From 9a7b20cbfdf20467fc2827eb360898cd8aaf5cd8 Mon Sep 17 00:00:00 2001
From: Janek Bevendorff <janek@jbev.net>
Date: Thu, 24 Dec 2020 00:09:51 +0100
Subject: [PATCH] Add dynamic theme switching on Windows 10

---
 src/gui/ApplicationSettingsWidget.cpp |  2 +-
 src/gui/Icons.cpp                     |  2 +-
 src/gui/osutils/winutils/WinUtils.cpp | 21 +++++++++++++--------
 src/gui/osutils/winutils/WinUtils.h   |  3 +++
 4 files changed, 18 insertions(+), 10 deletions(-)

diff --git a/src/gui/ApplicationSettingsWidget.cpp b/src/gui/ApplicationSettingsWidget.cpp
index d105b76d7..8fcb85cd8 100644
--- a/src/gui/ApplicationSettingsWidget.cpp
+++ b/src/gui/ApplicationSettingsWidget.cpp
@@ -251,7 +251,7 @@ void ApplicationSettingsWidget::loadSettings()
     }
 
     m_generalUi->trayIconAppearance->clear();
-#ifdef Q_OS_MACOS
+#if defined(Q_OS_MACOS) || defined(Q_OS_WIN)
     m_generalUi->trayIconAppearance->addItem(tr("Monochrome"), "monochrome");
 #else
     m_generalUi->trayIconAppearance->addItem(tr("Monochrome (light)"), "monochrome-light");
diff --git a/src/gui/Icons.cpp b/src/gui/Icons.cpp
index 2f117b4ff..1b40a3fe9 100644
--- a/src/gui/Icons.cpp
+++ b/src/gui/Icons.cpp
@@ -80,7 +80,7 @@ QIcon Icons::trayIcon(QString style)
     }
 
     QIcon i;
-#ifdef Q_OS_MACOS
+#if defined(Q_OS_MACOS) || defined(Q_OS_WIN)
     if (osUtils->isStatusBarDark()) {
         i = icon(QString("keepassxc-monochrome-light%1").arg(style), false);
     } else {
diff --git a/src/gui/osutils/winutils/WinUtils.cpp b/src/gui/osutils/winutils/WinUtils.cpp
index 302c3914c..1ccade5f5 100644
--- a/src/gui/osutils/winutils/WinUtils.cpp
+++ b/src/gui/osutils/winutils/WinUtils.cpp
@@ -29,6 +29,8 @@ WinUtils* WinUtils::instance()
 {
     if (!m_instance) {
         m_instance = new WinUtils(qApp);
+        m_instance->m_darkAppThemeActive = m_instance->isDarkMode();
+        m_instance->m_darkSystemThemeActive = m_instance->isStatusBarDark();
 
 #ifdef QT_DEBUG
         // Attach console to enable debug output
@@ -63,15 +65,17 @@ bool WinUtils::nativeEventFilter(const QByteArray& eventType, void* message, lon
 
     auto* msg = static_cast<MSG*>(message);
     switch (msg->message) {
-    /* TODO: indicate dark mode support for black title bar
-    case WM_CREATE:
-    case WM_INITDIALOG: {
-        if (msg->hwnd && winUtils()->isDarkMode()) {
+    case WM_SETTINGCHANGE:
+        if (m_darkAppThemeActive != isDarkMode()) {
+            m_darkAppThemeActive = !m_darkAppThemeActive;
+            emit interfaceThemeChanged();
+        }
 
+        if (m_darkSystemThemeActive != isStatusBarDark()) {
+            m_darkSystemThemeActive = !m_darkSystemThemeActive;
+            emit statusbarThemeChanged();
         }
         break;
-    }
-    */
     case WM_HOTKEY:
         triggerGlobalShortcut(msg->wParam);
         break;
@@ -89,8 +93,9 @@ bool WinUtils::isDarkMode() const
 
 bool WinUtils::isStatusBarDark() const
 {
-    // TODO: implement
-    return isDarkMode();
+    QSettings settings(R"(HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Themes\Personalize)",
+                       QSettings::NativeFormat);
+    return settings.value("SystemUsesLightTheme", 0).toInt() == 0;
 }
 
 bool WinUtils::isLaunchAtStartupEnabled() const
diff --git a/src/gui/osutils/winutils/WinUtils.h b/src/gui/osutils/winutils/WinUtils.h
index 9e9f72684..b7ef47573 100644
--- a/src/gui/osutils/winutils/WinUtils.h
+++ b/src/gui/osutils/winutils/WinUtils.h
@@ -72,6 +72,9 @@ private:
     int m_nextShortcutId = 1;
     QHash<QString, QSharedPointer<globalShortcut>> m_globalShortcuts;
 
+    bool m_darkAppThemeActive;
+    bool m_darkSystemThemeActive;
+
     Q_DISABLE_COPY(WinUtils)
 };