/**
 * Slideshow Lite plugin for jQuery
 *
 * v0.8.1
 *
 * Copyright (c) 2009 Fred Wu
 *
 * Dual licensed under the MIT and GPL licenses:
 *   http://www.opensource.org/licenses/mit-license.php
 *   http://www.gnu.org/licenses/gpl.html
 */

/**
 * Usage:
 *
 * // using default options
 * $("#slideshow").slideshow();
 *
 * // using some custom options
 * $("#slideshow2").slideshow({
 *   pauseSeconds: 4,
 *   height: 200,
 *   caption: false
 * });
 *
 * Configuration options:
 *
 * pauseSeconds  float    number of seconds between each photo to be displayed
 * fadeSpeed     float    number of seconds for the fading transition, the value should not exceed `pauseSeconds`
 * width         integer  width of the slideshow, in pixels
 * height        integer  height of the slideshow, in pixels
 * caption       boolean  display photo caption?
 * cssClass      string   name of the CSS class, defaults to `slideshowlite`
 * anchorTarget  string   name for the target="_xxx" attribute, defaults to `_self`
 */

(function ($) {
    $.fn.slideshow = function (options) {

        var defaults = {
            pauseSeconds: 2,
            fadeSpeed: 1.5,
            width: 468,
            height: 120,
            caption: true,
            cssClass: 'slideshowlite',
            anchorTarget: '_blank'
        };

        var options = $.extend(defaults, options);

        // ----------------------------------------
        // slideshow instance
        // ----------------------------------------

        var runInstance = function (target) {
            var items = $("a", target);
            var instance;

            // ----------------------------------------
            // some mandontory styling
            // ----------------------------------------

            if (!$(target).hasClass(options.cssClass)) $(target).addClass(options.cssClass);

            $(target).css({
                width: options.width + "px",
                height: options.height + "px"
            });

            // ----------------------------------------
            // create anchor links to make the structure simpler for manupilation
            // ----------------------------------------

            $("> img", target).wrap(document.createElement("a"));
            $("a", target).attr("target", options.anchorTarget);

            // ----------------------------------------
            // add item sequence markups
            // ----------------------------------------

            var i = 1;
            $("a", target).each(function () {
                $(this).attr("data-seq", i++);
            });

            // ----------------------------------------
            // create pagination and caption
            // ----------------------------------------

            $(target).append("<ul></ul>");
            $(target).append("<ol></ol>");
            var pagination = $("> ul", target);
            var caption = $("> ol", target);

            var i = 1;
            var j = 0;
            $("a", target).each(function () {
                pagination.append("<li><a href=\"#\">" + i++ + "</a></li>");
                caption.append("<li>" + $("img:nth(" + j++ + ")", target).attr("alt") + "</li>");
            });
            pagination.fadeTo(0, 0.8);
            caption.fadeTo(0, 0.8);
            caption.hide();

            // ----------------------------------------
            // shortcuts
            // ----------------------------------------

            var firstItem = $("> a:first", target);
            var lastItem = $("> a:last", target);
            var currentItem = firstItem;

            // ----------------------------------------
            // pagination highlight
            // ----------------------------------------

            var paginationHighlight = function (sequence) {
                $("> li > a", pagination).removeClass("current");
                $("> li > a:nth(" + sequence + ")", pagination).addClass("current");
            }

            // ----------------------------------------
            // caption
            // ----------------------------------------

            var showCaption = function (sequence) {
                caption.show();
                $("> li", caption).hide();
                $("> li:nth(" + sequence + ")", caption).fadeIn();
            }

            // ----------------------------------------
            // slideshow logic
            // ----------------------------------------

            var makeSlideshow = function () {

                // pagination click
                $("> li > a", pagination).click(function () {
                    if (!$(this).hasClass("current")) {
                        // select the current item after the pagination click
                        currentItem = $("a:nth(" + ($(this).text() - 1) + ")", target);

                        currentItem.show();
                        startSlideshow();
                    }
                    return false;
                });

                // pagination highlight
                paginationHighlight(currentItem.data("seq") - 1);

                // show caption
                if (options.caption == true) {
                    showCaption(currentItem.data("seq") - 1);
                }

                currentItem.css("z-index", 2);

                // show the current slide
                currentItem.fadeIn(options.fadeSpeed * 1000, function () {
                    $("> a", target).hide();
                    $(this).show();
                });

                // prepare for the next slide
                // determines the next item (or we need to rewind to the first item?)
                if ($("img", currentItem).attr("src") == $("img", lastItem).attr("src")) {
                    currentItem = firstItem;
                }
                else {
                    currentItem = currentItem.next();
                }

                currentItem.css("z-index", -1);
            };

            var startSlideshow = function () {
                clearInterval(instance);
                makeSlideshow();
                instance = setInterval(makeSlideshow, options.pauseSeconds * 1000);
            };

            // ----------------------------------------
            // start the slideshow!
            // ----------------------------------------

            startSlideshow();
        }

        // ----------------------------------------
        // run the slideshow instances!
        // ----------------------------------------

        if (this.length > 1) {
            this.each(function () {
                runInstance(this);
            });
        } else {
            runInstance(this);
        }

    };
})(jQuery);