/**
 * jcarousellite - jquery plugin to navigate images/any content in a carousel style widget.
 * @requires jquery v1.2 or above
 *
 * http://gmarwaha.com/jquery/jcarousellite/
 *
 * copyright (c) 2007 ganeshji marwaha (gmarwaha.com)
 * dual licensed under the mit and gpl licenses:
 * http://www.opensource.org/licenses/mit-license.php
 * http://www.gnu.org/licenses/gpl.html
 *
 * version: 1.0.1
 * note: requires jquery 1.2 or above from version 1.0.1
 */
/**
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btnnext : ��һ�ű�ť
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mousewheel : �ƿ�֧����껬�ֹ���������ֵ��false / true��ĭ��ϊfalse �򿪴�����ҫjquery ui���֧��
auto : �����զ����ŵ��ٶȣ�ĭ���զ������ǹرյģ���ʽ auto: 800 (ϊ�����ٶ�)
speed : ����ч���ٶ�
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vertical : ���������������ϊtrue�����ʾ��ֱ������ĭ��ϊfalse
circular : �ƿ��ظ����ţ��������ϊfalse�������һ����һ�ű�ť�͵㲻���ˣ�����һ����һ�ű�ť�͵㲻��
visible : ����ĭ����ʾ����li��ĭ����3��
start : ч���ӵڼ�����ʼ��ĭ��ϊ0
scroll : һ�λ�������li��ĭ����2
beforestart : ����ǽӿڣ�ÿ�λ���ч��ִ��֮ǰִ�е��զ��庯��
afterend : ����ǽӿڣ�ÿ�λ���ч��ִ��֮��ִ�е��զ��庯��
 */
 
/**
 * creates a carousel-style navigation widget for images/any-content from a simple html markup.
 *
 * the html markup that is used to build the carousel can be as simple as...
 *
 *  <div class="carousel">
 *      <ul>
 *          <li><img src="image/1.jpg" alt="1"></li>
 *          <li><img src="image/2.jpg" alt="2"></li>
 *          <li><img src="image/3.jpg" alt="3"></li>
 *      </ul>
 *  </div>
 *
 * as you can see, this snippet is nothing but a simple div containing an unordered list of images.
 * you don't need any special "class" attribute, or a special "css" file for this plugin.
 * i am using a class attribute just for the sake of explanation here.
 *
 * to navigate the elements of the carousel, you need some kind of navigation buttons.
 * for example, you will need a "previous" button to go backward, and a "next" button to go forward.
 * this need not be part of the carousel "div" itself. it can be any element in your page.
 * lets assume that the following elements in your document can be used as next, and prev buttons...
 *
 * <button class="prev">&lt;&lt;</button>
 * <button class="next">&gt;&gt;</button>
 *
 * now, all you need to do is call the carousel component on the div element that represents it, and pass in the
 * navigation buttons as options.
 *
 * $(".carousel").jcarousellite({
 *      btnnext: ".next",
 *      btnprev: ".prev"
 * });
 *
 * that's it, you would have now converted your raw div, into a magnificient carousel.
 *
 * there are quite a few other options that you can use to customize it though.
 * each will be explained with an example below.
 *
 * @param an options object - you can specify all the options shown below as an options object param.
 *
 * @option btnprev, btnnext : string - no defaults
 * @example
 * $(".carousel").jcarousellite({
 *      btnnext: ".next",
 *      btnprev: ".prev"
 * });
 * @desc creates a basic carousel. clicking "btnprev" navigates backwards and "btnnext" navigates forward.
 *
 * @option btngo - array - no defaults
 * @example
 * $(".carousel").jcarousellite({
 *      btnnext: ".next",
 *      btnprev: ".prev",
 *      btngo: [".0", ".1", ".2"]
 * });
 * @desc if you don't want next and previous buttons for navigation, instead you prefer custom navigation based on
 * the item number within the carousel, you can use this option. just supply an array of selectors for each element
 * in the carousel. the index of the array represents the index of the element. what i mean is, if the
 * first element in the array is ".0", it means that when the element represented by ".0" is clicked, the carousel
 * will slide to the first element and so on and so forth. this feature is very powerful. for example, i made a tabbed
 * interface out of it by making my navigation elements styled like tabs in css. as the carousel is capable of holding
 * any content, not just images, you can have a very simple tabbed navigation in minutes without using any other plugin.
 * the best part is that, the tab will "slide" based on the provided effect. :-)
 *
 * @option mousewheel : boolean - default is false
 * @example
 * $(".carousel").jcarousellite({
 *      mousewheel: true
 * });
 * @desc the carousel can also be navigated using the mouse wheel interface of a scroll mouse instead of using buttons.
 * to get this feature working, you have to do 2 things. first, you have to include the mouse-wheel plugin from brandon.
 * second, you will have to set the option "mousewheel" to true. that's it, now you will be able to navigate your carousel
 * using the mouse wheel. using buttons and mousewheel or not mutually exclusive. you can still have buttons for navigation
 * as well. they complement each other. to use both together, just supply the options required for both as shown below.
 * @example
 * $(".carousel").jcarousellite({
 *      btnnext: ".next",
 *      btnprev: ".prev",
 *      mousewheel: true
 * });
 *
 * @option auto : number - default is null, meaning autoscroll is disabled by default
 * @example
 * $(".carousel").jcarousellite({
 *      auto: 800,
 *      speed: 500
 * });
 * @desc you can make your carousel auto-navigate itself by specfying a millisecond value in this option.
 * the value you specify is the amount of time between 2 slides. the default is null, and that disables auto scrolling.
 * specify this value and magically your carousel will start auto scrolling.
 *
 * @option speed : number - 200 is default
 * @example
 * $(".carousel").jcarousellite({
 *      btnnext: ".next",
 *      btnprev: ".prev",
 *      speed: 800
 * });
 * @desc specifying a speed will slow-down or speed-up the sliding speed of your carousel. try it out with
 * different speeds like 800, 600, 1500 etc. providing 0, will remove the slide effect.
 *
 * @option easing : string - no easing effects by default.
 * @example
 * $(".carousel").jcarousellite({
 *      btnnext: ".next",
 *      btnprev: ".prev",
 *      easing: "bounceout"
 * });
 * @desc you can specify any easing effect. note: you need easing plugin for that. once specified,
 * the carousel will slide based on the provided easing effect.
 *
 * @option vertical : boolean - default is false
 * @example
 * $(".carousel").jcarousellite({
 *      btnnext: ".next",
 *      btnprev: ".prev",
 *      vertical: true
 * });
 * @desc determines the direction of the carousel. true, means the carousel will display vertically. the next and
 * prev buttons will slide the items vertically as well. the default is false, which means that the carousel will
 * display horizontally. the next and prev items will slide the items from left-right in this case.
 *
 * @option circular : boolean - default is true
 * @example
 * $(".carousel").jcarousellite({
 *      btnnext: ".next",
 *      btnprev: ".prev",
 *      circular: false
 * });
 * @desc setting it to true enables circular navigation. this means, if you click "next" after you reach the last
 * element, you will automatically slide to the first element and vice versa. if you set circular to false, then
 * if you click on the "next" button after you reach the last element, you will stay in the last element itself
 * and similarly for "previous" button and first element.
 *
 * @option visible : number - default is 3
 * @example
 * $(".carousel").jcarousellite({
 *      btnnext: ".next",
 *      btnprev: ".prev",
 *      visible: 4
 * });
 * @desc this specifies the number of items visible at all times within the carousel. the default is 3.
 * you are even free to experiment with real numbers. eg: "3.5" will have 3 items fully visible and the
 * last item half visible. this gives you the effect of showing the user that there are more images to the right.
 *
 * @option start : number - default is 0
 * @example
 * $(".carousel").jcarousellite({
 *      btnnext: ".next",
 *      btnprev: ".prev",
 *      start: 2
 * });
 * @desc you can specify from which item the carousel should start. remember, the first item in the carousel
 * has a start of 0, and so on.
 *
 * @option scrool : number - default is 1
 * @example
 * $(".carousel").jcarousellite({
 *      btnnext: ".next",
 *      btnprev: ".prev",
 *      scroll: 2
 * });
 * @desc the number of items that should scroll/slide when you click the next/prev navigation buttons. by
 * default, only one item is scrolled, but you may set it to any number. eg: setting it to "2" will scroll
 * 2 items when you click the next or previous buttons.
 *
 * @option beforestart, afterend : function - callbacks
 * @example
 * $(".carousel").jcarousellite({
 *      btnnext: ".next",
 *      btnprev: ".prev",
 *      beforestart: function(a) {
 *          alert("before animation starts:" + a);
 *      },
 *      afterend: function(a) {
 *          alert("after animation ends:" + a);
 *      }
 * });
 * @desc if you wanted to do some logic in your page before the slide starts and after the slide ends, you can
 * register these 2 callbacks. the functions will be passed an argument that represents an array of elements that
 * are visible at the time of callback.
 *
 *
 * @cat plugins/image gallery
 * @author ganeshji marwaha/ganeshread@gmail.com
 */

(function($) {                                          // compliant with jquery.noconflict()
$.fn.jcarousellite = function(o) {
    o = $.extend({
        btnprev: null,
        btnnext: null,
        btngo: null,
        mousewheel: false,
        auto: null,

        speed: 200,
        easing: null,

        vertical: false,
        circular: true,
        visible: 3,
        start: 0,
        scroll: 1,

        beforestart: null,
        afterend: null
    }, o || {});

    return this.each(function() {                           // returns the element collection. chainable.

        var running = false, animcss=o.vertical?"top":"left", sizecss=o.vertical?"height":"width";
        var div = $(this), ul = $("ul", div), tli = $("li", ul), tl = tli.size(), v = o.visible;

        if(o.circular) {
            ul.prepend(tli.slice(tl-v-1+1).clone())
              .append(tli.slice(0,v).clone());
            o.start += v;
        }

        var li = $("li", ul), itemlength = li.size(), curr = o.start;
        div.css("visibility", "visible");

        li.css({overflow: "hidden", float: o.vertical ? "none" : "left"});
        ul.css({margin: "0", padding: "0", position: "relative", "list-style-type": "none", "z-index": "1"});
        div.css({overflow: "hidden", position: "relative", "z-index": "2", left: "0px"});

        var lisize = o.vertical ? height(li) : width(li);   // full li size(incl margin)-used for animation
        var ulsize = lisize * itemlength;                   // size of full ul(total length, not just for the visible items)
        var divsize = lisize * v;                           // size of entire div(total length for just the visible items)

        li.css({width: li.width(), height: li.height()});
        ul.css(sizecss, ulsize+"px").css(animcss, -(curr*lisize));

        div.css(sizecss, divsize+"px");                     // width of the div. length of visible images

        if(o.btnprev)
            $(o.btnprev).click(function() {
                return go(curr-o.scroll);
            });

        if(o.btnnext)
            $(o.btnnext).click(function() {
                return go(curr+o.scroll);
            });

        if(o.btngo)
            $.each(o.btngo, function(i, val) {
                $(val).click(function() {
                    return go(o.circular ? o.visible+i : i);
                });
            });

        if(o.mousewheel && div.mousewheel)
            div.mousewheel(function(e, d) {
                return d>0 ? go(curr-o.scroll) : go(curr+o.scroll);
            });

        if(o.auto)
            setinterval(function() {
                go(curr+o.scroll);
            }, o.auto+o.speed);

        function vis() {
            return li.slice(curr).slice(0,v);
        };

        function go(to) {
            if(!running) {

                if(o.beforestart)
                    o.beforestart.call(this, vis());

                if(o.circular) {            // if circular we are in first or last, then goto the other end
                    if(to<=o.start-v-1) {           // if first, then goto last
                        ul.css(animcss, -((itemlength-(v*2))*lisize)+"px");
                        // if "scroll" > 1, then the "to" might not be equal to the condition; it can be lesser depending on the number of elements.
                        curr = to==o.start-v-1 ? itemlength-(v*2)-1 : itemlength-(v*2)-o.scroll;
                    } else if(to>=itemlength-v+1) { // if last, then goto first
                        ul.css(animcss, -( (v) * lisize ) + "px" );
                        // if "scroll" > 1, then the "to" might not be equal to the condition; it can be greater depending on the number of elements.
                        curr = to==itemlength-v+1 ? v+1 : v+o.scroll;
                    } else curr = to;
                } else {                    // if non-circular and to points to first or last, we just return.
                    if(to<0 || to>itemlength-v) return;
                    else curr = to;
                }                           // if neither overrides it, the curr will still be "to" and we can proceed.

                running = true;

                ul.animate(
                    animcss == "left" ? { left: -(curr*lisize) } : { top: -(curr*lisize) } , o.speed, o.easing,
                    function() {
                        if(o.afterend)
                            o.afterend.call(this, vis());
                        running = false;
                    }
                );
                // disable buttons when the carousel reaches the last/first, and enable when not
                if(!o.circular) {
                    $(o.btnprev + "," + o.btnnext).removeclass("disabled");
                    $( (curr-o.scroll<0 && o.btnprev)
                        ||
                       (curr+o.scroll > itemlength-v && o.btnnext)
                        ||
                       []
                     ).addclass("disabled");
                }

            }
            return false;
        };
    });
};

function css(el, prop) {
    return parseint($.css(el[0], prop)) || 0;
};
function width(el) {
    return  el[0].offsetwidth + css(el, 'marginleft') + css(el, 'marginright');
};
function height(el) {
    return el[0].offsetheight + css(el, 'margintop') + css(el, 'marginbottom');
};

})(jquery);