// SPDX-License-Identifier: GPL-3.0-or-later
// SPDX-FileCopyrightText: 2024 A-La-Karte Contributors

#include "gamelauncher.h"
#include "app.h"

#include <QCoreApplication>
#include <QDBusArgument>
#include <QDBusConnection>
#include <QDBusInterface>
#include <QDBusReply>
#include <QDBusVariant>
#include <QDateTime>
#include <QDesktopServices>
#include <QDir>
#include <QFileInfo>
#include <QProcess>
#include <QStandardPaths>
#include <QTimer>
#include <QUrl>

static QStringList steamCandidateRoots()
{
    const QString home = QDir::homePath();
    return {
        home + QStringLiteral("/.steam/root"),
        home + QStringLiteral("/.steam/steam"),
        home + QStringLiteral("/.local/share/Steam"),
        home + QStringLiteral("/.var/app/com.valvesoftware.Steam/data/Steam"),
        home + QStringLiteral("/.var/app/com.valvesoftware.Steam/.local/share/Steam"),
    };
}

static QVariant unwrapDbusVariant(QVariant v)
{
    if (v.canConvert<QDBusVariant>()) {
        v = v.value<QDBusVariant>().variant();
    }
    return v;
}

static QVariantMap unwrapVariantMap(const QVariantMap &map)
{
    QVariantMap out;
    for (auto it = map.constBegin(); it != map.constEnd(); ++it) {
        out.insert(it.key(), unwrapDbusVariant(it.value()));
    }
    return out;
}

static QString findSteamClientInstallPathFromProton(const QString &protonExe)
{
    if (protonExe.isEmpty()) {
        return {};
    }

    QDir dir(QFileInfo(protonExe).absoluteDir());
    for (int i = 0; i < 10; ++i) {
        if (dir.exists(QStringLiteral("steamapps"))) {
            return dir.absolutePath();
        }
        if (!dir.cdUp()) {
            break;
        }
    }

    for (const QString &root : steamCandidateRoots()) {
        if (QDir(root).exists(QStringLiteral("steamapps"))) {
            return root;
        }
    }

    return {};
}

static QString discoverDefaultProtonExecutable()
{
    static bool done = false;
    static QString cached;

    if (done) {
        return cached;
    }
    done = true;

    QStringList candidates;
    for (const QString &root : steamCandidateRoots()) {
        const QString compatTools = root + QStringLiteral("/compatibilitytools.d");
        QDir compatDir(compatTools);
        if (compatDir.exists()) {
            const QStringList toolDirs = compatDir.entryList(QDir::Dirs | QDir::NoDotAndDotDot);
            for (const QString &tool : toolDirs) {
                const QString protonPath = compatTools + QLatin1Char('/') + tool + QStringLiteral("/proton");
                if (QFileInfo::exists(protonPath)) {
                    candidates.append(protonPath);
                }
            }
        }

        const QString common = root + QStringLiteral("/steamapps/common");
        QDir commonDir(common);
        if (commonDir.exists()) {
            const QStringList dirs = commonDir.entryList(QDir::Dirs | QDir::NoDotAndDotDot);
            for (const QString &d : dirs) {
                if (!d.contains(QStringLiteral("Proton"), Qt::CaseInsensitive)) {
                    continue;
                }
                const QString protonPath = common + QLatin1Char('/') + d + QStringLiteral("/proton");
                if (QFileInfo::exists(protonPath)) {
                    candidates.append(protonPath);
                }
            }
        }
    }

    candidates.removeDuplicates();
    candidates.sort();

    for (const QString &c : candidates) {
        if (c.contains(QStringLiteral("Proton - Experimental"))) {
            cached = c;
            return cached;
        }
    }

    if (!candidates.isEmpty()) {
        cached = candidates.constLast();
    }

    return cached;
}

GameLauncher::GameLauncher(QObject *parent)
    : QObject(parent)
{
    QDBusConnection bus = QDBusConnection::sessionBus();
    if (bus.isConnected()) {
        bus.connect(QStringLiteral("org.kde.GameCenter1"),
                    QStringLiteral("/org/kde/GameCenter1"),
                    QStringLiteral("org.kde.GameCenter1"),
                    QStringLiteral("SessionAdded"),
                    this,
                    SLOT(onDaemonSessionAdded(QVariantMap)));

        bus.connect(QStringLiteral("org.kde.GameCenter1"),
                    QStringLiteral("/org/kde/GameCenter1"),
                    QStringLiteral("org.kde.GameCenter1"),
                    QStringLiteral("SessionChanged"),
                    this,
                    SLOT(onDaemonSessionChanged(QVariantMap)));

        bus.connect(QStringLiteral("org.kde.GameCenter1"),
                    QStringLiteral("/org/kde/GameCenter1"),
                    QStringLiteral("org.kde.GameCenter1"),
                    QStringLiteral("SessionRemoved"),
                    this,
                    SLOT(onDaemonSessionRemoved(QString, QVariantMap)));

        bus.connect(QStringLiteral("org.kde.GameCenter1"),
                    QStringLiteral("/org/kde/GameCenter1"),
                    QStringLiteral("org.kde.GameCenter1"),
                    QStringLiteral("LaunchFailed"),
                    this,
                    SLOT(onDaemonLaunchFailed(QVariantMap)));
    }

    if (auto *app = qobject_cast<App *>(parent)) {
        connect(app->gameModel(), &GameModel::countChanged, this, [this]() {
            QTimer::singleShot(0, this, [this]() {
                applyRunningStateToLibrary();
            });
        });
    }

    QTimer::singleShot(0, this, [this]() {
        checkDaemonAvailability();
        syncDaemonSessions();
    });
}

GameLauncher::~GameLauncher()
{
    m_daemonGameToSession.clear();
    m_daemonSessionToGame.clear();
}

bool GameLauncher::hasRunningGames() const
{
    return !m_daemonGameToSession.isEmpty();
}

QVariantMap GameLauncher::resolveLaunchInfo(Game *game) const
{
    QVariantMap info;
    info.insert(QStringLiteral("ok"), false);

    if (!game) {
        info.insert(QStringLiteral("error"), tr("No game selected"));
        return info;
    }

    info.insert(QStringLiteral("gameId"), game->id());
    info.insert(QStringLiteral("gameName"), game->name());
    info.insert(QStringLiteral("displayName"), game->name());
    info.insert(QStringLiteral("isRunning"), m_daemonGameToSession.contains(game->id()));

    // Detect provider from platform
    const QString platform = game->platform().toLower();
    if (platform == QLatin1String("steam")) {
        info.insert(QStringLiteral("provider"), QStringLiteral("steam"));
    } else if (platform == QLatin1String("lutris")) {
        info.insert(QStringLiteral("provider"), QStringLiteral("lutris"));
    } else {
        info.insert(QStringLiteral("provider"), QStringLiteral("manual"));
    }

    const QString command = game->launchCommand();
    info.insert(QStringLiteral("launchCommand"), command);
    if (command.isEmpty()) {
        info.insert(QStringLiteral("error"), tr("No launch command configured"));
        return info;
    }

    const QString runner = game->launchRunner().trimmed();
    const QString runnerPath = game->launchRunnerPath().trimmed();
    const QString prefixPath = game->launchPrefixPath().trimmed();
    const QVariantMap launchEnv = game->launchEnv();
    const bool hasLaunchOverrides = !runner.isEmpty() || !runnerPath.isEmpty() || !prefixPath.isEmpty() || !launchEnv.isEmpty();

    info.insert(QStringLiteral("runner"), runner);
    info.insert(QStringLiteral("runnerPath"), runnerPath);
    info.insert(QStringLiteral("prefixPath"), prefixPath);
    info.insert(QStringLiteral("workingDirectory"), game->workingDirectory());
    info.insert(QStringLiteral("hasLaunchOverrides"), hasLaunchOverrides);

    QVariantMap envOverrides;
    for (auto it = launchEnv.constBegin(); it != launchEnv.constEnd(); ++it) {
        const QString key = it.key();
        if (key.isEmpty() || key.contains(QLatin1Char('='))) {
            continue;
        }
        envOverrides.insert(key, it.value().toString());
    }
    info.insert(QStringLiteral("envOverrides"), envOverrides);

    if (!hasLaunchOverrides && command.startsWith(QLatin1String("steam://"))) {
        info.insert(QStringLiteral("ok"), true);
        info.insert(QStringLiteral("launchType"), QStringLiteral("url"));
        info.insert(QStringLiteral("url"), command);
        info.insert(QStringLiteral("provider"), QStringLiteral("steam"));
        return info;
    }

    if (!hasLaunchOverrides && command.startsWith(QLatin1String("lutris "))) {
        info.insert(QStringLiteral("ok"), true);
        info.insert(QStringLiteral("launchType"), QStringLiteral("url"));
        info.insert(QStringLiteral("url"), command.mid(7));
        info.insert(QStringLiteral("provider"), QStringLiteral("lutris"));
        return info;
    }

    QStringList parts;
    if (command.startsWith(QLatin1String("steam://"))) {
        parts = {QStringLiteral("xdg-open"), command};
    } else if (command.startsWith(QLatin1String("lutris "))) {
        parts = {QStringLiteral("xdg-open"), command.mid(7)};
    } else {
        parts = QProcess::splitCommand(command);
    }

    if (parts.isEmpty()) {
        info.insert(QStringLiteral("error"), tr("Invalid launch command"));
        return info;
    }

    const QString program = parts.takeFirst();
    info.insert(QStringLiteral("program"), program);
    info.insert(QStringLiteral("args"), parts);

    QString finalProgram = program;
    QStringList finalArgs = parts;

    QVariantMap effectiveEnv = envOverrides;

    if ((runner == QLatin1String("wine") || runner == QLatin1String("proton")) && (program == QLatin1String("xdg-open"))) {
        info.insert(QStringLiteral("error"), tr("This runner cannot be used with URL-based launch commands"));
        return info;
    }

    if (runner == QLatin1String("custom")) {
        if (runnerPath.isEmpty()) {
            info.insert(QStringLiteral("error"), tr("Custom runner is enabled but no runner path is configured"));
            return info;
        }
        finalProgram = runnerPath;
        finalArgs = {program};
        finalArgs.append(parts);
    } else if (runner == QLatin1String("wine")) {
        QString wineExe = runnerPath;
        if (wineExe.isEmpty()) {
            wineExe = QStandardPaths::findExecutable(QStringLiteral("wine"));
        }
        if (wineExe.isEmpty()) {
            info.insert(QStringLiteral("error"), tr("Wine runner is enabled but Wine was not found"));
            return info;
        }

        QString winePrefix = prefixPath;
        if (winePrefix.isEmpty()) {
            winePrefix = QStandardPaths::writableLocation(QStandardPaths::AppDataLocation) + QStringLiteral("/prefixes/") + game->id();
        }

        effectiveEnv.insert(QStringLiteral("WINEPREFIX"), winePrefix);
        info.insert(QStringLiteral("resolvedPrefixPath"), winePrefix);

        finalProgram = wineExe;
        finalArgs = {program};
        finalArgs.append(parts);
    } else if (runner == QLatin1String("proton")) {
        QString protonExe = runnerPath;
        if (protonExe.isEmpty()) {
            protonExe = discoverDefaultProtonExecutable();
        }
        if (protonExe.isEmpty()) {
            info.insert(QStringLiteral("error"), tr("Proton runner is enabled but no Proton installation was found"));
            return info;
        }

        const QString steamInstallPath = findSteamClientInstallPathFromProton(protonExe);
        info.insert(QStringLiteral("resolvedSteamInstallPath"), steamInstallPath);

        QString compatDataPath = prefixPath;
        if (compatDataPath.isEmpty()) {
            compatDataPath = QStandardPaths::writableLocation(QStandardPaths::AppDataLocation) + QStringLiteral("/prefixes/") + game->id();
        }

        effectiveEnv.insert(QStringLiteral("STEAM_COMPAT_DATA_PATH"), compatDataPath);
        info.insert(QStringLiteral("resolvedPrefixPath"), compatDataPath);

        if (!steamInstallPath.isEmpty()) {
            effectiveEnv.insert(QStringLiteral("STEAM_COMPAT_CLIENT_INSTALL_PATH"), steamInstallPath);
        }

        finalProgram = protonExe;
        finalArgs = {QStringLiteral("run"), program};
        finalArgs.append(parts);
    }

    info.insert(QStringLiteral("finalProgram"), finalProgram);
    info.insert(QStringLiteral("finalArgs"), finalArgs);
    info.insert(QStringLiteral("effectiveEnv"), effectiveEnv);
    info.insert(QStringLiteral("ok"), true);
    return info;
}

void GameLauncher::launchGame(Game *game)

{
    if (!game) {
        return;
    }

    // Check if already running
    if (m_daemonGameToSession.contains(game->id())) {
        Q_EMIT gameError(game, tr("Game is already running"));
        return;
    }

    const QVariantMap info = resolveLaunchInfo(game);
    if (!info.value(QStringLiteral("ok")).toBool()) {
        Q_EMIT gameError(game, info.value(QStringLiteral("error")).toString());
        return;
    }

    const QString launchCommand = info.value(QStringLiteral("launchCommand")).toString();
    const QString launchType = info.value(QStringLiteral("launchType")).toString();
    const QString provider = info.value(QStringLiteral("provider")).toString();

    if (info.value(QStringLiteral("runner")).toString() == QLatin1String("proton")) {
        const QString resolvedPrefixPath = info.value(QStringLiteral("resolvedPrefixPath")).toString();
        if (!resolvedPrefixPath.isEmpty()) {
            QDir().mkpath(resolvedPrefixPath);
        }
    }

    const QString finalProgram = info.value(QStringLiteral("finalProgram")).toString();
    const QStringList finalArgs = info.value(QStringLiteral("finalArgs")).toStringList();
    const QString workingDirectory = info.value(QStringLiteral("workingDirectory")).toString();
    const QVariantMap effectiveEnv = info.value(QStringLiteral("effectiveEnv")).toMap();

    // Always try daemon first — for all launch types
    {
        QDBusInterface iface(QStringLiteral("org.kde.GameCenter1"),
                             QStringLiteral("/org/kde/GameCenter1"),
                             QStringLiteral("org.kde.GameCenter1"),
                             QDBusConnection::sessionBus());
        QVariantMap launchSpec = {
            {QStringLiteral("command"), launchCommand},
            {QStringLiteral("gameId"), game->id()},
            {QStringLiteral("displayName"), game->name()},
            {QStringLiteral("provider"), provider},
            {QStringLiteral("origin"), QStringLiteral("ui")},
        };
        if (!finalProgram.isEmpty()) {
            launchSpec.insert(QStringLiteral("program"), finalProgram);
            launchSpec.insert(QStringLiteral("args"), finalArgs);
        }
        if (!effectiveEnv.isEmpty()) {
            launchSpec.insert(QStringLiteral("envOverrides"), effectiveEnv);
        }
        if (!workingDirectory.isEmpty()) {
            launchSpec.insert(QStringLiteral("workingDirectory"), workingDirectory);
        }

        const QDBusReply<QString> reply = iface.call(QStringLiteral("Launch"), launchSpec);
        if (reply.isValid() && !reply.value().isEmpty()) {
            m_daemonGameToSession.insert(game->id(), reply.value());
            m_daemonSessionToGame.insert(reply.value(), game->id());
            game->setRunning(true);
            game->setLastPlayed(QDateTime::currentDateTime());
            Q_EMIT gameStarted(game);
            Q_EMIT runningGamesChanged();

            if (App::instance()->config()->exitAfterLaunch()) {
                QTimer::singleShot(500, qApp, &QCoreApplication::quit);
            }
            return;
        }

        // Daemon call failed — fallback for URL-type commands only
        if (launchType == QLatin1String("url")) {
            const QString url = info.value(QStringLiteral("url")).toString();
            if (!url.isEmpty()) {
                QDesktopServices::openUrl(QUrl(url));
                game->setLastPlayed(QDateTime::currentDateTime());
                Q_EMIT gameStarted(game);
                return;
            }
        }

        // No fallback for non-URL commands — emit error
        Q_EMIT gameError(game, tr("Game Center daemon is not available"));
    }
}

void GameLauncher::stopGame(Game *game)
{
    if (!game) {
        return;
    }

    QDBusInterface iface(QStringLiteral("org.kde.GameCenter1"),
                         QStringLiteral("/org/kde/GameCenter1"),
                         QStringLiteral("org.kde.GameCenter1"),
                         QDBusConnection::sessionBus());
    iface.call(QStringLiteral("StopByGameId"), game->id());
}

bool GameLauncher::isGameRunning(Game *game) const
{
    return game && m_daemonGameToSession.contains(game->id());
}

void GameLauncher::onDaemonSessionAdded(const QVariantMap &session)
{
    const QVariantMap s = unwrapVariantMap(session);
    const QString sessionId = s.value(QStringLiteral("sessionId")).toString();
    const QString gameId = s.value(QStringLiteral("gameId")).toString();
    if (sessionId.isEmpty() || gameId.isEmpty()) {
        return;
    }

    if (m_daemonSessionToGame.contains(sessionId)) {
        return;
    }

    m_daemonGameToSession.insert(gameId, sessionId);
    m_daemonSessionToGame.insert(sessionId, gameId);

    Game *game = App::instance()->gameModel()->gameById(gameId);
    if (game) {
        game->setRunning(true);
    }
    Q_EMIT runningGamesChanged();

    applyRunningStateToLibrary();
}

void GameLauncher::onDaemonSessionChanged(const QVariantMap &session)
{
    const QVariantMap s = unwrapVariantMap(session);
    const QString sessionId = s.value(QStringLiteral("sessionId")).toString();
    const QString gameId = s.value(QStringLiteral("gameId")).toString();
    if (sessionId.isEmpty() || gameId.isEmpty()) {
        return;
    }

    m_daemonGameToSession.insert(gameId, sessionId);
    m_daemonSessionToGame.insert(sessionId, gameId);

    const QString state = s.value(QStringLiteral("state")).toString();
    if (state == QLatin1String("Exited")) {
        return;
    }

    Game *game = App::instance()->gameModel()->gameById(gameId);
    if (game) {
        game->setRunning(true);
    }

    Q_EMIT runningGamesChanged();

    applyRunningStateToLibrary();
}

void GameLauncher::onDaemonSessionRemoved(const QString &sessionId, const QVariantMap &finalState)
{
    if (sessionId.isEmpty()) {
        return;
    }

    QString gameId = m_daemonSessionToGame.take(sessionId);
    if (!gameId.isEmpty()) {
        m_daemonGameToSession.remove(gameId);
    } else {
        const QVariantMap fs = unwrapVariantMap(finalState);
        gameId = fs.value(QStringLiteral("gameId")).toString();
        if (!gameId.isEmpty()) {
            m_daemonGameToSession.remove(gameId);
        }
    }

    Game *game = !gameId.isEmpty() ? App::instance()->gameModel()->gameById(gameId) : nullptr;
    if (game) {
        game->setRunning(false);
        const QVariantMap fs = unwrapVariantMap(finalState);
        Q_EMIT gameStopped(game, fs.value(QStringLiteral("exitCode")).toInt());
    }
    Q_EMIT runningGamesChanged();

    applyRunningStateToLibrary();
}

void GameLauncher::onDaemonLaunchFailed(const QVariantMap &error)
{
    const QVariantMap e = unwrapVariantMap(error);
    QVariantMap context;
    {
        QVariant ctx = unwrapDbusVariant(e.value(QStringLiteral("context")));
        if (ctx.canConvert<QVariantMap>()) {
            context = ctx.toMap();
        } else if (ctx.canConvert<QDBusArgument>()) {
            context = qdbus_cast<QVariantMap>(ctx.value<QDBusArgument>());
        }
    }

    QString gameId = unwrapDbusVariant(context.value(QStringLiteral("gameId"))).toString();
    if (gameId.isEmpty()) {
        gameId = e.value(QStringLiteral("gameId")).toString();
    }
    if (gameId.isEmpty()) {
        return;
    }

    const QString message = e.value(QStringLiteral("error")).toString();
    if (message.isEmpty()) {
        return;
    }

    QTimer::singleShot(100, this, [this, gameId, message]() {
        if (m_daemonGameToSession.contains(gameId)) {
            return;
        }

        Game *game = App::instance()->gameModel()->gameById(gameId);
        if (!game) {
            return;
        }

        Q_EMIT gameError(game, message);
    });
}

void GameLauncher::syncDaemonSessions()
{
    QDBusInterface iface(QStringLiteral("org.kde.GameCenter1"),
                         QStringLiteral("/org/kde/GameCenter1"),
                         QStringLiteral("org.kde.GameCenter1"),
                         QDBusConnection::sessionBus());

    const QDBusReply<QVariantList> reply = iface.call(QStringLiteral("ListSessions"));
    if (!reply.isValid()) {
        return;
    }

    const QVariantList list = reply.value();
    for (const QVariant &v : list) {
        QVariantMap map;
        if (v.canConvert<QVariantMap>()) {
            map = v.toMap();
        } else if (v.canConvert<QDBusArgument>()) {
            map = qdbus_cast<QVariantMap>(v.value<QDBusArgument>());
        }
        if (!map.isEmpty()) {
            onDaemonSessionAdded(map);
        }
    }

    applyRunningStateToLibrary();
}

void GameLauncher::applyRunningStateToLibrary()
{
    const QList<Game *> games = App::instance()->gameModel()->allGames();
    for (Game *game : games) {
        if (!game) {
            continue;
        }
        const bool shouldBeRunning = m_daemonGameToSession.contains(game->id());
        game->setRunning(shouldBeRunning);
    }
}

void GameLauncher::checkDaemonAvailability()
{
    QDBusInterface iface(QStringLiteral("org.kde.GameCenter1"),
                         QStringLiteral("/org/kde/GameCenter1"),
                         QStringLiteral("org.kde.GameCenter1"),
                         QDBusConnection::sessionBus());

    const QDBusReply<QString> reply = iface.call(QStringLiteral("Ping"));
    const bool available = reply.isValid() && reply.value() == QLatin1String("ok");
    if (available != m_daemonAvailable) {
        m_daemonAvailable = available;
        Q_EMIT daemonAvailableChanged();
    }
}

bool GameLauncher::daemonAvailable() const
{
    return m_daemonAvailable;
}

void GameLauncher::retryDaemonConnection()
{
    checkDaemonAvailability();
    if (m_daemonAvailable) {
        syncDaemonSessions();
    }
}