MODULE clipboard ;

(*
   m2-GTK4 example - clipboard copy/paste between two entries.

   "Copy" puts the first entry's text on the clipboard; "Paste" reads the
   clipboard asynchronously and puts it in the second entry.

   Build:  make examples
   Run:    ./build/examples/clipboard
*)

FROM Gio IMPORT g_application_run;
FROM GtkApplication IMPORT gtk_application_new;
FROM GtkWindow IMPORT gtk_application_window_new, gtk_window_set_title,
   gtk_window_set_default_size, gtk_window_set_child, gtk_window_present;
FROM GtkBox IMPORT gtk_box_new, gtk_box_append, gtk_box_set_spacing;
FROM GtkEnums IMPORT GtkVertical, GtkHorizontal;
FROM GtkEntry IMPORT gtk_entry_new, gtk_entry_set_placeholder_text;
FROM GtkEditable IMPORT gtk_editable_get_text, gtk_editable_set_text;
FROM GtkButton IMPORT gtk_button_new_with_label;
FROM GtkWidget IMPORT gtk_widget_set_margin_top,
   gtk_widget_set_margin_bottom, gtk_widget_set_margin_start,
   gtk_widget_set_margin_end;
FROM Gdk IMPORT gdk_display_get_default, gdk_display_get_clipboard;
FROM GdkClipboard IMPORT gdk_clipboard_set_text,
   gdk_clipboard_read_text_async, gdk_clipboard_read_text_finish;
FROM GError IMPORT GError;
FROM GtkClosures IMPORT Connect2;
FROM GtkUtils IMPORT CStrToM2, Free, ClearError;
FROM SYSTEM IMPORT ADDRESS, ADR;
FROM libc IMPORT printf;

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

VAR
   clipboard, sourceEntry, destEntry: ADDRESS;

PROCEDURE OnCopy (button: ADDRESS; user: ADDRESS);
VAR
   text: ARRAY [0..255] OF CHAR;
BEGIN
   CStrToM2(gtk_editable_get_text(sourceEntry), text);
   gdk_clipboard_set_text(clipboard, text)
END OnCopy;

(* void on_read(GObject *source, GAsyncResult *result, gpointer user) *)
PROCEDURE OnRead (source: ADDRESS; result: ADDRESS; user: ADDRESS);
VAR
   s: ADDRESS;
   err: GError;
   text: ARRAY [0..255] OF CHAR;
BEGIN
   err := NIL;
   s := gdk_clipboard_read_text_finish(clipboard, result, err);
   IF s = NIL THEN
      ClearError(err)
   ELSE
      CStrToM2(s, text);
      gtk_editable_set_text(destEntry, text);
      Free(s)
   END
END OnRead;

PROCEDURE OnPaste (button: ADDRESS; user: ADDRESS);
BEGIN
   gdk_clipboard_read_text_async(clipboard, NIL, ADR(OnRead), NIL)
END OnPaste;

PROCEDURE OnActivate (application: ADDRESS; data: ADDRESS);
VAR
   window, box, buttons, copyButton, pasteButton: ADDRESS;
BEGIN
   clipboard := gdk_display_get_clipboard(gdk_display_get_default());

   sourceEntry := gtk_entry_new();
   gtk_entry_set_placeholder_text(sourceEntry, "type some text");
   destEntry := gtk_entry_new();
   gtk_entry_set_placeholder_text(destEntry, "pasted text appears here");

   copyButton := gtk_button_new_with_label("Copy");
   Connect2(copyButton, "clicked", OnCopy, NIL);
   pasteButton := gtk_button_new_with_label("Paste");
   Connect2(pasteButton, "clicked", OnPaste, NIL);

   buttons := gtk_box_new(GtkHorizontal, 8);
   gtk_box_append(buttons, copyButton);
   gtk_box_append(buttons, pasteButton);

   box := gtk_box_new(GtkVertical, 8);
   gtk_box_set_spacing(box, 8);
   gtk_widget_set_margin_top(box, 12);
   gtk_widget_set_margin_bottom(box, 12);
   gtk_widget_set_margin_start(box, 12);
   gtk_widget_set_margin_end(box, 12);
   gtk_box_append(box, sourceEntry);
   gtk_box_append(box, buttons);
   gtk_box_append(box, destEntry);

   window := gtk_application_window_new(application);
   gtk_window_set_title(window, "m2-GTK4 Clipboard");
   gtk_window_set_default_size(window, 360, 180);
   gtk_window_set_child(window, box);
   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 clipboard.