/*
 * Copyright (c) 2007, David A. Lindquist <david.lindquist@gmail.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * $Id: columnav.js 175 2007-08-04 06:03:03Z 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,

    DEFAULT_ERROR_MSG: 'Data unavailable',

    // PUBLIC API

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

    toString: function() {
        return '<ColumNav ' + this.id + '>';
    },

    // PRIVATE API

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

        this.datasource = cfg.datasource || cfg.source;
        this.request = null;
        this.counter = 1;
        this.numScrolled = 0;
        this.isMoving = false;
        if (cfg.animationSpeed === 0)
            cfg.animationSpeed = Number.MIN_VALUE; // so animationCompleteHandler
                                                   // will always run
        this.prevButtonStateHandler = cfg.prevButtonStateHandler;
        this.animationCompleteHandler = cfg.animationCompleteHandler;

        var prevElement = cfg.prevElement || cfg.prevId;
        if (prevElement)
            this.EVT.addListener(prevElement, 'click', this._prev, this, true);

        var me = this;
        this.carousel = new YAHOO.extension.Carousel(id,
                            {
                                animationCompleteHandler: function(type, args) { me._animationCompleteHandler(type, args, me) },
                                animationMethod:          cfg.animationMethod,
                                animationSpeed:           cfg.animationSpeed,
                                numVisible:               cfg.numVisible || 1,
                                prevButtonStateHandler:   function(type, args) { me._prevButtonStateHandler(type, args, me) },
                                prevElement:              prevElement,
                                scrollInc:                1
                            });

        if (this.carousel.cfg.getProperty('numVisible') > 1)
            this.DOM.addClass(this.carousel.carouselElem, 'columnav-multiple');

        // custom events

        if (typeof cfg.requestHandler == 'function') {
            this.onRequest = new YAHOO.util.CustomEvent('onRequest', this);
            this.onRequest.subscribe(cfg.requestHandler, this);
        }
        if (typeof cfg.responseHandler == 'function') {
            this.onResponse = new YAHOO.util.CustomEvent('onResponse', this);
            this.onResponse.subscribe(cfg.responseHandler, this);
        }
        if (typeof cfg.nextHandler == 'function' ||
            typeof cfg.linkAction == 'function') // DEPRECATED
        {
            var sig = cfg.nextHandler ? YAHOO.util.CustomEvent.LIST
                                      : YAHOO.util.CustomEvent.FLAT;
            this.onNext = new YAHOO.util.CustomEvent('onNext', this, false, sig);
            this.onNext.subscribe(cfg.nextHandler || cfg.linkAction, this);
        }
        if (typeof cfg.prevHandler == 'function') {
            this.onPrev = new YAHOO.util.CustomEvent('onPrev', this);
            this.onPrev.subscribe(cfg.prevHandler, this);
        }
        if (typeof cfg.paneHandler == 'function') {
            this.onPane = new YAHOO.util.CustomEvent('onPane', this);
            this.onPane.subscribe(cfg.paneHandler, 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._addPane(ds);
        else if (typeof ds == 'string')
            this._makeRequest(ds, null);
        else
            this._handleFailure({ argument: 'Invalid datasource' }, true);
    },

    _makeRequest: function(url, target) {
        var callback = {
            success:  this._handleSuccess,
            failure:  this._handleFailure,
            scope:    this,
            timeout:  Number(this.cfg.requestTimeout) || 5000,
            argument: 'Ajax request failed'
        };
        this._abortRequest();
        if (this.onRequest)
            this.onRequest.fire(url, target);
        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 content;
        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
                content = o.responseText.parseJSON();
            } catch (e) {
                o.argument = 'JSON parsing failed';
                this._handleFailure(o);
                return;
            }
        } else {
            if (o.responseXML == null) {
                o.argument = 'Malformed XML response';
                this._handleFailure(o);
                return;
            }
            var content = o.responseXML.documentElement;
            if ('ul' != content.tagName.toLowerCase())
                content = o.responseText;
        }
        if (this.onResponse)
            this.onResponse.fire('success');
        this._addPane(content);
    },

    _handleFailure: function(o, suppressEvent) {
        var list = document.createElement('ul');
        var item = document.createElement('li');
        var span = document.createElement('span');
        var error = o.argument || this.DEFAULT_ERROR_MSG;
        span.className = 'columnav-error';
        span.appendChild(document.createTextNode(error));
        item.appendChild(span);
        list.appendChild(item);
        if (this.onResponse && !suppressEvent)
            this.onResponse.fire('failure');
        this._addPane(list);
    },

    _handleKeypress: function(type, args, o) {
        var key = args[0];
        var evt = args[1];
        var target = this.EVT.getTarget(evt);
        var pane = target;
        while (!this.DOM.hasClass(pane, 'columnav-menu') &&
               !this.DOM.hasClass(pane, 'columnav-nonmenu'))
        {
            pane = pane.parentNode;
        }
        var isNonMenu = this.DOM.hasClass(pane, 'columnav-nonmenu');
        if (this.isMoving || isNonMenu) {
            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
            if (this._shouldScrollPrev(pane)) {
                this._prev(evt);
                o.carousel.scrollPrev();
                this.isMoving = true;
            } else {
                var prevPane = this._prevPane(pane);
                if (prevPane)
                    this._focus(prevPane);
            }
            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);
    },

    _addPane: function(content) {
        var pane, cls;
        if (typeof content == 'string') {
            pane = content;
            cls = 'columnav-nonmenu';
        } else {
            if (content.tagName && 'ul' != content.tagName.toLowerCase()) {
                pane = (document == content.ownerDocument)
                    ? content.cloneNode(true)
                    : content;
                cls = 'columnav-nonmenu';
            } else {
                pane = this._createMenu(content);
                cls = 'columnav-menu';
            }
        }
        this.carousel.addItem(this.counter, pane, cls);
        if (this.onPane)
            this.onPane.fire(this.counter);
        if (this._shouldScrollNext()) {
            this.carousel.scrollNext();
            this.isMoving = true;
        } else {
            if (this.counter > 1)
                this._focus(pane);
        }
        this.counter++;
    },

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

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

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

    _prev: function(e) {
        this._abortRequest();
        if (this.onPrev)
            this.onPrev.fire(this.EVT.getTarget(e), e);
    },

    _next: function(e) {
        if (this.isMoving) {
            this.EVT.stopEvent(e);
            return;
        }
        var target = this.EVT.getTarget(e);
        if (target.tagName == 'SPAN')
            target = target.parentNode;
        this._removePanes(target);
        var href = target.getAttribute('href');
        var rel = target.getAttribute('rel');
        var next = target.next;

        if (href !== null)
            this._highlight(target);
        if (this.counter - this.numScrolled == 2 && this.numScrolled > 0) {
                this.carousel.cfg.owner.scrollPrev();
                this.hack = true;
                this.EVT.stopEvent(e);
        }

        // fire custom event only after state established
        var go = true;
        if (this.onNext) {
            var arg = this.cfg.nextHandler ? target : e; // for backward compatibility
                                                         // with linkAction
            go = this.onNext.fire(arg, e);
        }

        if (next) {
            if (go) this._addPane(next);
        } else if (rel && rel.match(/\bajax\b/)) {
            if (go) this._makeRequest(href, target);
        } else {
            if (go) return true;
        }
        this.EVT.stopEvent(e);
    },

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

    _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(el) {
        if (this.DOM.hasClass(el, 'columnav-nonmenu')) {
            if (el.firstChild.focus) el.firstChild.focus();
            else el.focus();
        } else {
            var links = this._getNodes(el, this._links);
            for (var i = 0; i < links.length; i++) {
                if (this.DOM.hasClass(links[i], 'columnav-active')) {
                    links[i].focus();
                    return;
                }
            }
            if (links[0])
                links[0].focus();
        }
    },

    _animationCompleteHandler: function(type, args, me) {
        this.isMoving = false;
        if (args[0] == 'next') {
            this.numScrolled++;
            this._focus(this.carousel.carouselList.lastChild);
        }
        if (args[0] == 'prev') {
            this._removeLastPane();
            this.numScrolled--;
            if (this.carousel.cfg.getProperty('numVisible') == 1)
                this._focus(this.carousel.carouselList.lastChild);
        }
        if (typeof this.animationCompleteHandler == 'function')
            this.animationCompleteHandler(type, args, me);

    },

    _prevButtonStateHandler: function(type, args, me) {
        if (typeof this.prevButtonStateHandler == 'function')
            this.prevButtonStateHandler(type, args, me);
    },

    _removeLastPane: function() {
        if (!this.hack) {
            var list = this.carousel.carouselList;
            list.removeChild(list.lastChild);
            this.counter--;
        }
        this.hack = false;
    },

    _createMenu: function(node) {
        var menu = document.createElement('div');
        var title;
        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 o = { text: a.firstChild.data, next: 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));
            }
            title = node.getAttribute('title');
        } 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'], next: items[i].ul };
                for (var n in a) {
                    if ('@' == n.charAt(0)) {
                        var v = a[n];
                        o[n] = v;
                    }
                }
                menu.appendChild(this._createLink(o));
            }
            title = node['@title'];
            if (!title && node.ul)
                title = node.ul['@title'];
        }
        if (title)
            menu.setAttribute('title', title);
        return menu;
    },

    _createLink: function(o) {
        var a = document.createElement('a');
        var span = document.createElement('span');
        span.appendChild(document.createTextNode(o['text']));
        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.next = o['next'];
        if (o['next'] || (o['@rel'] && o['@rel'].match(/(?:^|\s+)ajax(?:\s+|$)/)))
            this.DOM.addClass(a, 'columnav-has-next');
        this.EVT.addListener(a, 'click', this._next, this, true);
        return a;
    },

    _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'); },

    // for backward compatibility
    ERROR_MSG: this.DEFAULT_ERROR_MSG,
    _addMenu: function(node) { this._addPane(node); },
    _prevMenu: function(menu) { return this._prevPane(menu); },
    _removeMenus: function(target) { this._removePanes(target); },
    _removeLastMenu: function() { this._removeLastPane(); }
};

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