/*  Copyright 2007  Scibuff - Tomas Vorobjov  (email : blog@scibuff.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 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
*/

if ( !com ) { var com = {}; }
if ( !com.scibuff ) { com.scibuff = {}; }
if ( !com.scibuff.dev ) { com.scibuff.dev = {}; }
if (!com.scibuff.dev.ajax) { 
	com.scibuff.dev.ajax = function(){
		// private fields
		var tmp = {};
		tmp.URL_CHECK_INTERVAL = 100;
		tmp.HASH_VARS_SEPARATOR = ';'
		tmp.internalUrlChange = false;
		tmp.oldURL = window.location.href;
		
		/**
		 * Checks if the window url has changed and if so,
		 * triggers a "change" events
		 */
		tmp.checkURL = function(){
			if ( tmp.oldURL != window.location.href ){
				tmp.oldURL = window.location.href;
				$( window.location ).trigger(
					pub.URL_CHANGED, { url : window.location.href }
				);
			}
		}
		
		/**
		 * This function is executed every time the browser's url
		 * is changed 
		 * @param {Object} event
		 * @param {Object} data
		 */
		tmp.urlChangeHandler = function( event, data ){
			if ( !tmp.internalUrlChange ){
				var data = tmp.getHashVars();
				if ( data[ pub.PAGE_VAR_NAME ] != "" ) {
					tmp.loadPageContent( data[ pub.PAGE_VAR_NAME ], "#content" );
				}				
				
			}	
			tmp.internalUrlChange = false;
		}
		
		/**
		 * Parses the url hash string into a vars (JSON) object
		 */
		tmp.getHashVars = function(){
			var url = window.location.href;
			if ( url.match('#') ){
				var hash = url.split('#')[1];
				var hashes = hash.split( tmp.HASH_VARS_SEPARATOR );
				var data = {};
				for ( var i in hashes ){
					if ( hashes[i] != "" ){
						var tuple = hashes[i].split("=");
						data[ tuple[0] ] = unescape(tuple[1]);
					}
				}
				return data;
			}
			return {};			
		}
		
		/**
		 * Sets the url hash string using the values from the vars object
		 * @param {Object} vars
		 */
		tmp.setHashVars = function( vars ){
			
			var url = window.location.href;
			
			if ( url.match('#') ){ url = url.split('#')[0]; }
			
			var hash = "";
			for ( var key in vars ){
				if ( vars[key] ) {
					hash += key + "=" + escape(vars[key]) + ";";
				}
			}
			
			tmp.internalUrlChange = true;
			window.location = url + "#" + hash;			
		}
		
		/**
		 * Sets ajax link to th
		 * @param {Object} element
		 * @param {Object} clickEvent
		 */
		tmp.setAjaxLink = function( element, clickEvent ){
			clickEvent.preventDefault();
			var url = element.attr("href");
			tmp.loadPageContent( url, "#content" );			
		};
		
		/**
		 * Loads content from the specified url
		 * @param {String} url
		 * @param {String} destination
		 */
		tmp.loadPageContent = function( url, destination ){
			var data = tmp.getHashVars();
			data[ pub.PAGE_VAR_NAME ] = url;
			tmp.setHashVars( data );
			$( destination ).load( url, { 'ajax': 'true' }, function(){
				$( destination + ' a.ajax-link').click( function( event ) {
					tmp.setAjaxLink( $(this), event );
				});
			});			
		}		
		
		// public fields
		var pub = {};
		pub.PAGE_VAR_NAME = "page";
		pub.URL_CHANGED = "change";
		pub.init = function(){
			var data = tmp.getHashVars();
			if ( data[ pub.PAGE_VAR_NAME ] != "" ) {
				tmp.loadPageContent( data[ pub.PAGE_VAR_NAME ], "#content" );
			}
			
			$( window.location ).bind( pub.URL_CHANGED, tmp.urlChangeHandler );
			
			setInterval( tmp.checkURL, tmp.URL_CHECK_INTERVAL );
			$('a.ajax-link').click( function( event ) {
				tmp.setAjaxLink( $(this), event );
			});	
		}
		
		return pub;
	}();
}

$(document).ready(function () {
	
	com.scibuff.dev.ajax.init();
	
});