/*!
 * CrossSlide jQuery plugin v0.6.2
 *
 * 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:
 *
 * 0.6.2  2010-09-29  Added support for rel attribute
 * 0.6.1  2010-08-02  Bugfixes
 * 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();

		// must be called on exactly 1 element
		if (self.length != 1)
			abort('crossSlide() must be called on exactly 1 element')

		// 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 img, elm;
				elm = img = $(format('<img src="{0}"/>', p.src));
				if (p.href)
					elm = $(format('<a href="{0}"></a>', p.href)).append(img);
				if (p.onclick)
					elm.click(p.onclick);
				if (p.alt)
					img.attr('alt', p.alt);
				if (p.rel)
					elm.attr('rel', p.rel);
				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.get(0));
							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.get(0));
							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.get(0), i_from, img_from.get(0));
							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.get(0), i_from, img_from.get(0));
							img_to.css(to_init);
							img_to[animate](to_anim, fade_ms, 'linear', chainf);
						};
					} else {
						var newf = function() {
							callback(i_to, img_to.get(0), i_from, img_from.get(0));
							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();
	}
})();
