#include "delsystemthemehelper.h"

#include <QBasicTimer>
#include <QWindow>
#include <QSettings>
#include <QLibrary>

#ifdef QT_WIDGETS_LIB
# include <QWidget>
#endif //QT_WIDGETS_LIB

#if QT_VERSION >= QT_VERSION_CHECK(6, 5, 0)
# include <QGuiApplication>
# include <QStyleHints>
#endif

#ifdef Q_OS_WIN
#include <Windows.h>

using DwmSetWindowAttributeFunc = HRESULT(WINAPI *)(HWND hwnd, DWORD dwAttribute, LPCVOID pvAttribute, DWORD cbAttribute);

static DwmSetWindowAttributeFunc pDwmSetWindowAttribute = nullptr;

static inline bool initializeFunctionPointers() {
 static bool initialized = false;
 if (!initialized) {
 HMODULE module = LoadLibraryW(L"dwmapi.dll");
 if (module) {
 if (!pDwmSetWindowAttribute) {
 pDwmSetWindowAttribute = reinterpret_cast<DwmSetWindowAttributeFunc>(
 GetProcAddress(module, "DwmSetWindowAttribute"));
 if (!pDwmSetWindowAttribute) {
 return false;
 }
 }
 initialized = true;
 }
 }

 return initialized;
}
#else //Q_OS_LINUX
# include <QPalette>
#endif //Q_OS_WIN

class DelSystemThemeHelperPrivate
{
public:
 DelSystemThemeHelperPrivate(DelSystemThemeHelper *q) : q_ptr(q) { }

 Q_DECLARE_PUBLIC(DelSystemThemeHelper);

 void _updateThemeColor() {
 Q_Q(DelSystemThemeHelper);

 auto nowThemeColor = q->getThemeColor();
 if (nowThemeColor != m_themeColor) {
 m_themeColor = nowThemeColor;
 emit q->themeColorChanged(nowThemeColor);
 }
 }

 void _updateColorScheme() {
 Q_Q(DelSystemThemeHelper);

 auto nowColorScheme = q->getColorScheme() ;
 if (nowColorScheme != m_colorScheme) {
 m_colorScheme = nowColorScheme;
 emit q->colorSchemeChanged(nowColorScheme);
 }
 }

 DelSystemThemeHelper *q_ptr;
 QColor m_themeColor;
 DelSystemThemeHelper::ColorScheme m_colorScheme = DelSystemThemeHelper::ColorScheme::None;

 QBasicTimer m_timer;
#ifdef Q_OS_WIN
 QSettings m_themeColorSettings { QSettings::UserScope, "Microsoft", "Windows\\DWM" };
 QSettings m_colorSchemeSettings { QSettings::UserScope, "Microsoft", "Windows\\CurrentVersion\\Themes\\Personalize" };
#endif
};

DelSystemThemeHelper::DelSystemThemeHelper(QObject *parent)
 : QObject{ parent }
 , d_ptr(new DelSystemThemeHelperPrivate(this))
{
 Q_D(DelSystemThemeHelper);

 d->m_themeColor = getThemeColor();
 d->m_colorScheme = getColorScheme();

 d->m_timer.start(200, this);

#if QT_VERSION >= QT_VERSION_CHECK(6, 5, 0)
 connect(QGuiApplication::styleHints(), &QStyleHints::colorSchemeChanged, this, [this](Qt::ColorScheme scheme){
 emit colorSchemeChanged(scheme == Qt::ColorScheme::Dark ? ColorScheme::Dark : ColorScheme::Light);
 });
#endif

#ifdef Q_OS_WIN
 initializeFunctionPointers();
#endif
}

DelSystemThemeHelper::~DelSystemThemeHelper()
{

}

QColor DelSystemThemeHelper::getThemeColor() const
{
 Q_D(const DelSystemThemeHelper);

#ifdef Q_OS_WIN
 return QColor::fromRgb(d->m_themeColorSettings.value("ColorizationColor").toUInt());
#else
 return QPalette().color(QPalette::Highlight);
#endif
}

DelSystemThemeHelper::ColorScheme DelSystemThemeHelper::getColorScheme() const
{
 Q_D(const DelSystemThemeHelper);
#if QT_VERSION >= QT_VERSION_CHECK(6, 5, 0)
 const auto scheme = QGuiApplication::styleHints()->colorScheme();
 return scheme == Qt::ColorScheme::Dark ? ColorScheme::Dark : ColorScheme::Light;
#else
#ifdef Q_OS_WIN
 /*! 0:深色 - 1:浅色 */
 return !d->m_colorSchemeSettings.value("AppsUseLightTheme").toBool() ? ColorScheme::Dark : ColorScheme::Light;
#else //linux
 const QPalette defaultPalette;
 const auto text = defaultPalette.color(QPalette::WindowText);
 const auto window = defaultPalette.color(QPalette::Window);
 return text.lightness() > window.lightness() ? ColorScheme::Dark : ColorScheme::Light;
#endif // Q_OS_WIN
#endif // QT_VERSION
}

QColor DelSystemThemeHelper::themeColor()
{
 Q_D(DelSystemThemeHelper);

 d->_updateThemeColor();

 return d->m_themeColor;
}

DelSystemThemeHelper::ColorScheme DelSystemThemeHelper::colorScheme()
{
 Q_D(DelSystemThemeHelper);

 d->_updateColorScheme();

 return d->m_colorScheme;
}

bool DelSystemThemeHelper::setWindowTitleBarMode(QWindow *window, bool isDark)
{
#ifdef Q_OS_WIN
 return bool(pDwmSetWindowAttribute ? !pDwmSetWindowAttribute(HWND(window->winId()), 20, &isDark, sizeof(BOOL)) : false);
#else
 return false;
#endif //Q_OS_WIN
}

#ifdef QT_WIDGETS_LIB
bool DelSystemThemeHelper::setWindowTitleBarMode(QWidget *window, bool isDark)
{
#ifdef Q_OS_WIN
 return bool(pDwmSetWindowAttribute ? !pDwmSetWindowAttribute(HWND(window->winId()), 20, &isDark, sizeof(BOOL)) : false);
#else
 return false;
#endif //Q_OS_WIN
}
#endif //QT_WIDGETS_LIB

void DelSystemThemeHelper::timerEvent(QTimerEvent *)
{
 Q_D(DelSystemThemeHelper);

 d->_updateThemeColor();

#if QT_VERSION < QT_VERSION_CHECK(6, 5, 0)
 d->_updateColorScheme();
#endif
}