Add an API to get the color scheme setting

settings/color.go

@@ -0,0 +1,43 @@
+package settings
+
+import (
+	"github.com/godbus/dbus/v5"
+	"github.com/rymdport/portal"
+)
+
+const readOneCallPath = settingsCallPath + ".ReadOne"
+
+// ColorScheme is the type of color scheme preference that the user has set.
+type ColorScheme uint8
+
+const (
+	NoPreference = ColorScheme(iota) // Indicates that no appearance preference was set.
+	Dark                             // Indicates that dark mode is preferred.
+	Light                            // Indicates that light mode is preferred.
+)
+
+// GetColorScheme returns the currently set color scheme.
+func GetColorScheme() (ColorScheme, error) {
+	dbusConn, err := dbus.SessionBus()
+	if err != nil {
+		return NoPreference, err
+	}
+
+	dbusObj := dbusConn.Object(portal.ObjectName, portal.ObjectPath)
+	call := dbusObj.Call(
+		readOneCallPath,
+		dbus.FlagNoAutoStart,
+		"org.freedesktop.appearance",
+		"color-scheme",
+	)
+	if call.Err != nil {
+		return NoPreference, err
+	}
+
+	var value uint8
+	if err = call.Store(&value); err != nil {
+		return NoPreference, err
+	}
+
+	return ColorScheme(value), nil
+}