#include <gtk/gtk.h>

static GtkWidget *main_window = NULL;

#define DND_INFO_TEXT_URI_LIST 10
#define DND_INFO_STRING        20

static GtkTargetEntry drop_targets[] = {
  { "text/uri-list",  0, DND_INFO_TEXT_URI_LIST },
  { "text/plain",     0, DND_INFO_STRING }
};

GdkDragAction select_action(GdkDragAction actions)
{
	GtkWidget *dialog;
	gint value;

	dialog = gtk_dialog_new();
	gtk_window_set_title(GTK_WINDOW(dialog), "どうしますか？");
	gtk_window_set_transient_for(GTK_WINDOW(dialog), GTK_WINDOW(main_window));
	gtk_window_set_destroy_with_parent(GTK_WINDOW(dialog), TRUE);
	gtk_window_set_policy(GTK_WINDOW(dialog), FALSE, FALSE, FALSE);
	gtk_dialog_set_has_separator(GTK_DIALOG(dialog), FALSE);
	if (actions & GDK_ACTION_COPY) {
		gtk_dialog_add_button(GTK_DIALOG(dialog), "コピー", GDK_ACTION_COPY);
	}
	if (actions & GDK_ACTION_MOVE) {
		gtk_dialog_add_button(GTK_DIALOG(dialog), "移動", GDK_ACTION_MOVE);
	}
	if (actions & GDK_ACTION_LINK) {
		gtk_dialog_add_button(GTK_DIALOG(dialog), "リンク", GDK_ACTION_LINK);
	}
	gtk_dialog_add_button(GTK_DIALOG(dialog), "キャンセル", 0);

	value = gtk_dialog_run(GTK_DIALOG(dialog));

	gtk_widget_destroy(dialog);

	if (value != 0 && value != GDK_ACTION_COPY && value != GDK_ACTION_MOVE && value != GDK_ACTION_LINK) {
		value = 0;
	}

	return value;
}

gboolean drag_motion(GtkWidget *widget,
					 GdkDragContext *context,
					 gint x,
					 gint y,
					 guint time_,
					 gpointer user_data)
{
	GList *list;
	GtkTargetList *target_list;
	GdkAtom target;
	gint width;
	gint height;

	g_print("<<< DRAG MOTION >>>\n");

	for (list = context->targets; list != NULL; list = g_list_next(list)) {
		g_print("[%s]\n", gdk_atom_name(list->data));
	}

	target_list = gtk_drag_dest_get_target_list(widget);
	target = gtk_drag_dest_find_target(widget, context, target_list);
	if (target == GDK_NONE) {
		gdk_drag_status(context, 0, time_);
		return FALSE;
	}

	gdk_window_get_geometry(widget->window, NULL, NULL, &width, &height, NULL);
	if (x < width / 2) {
		if (context->actions & GDK_ACTION_ASK) {
			g_print("suggested action = ASK\n");
			context->suggested_action = GDK_ACTION_ASK;
		} else {
			g_print("drop不可\n");
			return FALSE;
		}
	} else {
		if (context->actions & GDK_ACTION_COPY) {
			g_print("suggested action = COPY\n");
			context->suggested_action = GDK_ACTION_COPY;
		} else {
			g_print("drop不可\n");
			return FALSE;
		}
	}

	gdk_drag_status(context, context->suggested_action, time_);

	gtk_drag_highlight(widget);

	return TRUE;
}

void drag_leave(GtkWidget *widget,
				GdkDragContext *context,
				guint time_,
				gpointer user_data)
{
	g_print("<<< DRAG LEAVE >>>\n");

	gtk_drag_unhighlight(widget);
}

gboolean drag_drop(GtkWidget *widget,
				   GdkDragContext *context,
				   gint x,
				   gint y,
				   guint time_,
				   gpointer user_data)
{
	GtkTargetList *target_list;
	GdkAtom target;

	g_print("<<< DRAG DROP >>>\n");

	target_list = gtk_drag_dest_get_target_list(widget);
	target = gtk_drag_dest_find_target(widget, context, target_list);
	if (target == GDK_NONE) {
		gtk_drag_finish(context, FALSE, FALSE, time_);
		return FALSE;
	}

	gtk_drag_get_data(widget, context, target, time_);

	return TRUE;
}

void drag_data_received(GtkWidget *widget,
						GdkDragContext *context,
						gint x,
						gint y,
						GtkSelectionData *data,
						guint info,
						guint time_,
						gpointer user_data)
{
	gboolean result = FALSE;
	gboolean delete = FALSE;

	g_print("<<< DRAG DATA RECEIVED >>>\n");

	if (data->length == 0 || data->format != 8) {
		goto ERROR_EXIT;
	}

	if (info == DND_INFO_TEXT_URI_LIST) {
		gchar **uris;
		gchar **files;
		gchar *hostname;
		GError *error = NULL;
		gint i;

		uris = gtk_selection_data_get_uris(data);
		if (uris == NULL) {
			g_print("error\n");
			goto ERROR_EXIT;
		}

		for (i = 0; uris[i] != NULL; i++) ;
		files = g_new0(gchar *, i + 1);

		for (i = 0; uris[i] != NULL; i++) {
			files[i] = g_filename_from_uri(uris[i], &hostname, &error);
			if (files[i] == NULL) {
				g_print("error\n");
				g_clear_error(&error);
				g_free(hostname);
				g_strfreev(files);
				g_strfreev(uris);
				goto ERROR_EXIT;
			}
			g_free(hostname);
		}
		g_strfreev(uris);

		if (context->suggested_action == GDK_ACTION_ASK) {
			GdkDragAction action;

			/* ユーザーに質問する */
			action = select_action(context->actions);
			if (action == 0) {
				/* キャンセル */
				goto ERROR_EXIT;
			}
			context->action = action;
		}

		if (context->action == GDK_ACTION_COPY) {
			/* copy */
			for (i = 0; files[i] != NULL; i++) {
				g_print("copy %s\n", files[i]);
			}
			result = TRUE;
		} else if (context->action == GDK_ACTION_MOVE) {
			/* move */
			for (i = 0; files[i] != NULL; i++) {
				g_print("move %s\n", files[i]);
			}
			result = TRUE;
		} else if (context->action == GDK_ACTION_LINK) {
			/* symlink, boockmark, ... */
			for (i = 0; files[i] != NULL; i++) {
				g_print("link %s\n", files[i]);
			}
			result = TRUE;
		} else {
			g_print("error\n");
		}

		g_strfreev(files);
	} else if (info == DND_INFO_STRING) {
		if (context->actions & GDK_ACTION_COPY) {
			context->action = GDK_ACTION_COPY;
		}
		if (context->action == GDK_ACTION_COPY) {
			g_print("string = %*s\n", data->length, data->data);
			result = TRUE;
		}
	} else {
		g_print("error\n");
	}

ERROR_EXIT:
	gtk_drag_finish(context, result, delete, time_);
}

int main(int argc, char ** argv)
{
	GtkWidget *window;
	GtkWidget *label;

	gtk_init(&argc, &argv);

	main_window = window = gtk_window_new(GTK_WINDOW_TOPLEVEL);
	gtk_window_set_title(GTK_WINDOW(window), "dnd drop test");
	gtk_window_set_default_size(GTK_WINDOW(window), 300, 150);
	g_signal_connect(G_OBJECT(window), "destroy",
					 G_CALLBACK(gtk_main_quit), NULL);

	label = gtk_label_new("ここに落せ");
	gtk_widget_set_size_request(label, 200, 100);

	g_signal_connect(G_OBJECT(label), "drag-motion",
					 G_CALLBACK(drag_motion), NULL);

	g_signal_connect(G_OBJECT(label), "drag-leave",
					 G_CALLBACK(drag_leave), NULL);

	g_signal_connect(G_OBJECT(label), "drag-drop",
					 G_CALLBACK(drag_drop), NULL);

	g_signal_connect(G_OBJECT(label), "drag-data-received",
					 G_CALLBACK(drag_data_received), NULL);

	gtk_drag_dest_set(label,
					  /*GTK_DEST_DEFAULT_HIGHLIGHT*/0,
					  drop_targets,
					  sizeof(drop_targets) / sizeof(drop_targets[0]),
					  GDK_ACTION_COPY | GDK_ACTION_MOVE | GDK_ACTION_LINK | GDK_ACTION_ASK);

	gtk_container_add(GTK_CONTAINER(window), label);

	gtk_widget_show_all(window);

	gtk_main();
	return 0;
}