/**
 * Expandable page section widget
 *
 * Initializes all elements of a specific class as an expandable and
 * collapsable section. Does so in an accessible way.
 *
 * This code is licensed under the Mozilla Public License 1.1.
 *
 * Portions adapted from the jQuery Easing plugin written by Robert Penner and
 * used under the following license:
 *
 *   Copyright 2001 Robert Penner
 *   All rights reserved.
 *
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following conditions are
 *   met:
 *
 *   - Redistributions of source code must retain the above copyright notice,
 *     this list of conditions and the following disclaimer.
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *   - Neither the name of the author nor the names of contributors may be
 *     used to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 *   TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 *   PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 *   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 *   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 *   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 *   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 *   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * @copyright 2007-2010 Mozilla Foundation, 2007-2010 silverorange Inc.
 * @license   http://www.mozilla.org/MPL/MPL-1.1.html Mozilla Public License 1.1
 * @author    Michael Gauthier <mike@silverorange.com>
 */

// create namespace
if (typeof Mozilla == 'undefined') {
    var Mozilla = {};
}

// create namespace
if (typeof Mozilla.Expander == 'undefined') {
    Mozilla.Expander = {};
}

// string resources
Mozilla.Expander.OPEN_TEXT  = 'Show';
Mozilla.Expander.CLOSE_TEXT = 'Hide';

$(document).ready(function() {

    // add easing functions
    $.extend($.easing, {
        'expanderOpen':  function (x, t, b, c, d) {
            return c * (t /= d) * t + b;
        },
        'expanderClose': function (x, t, b, c, d) {
            return -c * (t /= d) * (t - 2) + b;
        }
    });

    function Expander(container)
    {
        if (typeof container == 'String') {
            container = $(container).get(0);
        }

        // parse group id
        var matches = container.className.match(
            /\bexpander-group-([A-Za-z0-9]+)\b/);

        if (matches && matches.length) {
            this.groupId = 'group-' + matches[1];
            if (!Expander.expandersByGroup[this.groupId]) {
                Expander.expandersByGroup[this.groupId] = [];
            }
            Expander.expandersByGroup[this.groupId].push(this);
        } else {
            this.groupId = null;
        }

        // get header and content elements as first two child elements
        var header     = $(':first', container);
        this.content   = $(':eq(1)', container);
        this.container = $(container);

        if (!this.container.attr('id')) {
            this.container.attr('id', Expander.generateId());
        }

        this.id = this.container.attr('id');

        // build header markup
        this.anchor = $('<a href="#" class="expander-anchor"/>');
        this.anchor.data('expander', this);
        while (header.get(0).firstChild) {
            $(header.get(0).firstChild).appendTo(this.anchor);
        }
        this.anchor.appendTo(header);
        this.anchor.click(function(e) {
            e.preventDefault();
            var expander = $(this).data('expander');
            expander.toggleWithAnimation();
        });

        // build content markup
        this.contentAnimation = $('<div class="expander-animation">');
        this.contentAnimation.data('expander', this);
        var contentPadding = $('<div class="expander-padding">');
        while (this.content.get(0).firstChild) {
            $(this.content.get(0).firstChild).appendTo(contentPadding);
        }
        contentPadding.appendTo(this.contentAnimation);
        this.contentAnimation.appendTo(this.content);

        // prevent closing during opening animation and vice versa
        this.semaphore = false;

        this.container.removeClass('expander');

        if (   (location.hash.substring(1) == this.id)
            || this.loadState() == Expander.OPEN
            || this.container.hasClass('expander-default-open')
        ) {
            this.open();
        } else {
            this.close();
        }
    }

    Expander.OPEN             = true;
    Expander.CLOSED           = false;
    Expander.OPEN_DURATION    = 250;
    Expander.CLOSE_DURATION   = 250;

    Expander.expanders        = [];
    Expander.expandersByGroup = {};

    Expander.idPrefix         = '-moz-expander-';
    Expander.idCount          = 0;

    Mozilla.Expander.openAll = function()
    {
        for (var i = 0; i < Expander.expanders.length; i++) {
            Expander.expanders[i].openWithAnimation();
        }
    };

    Mozilla.Expander.closeAll = function()
    {
        for (var i = 0; i < Expander.expanders.length; i++) {
            Expander.expanders[i].closeWithAnimation();
        }
    };

    Expander.generateId = function()
    {
        Expander.idCount++;
        return Expander.idPrefix + Expander.idCount;
    };

    Expander.prototype.toggle = function()
    {
        if (this.state == Expander.OPEN) {
            this.close();
        } else {
            this.open();
        }
    };

    Expander.prototype.saveState = function()
    {
        if (typeof sessionStorage != 'undefined') {
            var href = location.href.split('#')[0];
            var state = (this.state == Expander.OPEN) ?
                'open' : 'closed';

            sessionStorage.setItem(href + '-' + this.id, state);
        }
    };

    Expander.prototype.loadState = function()
    {
        var state = Expander.CLOSED;
        if (typeof sessionStorage != 'undefined') {
            var href = location.href.split('#')[0];
            var loadedState = sessionStorage.getItem(href + '-' + this.id);
            if (loadedState !== null) {
                state = (loadedState == 'open') ?
                    Expander.OPEN : Expander.CLOSED;
            }
        }
        return state;
    };

    Expander.prototype.toggleWithAnimation = function()
    {
        if (this.state == Expander.OPEN) {
            this.closeWithAnimation();
        } else {
            this.openWithAnimation();
        }
    };

    Expander.prototype.openWithAnimation = function()
    {
        if (this.semaphore || this.state === Expander.OPEN) {
            return;
        }

        this.container.removeClass('expander-closed');
        this.container.addClass('expander-open');

        // get display height
        this.content
            .css('overflow', 'hidden')
            .css('height', '0');

        this.contentAnimation
            .css('visibility', 'hidden')
            .css('overflow', 'hidden')
            .css('display', 'block')
            .css('height', 'auto');

        var height = this.contentAnimation.get(0).offsetHeight;

        this.contentAnimation
            .css('height', '0')
            .css('visibility', 'visible');

        this.content
            .css('height', '')
            .css('overflow', 'visible');

        this.contentAnimation.animate({
            'height': height
        }, Expander.OPEN_DURATION, 'expanderOpen', function() {
            var expander = $(this).data('expander');
            expander.handleOpen();
        });

        this.semaphore = true;

        // close other expanders in the group
        if (this.groupId !== null) {
            var expander;
            var expanderGroup = Expander.expandersByGroup[this.groupId];
            for (var i = 0; i < expanderGroup.length; i++) {
                expander = expanderGroup[i];
                if (expander !== this) {
                    expander.closeWithAnimation();
                }
            }
        }

        this.state = Expander.OPEN;
    };

    Expander.prototype.closeWithAnimation = function()
    {
        if (this.semaphore || this.state === Expander.CLOSED) {
            return;
        }

        this.container.removeClass('expander-open-complete');

        this.contentAnimation
            .css('overflow', 'hidden')
            .css('height', 'auto')

        this.contentAnimation.animate({
            height: 0
        },
        Expander.CLOSE_DURATION, 'expanderClose', function() {
            var expander = $(this).data('expander');
            expander.handleClose();
        });

        this.semaphore = true;

        this.state = Mozilla.Expander.CLOSED;
    };

    Expander.prototype.open = function()
    {
        this.container
            .removeClass('expander-closed')
            .addClass('expander-open')
            .addClass('expander-open-complete');

        this.semaphore = false;

        this.state = Expander.OPEN;
        this.anchor.attr('title', Mozilla.Expander.CLOSE_TEXT);

        // close other expanders in the group
        if (this.groupId !== null) {
            var expander;
            var expanderGroup = Expander.expandersByGroup[this.groupId];
            for (var i = 0; i < expanderGroup.length; i++) {
                expander = expanderGroup[i];
                if (expander !== this) {
                    expander.close();
                }
            }
        }

        this.saveState();
    };

    Expander.prototype.close = function()
    {
        this.container
            .removeClass('expander-open-complete')
            .removeClass('expander-open')
            .addClass('expander-closed');

        this.semaphore = false;

        this.state = Expander.CLOSED;
        this.anchor.attr('title', Mozilla.Expander.OPEN_TEXT);

        this.saveState();
    };

    Expander.prototype.handleOpen = function()
    {
        this.container.addClass('expander-open-complete');

        // allow font resizing to work again and re-set overflow to visible
        // for styles that might depend on it
        this.contentAnimation
            .css('height', 'auto')
            .css('overflow', 'visible');

        this.anchor.attr('title', Mozilla.Expander.CLOSE_TEXT);

        this.semaphore = false;

        this.saveState();
    };

    Expander.prototype.handleClose = function()
    {
        this.container
            .removeClass('expander-open')
            .addClass('expander-closed');

        this.anchor.attr('title', Mozilla.Expander.OPEN_TEXT);

        this.semaphore = false;

        this.saveState();
    };

    // remember link location
    var hash = location.hash;

    // create expanders
    $('.expander').each(function() {
        Expander.expanders.push(new Expander(this));
    });

    // reset link location since the link may have moved on the page
    if (hash) {
        if ((/safari/gi).test(navigator.userAgent)) {
            location.hash = '#nothing'; /* Safari hack */
        }
        location.hash = hash;
    }
});