WMTheme (Haiku): implement

CMakeLists.txt

@@ -1257,7 +1257,7 @@ elseif(Haiku)
         src/detection/wifi/wifi_nosupport.c
         src/detection/wm/wm_nosupport.c
         src/detection/de/de_nosupport.c
-        src/detection/wmtheme/wmtheme_nosupport.c
+        src/detection/wmtheme/wmtheme_haiku.cpp
         src/detection/camera/camera_nosupport.c
     )
 elseif(GNU)

src/detection/wmtheme/wmtheme_haiku.cpp

@@ -0,0 +1,30 @@
+extern "C" {
+#include "fastfetch.h"
+#include "wmtheme.h"
+}
+
+#include <Application.h>
+#include <private/interface/DecorInfo.h>
+
+bool ffDetectWmTheme(FFstrbuf* themeOrError)
+{
+    // We need a valid be_app to query the app_server here.
+    BApplication app("application/x-vnd.fastfetch-cli-fastfetch");
+
+    DecorInfoUtility *util = new DecorInfoUtility();
+    DecorInfo* decor = NULL;
+
+    if (util) {
+        decor = util->CurrentDecorator();
+        if (decor) {
+            ffStrbufAppendS(themeOrError, decor->Name().String());
+        }
+        delete util;
+        if (decor) {
+            return true;
+        }
+    }
+
+    ffStrbufAppendS(themeOrError, "Failed to get DecorInfo");
+    return false;
+}