/**
 * tools.scrollable 1.1.2 - Scroll your HTML with eye candy.
 * 
 * Copyright (c) 2009 Tero Piirainen
 * http://flowplayer.org/tools/scrollable.html
 *
 * Dual licensed under MIT and GPL 2+ licenses
 * http://www.opensource.org/licenses
 *
 * Launch  : March 2008
 * Date: ${date}
 * Revision: ${revision} 
 */
(function($) { 
    
  // static constructs
  $.tools = $.tools || {};
  
  $.tools.scrollable = {
    version: '1.1.2',
    
    conf: {
      
      // basics
      size: 4,
      vertical: false,
      speed: 400,
      keyboard: true,   
      
      // by default this is the same as size
      keyboardSteps: null, 
      
      // other
      disabledClass: 'disabled',
      hoverClass: null,   
      clickable: false,
      activeClass: 'active', 
      easing: 'swing',
      loop: false,
      
      items: '.items',
      item: null,
      
      // navigational elements      
      prev: '.prev',
      next: '.next',
      prevPage: '.prevPage',
      nextPage: '.nextPage', 
      api: false
      
      // CALLBACKS: onBeforeSeek, onSeek, onReload
    } 
  };
        
  var current;    
  
  // constructor
  function Scrollable(root, conf) {   
    
    // current instance
    var self = this, $self = $(this),
       horizontal = !conf.vertical,
       wrap = root.children(),
       index = 0,
       forward;  
    
    
    if (!current) { current = self; }
    
    // bind all callbacks from configuration
    $.each(conf, function(name, fn) {
      if ($.isFunction(fn)) { $self.bind(name, fn); }
    });
    
    if (wrap.length > 1) { wrap = $(conf.items, root); }
    
    // navigational items can be anywhere when globalNav = true
    function find(query) {
      var els = $(query);
      return conf.globalNav ? els : root.parent().find(query);  
    }
    
    // to be used by plugins
    root.data("finder", find);
    
    // get handle to navigational elements
    var prev = find(conf.prev),
       next = find(conf.next),
       prevPage = find(conf.prevPage),
       nextPage = find(conf.nextPage);

    
    // methods
    $.extend(self, {
      
      getIndex: function() {
        return index; 
      },
      
      getClickIndex: function() {
        var items = self.getItems(); 
        return items.index(items.filter("." + conf.activeClass)); 
      },
  
      getConf: function() {
        return conf;  
      },
      
      getSize: function() {
        return self.getItems().size();  
      },
  
      getPageAmount: function() {
        return Math.ceil(this.getSize() / conf.size);   
      },
      
      getPageIndex: function() {
        return Math.ceil(index / conf.size);  
      },

      getNaviButtons: function() {
        return prev.add(next).add(prevPage).add(nextPage);  
      },
      
      getRoot: function() {
        return root;  
      },
      
      getItemWrap: function() {
        return wrap;  
      },
      
      getItems: function() {
        return wrap.children(conf.item);  
      },
      
      getVisibleItems: function() {
        return self.getItems().slice(index, index + conf.size); 
      },
      
      /* all seeking functions depend on this */    
      seekTo: function(i, time, fn) {

        if (i < 0) { i = 0; }       
        
        // nothing happens
        if (index === i) { return self; }       
        
        // function given as second argument
        if ($.isFunction(time)) {
          fn = time;
        }

        // seeking exceeds the end         
        if (i > self.getSize() - conf.size) { 
          return conf.loop ? self.begin() : this.end(); 
        }         

        var item = self.getItems().eq(i);         
        if (!item.length) { return self; }        
        
        // onBeforeSeek
        var e = $.Event("onBeforeSeek");

        $self.trigger(e, [i]);        
        if (e.isDefaultPrevented()) { return self; }        
        
        // get the (possibly altered) speed
        if (time === undefined || $.isFunction(time)) { time = conf.speed; }
        
        function callback() {
          if (fn) { fn.call(self, i); }
          $self.trigger("onSeek", [i]);
        }
        
        if (horizontal) {
          wrap.animate({left: -item.position().left}, time, conf.easing, callback);         
        } else {
          wrap.animate({top: -item.position().top}, time, conf.easing, callback);             
        }
        
        
        current = self;
        index = i;        
        
        // onStart
        e = $.Event("onStart");
        $self.trigger(e, [i]);        
        if (e.isDefaultPrevented()) { return self; }        
  
        
        /* default behaviour */
        
        // prev/next buttons disabled flags
        prev.add(prevPage).toggleClass(conf.disabledClass, i === 0);
        next.add(nextPage).toggleClass(conf.disabledClass, i >= self.getSize() - conf.size);
        
        return self; 
      },      
      
        
      move: function(offset, time, fn) {
        forward = offset > 0;
        return this.seekTo(index + offset, time, fn);
      },
      
      next: function(time, fn) {
        return this.move(1, time, fn);  
      },
      
      prev: function(time, fn) {
        return this.move(-1, time, fn); 
      },
      
      movePage: function(offset, time, fn) {
        forward = offset > 0;
        var steps = conf.size * offset;
        
        var i = index % conf.size;
        if (i > 0) {
          steps += (offset > 0 ? -i : conf.size - i);
        }
        
        return this.move(steps, time, fn);    
      },
      
      prevPage: function(time, fn) {
        return this.movePage(-1, time, fn);
      },  
  
      nextPage: function(time, fn) {
        return this.movePage(1, time, fn);
      },      
      
      setPage: function(page, time, fn) {
        return this.seekTo(page * conf.size, time, fn);
      },      
      
      begin: function(time, fn) {
        forward = false;
        return this.seekTo(0, time, fn);  
      },
      
      end: function(time, fn) {
        forward = true;
        var to = this.getSize() - conf.size;
        return to > 0 ? this.seekTo(to, time, fn) : self; 
      },
      
      reload: function() {        
        $self.trigger("onReload");
        return self;
      },      
      
      focus: function() {
        current = self;
        return self;
      },
      
      click: function(i) {
        
        var item = self.getItems().eq(i), 
           klass = conf.activeClass,
           size = conf.size;      
        
        // check that i is sane
        if (i < 0 || i >= self.getSize()) { return self; }
        
        // size == 1              
        if (size == 1) {
          if (conf.loop) { return self.next(); }
          
          if (i === 0 || i == self.getSize() -1)  { 
            forward = (forward === undefined) ? true : !forward;   
          }
          return forward === false  ? self.prev() : self.next(); 
        } 
        
        // size == 2
        if (size == 2) {
          if (i == index) { i--; }
          self.getItems().removeClass(klass);
          item.addClass(klass);         
          return self.seekTo(i, time, fn);
        }       
    
        if (!item.hasClass(klass)) {        
          self.getItems().removeClass(klass);
          item.addClass(klass);
          var delta = Math.floor(size / 2);
          var to = i - delta;
    
          // next to last item must work
          if (to > self.getSize() - size) { 
            to = self.getSize() - size; 
          }
    
          if (to !== i) {
            return self.seekTo(to);   
          }
        }
        
        return self;
      },
      
      // bind / unbind
      bind: function(name, fn) {
        $self.bind(name, fn);
        return self;  
      },  
      
      unbind: function(name) {
        $self.unbind(name);
        return self;  
      }     
      
    });
    
    // callbacks  
    $.each("onBeforeSeek,onStart,onSeek,onReload".split(","), function(i, ev) {
      self[ev] = function(fn) {
        return self.bind(ev, fn); 
      };
    });  
      
      
    // prev button    
    prev.addClass(conf.disabledClass).click(function() {
      self.prev(); 
    });
    

    // next button
    next.click(function() { 
      self.next(); 
    });
    
    // prev page button
    nextPage.click(function() { 
      self.nextPage(); 
    });
    
    if (self.getSize() < conf.size) {
      next.add(nextPage).addClass(conf.disabledClass);  
    }
    

    // next page button
    prevPage.addClass(conf.disabledClass).click(function() { 
      self.prevPage(); 
    });   
    
    
    // hover
    var hc = conf.hoverClass, keyId = "keydown." + Math.random().toString().substring(10); 
      
    self.onReload(function() { 

      // hovering
      if (hc) {
        self.getItems().hover(function()  {
          $(this).addClass(hc);   
        }, function() {
          $(this).removeClass(hc);  
        });           
      }
      
      // clickable
      if (conf.clickable) {
        self.getItems().each(function(i) {
          $(this).unbind("click.scrollable").bind("click.scrollable", function(e) {
            if ($(e.target).is("a")) { return; }  
            return self.click(i);
          });
        });
      }       
      
      // keyboard     
      if (conf.keyboard) {        
        
        // keyboard works on one instance at the time. thus we need to unbind first
        $(document).unbind(keyId).bind(keyId, function(evt) {

          // do nothing with CTRL / ALT buttons
          if (evt.altKey || evt.ctrlKey) { return; }
          
          // do nothing for unstatic and unfocused instances
          if (conf.keyboard != 'static' && current != self) { return; }
          
          var s = conf.keyboardSteps;       
                    
          if (horizontal && (evt.keyCode == 37 || evt.keyCode == 39)) {         
            self.move(evt.keyCode == 37 ? -s : s);
            return evt.preventDefault();
          } 
          
          if (!horizontal && (evt.keyCode == 38 || evt.keyCode == 40)) {
            self.move(evt.keyCode == 38 ? -s : s);
            return evt.preventDefault();
          }
          
          return true;
          
        });
        
      } else  {
        $(document).unbind(keyId);  
      }       

    });
    
    self.reload(); 
    
  } 

    
  // jQuery plugin implementation
  $.fn.scrollable = function(conf) { 
      
    // already constructed --> return API
    var el = this.eq(typeof conf == 'number' ? conf : 0).data("scrollable");
    if (el) { return el; }     
 
    var globals = $.extend({}, $.tools.scrollable.conf);
    conf = $.extend(globals, conf);
    
    conf.keyboardSteps = conf.keyboardSteps || conf.size;
    
    this.each(function() {      
      el = new Scrollable($(this), conf);
      $(this).data("scrollable", el); 
    });
    
    return conf.api ? el: this; 
    
  };
      
  
})(jQuery);