/*!
 * CrossSlide jQuery plugin v0.6
 *
 * Copyright 2007-2010 by Tobia Conforto <tobia.conforto@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 51
 * Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */
/* Changelog:
 *
 * 0.6    2010-07-03  Variant Ken Burns effect
 * 0.5    2010-06-13  Support for animation control and event callbacks
 * 0.4.2  2010-06-07  Bugfix
 * 0.4.1  2010-06-04  Added target option
 * 0.4    2010-05-20  Better error reporting, published on GitHub
 * 0.3.7  2009-05-14  Fixed bug when container div's CSS position is not set
 * 0.3.6  2009-04-16  Added alt option
 * 0.3.5  2009-03-12  Fixed usage of href parameter in 'Ken Burns' mode
 * 0.3.4  2009-03-12  Added shuffle option,
 *                    contrib. by Ralf Santbergen <ralf_santbergen@hotmail.com>
 * 0.3.3  2008-12-14  Added onclick option
 * 0.3.2  2008-11-11  Fixed CSS bugs, contrib. by Erwin Bot <info@ixgcms.nl>
 * 0.3.1  2008-11-11  Better error messages
 * 0.3    2008-10-22  Option to repeat the animation a fixed number of times
 * 0.2    2008-10-15  Linkable images, contrib. by Tim Rainey <tim@zmlabs.com>
 * 0.1.1  2008-09-18  Compatibility with prototype.js
 * 0.1    2008-08-21  Re-released under GPL v2
 * 0.1    2007-08-19  Initial release
 */

(function () {
    var $ = jQuery,
		animate = ($.fn.startAnimation ? 'startAnimation' : 'animate'),
		pause_missing = 'pause plugin missing.';

    // utility to format a string with {0}, {1}... placeholders
    function format(str) {
        for (var i = 1; i < arguments.length; i++)
            str = str.replace(new RegExp('\\{' + (i - 1) + '}', 'g'), arguments[i]);
        return str;
    }

    // utility to abort with a message to the error console
    function abort() {
        arguments[0] = 'CrossSlide: ' + arguments[0];
        throw new Error(format.apply(null, arguments));
    }

    // utility to parse "from" and "to" parameters
    function parse_position_param(param) {
        var zoom = 1;
        var tokens = param.replace(/^\s*|\s*$/g, '').split(/\s+/);
        if (tokens.length > 3) throw new Error();
        if (tokens[0] == 'center')
            if (tokens.length == 1)
                tokens = ['center', 'center'];
            else if (tokens.length == 2 && tokens[1].match(/^[\d.]+x$/i))
                tokens = ['center', 'center', tokens[1]];
        if (tokens.length == 3)
            zoom = parseFloat(tokens[2].match(/^([\d.]+)x$/i)[1]);
        var pos = tokens[0] + ' ' + tokens[1];
        if (pos == 'left top' || pos == 'top left')
            return { xrel: 0, yrel: 0, zoom: zoom };
        if (pos == 'left center' || pos == 'center left')
            return { xrel: 0, yrel: .5, zoom: zoom };
        if (pos == 'left bottom' || pos == 'bottom left')
            return { xrel: 0, yrel: 1, zoom: zoom };
        if (pos == 'center top' || pos == 'top center')
            return { xrel: .5, yrel: 0, zoom: zoom };
        if (pos == 'center center')
            return { xrel: .5, yrel: .5, zoom: zoom };
        if (pos == 'center bottom' || pos == 'bottom center')
            return { xrel: .5, yrel: 1, zoom: zoom };
        if (pos == 'right top' || pos == 'top right')
            return { xrel: 1, yrel: 0, zoom: zoom };
        if (pos == 'right center' || pos == 'center right')
            return { xrel: 1, yrel: .5, zoom: zoom };
        if (pos == 'right bottom' || pos == 'bottom right')
            return { xrel: 1, yrel: 1, zoom: zoom };
        return {
            xrel: parseInt(tokens[0].match(/^(\d+)%$/)[1]) / 100,
            yrel: parseInt(tokens[1].match(/^(\d+)%$/)[1]) / 100,
            zoom: zoom
        };
    }

    $.fn.crossSlide = function (opts, plan, callback) {
        var self = this,
				self_width = this.width(),
				self_height = this.height();

        // saving params for crossSlide.restart
        self.get(0).crossSlideArgs = [opts, plan, callback];

        // make working copy of plan
        plan = $.map(plan, function (p) {
            return $.extend({}, p);
        });

        // options with default values
        if (!opts.easing)
            opts.easing = opts.variant ? 'swing' : 'linear';
        if (!callback)
            callback = function () { };

        // first preload all the images, while getting their actual width and height
        (function (proceed) {

            var n_loaded = 0;
            function loop(i, img) {
                // this loop is a for (i = 0; i < plan.length; i++)
                // with independent var i, img (for the onload closures)
                img.onload = function (e) {
                    n_loaded++;
                    plan[i].width = img.width;
                    plan[i].height = img.height;
                    if (n_loaded == plan.length)
                        proceed();
                }
                img.src = plan[i].src;
                if (i + 1 < plan.length)
                    loop(i + 1, new Image());
            }
            loop(0, new Image());

        })(function () { // then proceed

            // check global params
            if (!opts.fade)
                abort('missing fade parameter.');
            if (opts.speed && opts.sleep)
                abort('you cannot set both speed and sleep at the same time.');

            // conversion from sec to ms; from px/sec to px/ms
            var fade_ms = Math.round(opts.fade * 1000);
            if (opts.sleep)
                var sleep = Math.round(opts.sleep * 1000);
            if (opts.speed)
                var speed = opts.speed / 1000,
						fade_px = Math.round(fade_ms * speed);

            // set container css
            self.empty().css({
                overflow: 'hidden',
                padding: 0
            });
            if (!/^(absolute|relative|fixed)$/.test(self.css('position')))
                self.css({ position: 'relative' });
            if (!self.width() || !self.height())
                abort('container element does not have its own width and height');

            // random sorting
            if (opts.shuffle)
                plan.sort(function () {
                    return Math.random() - 0.5;
                });

            // prepare each image
            for (var i = 0; i < plan.length; ++i) {

                var p = plan[i];
                if (!p.src)
                    abort('missing src parameter in picture {0}.', i + 1);

                if (speed) { // speed/dir mode

                    // check parameters and translate speed/dir mode into full mode
                    // (from/to/time)
                    switch (p.dir) {
                        case 'up':
                            p.from = { xrel: .5, yrel: 0, zoom: 1 };
                            p.to = { xrel: .5, yrel: 1, zoom: 1 };
                            var slide_px = p.height - self_height - 2 * fade_px;
                            break;
                        case 'down':
                            p.from = { xrel: .5, yrel: 1, zoom: 1 };
                            p.to = { xrel: .5, yrel: 0, zoom: 1 };
                            var slide_px = p.height - self_height - 2 * fade_px;
                            break;
                        case 'left':
                            p.from = { xrel: 0, yrel: .5, zoom: 1 };
                            p.to = { xrel: 1, yrel: .5, zoom: 1 };
                            var slide_px = p.width - self_width - 2 * fade_px;
                            break;
                        case 'right':
                            p.from = { xrel: 1, yrel: .5, zoom: 1 };
                            p.to = { xrel: 0, yrel: .5, zoom: 1 };
                            var slide_px = p.width - self_width - 2 * fade_px;
                            break;
                        default:
                            abort('missing or malformed dir parameter in picture {0}.', i + 1);
                    }
                    if (slide_px <= 0)
                        abort('impossible animation: either picture {0} is too small or '
							+ 'div is too large or fade duration too long.', i + 1);
                    p.time_ms = Math.round(slide_px / speed);

                } else if (!sleep) { // full mode

                    // check and parse parameters
                    if (!p.from || !p.to || !p.time)
                        abort('missing either speed/sleep option, or from/to/time params '
							+ 'in picture {0}.', i + 1);
                    try {
                        p.from = parse_position_param(p.from)
                    } catch (e) {
                        abort('malformed "from" parameter in picture {0}.', i + 1);
                    }
                    try {
                        p.to = parse_position_param(p.to)
                    } catch (e) {
                        abort('malformed "to" parameter in picture {0}.', i + 1);
                    }
                    if (!p.time)
                        abort('missing "time" parameter in picture {0}.', i + 1);
                    p.time_ms = Math.round(p.time * 1000)
                }

                // precalculate left/top/width/height bounding values
                if (p.from)
                    $.each([p.from, p.to], function (i, each) {
                        each.width = Math.round(p.width * each.zoom);
                        each.height = Math.round(p.height * each.zoom);
                        each.left = Math.round((self_width - each.width) * each.xrel);
                        each.top = Math.round((self_height - each.height) * each.yrel);
                    });

                // append the image (or anchor) element to the container
                var elm;
                if (p.href) {
                    elm = $(format('<a href="{0}"><img src="{1}"/></a>', p.href, p.src));
                } else {
                    if (p.mapname) {
                        
                        elm = $(format('<img src="{0}" usemap="{1}"/>', p.src, p.mapname));
                    } else {
                        elm = $(format('<img src="{0}"/>', p.src));
                    }
                }
                if (p.onclick)
                    elm.click(p.onclick);
                if (p.alt)
                    elm.find('img').attr('alt', p.alt);
                if (p.href && p.target)
                    elm.attr('target', p.target);
                elm.appendTo(self);
            }
            delete speed; // speed mode has now been translated to full mode

            // utility to compute the css for a given phase between p.from and p.to
            // 0: begin fade-in, 1: end fade-in, 2: begin fade-out, 3: end fade-out
            function position_to_css(p, phase) {
                var pos = [0, fade_ms / (p.time_ms + 2 * fade_ms),
					1 - fade_ms / (p.time_ms + 2 * fade_ms), 1][phase];
                return {
                    left: Math.round(p.from.left + pos * (p.to.left - p.from.left)),
                    top: Math.round(p.from.top + pos * (p.to.top - p.from.top)),
                    width: Math.round(p.from.width + pos * (p.to.width - p.from.width)),
                    height: Math.round(p.from.height + pos * (p.to.height - p.from.height))
                };
            }

            // find images to animate and set initial css attributes
            var imgs = self.find('img').css({
                position: 'absolute',
                visibility: 'hidden',
                top: 0,
                left: 0,
                border: 0
            });

            // show first image
            imgs.eq(0).css({ visibility: 'visible' });
            if (!sleep)
                imgs.eq(0).css(position_to_css(plan[0], opts.variant ? 0 : 1));

            // create animation chain
            var countdown = opts.loop;
            function create_chain(i, chainf) {
                // building the chain backwards, or inside out

                if (i % 2 == 0) {
                    if (sleep) {
                        // single image sleep
                        var i_sleep = i / 2,
								i_hide = (i_sleep - 1 + plan.length) % plan.length,
								img_sleep = imgs.eq(i_sleep),
								img_hide = imgs.eq(i_hide);
                        var newf = function () {
                            callback(i_sleep, img_sleep);
                            img_hide.css('visibility', 'hidden');
                            setTimeout(chainf, sleep);
                        };
                    } else {
                        // single image animation
                        var i_slide = i / 2,
								i_hide = (i_slide - 1 + plan.length) % plan.length,
								img_slide = imgs.eq(i_slide),
								img_hide = imgs.eq(i_hide),
								time = plan[i_slide].time_ms,
								slide_anim = position_to_css(plan[i_slide],
									opts.variant ? 3 : 2);
                        var newf = function () {
                            callback(i_slide, img_slide);
                            img_hide.css('visibility', 'hidden');
                            img_slide[animate](slide_anim, time, opts.easing, chainf);
                        };
                    }
                } else {
                    // double image animation
                    var i_from = Math.floor(i / 2),
							i_to = Math.ceil(i / 2) % plan.length,
							img_from = imgs.eq(i_from),
							img_to = imgs.eq(i_to),
							from_anim = {},
							to_init = { visibility: 'visible' },
							to_anim = {};
                    if (i_to > i_from) {
                        to_init.opacity = 0;
                        to_anim.opacity = 1;
                        if (opts.doubleFade)
                            from_anim.opacity = 0;
                    } else {
                        from_anim.opacity = 0;
                        if (opts.doubleFade) {
                            to_init.opacity = 0;
                            to_anim.opacity = 1;
                        }
                    }
                    if (!sleep) {
                        // moving images
                        $.extend(to_init, position_to_css(plan[i_to], 0));
                        if (!opts.variant) {
                            $.extend(from_anim, position_to_css(plan[i_from], 3));
                            $.extend(to_anim, position_to_css(plan[i_to], 1));
                        }
                    }
                    if ($.isEmptyObject(to_anim)) {
                        var newf = function () {
                            callback(i_to, img_to, i_from, img_from);
                            img_to.css(to_init);
                            img_from[animate](from_anim, fade_ms, 'linear', chainf);
                        };
                    } else if ($.isEmptyObject(from_anim)) {
                        var newf = function () {
                            callback(i_to, img_to, i_from, img_from);
                            img_to.css(to_init);
                            img_to[animate](to_anim, fade_ms, 'linear', chainf);
                        };
                    } else {
                        var newf = function () {
                            callback(i_to, img_to, i_from, img_from);
                            img_to.css(to_init);
                            img_to[animate](to_anim, fade_ms, 'linear');
                            img_from[animate](from_anim, fade_ms, 'linear', chainf);
                        };
                    }
                }

                // if the loop option was requested, push a countdown check
                if (opts.loop && i == plan.length * 2 - 2) {
                    var newf_orig = newf;
                    newf = function () {
                        if (--countdown) newf_orig();
                    }
                }

                if (i > 0)
                    return create_chain(i - 1, newf);
                else
                    return newf;
            }
            var animation = create_chain(plan.length * 2 - 1,
				function () { return animation(); });

            // start animation
            animation();
        });
        return self;
    };

    $.fn.crossSlideFreeze = function () {
        this.find('img').stop();
    }

    $.fn.crossSlideStop = function () {
        this.find('img').stop().remove();
    }

    $.fn.crossSlideRestart = function () {
        this.find('img').stop().remove();
        $.fn.crossSlide.apply(this, this.get(0).crossSlideArgs);
    }

    $.fn.crossSlidePause = function () {
        if (!$.fn.pause)
            abort(pause_missing);
        this.find('img').pause();
    }

    $.fn.crossSlideResume = function () {
        if (!$.fn.pause)
            abort(pause_missing);
        this.find('img').resume();
    }
})();

