/*!
 * jQuery.SerialScroll
 * Copyright (c) 2007-2008 Ariel Flesler - aflesler(at)gmail(dot)com | http://flesler.blogspot.com
 * Dual licensed under MIT and GPL.
 * Date: 06/14/2009
 *
 * @projectDescription Animated scrolling of series.
 * @author Ariel Flesler
 * @version 1.2.2
 *
 * @id jQuery.serialScroll
 * @id jQuery.fn.serialScroll
 * @param {Object} settings Hash of settings, it is passed in to jQuery.ScrollTo, none is required.
 * @return {jQuery} Returns the same jQuery object, for chaining.
 *
 * @link {http://flesler.blogspot.com/2008/02/jqueryserialscroll.html Homepage}
 *
 * Notes:
 *  - The plugin requires jQuery.ScrollTo.
 *  - The hash of settings, is passed to jQuery.ScrollTo, so its settings can be used as well.
 */
;(function( $ ){

  var $serialScroll = $.serialScroll = function( settings ){
    return $(window).serialScroll( settings );
  };

  // Many of these defaults, belong to jQuery.ScrollTo, check it's demo for an example of each option.
  // @link {http://demos.flesler.com/jquery/scrollTo/ ScrollTo's Demo}
  $serialScroll.defaults = {// the defaults are public and can be overriden.
    duration:1000, // how long to animate.
    axis:'x', // which of top and left should be scrolled
    event:'click', // on which event to react.
    start:0, // first element (zero-based index)
    step:1, // how many elements to scroll on each action
    lock:true,// ignore events if already animating
    cycle:true, // cycle endlessly ( constant velocity )
    constant:true // use contant speed ?
    /*
    navigation:null,// if specified, it's a selector a collection of items to navigate the container
    target:window, // if specified, it's a selector to the element to be scrolled.
    interval:0, // it's the number of milliseconds to automatically go to the next
    lazy:false,// go find the elements each time (allows AJAX or JS content, or reordering)
    stop:false, // stop any previous animations to avoid queueing
    force:false,// force the scroll to the first element on start ?
    jump: false,// if true, when the event is triggered on an element, the pane scrolls to it
    items:null, // selector to the items (relative to the matched elements)
    prev:null, // selector to the 'prev' button
    next:null, // selector to the 'next' button
    onBefore: function(){}, // function called before scrolling, if it returns false, the event is ignored
    exclude:0 // exclude the last x elements, so we cannot scroll past the end
    */
  };

  $.fn.serialScroll = function( options ){

    return this.each(function(){
      var 
        settings = $.extend( {}, $serialScroll.defaults, options ),
        event = settings.event, // this one is just to get shorter code when compressed
        step = settings.step, // ditto
        lazy = settings.lazy, // ditto
        context = settings.target ? this : document, // if a target is specified, then everything's relative to 'this'.
        $pane = $(settings.target || this, context),// the element to be scrolled (will carry all the events)
        pane = $pane[0], // will be reused, save it into a variable
        items = settings.items, // will hold a lazy list of elements
        active = settings.start, // active index
        auto = settings.interval, // boolean, do auto or not
        nav = settings.navigation, // save it now to make the code shorter
        timer; // holds the interval id
        
     
        
      if( !lazy )// if not lazy, save the items now
        items = getItems();

      if( settings.force )
        jump( {}, active );// generate an initial call

      // Button binding, optional
      $(settings.prev||[], context).bind( event, -step, move );
      $(settings.next||[], context).bind( event, step, move );

      // Custom events bound to the container
      if( !pane.ssbound )// don't bind more than once
        $pane
          .bind('prev.serialScroll', -step, move ) // you can trigger with just 'prev'
          .bind('next.serialScroll', step, move ) // f.e: $(container).trigger('next');
          .bind('goto.serialScroll', jump ); // f.e: $(container).trigger('goto', 4 );
        
        
      if( auto )
        $pane
          .bind('start.serialScroll', function(e){
            if( !auto ){
              clear();
              auto = true;
              next();
            }
           })
          .bind('stop.serialScroll', function(){// stop a current animation
            clear();
            auto = false;
          });

      $pane.bind('notify.serialScroll', function(e, elem){// let serialScroll know that the index changed externally
        var i = index(elem);
        if( i > -1 )
        active = i;
        
 

        if( auto ){
          clear();// clear any possible automatic scrolling.
          timer = setTimeout( next, settings.interval ); 
        }
        
        
        
        // Test for the length of items and the hash value
        var length = items.length;
        var currentHash = window.location.hash
        
        if(currentHash === '#0'){
            $('.prev').fadeTo(200, 0.25);
        }
        else {
          $('.prev').fadeTo(200, 1);
        }
        if (currentHash === '#' + (length - 1)) {
          $('.next').fadeTo(200, 0.25);
        }
        else {
          $('.next').fadeTo(200, 1);
        }
  
          
      });

      pane.ssbound = true;// avoid many bindings

      if( settings.jump )// can't use jump if using lazy items and a non-bubbling event
        (lazy ? $pane : getItems()).bind( event, function( e ){
          jump( e, index(e.target) );
        });

      if( nav )
        nav = $(nav, context).bind(event, function( e ){
          e.data = Math.round(getItems().length / nav.length) * nav.index(this);
          jump( e, this );
        });

      function move( e ){
        e.data += active;
        jump( e, this );
      };
      function jump( e, button ){
        if( !isNaN(button) ){// initial or special call from the outside $(container).trigger('goto',[index]);
          e.data = button;
          button = pane;
       
       
        }

        var
          pos = e.data, n,
          real = e.type, // is a real event triggering ?
          $items = settings.exclude ? getItems().slice(0,-settings.exclude) : getItems(),// handle a possible exclude
          limit = $items.length,
          elem = $items[pos],
          duration = settings.duration;
          
      

        if( !elem ){ // exceeded the limits
          n = pos < 0 ? 0 : limit - 1;
          if( active != n )// we exceeded for the first time
            pos = n;
          else if( !settings.cycle )// this is a bad case
            return;
          else
            pos = limit - n - 1;// invert, go to the other side
          elem = $items[pos];
        }

        if( !elem || settings.lock && $pane.is(':animated') || // no animations while busy
          real && settings.onBefore &&
          settings.onBefore(e, elem, $pane, getItems(), pos) === false ) return;

        if( settings.stop )
          $pane.queue('fx',[]).stop();// remove all its animations

        if( settings.constant )
          duration = Math.abs(duration/step * (active - pos ));// keep constant velocity

        $pane
          .scrollTo( elem, duration, settings )// do scroll
          .trigger('notify.serialScroll',[pos]);// in case serialScroll was called on this elem more than once.
      };

      function next(){// I'll use the namespace to avoid conflicts
        $pane.trigger('next.serialScroll');

      
      };

      function clear(){
        clearTimeout(timer);
      };

      function getItems(){
        return $( items, pane );
        
      };
        
      
      
      function index( elem ){
        if( !isNaN(elem) ) return elem;// number
        var $items = getItems(), i;
        while(( i = $items.index(elem)) == -1 && elem != pane )// see if it matches or one of its ancestors
          elem = elem.parentNode;
        return i;
      };
    });
  };

})( jQuery );