/*
 * Bittorrent Client using Qt and libtorrent.
 * Copyright (C) 2019  Prince Gupta <jagannatharjun11@gmail.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
 * USA.
 *
 * In addition, as a special exception, the copyright holders give permission to
 * link this program with the OpenSSL project's "OpenSSL" library (or with
 * modified versions of it that use the same license as the "OpenSSL" library),
 * and distribute the linked executables. You must obey the GNU General Public
 * License in all respects for all of the code used other than "OpenSSL".  If
 * you modify file(s), you may extend this exception to your version of the
 * file(s), but you are not obligated to do so. If you do not wish to do so,
 * delete this exception statement from your version.
 */

#include "uithememanager.h"

#include <QApplication>
#include <QFile>
#include <QIcon>
#include <QResource>

#include "base/iconprovider.h"
#include "base/logger.h"
#include "base/preferences.h"
#include "base/utils/fs.h"

UIThemeManager *UIThemeManager::m_instance = nullptr;

void UIThemeManager::freeInstance()
{
    if (m_instance) {
        delete m_instance;
        m_instance = nullptr;
    }
}

void UIThemeManager::initInstance()
{
    if (!m_instance)
        m_instance = new UIThemeManager;
}

UIThemeManager::UIThemeManager()
{
    const Preferences *const pref = Preferences::instance();
    if (pref->useCustomUITheme()
        && !QResource::registerResource(pref->customUIThemePath(), "/uitheme"))
        LogMsg(tr("Failed to load UI theme from file: \"%1\"").arg(pref->customUIThemePath()), Log::WARNING);

#if (defined(Q_OS_UNIX) && !defined(Q_OS_MAC))
    m_useSystemTheme = pref->useSystemIconTheme();
#endif
}

UIThemeManager *UIThemeManager::instance()
{
    return m_instance;
}

void UIThemeManager::applyStyleSheet() const
{
    if (!Preferences::instance()->useCustomUITheme()) {
        qApp->setStyleSheet({});
        return;
    }

    QFile qssFile(":uitheme/stylesheet.qss");
    if (!qssFile.open(QIODevice::ReadOnly | QIODevice::Text)) {
        qApp->setStyleSheet({});
        LogMsg(tr("Couldn't apply theme stylesheet. stylesheet.qss couldn't be opened. Reason: %1").arg(qssFile.errorString())
               , Log::WARNING);
        return;
    }

    qApp->setStyleSheet(qssFile.readAll());
}

QIcon UIThemeManager::getIcon(const QString &iconId) const
{
    return getIcon(iconId, iconId);
}

QIcon UIThemeManager::getIcon(const QString &iconId, const QString &fallback) const
{
#if (defined(Q_OS_UNIX) && !defined(Q_OS_MAC))
    if (m_useSystemTheme) {
        QIcon icon = QIcon::fromTheme(iconId);
        if (icon.name() != iconId)
            icon = QIcon::fromTheme(fallback, QIcon(IconProvider::instance()->getIconPath(iconId)));
        return icon;
    }
#else
    Q_UNUSED(fallback)
#endif
    // cache to avoid rescaling svg icons
    static QHash<QString, QIcon> iconCache;
    const auto iter = iconCache.find(iconId);
    if (iter != iconCache.end())
        return *iter;

    const QIcon icon {IconProvider::instance()->getIconPath(iconId)};
    iconCache[iconId] = icon;
    return icon;
}

QIcon UIThemeManager::getFlagIcon(const QString &countryIsoCode) const
{
    if (countryIsoCode.isEmpty()) return {};
    return QIcon(":/icons/flags/" + countryIsoCode.toLower() + ".svg");
}

QString UIThemeManager::getIconPath(const QString &iconId) const
{
#if (defined(Q_OS_UNIX) && !defined(Q_OS_MAC))
    if (m_useSystemTheme) {
        QString path = Utils::Fs::tempPath() + iconId + ".png";
        if (!QFile::exists(path)) {
            const QIcon icon = QIcon::fromTheme(iconId);
            if (!icon.isNull())
                icon.pixmap(32).save(path);
            else
                path = IconProvider::instance()->getIconPath(iconId);
        }

        return path;
    }
#endif
    return IconProvider::instance()->getIconPath(iconId);
}