// Copyright 2015 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.

#pragma once

#include <atomic>

#include <QImage>
#include <QRunnable>
#include <QStandardItem>
#include <QString>

#include "citra_qt/util/util.h"
#include "common/string_util.h"
#include "common/color.h"

#include "core/loader/loader.h"

#include "video_core/utils.h"

/**
 * Tests if data is a valid SMDH by its length and magic number.
 * @param smdh_data data buffer to test
 * @return bool test result
 */
static bool IsValidSMDH(const std::vector<u8>& smdh_data) {
    if (smdh_data.size() < sizeof(Loader::SMDH))
        return false;

    u32 magic;
    memcpy(&magic, smdh_data.data(), 4);

    return Loader::MakeMagic('S', 'M', 'D', 'H') == magic;
}

/**
 * Gets game icon from SMDH
 * @param sdmh SMDH data
 * @param large If true, returns large icon (48x48), otherwise returns small icon (24x24)
 * @return QPixmap game icon
 */
static QPixmap GetIconFromSMDH(const Loader::SMDH& smdh, bool large) {
    u32 size;
    const u8* icon_data;

    if (large) {
        size = 48;
        icon_data = smdh.large_icon.data();
    } else {
        size = 24;
        icon_data = smdh.small_icon.data();
    }

    QImage icon(size, size, QImage::Format::Format_RGB888);
    for (u32 x = 0; x < size; ++x) {
        for (u32 y = 0; y < size; ++y) {
            u32 coarse_y = y & ~7;
            auto v = Color::DecodeRGB565(
                icon_data + VideoCore::GetMortonOffset(x, y, 2) + coarse_y * size * 2);
            icon.setPixel(x, y, qRgb(v.r(), v.g(), v.b()));
        }
    }
    return QPixmap::fromImage(icon);
}

/**
 * Gets the default icon (for games without valid SMDH)
 * @param large If true, returns large icon (48x48), otherwise returns small icon (24x24)
 * @return QPixmap default icon
 */
static QPixmap GetDefaultIcon(bool large) {
    int size = large ? 48 : 24;
    QPixmap icon(size, size);
    icon.fill(Qt::transparent);
    return icon;
}

/**
 * Gets the short game title fromn SMDH
 * @param sdmh SMDH data
 * @param language title language
 * @return QString short title
 */
static QString GetShortTitleFromSMDH(const Loader::SMDH& smdh, Loader::SMDH::TitleLanguage language) {
    return QString::fromUtf16(smdh.titles[static_cast<int>(language)].short_title.data());
}

class GameListItem : public QStandardItem {

public:
    GameListItem(): QStandardItem() {}
    GameListItem(const QString& string): QStandardItem(string) {}
    virtual ~GameListItem() override {}
};


/**
 * A specialization of GameListItem for path values.
 * This class ensures that for every full path value it holds, a correct string representation
 * of just the filename (with no extension) will be displayed to the user.
 * If this class recieves valid SMDH data, it will also display game icons and titles.
 */
class GameListItemPath : public GameListItem {

public:
    static const int FullPathRole = Qt::UserRole + 1;
    static const int TitleRole = Qt::UserRole + 2;

    GameListItemPath(): GameListItem() {}
    GameListItemPath(const QString& game_path, const std::vector<u8>& smdh_data): GameListItem()
    {
        setData(game_path, FullPathRole);

        if (!IsValidSMDH(smdh_data)) {
            // SMDH is not valid, set a default icon
            setData(GetDefaultIcon(true), Qt::DecorationRole);
            return;
        }

        Loader::SMDH smdh;
        memcpy(&smdh, smdh_data.data(), sizeof(Loader::SMDH));

        // Get icon from SMDH
        setData(GetIconFromSMDH(smdh, true), Qt::DecorationRole);

        // Get title form SMDH
        setData(GetShortTitleFromSMDH(smdh, Loader::SMDH::TitleLanguage::English), TitleRole);
    }

    QVariant data(int role) const override {
        if (role == Qt::DisplayRole) {
            std::string filename;
            Common::SplitPath(data(FullPathRole).toString().toStdString(), nullptr, &filename, nullptr);
            QString title = data(TitleRole).toString();
            return QString::fromStdString(filename) + (title.isEmpty() ? "" : "\n    " + title);
        } else {
            return GameListItem::data(role);
        }
    }
};


/**
 * A specialization of GameListItem for size values.
 * This class ensures that for every numerical size value it holds (in bytes), a correct
 * human-readable string representation will be displayed to the user.
 */
class GameListItemSize : public GameListItem {

public:
    static const int SizeRole = Qt::UserRole + 1;

    GameListItemSize(): GameListItem() {}
    GameListItemSize(const qulonglong size_bytes): GameListItem()
    {
        setData(size_bytes, SizeRole);
    }

    void setData(const QVariant& value, int role) override
    {
        // By specializing setData for SizeRole, we can ensure that the numerical and string
        // representations of the data are always accurate and in the correct format.
        if (role == SizeRole) {
            qulonglong size_bytes = value.toULongLong();
            GameListItem::setData(ReadableByteSize(size_bytes), Qt::DisplayRole);
            GameListItem::setData(value, SizeRole);
        } else {
            GameListItem::setData(value, role);
        }
    }

    /**
     * This operator is, in practice, only used by the TreeView sorting systems.
     * Override it so that it will correctly sort by numerical value instead of by string representation.
     */
    bool operator<(const QStandardItem& other) const override
    {
        return data(SizeRole).toULongLong() < other.data(SizeRole).toULongLong();
    }
};


/**
 * Asynchronous worker object for populating the game list.
 * Communicates with other threads through Qt's signal/slot system.
 */
class GameListWorker : public QObject, public QRunnable {
    Q_OBJECT

public:
    GameListWorker(QString dir_path, bool deep_scan):
            QObject(), QRunnable(), dir_path(dir_path), deep_scan(deep_scan) {}

public slots:
    /// Starts the processing of directory tree information.
    void run() override;
    /// Tells the worker that it should no longer continue processing. Thread-safe.
    void Cancel();

signals:
    /**
     * The `EntryReady` signal is emitted once an entry has been prepared and is ready
     * to be added to the game list.
     * @param entry_items a list with `QStandardItem`s that make up the columns of the new entry.
     */
    void EntryReady(QList<QStandardItem*> entry_items);
    void Finished();

private:
    QString dir_path;
    bool deep_scan;
    std::atomic_bool stop_processing;

    void AddFstEntriesToGameList(const std::string& dir_path, bool deep_scan);
};