/*
* Copyright (c) 2007, David A. Lindquist (stringify.com)
* Some Rights Reserved
*
* This code is licensed under the Creative Commons Attribution 2.5 License
* (http://creativecommons.org/licenses/by/2.5/). Please maintain the above
* license and copyright statements when using this code.
*
* $Id: columnav.js 518 2007-02-27 04:50:56Z david $
*/
YAHOO.namespace('extension');

YAHOO.extension.ColumNav = function(id, cfg) {
	this._init(id, cfg);
};

YAHOO.extension.ColumNav.prototype = {

	DOM: YAHOO.util.Dom,
	EVT: YAHOO.util.Event,
	CON: YAHOO.util.Connect,

	ERROR_MSG: 'data unavailable',

	// PUBLIC API

	reset: function() {
		this.carousel.clear();
		this._init(this.id, this.cfg);
	},

	// PRIVATE API

	_init: function(id, cfg) {
		this.id = id;
		this.cfg = cfg; // make this a YAHOO.util.Config object?

		this.datasource = cfg.datasource || cfg.source;
		this.linkAction = cfg.linkAction || this._defaultLinkAction;
		this.request = null;
		this.counter = 1;
		this.numScrolled = 0;
		this.moving = false;
		if (cfg.animationSpeed === 0)
		cfg.animationSpeed = Number.MIN_VALUE; // so animationCompleteHandler
		// will always run
		this.carousel = new YAHOO.extension.Carousel(id,
		{
		'animationCompleteHandler': this._animationCompleteHandler,
		'animationSpeed':           cfg.animationSpeed,
		'loadPrevHandler':          this._loadPrevHandler,
		'numVisible':               cfg.numVisible || 1,
		'prevElement':              cfg.prevElement || cfg.prevId,
		'scrollInc':                1
		});
		this.carousel.cn = this;

		var notOpera = (navigator.userAgent.match(/opera/i) == null);
		var kl = new YAHOO.util.KeyListener(this.carousel.carouselElem,
		{ ctrl: notOpera, keys: [37, 38, 39, 40] },
		{ fn: this._handleKeypress,
		scope: this,
		correctScope: true });
		kl.enable();

		var ds = this.datasource;
		if (ds && typeof ds == 'object')
		this._addMenu(ds);
		else if (typeof ds == 'string')
		this._makeRequest(ds);
		else
		this._handleFailure({});
	},

	_loadPrevHandler: function(type, args) {
		this.cn._abortRequest();
	},

	_makeRequest: function(url) {
		var callback = {
		'success':  this._handleSuccess,
		'failure':  this._handleFailure,
		'scope':    this,
		'timeout':  5000
		};
		this._abortRequest();
		this.request = this.CON.asyncRequest('GET', url, callback);
	},

	_abortRequest: function() {
		if (this.request && this.CON.isCallInProgress(this.request))
		this.CON.abort(this.request);
	},

	_handleSuccess: function(o) {
		var node;
		var contentType = o.getResponseHeader['Content-Type'];
		if ('application/json' == contentType.replace(/\s+$/,'')) { // IE reports Content-Type
			// having trailing ASCII 13
			try {
				// requires http://www.json.org/json.js
				node = o.responseText.parseJSON();
			} catch (e) {
				this._handleFailure(o);
				return;
			}
		} else {
			node = o.responseXML.documentElement;
		}
		this._addMenu(node);
	},

	_handleFailure: function(o) {
		var list = document.createElement('ul');
		var item = document.createElement('li');
		var span = document.createElement('span');
		span.className = 'columnav-error';
		span.appendChild(document.createTextNode(this.ERROR_MSG));
		item.appendChild(span);
		list.appendChild(item);
		this._addMenu(list);
	},

	_handleKeypress: function(type, args, o) {
		var key = args[0];
		var evt = args[1];
		var target = this.EVT.getTarget(evt);
		if (this.moving) {
			this.EVT.stopEvent(evt);
			return;
		}
		if (target.tagName != 'A') {
			var links = this._getNodes(this.carousel.carouselList.lastChild,
			this._links);
			links[0].focus();
			return;
		}
		switch (key) {
			case 37: // left
			var menu = target.parentNode.parentNode;
			if (this._shouldScrollPrev(menu)) {
				o.carousel.scrollPrev();
				this.moving = true;
			} else {
				var prevMenu = this._prevMenu(menu);
				if (prevMenu)
				this._focus(prevMenu);
			}
			break;
			case 38: // up
			if (target.previousSibling)
			target.previousSibling.focus();
			break;
			case 39: // right
			this._next(evt);
			break;
			case 40: // down
			if (target.nextSibling)
			target.nextSibling.focus();
			break;
		}
		this.EVT.stopEvent(evt);
	},

	_addMenu: function(node) {
		var menu = this._createMenu(node);
		this.carousel.addItem(this.counter++, menu);
		if (this._shouldScrollNext()) {
			this.carousel.scrollNext();
			this.moving = true;
		} else {
			if (this.counter > 2)
			this._focus(menu);
		}
	},

	_shouldScrollNext: function() {
		var numVisible = this.carousel.cfg.getProperty('numVisible');
		return ((this.counter - 1) - this.numScrolled > numVisible);
	},

	_shouldScrollPrev: function(menu) {
		var menus = this._getNodes(this.carousel.carouselList,
		this._childElements);
		var i = 0;
		for ( ; i < menus.length; i++) {
			if (menu == menus[i]) break;
		}
		return (i > 0 && i == this.numScrolled);
	},

	_prevMenu: function(menu) {
		var prevLi = menu.previousSibling;
		if (prevLi)
		return prevLi.getElementsByTagName('div')[0];
		return null;
	},

	_next: function(e) {
		if (this.moving) {
			this.EVT.stopEvent(e);
			return;
		}
		var target = this.EVT.getTarget(e);
		if (target.tagName == 'SPAN') {
			target = target.parentNode;
		} else if (target.tagName == 'IMG') {
			target = target.parentNode.parentNode;
		}
		this._removeMenus(target);
		var href = target.getAttribute('href');
		var rel = target.getAttribute('rel');
		var list = target.list;
		if (href !== null)
		this._highlight(target);
		if (list)
		this._addMenu(list);
		else if (rel && rel.match(/\bajax\b/))
		this._makeRequest(href);
		else {
			if (this.linkAction(e))
			return true;
		}
		this.EVT.stopEvent(e);
	},

	_removeMenus: function(target) {
		var li = target.parentNode.parentNode;
		var list = this.carousel.carouselList;
		while (li != list.lastChild) {
			list.removeChild(list.lastChild);
			this.counter--;
		}
	},

	_highlight: function(target) {
		var items = this._getNodes(target.parentNode, this._childElements);
		for (var i = 0; i < items.length; i++)
		this.DOM.removeClass(items[i], 'columnav-active');
		this.DOM.addClass(target, 'columnav-active');
	},

	_focus: function(menu) {
		var links = this._getNodes(menu, this._links);
		for (var i = 0; i < links.length; i++) {
			if (this.DOM.hasClass(links[i], 'columnav-active')) {
				links[i].focus();
				return;
			}
		}
		links[0].focus();
	},

	_animationCompleteHandler: function(type, args) {
		this.cn.moving = false;
		if (args[0] == 'next') {
			this.cn.numScrolled++;
			this.cn._focus(this.carouselList.lastChild);
		}
		if (args[0] == 'prev') {
			this.cn._removeLastMenu();
			this.cn.numScrolled--;
			if (this.cfg.getProperty('numVisible') == 1)
			this.cn._focus(this.carouselList.lastChild);
		}
	},

	_removeLastMenu: function() {
		var list = this.carousel.carouselList;
		list.removeChild(list.lastChild);
		this.counter--;
	},

	_createMenu: function(node) {
		var menu = document.createElement('div');
		menu.style["height"] = "300px";
		if (node.nodeType) { // DOM
			var items = this._getNodes(node, this._childElements);
			for (var i = 0; i < items.length; i++) {
				var ce = this._getNodes(items[i], this._childElements);
				var a = ce[0];
				var item_content = a.firstChild;
				if (item_content.tagName == 'img') {
					var o = { text: item_content.attributes[0].value, list: ce[1] };
				} else {
	                var o = { text: a.firstChild.data, list: ce[1] };
				}
				for (var j = 0; j < a.attributes.length; j++) {
					if (a.attributes[j].specified) {
						var n = '@' + a.attributes[j].name.toLowerCase();
						var v = a.attributes[j].value;
						o[n] = v;
					}
				}
				menu.appendChild(this._createLink(o));
			}
		} else { // JSON
			var items = node.li || node.ul.li;
			for (var i = 0; i < items.length; i++) {
				var a = items[i].a;
				var o = { text: a['#text'], list: items[i].ul };
				for (var n in a) {
					if ('@' == n.charAt(0)) {
						var v = a[n];
						o[n] = v;
					}
				}
				menu.appendChild(this._createLink(o));
			}
		}
		return menu;
	},

	_createLink: function(o) {
		var a = document.createElement('a');
		try {
			var tagQ = o['text'].indexOf("png");
		} catch(error) {
			var tagQ = -1;
		}
		var span = document.createElement('span');
		if (tagQ < 0) {
			span.appendChild(document.createTextNode(o['text']));
			a.appendChild(span);
		} else {
			var img = document.createElement('img');
			var source = o['text']//.match(/src=\"(.*)\"/);
			img.setAttribute('src', source);
			span.appendChild(img);
			a.appendChild(span);
		}

		for (var n in o) {
			if ('@' == n.charAt(0)) {
				var v = o[n];
				if (n == '@class')
				a.className = v;
				else
				a.setAttribute(n.substring(1), v);
			}
		}

		a.list = o['list'];
		if (o['list'] || (o['@rel'] && o['@rel'].match(/(?:^|\s+)ajax(?:\s+|$)/)))
		this.DOM.addClass(a, 'columnav-has-menu');
		this.EVT.addListener(a, 'click', this._next, this, true);
		return a;
	},

	_defaultLinkAction: function() { return true; },

	_getNodes: function(root, filter) {
		var node = root;
		var nodes = [];
		var next;
		var f = filter || function() { return true; }
		while (node != null) {
			if (node.hasChildNodes())
			node = node.firstChild;
			else if (node != root && null != (next = node.nextSibling))
			node = next;
			else {
				next = null;
				for ( ; node != root; node = node.parentNode) {
					next = node.nextSibling;
					if (next != null) break;
				}
				node = next;
			}
			if (node != null && f(node, root))
			nodes.push(node);
		}
		return nodes;
	},

	_childElements: function(node, root) {
		return (node.nodeType == 1 && node.parentNode == root);
	},

	_links: function(node) { return (node.tagName == 'A'); }
};

YAHOO.extension.ColumnNav = YAHOO.extension.ColumNav;