MODULE builder ;

(*
   m2-GTK4 example - building a window from a .ui file with GtkBuilder.

   Loads examples/builder.ui (object ids: window, button, status), wires
   the button's "clicked" signal to update the status label, and shows
   the window.

   Build:  make examples
   Run:    ./build/examples/builder      (from the repository root)
*)

FROM Gio IMPORT g_application_run;
FROM GtkApplication IMPORT gtk_application_new;
FROM GtkBuilder IMPORT GtkBuilder, gtk_builder_new, gtk_builder_add_from_file,
   gtk_builder_get_object;
FROM GtkWindow IMPORT gtk_window_set_application, gtk_window_present;
FROM GtkLabel IMPORT gtk_label_set_text;
FROM GError IMPORT GError;
FROM GtkClosures IMPORT Connect2;
FROM GtkUtils IMPORT ErrorMessage, ClearError;
FROM SYSTEM IMPORT ADDRESS, ADR;
FROM libc IMPORT printf;

CONST
   AppId = "org.example.m2gtk4.Builder";

VAR
   builder: ADDRESS;

PROCEDURE OnClicked (button: ADDRESS; user: ADDRESS);
BEGIN
   gtk_label_set_text(user, "Button clicked!")
END OnClicked;

PROCEDURE OnActivate (application: ADDRESS; data: ADDRESS);
VAR
   window, button, status: ADDRESS;
   err: GError;
   buf: ARRAY [0..255] OF CHAR;
BEGIN
   builder := gtk_builder_new();
   err := NIL;
   IF gtk_builder_add_from_file(builder, "examples/builder.ui", err) = 0 THEN
      ErrorMessage(err, buf);
      printf("failed to load examples/builder.ui: %s\n", buf);
      printf("(run this example from the repository root)\n");
      ClearError(err);
      HALT(1)
   END;

   window := gtk_builder_get_object(builder, "window");
   button := gtk_builder_get_object(builder, "button");
   status := gtk_builder_get_object(builder, "status");

   Connect2(button, "clicked", OnClicked, status);

   gtk_window_set_application(window, application);
   gtk_window_present(window)
END OnActivate;

VAR
   app: ADDRESS;
BEGIN
   app := gtk_application_new(AppId, 0);
   IF app = NIL THEN
      printf("gtk_application_new failed\n");
      HALT(1)
   END;
   Connect2(app, "activate", OnActivate, NIL);
   g_application_run(app, 0, NIL)
END builder.