/*

 * Copyright 2007-2009 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.

 *

 * Versions: 0.1    2007-08-19  Initial release

 *                  2008-08-21  Re-released under GPL v2

 *           0.1.1  2008-09-18  Compatibility with prototype.js

 *           0.2    2008-10-15  Linkable images, contributed by Tim Rainey <tim@zmlabs.com>

 *           0.3    2008-10-22  Added option to repeat the animation a number of times, then stop

 *           0.3.1  2008-11-11  Better error messages

 *           0.3.2  2008-11-11  Fixed a couple of CSS bugs, contributed by Erwin Bot <info@ixgcms.nl>

 *           0.3.3  2008-12-14  Added onclick option

 *           0.3.4  2009-03-12  Added shuffle option, contributed by Ralf Santbergen <ralf_santbergen@hotmail.com>

 *           0.3.5  2009-03-12  Fixed usage of href parameter in 'Ken Burns' mode

 *           0.3.6  2009-04-16  Added alt option

 *           0.3.7  2009-05-14  Fixed bug when container div doesn't have a position CSS attribute

 */



jQuery.fn.crossSlide = function(opts, plan) {

	var self = this,

			self_width = this.width(),

			self_height = this.height();



	// generic utilities

	function format(str) {

		for (var i = 1; i < arguments.length; i++)

			str = str.replace(new RegExp('\\{' + (i-1) + '}', 'g'), arguments[i]);

		return str;

	}



	function abort() {

		arguments[0] = 'crossSlide: ' + arguments[0];

		throw format.apply(null, arguments);

	}

	



	// first preload all the images, while getting their actual width and height

	(function(proceed) {



		var n_loaded = 0;

		function loop(i, img) {

			// for (i = 0; i < plan.length; i++) but with independent var i, img (for the 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



		// 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

			};

		}



		// utility to compute the css for a given phase between p.from and p.to

		// phase = 1: begin fade-in,  2: end fade-in,  3: begin fade-out,  4: end fade-out

		function position_to_css(p, phase) {

			switch (phase) {

				case 1:

					var pos = 0;

					break;

				case 2:

					var pos = fade_ms / (p.time_ms + 2 * fade_ms);

					break;

				case 3:

					var pos = 1 - fade_ms / (p.time_ms + 2 * fade_ms);

					break;

				case 4:

					var pos = 1;

					break;

			}

			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))

			};

		}



		// 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('picture number {0} is too short for the desired fade duration.', 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)

				jQuery.each([ p.from, p.to ], function(i, from_to) {

					from_to.width  = Math.round(p.width  * from_to.zoom);

					from_to.height = Math.round(p.height * from_to.zoom);

					from_to.left   = Math.round((self_width  - from_to.width)  * from_to.xrel);

					from_to.top    = Math.round((self_height - from_to.height) * from_to.yrel);

				});



			// append the image (or anchor) element to the container

			var elm;

			if (p.href)

				elm = jQuery(format('<a href="{0}"><img src="{1}"/></a>', p.href, p.src));

			else

				elm = jQuery(format('<img src="{0}"/>', p.src));

			if (p.onclick)

				elm.click(p.onclick);

			if (p.alt)

				elm.find('img').attr('alt', p.alt);

			elm.appendTo(self);

		}

		speed = undefined;  // speed mode has now been translated to full mode



		// 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], 2));



		// 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) {



					// still 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() {

						img_hide.css('visibility', 'hidden');

						setTimeout(chainf, sleep);

					};



				} else {



					// single image slide



					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], 3);



					var newf = function() {

						img_hide.css('visibility', 'hidden');

						img_slide.animate(slide_anim, time, 'linear', chainf);

					};



				}

			} else {

				if (sleep) {



					// still image cross-fade



					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;

					} else {

						from_anim.opacity = 0;

					}



					var newf = function() {

						img_to.css(to_init);

						if (from_anim.opacity != undefined)

							img_from.animate(from_anim, fade_ms, 'linear', chainf);

						else

							img_to.animate(to_anim, fade_ms, 'linear', chainf);

					};



				} else {



					// cross-slide + cross-fade



					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 = position_to_css(plan[i_from], 4),

							to_init = position_to_css(plan[i_to], 1),

							to_anim = position_to_css(plan[i_to], 2);



					if (i_to > i_from) {

						to_init.opacity = 0;

						to_anim.opacity = 1;

					} else {

						from_anim.opacity = 0;

					}

					to_init.visibility = 'visible';



					var newf = function() {

						img_from.animate(from_anim, fade_ms, 'linear');

						img_to.css(to_init);

						img_to.animate(to_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;

};


