feat: centralize theming in theme-manager (palette/tokens, CSS, dark-mode, setup UI), add tests + win32/meson wiring

src/fe-gtk/theme/theme-policy.c

@@ -0,0 +1,59 @@
+#include "theme-policy.h"
+
+#include <gtk/gtk.h>
+
+#include "../fe-gtk.h"
+#include "../../common/zoitechat.h"
+#include "../../common/zoitechatc.h"
+
+gboolean
+theme_policy_system_prefers_dark (void)
+{
+	GtkSettings *settings = gtk_settings_get_default ();
+	gboolean prefer_dark = FALSE;
+	char *theme_name = NULL;
+#ifdef G_OS_WIN32
+	gboolean have_win_pref = FALSE;
+
+	if (fe_win32_high_contrast_is_enabled ())
+		return FALSE;
+
+	have_win_pref = fe_win32_try_get_system_dark (&prefer_dark);
+	if (!have_win_pref)
+#endif
+	if (settings && g_object_class_find_property (G_OBJECT_GET_CLASS (settings),
+	                                              "gtk-application-prefer-dark-theme"))
+	{
+		g_object_get (settings, "gtk-application-prefer-dark-theme", &prefer_dark, NULL);
+	}
+
+	if (settings && !prefer_dark)
+	{
+		g_object_get (settings, "gtk-theme-name", &theme_name, NULL);
+		if (theme_name)
+		{
+			char *lower = g_ascii_strdown (theme_name, -1);
+			if (g_str_has_suffix (lower, "-dark") || g_strrstr (lower, "dark"))
+				prefer_dark = TRUE;
+			g_free (lower);
+			g_free (theme_name);
+		}
+	}
+
+	return prefer_dark;
+}
+
+gboolean
+theme_policy_is_dark_mode_active (unsigned int mode)
+{
+	if (mode == ZOITECHAT_DARK_MODE_AUTO)
+		return theme_policy_system_prefers_dark ();
+
+	return fe_dark_mode_is_enabled_for (mode);
+}
+
+gboolean
+theme_policy_is_app_dark_mode_active (void)
+{
+	return theme_policy_is_dark_mode_active (prefs.hex_gui_dark_mode);
+}