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

#include "steamimporter.h"

#include <QDir>
#include <QFile>
#include <QFileInfo>
#include <QRegularExpression>
#include <QStandardPaths>
#include <QTextStream>

SteamImporter::SteamImporter(QObject *parent)
    : PlatformImporter(parent)
{
}

QString SteamImporter::platformName() const
{
    return QStringLiteral("Steam");
}

QString SteamImporter::platformId() const
{
    return QStringLiteral("steam");
}

bool SteamImporter::isAvailable() const
{
    return !findSteamPath().isEmpty();
}

QString SteamImporter::findSteamPath() const
{
    // Common Steam installation paths on Linux
    QStringList possiblePaths = {expandPath(QStringLiteral("~/.steam/steam")),
                                 expandPath(QStringLiteral("~/.local/share/Steam")),
                                 expandPath(QStringLiteral("~/.var/app/com.valvesoftware.Steam/.steam/steam")),
                                 expandPath(QStringLiteral("~/.var/app/com.valvesoftware.Steam/.local/share/Steam")),
                                 QStringLiteral("/usr/share/steam"),
                                 QStringLiteral("/usr/local/share/steam")};

    for (const QString &path : possiblePaths) {
        if (directoryExists(path)) {
            return path;
        }
    }

    return {};
}

QString SteamImporter::steamPath() const
{
    return findSteamPath();
}

QStringList SteamImporter::findLibraryFolders() const
{
    QStringList folders;
    QString steamDir = findSteamPath();

    if (steamDir.isEmpty()) {
        return folders;
    }

    // Add main Steam directory
    QString steamApps = steamDir + QStringLiteral("/steamapps");
    if (directoryExists(steamApps)) {
        folders.append(steamApps);
    }

    // Parse libraryfolders.vdf
    QString libraryFoldersPath = steamApps + QStringLiteral("/libraryfolders.vdf");
    QFile file(libraryFoldersPath);

    if (!file.open(QIODevice::ReadOnly | QIODevice::Text)) {
        return folders;
    }

    QTextStream in(&file);
    QString content = in.readAll();

    // Simple VDF parser for library folders
    static QRegularExpression pathRegex(QStringLiteral("\"path\"\\s+\"([^\"]+)\""));
    QRegularExpressionMatchIterator it = pathRegex.globalMatch(content);

    while (it.hasNext()) {
        QRegularExpressionMatch match = it.next();
        QString path = match.captured(1);
        QString appsPath = path + QStringLiteral("/steamapps");

        if (directoryExists(appsPath) && !folders.contains(appsPath)) {
            folders.append(appsPath);
        }
    }

    return folders;
}

Game *SteamImporter::parseAppManifest(const QString &path)
{
    QFile file(path);
    if (!file.open(QIODevice::ReadOnly | QIODevice::Text)) {
        return nullptr;
    }

    QTextStream in(&file);
    QString content = in.readAll();

    // Simple VDF parser
    auto getValue = [&content](const QString &key) -> QString {
        QRegularExpression regex(QStringLiteral("\"%1\"\\s+\"([^\"]+)\"").arg(key));
        QRegularExpressionMatch match = regex.match(content);
        return match.hasMatch() ? match.captured(1) : QString();
    };

    QString appId = getValue(QStringLiteral("appid"));
    QString name = getValue(QStringLiteral("name"));
    QString installDir = getValue(QStringLiteral("installdir"));

    if (appId.isEmpty() || name.isEmpty()) {
        return nullptr;
    }

    // Skip tools and other non-game content
    QString stateFlags = getValue(QStringLiteral("StateFlags"));
    if (stateFlags == QLatin1String("2")) {
        // Only partially installed
    }

    Game *game = new Game(QStringLiteral("steam-%1").arg(appId), name);
    game->setPlatform(platformName());
    game->setPlatformId(appId);
    game->setLaunchCommand(QStringLiteral("steam://rungameid/%1").arg(appId));

    // Find cover image
    QUrl coverUrl = findCoverImage(appId);
    if (coverUrl.isValid()) {
        game->setCoverUrl(coverUrl);
    }

    // Set installation directory
    QFileInfo manifestInfo(path);
    QString gameDir = manifestInfo.absolutePath() + QStringLiteral("/common/") + installDir;
    game->setWorkingDirectory(gameDir);

    game->setInstalled(true);

    return game;
}

QUrl SteamImporter::findCoverImage(const QString &appId) const
{
    QString steamDir = findSteamPath();
    if (steamDir.isEmpty()) {
        return {};
    }

    // Check local cache first
    QStringList coverNames = {QStringLiteral("library_600x900.jpg"),
                              QStringLiteral("library_600x900_2x.jpg"),
                              QStringLiteral("header.jpg"),
                              QStringLiteral("capsule_616x353.jpg")};

    QString cacheDir = steamDir + QStringLiteral("/appcache/librarycache");
    for (const QString &coverName : coverNames) {
        QString coverPath = cacheDir + QStringLiteral("/%1_%2").arg(appId, coverName);
        if (QFile::exists(coverPath)) {
            return QUrl::fromLocalFile(coverPath);
        }
    }

    // Check alternative grid path
    QString gridDir = steamDir + QStringLiteral("/userdata");
    QDir userDataDir(gridDir);
    QStringList userDirs = userDataDir.entryList(QDir::Dirs | QDir::NoDotAndDotDot);

    for (const QString &userDir : userDirs) {
        QString gridPath = gridDir + QStringLiteral("/%1/config/grid").arg(userDir);
        QDir grid(gridPath);

        if (grid.exists()) {
            QStringList filters = {appId + QStringLiteral("p.*"), appId + QStringLiteral(".*")};
            QStringList images = grid.entryList(filters, QDir::Files);

            if (!images.isEmpty()) {
                return QUrl::fromLocalFile(gridPath + QStringLiteral("/") + images.first());
            }
        }
    }

    // Return Steam CDN URL as fallback
    return QUrl(QStringLiteral("https://steamcdn-a.akamaihd.net/steam/apps/%1/library_600x900_2x.jpg").arg(appId));
}

QList<Game *> SteamImporter::importGames()
{
    QList<Game *> games;
    QStringList libraryFolders = findLibraryFolders();

    int total = 0;
    int current = 0;

    // Count manifests first
    for (const QString &folder : libraryFolders) {
        QDir dir(folder);
        total += dir.entryList({QStringLiteral("appmanifest_*.acf")}, QDir::Files).count();
    }

    for (const QString &folder : libraryFolders) {
        QDir dir(folder);
        QStringList manifests = dir.entryList({QStringLiteral("appmanifest_*.acf")}, QDir::Files);

        for (const QString &manifest : manifests) {
            Game *game = parseAppManifest(folder + QStringLiteral("/") + manifest);
            if (game) {
                games.append(game);
            }
            current++;
            Q_EMIT importProgress(current, total);
        }
    }

    return games;
}