/*!
 * 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();
      opts.started_callback = opts.started_callback || function() {};
      opts.started_callback();
      opts.started_callback = function() {};
    });

    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();
  }
})();

