/**
 * jquery.scrollable 1.0.5 - Scroll your HTML with eye candy.
 *
 * Copyright (c) 2009 Tero Piirainen
 * http://flowplayer.org/tools/scrollable.html
 *
 * Dual licensed under MIT and GPL 2+ licenses
 * http://www.opensource.org/licenses
 *
 * Launch  : March 2008
 * Date: 2009-06-12 11:02:45 +0000 (Fri, 12 Jun 2009)
 * Revision: 1911
 */
(function($) {

    // static constructs
    $.tools = $.tools || {version: {}};

    $.tools.version.scrollable = '1.0.5';

    var current = null;


    // constructor
    function Scrollable(root, conf) {

        // current instance
        var self = this;
        if (!current) { current = self; }

        // generic binding function
        function bind(name, fn) {
            $(self).bind(name, function(e, args)  {
                if (fn && fn.call(this, args.index) === false && args) {
                    args.proceed = false;
                }
            });

            return self;
        }

        // bind all callbacks from configuration
        $.each(conf, function(name, fn) {
            if ($.isFunction(fn)) { bind(name, fn); }
        });


        // horizontal flag
        var horizontal = !conf.vertical;

        // wrap (root elements for items)
        var wrap = $(conf.items, root);

        // current index
        var index = 0;

        function find(query, ctx) {
            return query.indexOf("#") != -1 ? $(query).eq(0) : ctx.siblings(query).eq(0);
        }

        // get handle to navigational elements
        var navi = find(conf.navi, root);
        var prev = find(conf.prev, root);
        var next = find(conf.next, root);
        var prevPage = find(conf.prevPage, root);
        var nextPage = find(conf.nextPage, root);


        // methods
        $.extend(self, {

            getIndex: function() {
                return index;
            },

            getConf: function() {
                return conf;
            },

            getSize: function() {
                return self.getItems().size();
            },

            getPageAmount: function() {
                return Math.ceil(this.getSize() / conf.size);
            },

            getPageIndex: function() {
                return Math.ceil(index / conf.size);
            },

            getRoot: function() {
                return root;
            },

            getItemWrap: function() {
                return wrap;
            },

            getItems: function() {
                return wrap.children();
            },

            getVisibleItems: function() {
                return self.getItems().slice(index, index + conf.size);
            },

            /* all seeking functions depend on this */
            seekTo: function(i, time, fn) {

                // default speed
                if (time === undefined) { time = conf.speed; }

                // function given as second argument
                if ($.isFunction(time)) {
                    fn = time;
                    time = conf.speed;
                }

                if (i < 0) { i = 0; }
                if (i > self.getSize() - conf.size) { return self; }

                var item = self.getItems().eq(i);
                if (!item.length) { return self; }


                // onBeforeSeek
                var p = {index: i, proceed: true};
                $(self).trigger("onBeforeSeek", p);
                if (!p.proceed) { return self; }


                if (horizontal) {
                     var left = -item.position().left;
                    wrap.animate({left: left}, time, conf.easing, fn ? function() { fn.call(self); } : null);

                } else {
                    var top = -item.position().top;
                    wrap.animate({top: top}, time, conf.easing, fn ? function() { fn.call(self); } : null);
                }


                // navi status update
                if (navi.length) {
                    var klass = conf.activeClass;
                    var page = Math.ceil(i / conf.size);
                    page = Math.min(page, navi.children().length - 1);
                    navi.children().removeClass(klass).eq(page).addClass(klass);
                }

                // prev buttons disabled flag
                if (i === 0) {
                    prev.add(prevPage).addClass(conf.disabledClass);
                } else {
                    prev.add(prevPage).removeClass(conf.disabledClass);
                }

                // next buttons disabled flag
                if (i >= self.getSize() - conf.size) {
                    next.add(nextPage).addClass(conf.disabledClass);
                } else {
                    next.add(nextPage).removeClass(conf.disabledClass);
                }

                current = self;
                index = i;

                // onSeek after index being updated
                $(self).trigger("onSeek", {index: i});
                return self;
            },


            move: function(offset, time, fn) {
                var to = index + offset;
                if (conf.loop && to > (self.getSize() - conf.size)) {
                    to = 0;
                }
                return this.seekTo(to, time, fn);
            },

            next: function(time, fn) {
                return this.move(1, time, fn);
            },

            prev: function(time, fn) {
                return this.move(-1, time, fn);
            },

            movePage: function(offset, time, fn) {
                return this.move(conf.size * offset, time, fn);
            },

            setPage: function(page, time, fn) {
                var size = conf.size;
                var index = size * page;
                var lastPage = index + size >= this.getSize();
                if (lastPage) {
                    index = this.getSize() - conf.size;
                }
                return this.seekTo(index, time, fn);
            },

            prevPage: function(time, fn) {
                return this.setPage(this.getPageIndex() - 1, time, fn);
            },

            nextPage: function(time, fn) {
                return this.setPage(this.getPageIndex() + 1, time, fn);
            },

            begin: function(time, fn) {
                return this.seekTo(0, time, fn);
            },

            end: function(time, fn) {
                return this.seekTo(this.getSize() - conf.size, time, fn);
            },

            reload: function() {
                return load();
            },

            click: function(index, time, fn) {

                var item = self.getItems().eq(index);
                var klass = conf.activeClass;

                // check that index is sane
                if (index < 0 || index >= this.getSize()) { return self; }


                // special case with two items
                if (conf.size == 2) {
                    if (index == self.getIndex()) { index--; }
                    self.getItems().removeClass(klass);
                    item.addClass(klass);
                    return this.seekTo(index, time, fn);
                }


                if (!item.hasClass(klass)) {
                    self.getItems().removeClass(klass);
                    item.addClass(klass);
                    var delta = Math.floor(conf.size / 2);
                    var to = index - delta;

                    // next to last item must work
                    if (to > self.getSize() - conf.size) {
                        to = self.getSize() - conf.size;
                    }

                    if (to !== index) {
                        return this.seekTo(to, time, fn);
                    }
                }

                return self;
            },

            // callback functions
            onBeforeSeek: function(fn) {
                return bind("onBeforeSeek", fn);
            },

            onSeek: function(fn) {
                return bind("onSeek", fn);
            }

        });


        // mousewheel
        if ($.isFunction($.fn.mousewheel)) {
            root.bind("mousewheel.scrollable", function(e, delta)  {
                // opera goes to opposite direction
                var step = $.browser.opera ? 1 : -1;

                self.move(delta > 0 ? step : -step, 50);
                return false;
            });
        }

        // prev button
        prev.addClass(conf.disabledClass).click(function() {
            self.prev();
        });


        // next button
        next.click(function() {
            self.next();
        });

        // prev page button
        nextPage.click(function() {
            self.nextPage();
        });


        // next page button
        prevPage.addClass(conf.disabledClass).click(function() {
            self.prevPage();
        });


        // keyboard
        if (conf.keyboard) {

            // keyboard works on one instance at the time. thus we need to unbind first
            $(document).unbind("keydown.scrollable").bind("keydown.scrollable", function(evt) {

                var el = current;
                if (!el || evt.altKey || evt.ctrlKey) { return; }

                if (horizontal && (evt.keyCode == 37 || evt.keyCode == 39)) {
                    el.move(evt.keyCode == 37 ? -1 : 1);
                    return evt.preventDefault();
                }

                if (!horizontal && (evt.keyCode == 38 || evt.keyCode == 40)) {
                    el.move(evt.keyCode == 38 ? -1 : 1);
                    return evt.preventDefault();
                }

                return true;

            });
        }

        // navi
        function load() {

            // generate new entries
            if (navi.is(":empty") || navi.data("me") == self) {

                navi.empty();
                navi.data("me", self);

                for (var i = 0; i < self.getPageAmount(); i++) {

                    var item = $("<" + conf.naviItem + "/>").attr("href", i).click(function(e) {
                        var el = $(this);
                        el.parent().children().removeClass(conf.activeClass);
                        el.addClass(conf.activeClass);
                        self.setPage(el.attr("href"));
                        return e.preventDefault();
                    });

                    if (i === 0) { item.addClass(conf.activeClass); }
                    navi.append(item);
                }

            // assign onClick events to existing entries
            } else {

                // find a entries first -> syntaxically correct
                var els = navi.children();

                els.each(function(i)  {
                    var item = $(this);
                    item.attr("href", i);
                    if (i === 0) { item.addClass(conf.activeClass); }

                    item.click(function() {
                        navi.find("." + conf.activeClass).removeClass(conf.activeClass);
                        item.addClass(conf.activeClass);
                        self.setPage(item.attr("href"));
                    });

                });
            }


            // item.click()
            if (conf.clickable) {
                self.getItems().each(function(index, arg) {
                    var el = $(this);
                    if (!el.data("set")) {
                        el.bind("click.scrollable", function() {
                            self.click(index);
                        });
                        el.data("set", true);
                    }
                });
            }


            // hover
            if (conf.hoverClass) {
                self.getItems().hover(function()  {
                    $(this).addClass(conf.hoverClass);
                }, function() {
                    $(this).removeClass(conf.hoverClass);
                });
            }

            return self;
        }

        load();


        // interval stuff
        var timer = null;

        function setTimer() {

            // do not start additional timer if already exists
            if (timer) { return; }

            // construct new timer
            timer = setInterval(function()  {

                // check if interval is being changed dynamically during runtime
                if (conf.interval === 0) {
                    clearInterval(timer);
                    timer = 0;
                    return;
                }

                self.next();
            }, conf.interval);
        }

        if (conf.interval > 0) {

            // when mouse enters, autoscroll stops
            root.hover(function() {
                clearInterval(timer);
                timer = 0;

            }, function() {
                setTimer();
            });

            setTimer();
        }

    }


    // jQuery plugin implementation
    $.fn.scrollable = function(conf) {

        // already constructed --> return API
        var el = this.eq(typeof conf == 'number' ? conf : 0).data("scrollable");
        if (el) { return el; }


        var opts = {

            // basics
            size: 5,
            vertical:false,
            clickable: true,
            loop: false,
            interval: 0,
            speed: 400,
            keyboard: true,

            // other
            activeClass:'active',
            disabledClass: 'disabled',
            hoverClass: null,
            easing: 'swing',

            // navigational elements
            items: '.items',
            prev: '.prev',
            next: '.next',
            prevPage: '.prevPage',
            nextPage: '.nextPage',
            navi: '.navi',
            naviItem: 'a',
            api:false,


            // callbacks
            onBeforeSeek: null,
            onSeek: null

        };


        $.extend(opts, conf);

        this.each(function() {
            el = new Scrollable($(this), opts);
            $(this).data("scrollable", el);
        });

        return opts.api ? el: this;

    };


})(jQuery);