/* GTK drag'n'drop support for Emacs
   Copyright (C) 2020 Free Software Foundation, Inc.

   This file is part of GNU Emacs.

   GNU Emacs is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or (at
   your option) any later version.

   GNU Emacs is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.  */

#include "pgtkdnd.h"
#include "config.h"
#include "pgtkterm.h"
#include "buffer.h"

static GdkContentFormats *formats;

void
pgtk_dnd_global_init (void)
{
  formats = gdk_content_formats_new ((const char *[])
				     {"text/plain", NULL}, 1);
}


static void
drag_callback (GtkDropTarget *dest,
	       GValue        *drop,
	       gdouble        x,
	       gdouble        y,
	       gpointer       userptr)
{
  struct frame *target_frame = userptr;
  gchar *c = g_strdup (g_value_get_string (drop));
  size_t idx;
  size_t idz = 0;
  for (idx = 0; idz < strlen (c);)
    {
      if (c[idz] != '\xd')
	{
	  c[idx] = c[idz];
	  ++idx;
	  ++idz;
	}
      else
	{
	  ++idz;
	}
    }
  c[idx] = 0;
  Lisp_Object str = build_string_from_utf8 (c);
  union buffered_input_event inev;
  EVENT_INIT (inev.ie);
  inev.ie.kind = DRAG_N_DROP_EVENT;
  inev.ie.arg = list2 (Qstring, str);
  inev.ie.modifiers = 0;
  XSETINT (inev.ie.x, (int) round (x));
  XSETINT (inev.ie.y, (int) round (y));
  XSETFRAME (inev.ie.frame_or_window, target_frame);
  inev.ie.timestamp = time (NULL);

  evq_enqueue (&inev);
}


static GdkDragAction
drag_move_cb (GtkDropTarget *dest,
	      gdouble        x,
	      gdouble        y,
	      gpointer userptr)
{
  struct frame *f = userptr;
  enum window_part part;
  Lisp_Object window = window_from_coordinates (f, (int) x, (int) y, &part, 1, 1);
  if (part != ON_TEXT)
    return false;
  if (NILP (window))
    return false;
  Fselect_window (window, Qnil);
  Lisp_Object frame;
  XSETFRAME (frame, f);
  Lisp_Object posn = Fposn_at_x_y (make_fixnum (x),
				   make_fixnum (y),
				   frame,
				   Qnil);
  Lisp_Object posn_point = call1 (intern_c_string ("posn-point"), posn);
  Fset_window_point (window, posn_point);
  redisplay ();
  return GDK_ACTION_COPY;
}

void
pgtk_dnd_init (struct frame *f)
{
  FRAME_X_OUTPUT (f)->di.target = gtk_drop_target_new (G_TYPE_STRING,
						       GDK_ACTION_COPY |
						       GDK_ACTION_MOVE);
  gtk_widget_add_controller (FRAME_GTK_WIDGET (f),
			     GTK_EVENT_CONTROLLER (FRAME_X_OUTPUT (f)->di.target));
  g_signal_connect (G_OBJECT (FRAME_X_OUTPUT (f)->di.target),
		    "drop", G_CALLBACK (drag_callback), f);
  g_signal_connect (G_OBJECT (FRAME_X_OUTPUT (f)->di.target),
		    "motion", G_CALLBACK (drag_move_cb), f);
}