemClicked, this, [this](QListWidgetItem *item) {
+        if (!item) {
+            return;
+        }
+
+        setCurrentRow(eventList->row(item));
+        emit eventSelected(item->data(EventIndexRole).toInt());
+    });
+
+    if (hasEvents) {
+        setCurrentRow(-1);
+    }
+}
+
+void ReplayEventSidebar::setCurrentEvent(int eventIndex)
+{
+    if (eventIndices.isEmpty()) {
+        setCurrentRow(-1);
+        return;
+    }
+
+    // The rows hold a subset of the replay's events, in playback order, so the last row at or before eventIndex is the
+    // one the game state has reached. An eventIndex of -1 (nothing replayed yet) selects no row.
+    const auto it = std::upper_bound(eventIndices.cbegin(), eventIndices.cend(), eventIndex);
+    const int row = static_cast<int>(it - eventIndices.cbegin()) - 1;
+    setCurrentRow(row);
+}
+
+void ReplayEventSidebar::setCurrentRow(int row)
+{
+    if (row < 0 || row >= eventList->count()) {
+        row = -1;
+    }
+
+    if (row >= 0) {
+        // The view's current index also moves on mouse press and can be deselected by a ctrl-click,
+        // so the cached row alone cannot tell whether the view is already in the desired state.
+        const QListWidgetItem *item = eventList->item(row);
+        if (row == eventList->currentRow() && item && item->isSelected()) {
+            return;
+        }
+    } else if (row == currentRow) {
+        return;
+    }
+
+    currentRow = row;
+    eventList->setCurrentRow(currentRow);
+
+    if (currentRow >= 0) {
+        QListWidgetItem *item = eventList->item(currentRow);
+        if (!eventList->viewport()->rect().contains(eventList->visualItemRect(item))) {
+            eventList->scrollToItem(item, QAbstractItemView::PositionAtCenter);
+        }
+    }
+}

cockatrice/src/interface/widgets/replay/replay_event_sidebar.h

@@ -0,0 +1,50 @@
+#ifndef COCKATRICE_REPLAY_EVENT_SIDEBAR_H
+#define COCKATRICE_REPLAY_EVENT_SIDEBAR_H
+
+#include <QList>
+#include <QWidget>
+#include <qtmetamacros.h>
+
+class GameReplay;
+class QLabel;
+class QListWidget;
+
+/**
+ * @brief A scrollable list of replay events that can be used to seek the replay.
+ *
+ * The sidebar copies the event data it needs at construction time. It does not keep a reference to the replay or to
+ * the replay manager.
+ */
+class ReplayEventSidebar : public QWidget
+{
+    Q_OBJECT
+
+public:
+    /**
+     * @param parent The parent widget
+     * @param replay The replay to build the event list from
+     * @param timeline Event index to time in milliseconds, as used by ReplayManager
+     */
+    ReplayEventSidebar(QWidget *parent, const GameReplay *replay, const QList<int> &timeline);
+
+public slots:
+    /**
+     * @brief Highlights the row of the event the game state has reached.
+     *
+     * @param eventIndex Index into the replay's event list, or -1 when nothing has been replayed yet
+     */
+    void setCurrentEvent(int eventIndex);
+
+signals:
+    void eventSelected(int eventIndex);
+
+private:
+    void setCurrentRow(int row);
+
+    QListWidget *eventList;
+    QLabel *emptyLabel;
+    QList<int> eventIndices; ///< Replay event index of each row, ascending
+    int currentRow = -1;
+};
+
+#endif // COCKATRICE_REPLAY_EVENT_SIDEBAR_H

cockatrice/src/interface/widgets/replay/replay_manager.h

@@ -66,6 +66,16 @@ public:
         return replayTimeline;
     }
 
+    /**
+     * @brief Index of the last event the game state has processed.
+     *
+     * @return The event index, or -1 while no event has been replayed yet
+     */
+    [[nodiscard]] int getLastProcessedEventIndex() const
+    {
+        return currentEvent - 1;
+    }
+
     void setTimeScaleFactor(qreal _timeScaleFactor);
     void setSkipEmptySections(bool value);
 

cockatrice/src/interface/widgets/replay/replay_widget.cpp

@@ -19,6 +19,11 @@
 
 class GameReplay;
 
+int ReplayWidget::getLastProcessedEventIndex() const
+{
+    return replayManager->getLastProcessedEventIndex();
+}
+
 ReplayWidget::ReplayWidget(QWidget *parent, GameReplay *replay)
     : QWidget(parent), replayPlayButton(nullptr), replayFastForwardButton(nullptr), aReplaySkipForward(nullptr),
       aReplaySkipBackward(nullptr), aReplaySkipForwardBig(nullptr), aReplaySkipBackwardBig(nullptr)

cockatrice/src/interface/widgets/replay/replay_widget.h

@@ -38,6 +38,11 @@ public:
 
     [[nodiscard]] const QList<int> &getReplayTimeline() const;
 
+    /**
+     * @brief Index of the last replay event the game state has processed, or -1 before the first event.
+     */
+    [[nodiscard]] int getLastProcessedEventIndex() const;
+
 public slots:
     void seekToEvent(int eventIndex);
 

cockatrice/src/interface/widgets/tabs/tab_game.cpp

@@ -26,6 +26,7 @@
 #include "../interface/widgets/utility/line_edit_completer.h"
 #include "../main.h"
 #include "../menus/tearoff_menu.h"
+#include "../replay/replay_event_sidebar.h"
 #include "../replay/replay_widget.h"
 #include "../utility/visibility_change_listener.h"
 #include "card/card_completer_proxy_model.h"
@@ -97,7 +98,7 @@ class Message;
 } // namespace google
 
 TabGame::TabGame(TabSupervisor *_tabSupervisor, GameReplay *_replay)
-    : Tab(_tabSupervisor), sayLabel(nullptr), sayEdit(nullptr)
+    : Tab(_tabSupervisor), sayLabel(nullptr), sayEdit(nullptr), replayDock(nullptr), historyDock(nullptr)
 {
     // THIS CTOR IS USED ON REPLAY
     game = new Replay(this, _replay, tabSupervisor->getIsLocalGame(), &SettingsCache::instance().userInterface(),
@@ -113,6 +114,7 @@ TabGame::TabGame(TabSupervisor *_tabSupervisor, GameReplay *_replay)
     addDockWidget(Qt::RightDockWidgetArea, cardInfoDock);
     addDockWidget(Qt::RightDockWidgetArea, playerListDock);
     addDockWidget(Qt::RightDockWidgetArea, messageLayoutDock);
+    addDockWidget(Qt::LeftDockWidgetArea, historyDock);
     addDockWidget(Qt::BottomDockWidgetArea, replayDock);
 
     mainWidget = new QStackedWidget(this);
@@ -154,6 +156,7 @@ TabGame::TabGame(TabSupervisor *_tabSupervisor,
     createPlayAreaWidget();
     createDeckViewContainerWidget();
     replayDock = nullptr;
+    historyDock = nullptr;
 
     addDockWidget(Qt::RightDockWidgetArea, cardInfoDock);
     addDockWidget(Qt::RightDockWidgetArea, playerListDock);
@@ -345,6 +348,9 @@ void TabGame::retranslateUi()
     }
     cardInfoDock->setWindowTitle(tr("Card Info") + (cardInfoDock->isWindow() ? tabText : QString()));
     messageLayoutDock->setWindowTitle(tr("Messages") + (messageLayoutDock->isWindow() ? tabText : QString()));
+    if (historyDock) {
+        historyDock->setWindowTitle(tr("Game History") + (historyDock->isWindow() ? tabText : QString()));
+    }
     if (replayDock) {
         replayDock->setWindowTitle(tr("Replay Timeline") + (replayDock->isWindow() ? tabText : QString()));
     }
@@ -418,6 +424,9 @@ void TabGame::retranslateUi()
     dockToActions[messageLayoutDock].menu->setTitle(tr("Messages"));
     dockToActions[playerListDock].menu->setTitle(tr("Player List"));
 
+    if (historyDock) {
+        dockToActions[historyDock].menu->setTitle(tr("Game History"));
+    }
     if (replayDock) {
         dockToActions[replayDock].menu->setTitle(tr("Replay Timeline"));
     }
@@ -1192,6 +1201,10 @@ void TabGame::createViewMenuItems()
     registerDockWidget(viewMenu, messageLayoutDock, {250, 200});
     registerDockWidget(viewMenu, playerListDock, {250, 50});
 
+    if (historyDock) {
+        registerDockWidget(viewMenu, historyDock, {280, 400});
+    }
+
     if (replayDock) {
         registerDockWidget(viewMenu, replayDock, {900, 100});
     }
@@ -1261,6 +1274,12 @@ void TabGame::actResetLayout()
     addDockWidget(Qt::RightDockWidgetArea, playerListDock);
     addDockWidget(Qt::RightDockWidgetArea, messageLayoutDock);
 
+    if (historyDock) {
+        historyDock->setVisible(true);
+        historyDock->setFloating(false);
+        addDockWidget(Qt::LeftDockWidgetArea, historyDock);
+    }
+
     if (replayDock) {
         replayDock->setVisible(true);
         replayDock->setFloating(false);
@@ -1269,6 +1288,9 @@ void TabGame::actResetLayout()
         cardInfoDock->resize(250, 360);
         messageLayoutDock->resize(250, 200);
         playerListDock->resize(250, 50);
+        if (historyDock) {
+            historyDock->resize(280, 400);
+        }
         replayDock->resize(900, 100);
     } else {
         cardInfoDock->resize(250, 360);
@@ -1322,6 +1344,22 @@ void TabGame::createReplayDock(GameReplay *replay)
             [this](const auto &event, auto options) {
                 game->getGameEventHandler()->processGameEventContainer(event, nullptr, options);
             });
+
+    auto *historySidebar = new ReplayEventSidebar(nullptr, replay, replayWidget->getReplayTimeline());
+    historyDock = new QDockWidget(this);
+    historyDock->setObjectName("historyDock");
+    historyDock->setFeatures(QDockWidget::DockWidgetClosable | QDockWidget::DockWidgetFloatable |
+                             QDockWidget::DockWidgetMovable);
+    historyDock->setWidget(historySidebar);
+    historyDock->setFloating(false);
+
+    connect(historySidebar, &ReplayEventSidebar::eventSelected, replayWidget, &ReplayWidget::seekToEvent);
+    // The sidebar highlights events rather than times, so ask the manager which event the game state has reached.
+    connect(replayWidget, &ReplayWidget::timeChanged, historySidebar,
+            [this, historySidebar] { historySidebar->setCurrentEvent(replayWidget->getLastProcessedEventIndex()); });
+
+    // No event has been replayed yet when the sidebar is connected, so apply the initial state explicitly.
+    historySidebar->setCurrentEvent(replayWidget->getLastProcessedEventIndex());
 }
 
 void TabGame::createDeckViewContainerWidget(bool bReplay)

cockatrice/src/interface/widgets/tabs/tab_game.h

@@ -50,6 +50,7 @@ class AbstractClient;
 class GameView;
 class GameScene;
 class ReplayWidget;
+class ReplayEventSidebar;
 class CardInfoFrameWidget;
 class QLabel;
 class QPushButton;
@@ -89,7 +90,7 @@ private:
     QMap<int, TabbedDeckViewContainer *> deckViewContainers;
     QVBoxLayout *deckViewContainerLayout;
     QWidget *gamePlayAreaWidget, *deckViewContainerWidget;
-    QDockWidget *cardInfoDock, *messageLayoutDock, *playerListDock, *replayDock;
+    QDockWidget *cardInfoDock, *messageLayoutDock, *playerListDock, *replayDock, *historyDock;
     QAction *playersSeparator;
     QMenu *gameMenu, *viewMenu;
     TearOffMenu *phasesMenu;