/**
 * @author Bruno Bornsztein <bruno@missingmethod.com>
 * @copyright 2007 Curbly LLC
 * @package Glider
 * @license MIT
 * @url http://www.missingmethod.com/projects/glider/
 * @version 0.0.3
 * @dependencies prototype.js 1.5.1+, effects.js
 */
/*  Thanks to Andrew Dupont for refactoring help and code cleanup - http://andrewdupont.net/  */
Glider = Class.create();
Object.extend(Object.extend(Glider.prototype, Abstract.prototype), {
  initialize: function(wrapper, options){
    this.scrolling  = false;
    this.wrapper    = $(wrapper);
    this.scroller   = this.wrapper.down('.scroller');
    this.sections   = this.wrapper.select('.section');
    this.options    = Object.extend({ duration: 1.0, frequency: 3 }, options || {});
    this.sections.each( function(section, index) { section._index = index; });
    this.events = { click: this.click.bind(this) };
    this.addObservers();
    if(this.options.initialSection) {
      this.moveTo(this.options.initialSection, this.scroller, { duration: this.options.duration });
    }
  },
  addObservers: function() {
    var controls = this.wrapper.getElementsBySelector('div.controls a.sectionlink');
    controls.invoke('observe', 'click', this.events.click);
  },
  click: function(event) {
    this.stop();
    var element = Event.findElement(event, 'a');
    element.addClassName('current_section');
    if (this.scrolling) this.scrolling.cancel();
    this.moveTo(element.href.split("#")[1], this.scroller, { duration:this.options.duration });     
    Event.stop(event);
  },
  moveTo: function(element, container, options) {
    this.current = $( element );
    var containerOffset = Element.cumulativeOffset( container );
    var elementOffset = Element.cumulativeOffset( $(element) );
    this.scrolling = new Effect.SmoothScroll( container, { duration: options.duration, x:(elementOffset[0]-containerOffset[0]), y:(elementOffset[1]-containerOffset[1]) } );
    return false;
  },
  next: function(){
    if (this.current) {
      var currentIndex = this.current._index;
      var nextIndex = (this.sections.length - 1 == currentIndex) ? 0 : currentIndex + 1;
    } else {
      var nextIndex = 1;
    }
    this.moveTo( this.sections[nextIndex], this.scroller, { duration: this.options.duration } );
    return false;
  },
  previous: function(){
    if (this.current) {
      var currentIndex = this.current._index;
      var prevIndex = (currentIndex == 0) ? this.sections.length - 1 : currentIndex - 1;
    } else {
      var prevIndex = this.sections.length - 1;
    }
    this.moveTo( this.sections[prevIndex], this.scroller, { duration: this.options.duration } );
    return false;
  },
  stop: function()
  {
    clearTimeout(this.timer);
  },
  start: function()
  {
    this.periodicallyUpdate();
  },
  periodicallyUpdate: function()
  {
    if (this.timer != null) {
      clearTimeout(this.timer);
      this.next();
    }
    this.timer = setTimeout(this.periodicallyUpdate.bind(this), this.options.frequency*1000);
  }
});
Effect.SmoothScroll = Class.create();
Object.extend(Object.extend(Effect.SmoothScroll.prototype, Effect.Base.prototype), {
  initialize: function(element) {
    this.el = $(element);
    var options = Object.extend({
      x: 0,
      y: 0,
      mode: 'absolute'
    }, arguments[1] || {}  );
    this.start(options);
  },
  setup: function() {
    if(this.options.continuous && !this.el._ext ) {
      this.el.cleanWhitespace();
      this.el._ext=true;
      this.el.appendChild(this.el.firstChild);
    }
    this.originalLeft = this.el.scrollLeft;
    this.originalTop = this.el.scrollTop;
    if(this.options.mode == 'absolute') {
      this.options.x -= this.originalLeft;
      this.options.y -= this.originalTop;
    }
  },
  update: function(position) {
    //console.log(position);
    this.el.scrollLeft = this.options.x * position + this.originalLeft;
    this.el.scrollTop  = this.options.y * position + this.originalTop;
  }
});