remove broken system paellete detection within our custom style

remove custom binding between c++ native Qt API for system palette and
our QML styling code for colors detection

fixes many issues with dark mode using Windows native style

Signed-off-by: Matthieu Gallien <matthieu.gallien@nextcloud.com>

src/libsync/theme.cpp

@@ -928,49 +928,12 @@ void Theme::connectToPaletteSignal()
 {
     if (!_paletteSignalsConnected) {
         if (const auto ptr = qobject_cast<QGuiApplication *>(QGuiApplication::instance())) {
-            connect(ptr, &QGuiApplication::paletteChanged, this, &Theme::systemPaletteChanged);
             connect(ptr->styleHints(), &QStyleHints::colorSchemeChanged, this, &Theme::darkModeChanged);
             _paletteSignalsConnected = true;
         }
     }
 }
 
-QVariantMap Theme::systemPalette()
-{
-    connectToPaletteSignal();
-#if defined(Q_OS_WIN)
-    auto systemPalette = QGuiApplication::palette();
-    if(darkMode()) {
-        systemPalette = reserveDarkPalette;
-    }
-#else
-    const auto systemPalette = QGuiApplication::palette();
-#endif
-
-    return QVariantMap {
-        { QStringLiteral("base"), systemPalette.base().color() },
-        { QStringLiteral("alternateBase"), systemPalette.alternateBase().color() },
-        { QStringLiteral("text"), systemPalette.text().color() },
-        { QStringLiteral("toolTipBase"), systemPalette.toolTipBase().color() },
-        { QStringLiteral("toolTipText"), systemPalette.toolTipText().color() },
-        { QStringLiteral("brightText"), systemPalette.brightText().color() },
-        { QStringLiteral("buttonText"), systemPalette.buttonText().color() },
-        { QStringLiteral("button"), systemPalette.button().color() },
-        { QStringLiteral("highlightedText"), systemPalette.highlightedText().color() },
-        { QStringLiteral("placeholderText"), systemPalette.placeholderText().color() },
-        { QStringLiteral("windowText"), systemPalette.windowText().color() },
-        { QStringLiteral("window"), systemPalette.window().color() },
-        { QStringLiteral("dark"), systemPalette.dark().color() },
-        { QStringLiteral("highlight"), systemPalette.highlight().color() },
-        { QStringLiteral("light"), systemPalette.light().color() },
-        { QStringLiteral("link"), systemPalette.link().color() },
-        { QStringLiteral("midlight"), systemPalette.midlight().color() },
-        { QStringLiteral("mid"), systemPalette.mid().color() },
-        { QStringLiteral("linkVisited"), systemPalette.linkVisited().color() },
-        { QStringLiteral("shadow"), systemPalette.shadow().color() },
-    };
-}
-
 bool Theme::darkMode()
 {
     connectToPaletteSignal();

src/libsync/theme.h

@@ -67,7 +67,6 @@ class OWNCLOUDSYNC_EXPORT Theme : public QObject
 
     Q_PROPERTY(QColor defaultColor READ defaultColor CONSTANT)
 
-    Q_PROPERTY(QVariantMap systemPalette READ systemPalette NOTIFY systemPaletteChanged)
     Q_PROPERTY(bool darkMode READ darkMode NOTIFY darkModeChanged)
 public:
     enum CustomMediaType {
@@ -594,7 +593,6 @@ public:
 
     static constexpr const char *themePrefix = ":/client/theme/";
 
-    QVariantMap systemPalette();
     bool darkMode();
 
 public slots:
@@ -619,7 +617,6 @@ protected:
 
 signals:
     void systrayUseMonoIconsChanged(bool);
-    void systemPaletteChanged(const QPalette &palette);
     void darkModeChanged();
     void overrideServerUrlChanged();
     void forceOverrideServerUrlChanged();

theme/Style/Style.qml

@@ -8,17 +8,20 @@ QtObject {
     readonly property int pixelSize: fontMetrics.font.pixelSize
     readonly property bool darkMode: Theme.darkMode
 
+    property SystemPalette nativePalette: SystemPalette {
+    }
+
     // Colors
     readonly property color ncBlue:      Theme.wizardHeaderBackgroundColor
     readonly property color ncHeaderTextColor: Theme.wizardHeaderTitleColor
-    readonly property color ncTextColor: Theme.systemPalette.windowText
+    readonly property color ncTextColor: nativePalette.text
     readonly property color ncTextBrightColor: "white"
     readonly property color ncSecondaryTextColor: "#808080"
     readonly property color lightHover: Theme.darkMode ? Qt.lighter(backgroundColor, 2) : Qt.darker(backgroundColor, 1.05)
     readonly property color darkerHover: Theme.darkMode ? Qt.lighter(backgroundColor, 2.35) : Qt.darker(backgroundColor, 1.25)
     readonly property color menuBorder: Theme.darkMode ? Qt.lighter(backgroundColor, 2.5) : Qt.darker(backgroundColor, 1.5)
-    readonly property color backgroundColor: Theme.systemPalette.window
-    readonly property color buttonBackgroundColor: Theme.systemPalette.button
+    readonly property color backgroundColor: nativePalette.window
+    readonly property color buttonBackgroundColor: nativePalette.button
     readonly property color positiveColor: Qt.rgba(0.38, 0.74, 0.38, 1)
 
     readonly property color currentUserHeaderColor: UserModel.currentUser ? UserModel.currentUser.headerColor : ncBlue