/*
 * Swipe 1.0
 *
 * Brad Birdsall, Prime
 * Copyright 2011, Licensed GPL & MIT
 *
*/

window.Swipe = function(element, options) {

  // return immediately if element doesn't exist
  if (!element) return null;

  var _this = this;

  // retreive options
  this.options = options || {};
  this.index = this.options.startSlide || 0;
  this.speed = this.options.speed || 300;
  this.callback = this.options.callback || function() {};
  this.delay = this.options.auto || 0;
  
  // reference dom elements
  this.container = element;
  this.element = this.container.children[0]; // the slide pane

  // static css
  this.container.style.overflow = 'hidden';
  this.element.style.listStyle = 'none';

  // browser flags
  this.IEBrowser = (navigator.appName == "Microsoft Internet Explorer");
  this.FireFoxNoTransitionSupport = false;
  
  if (/Firefox[\/\s](\d+\.\d+)/.test(navigator.userAgent))
  { //test for Firefox/x.x or Firefox x.x (ignoring remaining digits);
     var ffversion=new Number(RegExp.$1) // capture x.x portion and store as a number
     if (ffversion < 4)
     {
      this.FireFoxNoTransitionSupport = true;
     }
  }
  
  // trigger slider initialization
  this.setup();

  // setup auto slideshow
  this.start();

  // add event listeners
    if (this.element.addEventListener)
    {
      this.element.addEventListener('touchstart', this, false);
      this.element.addEventListener('touchmove', this, false);
      this.element.addEventListener('touchend', this, false);
      this.element.addEventListener('webkitTransitionEnd', this, false);
      this.element.addEventListener('msTransitionEnd', this, false);
      this.element.addEventListener('oTransitionEnd', this, false);
      this.element.addEventListener('transitionend', this, false);
      window.addEventListener('resize', this, false);
    }
};

Swipe.prototype = {

  setup: function() {

    // get and measure amt of slides
    this.slides = this.element.children;
    this.length = this.slides.length;

    // return immediately if their are less than two slides
    if (this.length < 2) return null;

    // hide slider element but keep positioning during setup
    this.container.style.visibility = 'hidden';

    // determine width of each slide
    this.width = this.container.getBoundingClientRect().width;
    
    if (this.width == null)
    {
        this.width = this.container.getBoundingClientRect().right - this.container.getBoundingClientRect().left;
    }

    // dynamic css
    this.element.style.width = (this.slides.length * this.width) + 'px';
    var index = this.slides.length;
    while (index--) {
      var el = this.slides[index];
      el.style.width = this.width + 'px';
      el.style.display = 'table-cell';
      el.style.verticalAlign = 'top';
    }

    // set start position and force translate to remove initial flickering
    this.slide(this.index, 0); 

    // show slider element
    this.container.style.visibility = 'visible';

  },

  slide: function(index, duration) {
    
    //This code was added by Frank D Perez to overcome the lack of transform exit events in IE;
    if (this.IEBrowser || this.FireFoxNoTransitionSupport) //IE
    {
        for (var i=0;i<this.length;i++)
        {
            if (i >= index)
            {
                document.getElementById("slide" + i).style.display = "table-cell";
            }
            else
            {
                document.getElementById("slide" + i).style.display = "none";
            }
        }
        
    }
    else {
        var style = this.element.style;

        // set duration speed (0 represents 1-to-1 scrolling)
        style.webkitTransitionDuration = style.MozTransitionDuration = style.msTransitionDuration = style.OTransitionDuration = style.transitionDuration = duration + 'ms';

        // translate to given index position
        style.webkitTransform = 'translate3d(' + -(index * this.width) + 'px,0,0)';
        style.msTransform = style.MozTransform = style.OTransform = 'translateX(' + -(index * this.width) + 'px)';
    }
    
    // set new index to allow for expression arguments
    this.index = index;
    slideIndexUpdate(index);
  },

  getPos: function() {
    
    // return current index position
    return this.index;

  },

  prev: function(delay) {

    // cancel slideshow
    //this.delay = delay || 0;
    this.delay = thisDelay || 0;
    clearTimeout(this.interval);

    // if not at first slide
    if (this.index) this.slide(this.index-1, this.speed);

  },

  next: function(delay) {

    // cancel slideshow
    this.delay = delay || 0;
    clearTimeout(this.interval);

    if (this.index < this.length - 1) this.slide(this.index+1, this.speed); // if not last slide
    else this.slide(0, this.speed); //if last slide return to start
    
    //This code was added by Frank D Perez to overcome the lack of transform exit events in IE and Firefox;
    if (this.IEBrowser || this.FireFoxNoTransitionSupport)
    {
        if (this.delay) this.start();    
    }
    
  },

  start: function() {

    var _this = this;

    this.interval = (this.delay)
      ? setTimeout(function() { 
        _this.next(_this.delay);
      }, this.delay)
      : 0;
  
  },

  handleEvent: function(e) {
    switch (e.type) {
      case 'touchstart': this.onTouchStart(e); break;
      case 'touchmove': this.onTouchMove(e); break;
      case 'touchend': this.onTouchEnd(e); break;
      case 'webkitTransitionEnd':
      case 'msTransitionEnd':
      case 'oTransitionEnd':
      case 'transitionend': this.transitionEnd(e); break;
      case 'resize': this.setup(); break;
    }
  },

  transitionEnd: function(e) {
    
    if (this.delay) this.start();
    
    this.callback(e, this.index, this.slides[this.index]);

  },

  onTouchStart: function(e) {

    // cancel slideshow
    clearTimeout(this.interval);
    
    this.start = {

      // get touch coordinates for delta calculations in onTouchMove
      pageX: e.touches[0].pageX,
      pageY: e.touches[0].pageY,

      // set initial timestamp of touch sequence
      time: Number( new Date() )

    };

    // used for testing first onTouchMove event
    this.isScrolling = undefined;
    
    // reset deltaX
    this.deltaX = 0;

    // set transition time to 0 for 1-to-1 touch movement
    this.element.style.webkitTransitionDuration = 0;

  },

  onTouchMove: function(e) {

    this.deltaX = e.touches[0].pageX - this.start.pageX;

    // determine if scrolling test has run - one time test
    if ( typeof this.isScrolling == 'undefined') {
      this.isScrolling = !!( this.isScrolling || Math.abs(this.deltaX) < Math.abs(e.touches[0].pageY - this.start.pageY) );
    }

    // if user is not trying to scroll vertically
    if (!this.isScrolling) {

      // prevent native scrolling 
      e.preventDefault();

      // increase resistance if first or last slide
      this.deltaX = 
        this.deltaX / 
          ( (!this.index && this.deltaX > 0               // if first slide and sliding left
            || this.index == this.length - 1              // or if last slide and sliding right
            && this.deltaX < 0                            // and if sliding at all
          ) ?                      
          ( Math.abs(this.deltaX) / this.width + 1 )      // determine resistance level
          : 1 );                                          // no resistance if false
      
      // translate immediately 1-to-1
      this.element.style.webkitTransform = 'translate3d(' + (this.deltaX - this.index * this.width) + 'px,0,0)';

    }

  },

  onTouchEnd: function(e) {

    // determine if slide attempt triggers next/prev slide
    var isValidSlide = 
          Number(new Date()) - this.start.time < 250      // if slide duration is less than 250ms
          && Math.abs(this.deltaX) > 20                   // and if slide amt is greater than 20px
          || Math.abs(this.deltaX) > this.width/2,        // or if slide amt is greater than half the width

    // determine if slide attempt is past start and end
        isPastBounds = 
          !this.index && this.deltaX > 0                          // if first slide and slide amt is greater than 0
          || this.index == this.length - 1 && this.deltaX < 0;    // or if last slide and slide amt is less than 0

    // if not scrolling vertically
    if (!this.isScrolling) {

      // call slide function with slide end value based on isValidSlide and isPastBounds tests
      this.slide( this.index + ( isValidSlide && !isPastBounds ? (this.deltaX < 0 ? 1 : -1) : 0 ), this.speed );

    }

  }

};