/*
 * Accordion 1.1 - jQuery menu widget
 *
 * Copyright (c) 2006 Jörn Zaefferer, Frank Marcia
 *
 * Dual licensed under the MIT and GPL licenses:
 *   http://www.opensource.org/licenses/mit-license.php
 *   http://www.gnu.org/licenses/gpl.html
 *
 * Revision: $Id: jquery.accordion.js 1260 2007-02-03 17:56:55Z joern $
 *
 */

// nextUntil is necessary, would be nice to have this in jQuery core
jQuery.fn.nextUntil = function(expr) {
    var match = [];

    // We need to figure out which elements to push onto the array
    this.each(function(){
        // Traverse through the sibling nodes
        for( var i = this.nextSibling; i; i = i.nextSibling ) {
            // Make sure that we're only dealing with elements
            if ( i.nodeType != 1 ) continue;

            // If we find a match then we need to stop
            if ( jQuery.filter( expr, [i] ).r.length ) break;

            // Otherwise, add it on to the stack
            match.push( i );
        }
    });

    return this.pushStack( match, arguments );
};

/**
 * Make the selected elements Accordion widgets.
 *
 * Semantic requirements:
 *
 * If the structure of your container is flat with unique
 * tags for header and content elements, eg. a definition list
 * (dl > dt + dd), you don't have to specify any options at
 * all.
 *
 * If your structure uses the same elements for header and
 * content or uses some kind of nested structure, you have to
 * specify the header elements, eg. via class, see the second example.
 *
 * Use activate(Number) to change the active content programmatically.
 *
 * @example $('#list1').Accordion();
 * @before <dl id="list1">
 *   <dt>Header 1</dt>
 *   <dd>Content 1</dd>
 *   <dt>Header 2</dt>
 *   <dd>Content 2</dd>
 * </dl>
 * @desc Creates an Accordion from the given definition list
 *
 * @example $('#list2').Accordion({
 *   header: 'div.title'
 * });
 * @before <div id="nav">
 *  <div>
 *    <div class="title">Header 1</div>
 *    <div>Content 1</div>
 *  </div>
 *  <div>
 *    <div class="title">Header 2</div>
 *    <div>Content 2</div>
 *  </div>
 * </div>
 * @desc Creates an Accordion from the given div structure
 *
 * @example $('#nav').Accordion({
 *   header: 'a.head'
 * });
 * @before <ul id="nav">
 *   <li>
 *     <a class="head">Header 1</a>
 *     <ul>
 *       <li><a href="#">Link 1</a></li>
 *       <li><a href="#">Link 2></a></li>
 *     </ul>
 *   </li>
 *   <li>
 *     <a class="head">Header 2</a>
 *     <ul>
 *       <li><a href="#">Link 3</a></li>
 *       <li><a href="#">Link 4></a></li>
 *     </ul>
 *   </li>
 * </ul>
 * @desc Creates an Accordion from the given navigation list
 *
 * @example $('#accordion').Accordion().change(function(event, newHeader, oldHeader, newContent, oldContent) {
 *   $('#status').html(newHeader.text());
 * });
 * @desc Updates the #status element with the text of the selected header every time the accordion changes
 *
 * @param Map options key/value pairs of optional settings.
 * @option String|Element|jQuery|Boolean active Selector for the active element, default is the first child, set to false to display none at start
 * @option String|Element|jQuery header Selector for the header element, eg. div.title, a.head, default is the first child's tagname
 * @option String|Number showSpeed Speed for the slideIn, default is 'slow'
 * @option String|Number hideSpeed Speed for the slideOut, default is 'fast'
 * @option String selectedClass Class for active header elements, default is 'selected'
 * @option Boolean alwaysOpen Whether there must be one content element open, default is true. 
 *
 * @event change Called everytime the accordion changes, params: event, newHeader, oldHeader, newContent, oldContent
 * @type jQuery
 * @see activate(Number)
 * @name Accordion
 * @cat Plugins/Accordion
 */

/**
 * Activate a content part of the Accordion programmatically at the given zero-based index.
 *
 * If the index is not specified, it defaults to zero, if it is an invalid index, eg. a string,
 * nothing happens.
 *
 * @example $('#accordion').activate(1);
 * @desc Activate the second content of the Accordion contained in <div id="accordion">.
 *
 * @example $('#nav').activate();
 * @desc Activate the first content of the Accordion contained in <ul id="nav">.
 *
 * @param Number index (optional) An Integer specifying the zero-based index of the content to be
 *				 activated. Default: 0
 *
 * @type jQuery
 * @name activate
 * @cat Plugins/Accordion
 */

// create private scope with $ alias for jQuery
(function($) {
	// save reference to plugin method
	var plugin = $.fn.Accordion = function(settings) {

		// setup configuration
		settings = $.extend({}, plugin.defaults, {
			// define context defaults
			header: $(':first-child', this)[0].tagName // take first childs tagName as header
		}, settings);

		// calculate active if not specified, using the first header
		var container = this,
			active = settings.active ? $(settings.active, this) : settings.active === false ? $("<div>") : $(settings.header, this).eq(0),
			running = 0;

		container.find(settings.header)
			.not(active && active[0] || "")
			.nextUntil(settings.header)
			.hide();
		active.addClass(settings.selectedClass);

		var clickHandler = function(event) {
			// get the click target
			var clicked = $(event.target);
			
			var clickedActive = clicked[0] == active[0];
			
			// if animations are still active, or the active header is the target, ignore click
			if(running || (settings.alwaysOpen && clickedActive) || !clicked.is(settings.header))
				return;

			// switch classes
			active.removeClass(settings.selectedClass);
			clicked.addClass(settings.selectedClass);

			// find elements to show and hide
			var toShow = clicked.nextUntil(settings.header),
				toHide = active.nextUntil(settings.header),
				data = [clicked, active, toShow, toHide];
			active = clicked;
			// count elements to animate
			running = toHide.size() + toShow.size();
			var finished = function() {
				if(--running)
					return;

				// trigger custom change event
				container.trigger("change", data);
			};
			// TODO if hideSpeed is set to zero, animations are crappy
			// workaround: use hide instead
			// solution: animate should check for speed of 0 and do something about it
			if(!settings.alwaysOpen && clickedActive) {
				toShow.slideToggle(settings.showSpeed, finished);
				finished();
			} else {
				toHide.filter(":hidden").each(finished).end().filter(":visible").slideUp(settings.hideSpeed, finished);
				toShow.slideDown(settings.showSpeed, finished);
			}

			return false;
		};
		var activateHandlder = function(event, index) {
			// call clickHandler with custom event
			clickHandler({
				target: $(settings.header, this)[index]
			});
		};

		return container
			.click(clickHandler)
			.bind("activate", activateHandlder);
	};
	// define static defaults
	plugin.defaults = {
		selectedClass: "selected",
		showSpeed: 'slow',
		hideSpeed: 'fast',
		alwaysOpen: true
	};

	// shortcut for trigger, nicer API and easily to document
	$.fn.activate = function(index) {
		return this.trigger('activate', [index || 0]);
	};

})(jQuery);