/**
 * napCarousel - jQuery plugin to create scrollable carousels.
 * @requires jQuery v1.3 or above
 * @requires jquery.event.drag-1.4.js for scrollbar control
 * @author Lee Daffen ()
 * @version 1.0.1 (23/4/2009)
 *
 * Uses elements from jCarouselLite v1.0.1
 * Copyright (c) 2008 Ganeshji Marwaha (gmarwaha.com)
 *
 */

/**
 * 16/11/09
 * Documentation moved to http://confluence.net-a-porter.com/display/WCT/jQuery+Carousel
 */

(function($) {
$.fn.napCarousel = function(o, callback) {
    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,
        animate: true,

        beforeStart: null,
        afterEnd: null,

        scrollbar: {},

        reset: false
    }, o || {});

    // reset carousel control event bindings to allow 'on the fly' rebuilding of the carousel
    if(o.reset) {
        if(o.btnPrev) $(o.btnPrev).unbind("click");
        if(o.btnNext) $(o.btnNext).unbind("click");
    }

	return this.each(function() {

        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;

            // can't have a scrollbar on a circular carousel so hide the div if it's there
            if(o.scrollbar.bar) $(o.scrollbar.bar).css("visibility","hidden");
            o.scrollbar = {};
        }

        var showScrollbar = (o.scrollbar && o.scrollbar.bar && o.scrollbar.handle) ? true : false ;

        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

		//hide scroll bar if items in the carousel are less than the items visible
		if(o.scrollbar.autohide) {
			if (itemLength <= v) {
				$(o.scrollbar.bar).css("display", "none");
			} else {
				$(o.scrollbar.bar).css("display", "block");
			}
		}

        // hide left and right carousel controls
		if(!o.circular) {
			//$(o.btnPrev + "," + o.btnNext).removeClass("disabled");
			$(o.btnPrev).removeClass("disabled-prev");
			$(o.btnPrev).addClass("previous-button");
			$(o.btnNext).removeClass("disabled-next");
			$(o.btnNext).addClass("next-button");
			$(curr-o.scroll<0 && o.btnPrev).addClass("disabled-prev");
			$(curr-o.scroll<0 && o.btnPrev).removeClass("previous-button");
			$(curr+o.scroll > itemLength-v && o.btnNext).addClass("disabled-next");
			$(curr+o.scroll > itemLength-v && o.btnNext).removeClass("next-button");
		}

        // scrollbar extension
        if(showScrollbar) {
            var isMouseOver = false,
                scrollbarEl = $(o.scrollbar.bar),           // jQuery element object reference for the scroll bar
                scrollhandleEl = $(o.scrollbar.handle),     // jQuery element object reference for the scroll handle
                scrollbarWidth = scrollbarEl.width();       // interior width of the scroll bar

            // set the proportionate width of the scroll handle
            scrollhandleEl.css("width",(divSize/ulSize)*scrollbarWidth);

            if(o.reset) {
                // reset some event bindings to allow 'on the fly' rebuilding of the carousel
                scrollbarEl.unbind("click");
                scrollhandleEl.unbind("dragstart").unbind("drag").unbind("dragend");
                // reset the position of the scroll handle
                scrollhandleEl.css("left",0);
            }

            var minX = scrollbarEl.offset().left,                           // left-most edge of the scroll bar
                maxX = minX + scrollbarWidth,                               // right-most edge of the scroll bar
                scrollhandleWidth = scrollhandleEl.width(),                 // interior width of the scroll handle
                maxScrollX = (minX + scrollbarWidth) - scrollhandleWidth,   // max right posision of the scroll handle
                scrollProportion = ul.width() / scrollbarWidth,             // ratio of pixels in carousel list to pixels in scroll bar
                minLeft = (isNaN(parseInt(scrollhandleEl.css("left")))) ? scrollhandleEl.offset().left - minX : parseInt(scrollhandleEl.css("left")),
                maxLeft = scrollbarWidth - scrollhandleWidth + minLeft,
                handleLeftPos;

            scrollhandleEl.hover(
                function() {
                    isMouseOver = true;
                },
                function() {
                    isMouseOver = false;
            });

            // add paginated scrolling when the user clicks on the scrollbar
            scrollbarEl.bind("click", function(e) {
                var availLeft = curr,
                    availRight = itemLength - o.visible - curr;

                handleLeftPos = (isNaN(parseInt(scrollhandleEl.css("left")))) ? minLeft : parseInt(scrollhandleEl.css("left"));

                if(!isMouseOver && e.pageX >= minX && e.pageX <= maxX) {
                    if(e.pageX > handleLeftPos + minX) {
                        var rightAmount = (availRight < o.visible) ? availRight : o.visible ;
                        return go(Math.floor(curr)+Math.ceil(rightAmount), false, o.animate);
                    } else if(e.pageX < handleLeftPos + minX) {
                        var leftAmount = (availLeft < o.visible) ? availLeft : o.visible ;
                        return go(Math.ceil(curr)-Math.ceil(leftAmount), false, o.animate);
                    } else {
                        return false;
                    }
                }
            });

            // make the scroll handle draggable
            scrollhandleEl.bind("dragstart", function(e) {
                handleLeftPos = (isNaN(parseInt(scrollhandleEl.css("left")))) ? minLeft : parseInt(scrollhandleEl.css("left"));
                eventOffset = e.pageX - handleLeftPos;
            })
            .bind("drag", function(e) {
                if(e.pageX - eventOffset > minLeft && e.pageX - eventOffset < maxLeft) {
                    scrollhandleEl.css("left",e.pageX - eventOffset);
                    ul.css("left", (e.pageX - eventOffset - minLeft) * -1 * scrollProportion);
                }
            })
            .bind("dragend", function(e) {
                var currentIndex = (e.pageX - eventOffset - minLeft) * scrollProportion;
                //return go(Math.round(currentIndex/liSize),true);
                curr = currentIndex/liSize;
                currInt = Math.round(curr);
                // park the scroll handle to the left or right if the user has dragged it to either end
                if(o.scrollbar.autopark === true && (currInt == 0 || currInt == itemLength-o.visible)) {
                    return go(currInt, false, o.animate);
                } else {
                    return go(curr, false, o.animate);
                }
            });
        }

        if(o.btnPrev)
            $(o.btnPrev).bind("click", function() {
                return go(Math.ceil(curr)-o.scroll, false, o.animate);
            });

        if(o.btnNext)
            $(o.btnNext).bind("click", function() {
                return go(Math.floor(curr)+o.scroll, false, o.animate);
            });

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

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

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

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

        function moveNext(anim) {
            return go(Math.ceil(curr)+o.scroll, false, anim);
        }

        function movePrev(anim) {
            return go(Math.floor(curr)-o.scroll, false, anim);
        }

        function go(to, dragging, anim) {
            var draggingBool = (typeof dragging !== 'undefined') ? dragging : false;
            var animBool = (typeof anim !== 'undefined') ? anim : true;

            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;

                if(animBool) {
                    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;
                        }
                    );
                } else {
                    var styles = animCss == "left" ? { left: -(curr*liSize) } : { top: -(curr*liSize) };

                    ul.css(styles);
                    if(o.afterEnd) o.afterEnd.call(this, vis());
                    running = false;
                }

                if(showScrollbar && !draggingBool) {
                    scrollhandleEl.animate({
                        left: (curr*liSize)/scrollProportion+minLeft
                    }, o.speed, o.easing);
                }

                // Disable buttons when the carousel reaches the last/first, and enable when not
                if(!o.circular) {
                    $(o.btnPrev).removeClass("disabled-prev");
					$(o.btnPrev).addClass("previous-button");
					$(o.btnNext).removeClass("disabled-next");
					$(o.btnNext).addClass("next-button");
                    $(curr-o.scroll<0 && o.btnPrev).addClass("disabled-prev");
					$(curr-o.scroll<0 && o.btnPrev).removeClass("previous-button");
					$(curr+o.scroll > itemLength-v && o.btnNext).addClass("disabled-next");
					$(curr+o.scroll > itemLength-v && o.btnNext).removeClass("next-button");
                }
            }
			return false;
        }

		// expose the private methods to the return scope of the constructor
		this.vis = vis;
		this.go = go;
        this.movePrev = movePrev;
        this.moveNext = moveNext;

		// expose these methods to the public scope via a callback
		if(callback) callback.call(this, this);
	});
};

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);