/* 
 * This file part of gsopcast - A gtk front-end of p2p tv sopcast.
 * http://gsopcast.googlecode.com
 * Copyright (C) 2008 Ha Shao <hashao2@gmail.com>
 *
 * This program 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 2 of the License, or
 * (at your option) any later version.
 *
 * This program 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 Library General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/* Handle remote command for the unique instance.
 *
 * Basically, we create a clipboard, say uniq_clipboard, as the inter-process
 * communication channel.
 *
 * At start up, check if we can get anything from the clipboard.
 *
 * If not, we are the first instance, we set the clipboard content to "NONE".
 * We then connect to the "owner-change" signal of the clipboard.  remote
 * commands will come from the clipboard. When we receive a new command from
 * the clipboard, we reset the clipboard content back to "NONE".
 *
 * If yes, there is a instance running. We paste a command to the clipboard
 * from the new instance. Then we sit on the new instance and wait the clipboard
 * content change to "NONE" again, i.e. the first instance handled our request
 * already. Once the command is handled, we quit the remote instance.
 *
 * There might be some race-conditions, but we are creating a *simple* unique
 * instance function. Big deal.
 * 
 * If we want a complete solution, we will use gtkunique when it is widely spead.
 */

#include <string.h>
#include <gtk/gtk.h>
#include "unique.h"
#include "callbacks.h"

// Return the selection/clipboard for our unique instance atom.
GtkClipboard* get_unique_clip(){
    GdkAtom atom;
    GtkClipboard *clip;

#if GTK_CHECK_VERSION(2,10,0)
    atom = gdk_atom_intern_static_string(unique_clipboard_name);
#else
    atom = gdk_atom_intern(unique_clipboard_name, FALSE);
#endif
    clip = gtk_clipboard_get(atom);
    return clip;
}

// Check if there is already a instance running.
gboolean is_running(){
    GdkAtom atom;
    GtkClipboard *clip;
    gboolean ret = FALSE;
    clip = get_unique_clip();
    if(gtk_clipboard_wait_is_text_available(clip)){
	ret = TRUE;
    }
    return ret;
}

// For the main instance, setup clipboard to accept uri remote command.
void setup_unique(void){
    GtkClipboard *clip;
    clip = get_unique_clip();
    g_signal_connect(clip, "owner-change", 
	    G_CALLBACK(remote_call), NULL);
}

// Set a text to the clipboard
void unique_set_text(const gchar *text, gboolean store){
    GtkClipboard *clip;
    clip = get_unique_clip();
    gtk_clipboard_set_text(clip, text, strlen(text));
}

//------------------------------------------------------
//Dealing with remote instance.
/* Wait for the remote changed the clipboard to NONE before we quit. */
gboolean timeout_me(void *data){
    gchar *text;
    GtkClipboard *clip = GTK_CLIPBOARD(data);
    text = gtk_clipboard_wait_for_text(clip);
    if (text && (strcmp(text, "NONE") == 0)){
	gtk_main_quit();
	return FALSE;
    }
    if (text)
	g_free(text);
    return TRUE;

}

// Some bridge function.
void quit_on_owner_change(GtkClipboard *clip, GdkEvent *event, gpointer data){
    g_timeout_add(200, timeout_me, clip);
}

/* Paste uri to clipboard and quit.
 * Cannot quit immediately because the remote instance need us to get the
 * uri from the clipboard. If we quit, the clipboard will be reset immediately.
 */
void unique_paste_uri(const gchar *text){
    GtkClipboard *clip;
    clip = get_unique_clip();
    gtk_clipboard_clear(clip);
    gtk_clipboard_set_text(clip, text, strlen(text));
    g_signal_connect(clip, "owner-change", 
	    G_CALLBACK(quit_on_owner_change), NULL);
    gtk_main();
}