/*
 * jQuery Carousel Plugin v1.0
 * http://richardscarrott.co.uk/posts/view/jquery-carousel-plugin
 *
 * Copyright (c) 2010 Richard Scarrott
 *
 * Dual licensed under the MIT and GPL licenses:
 * http://www.opensource.org/licenses/mit-license.php
 * http://www.gnu.org/licenses/gpl.html
 *
 * Requires jQuery v1.4+
 *
 */

// prototypal inheritance
if (typeof Object.create !== 'function') {
    Object.create = function (o) {
        function F() {}
        F.prototype = o;
        return new F();
    };
}

(function($) {
    // ie alias
    var headache = $.browser.msie && $.browser.version.substr(0,1)<9;

    // carousel
    var Carousel = {
        settings: {
            itemsPerPage: 1,
            itemsPerTransition: 1,
            noOfRows: 1,
            pagination: true,
            nextPrevLinks: true,
            speed: 'normal',
            easing: 'swing'
        },
        init: function(el, options) {
            if (!el.length) {return false;}
            this.options = $.extend({}, this.settings, options);
            this.itemIndex = 0;    
            this.container = el;
            this.runner = this.container.find('ul');
            this.items = this.runner.children('li');
            this.noOfItems = this.items.length;
            this.setRunnerWidth();
            if (this.noOfItems <= this.options.itemsPerPage) {return false;} // bail if there are too few items to paginate
            this.insertMask();
            this.noOfPages = Math.ceil((this.noOfItems - this.options.itemsPerPage) / this.options.itemsPerTransition) + 1;
            if (this.options.pagination) {this.insertPagination();}
            if (this.options.nextPrevLinks) {this.insertNextPrevLinks();}
            this.updateBtnStyles();
        },
        insertMask: function() {
            this.runner.wrap('<div class="mask" />');
            this.mask = this.container.find('div.mask');
        },
        setRunnerWidth: function() {
            this.noOfItems = Math.round(this.noOfItems / this.options.noOfRows);
            var width =  this.items.outerWidth(true) * this.noOfItems;
            this.runner.width(width);
        },
        insertPagination: function() {
            var i, links = [];
            this.paginationLinks = $('<ol class="pagination-links" />');
            for (i = 0; i < this.noOfPages; i++) {
                links[i] = '<li><a href="#item-' + i + '">' + (i + 1) + '</a></li>';
            }
            this.paginationLinks
                .append(links.join(''))
                .appendTo(this.container)
                .find('a')
                    .bind('click.carousel', $.proxy(this, 'paginationHandler'));
        },
        paginationHandler: function(e) {
            this.itemIndex = e.target.hash.substr(1).split('-')[1] * this.options.itemsPerTransition;
            this.animate();
            return false;
        },
        insertNextPrevLinks: function() {
            this.prevLink = $('<a href="#" class="prev"></a>')
                                .bind('click.carousel', $.proxy(this, 'prevItem'))
                                .appendTo(this.container);
            this.nextLink = $('<a href="#" class="next"></a>')
                                .bind('click.carousel', $.proxy(this, 'nextItem'))
                                .appendTo(this.container);
        },
        nextItem: function() {
            this.itemIndex = this.itemIndex + this.options.itemsPerTransition;
            this.animate();
            return false;
        },
        prevItem: function() {
            this.itemIndex = this.itemIndex - this.options.itemsPerTransition;
            this.animate();
            return false;
        },
        updateBtnStyles: function() {
            if (this.options.pagination) {
                this.paginationLinks
                    .children('li')
                        .removeClass('current')
                        .eq(Math.ceil(this.itemIndex / this.options.itemsPerTransition))
                            .addClass('current');
            }

            if (this.options.nextPrevLinks) {
                this.nextLink
                    .add(this.prevLink)
                        .removeClass('disabled');
                if (this.itemIndex === (this.noOfItems - this.options.itemsPerPage)) {
                    this.nextLink.addClass('disabled');
                } 
                else if (this.itemIndex === 0) {
                    this.prevLink.addClass('disabled');
                }
            }
        },
        animate: function() {
            var nextItem, pos;
            // check whether there are enough items to animate to
            if (this.itemIndex > (this.noOfItems - this.options.itemsPerPage)) {
                this.itemIndex = this.noOfItems - this.options.itemsPerPage; // go to last panel - items per transition
            }
            if (this.itemIndex < 0) {
                this.itemIndex = 0; // go to first
            }
            nextItem = this.items.eq(this.itemIndex);
            pos = nextItem.position();
            
            if (headache) {
                this.runner
                    .stop()
                    .animate({left: -pos.left}, this.options.speed, this.options.easing);
            }
            else {
                this.mask
                    .stop()
                    .animate({scrollLeft: pos.left}, this.options.speed, this.options.easing);
            }
            this.updateBtnStyles();
        }
    };

    // bridge
    $.fn.carousel = function(options) {
        return this.each(function() {
            var obj = Object.create(Carousel);
            obj.init($(this), options);
            $.data(this, 'carousel', obj);
        });
    };
})(jQuery);