document.observe("dom:loaded", function() {
  $('panel_1').addClassName('active');
  $('prevSlideButton').fade();
  $('prevArrowButton').fade();
  
  $('nextSlideButton').observe('click', function(event) {
    slideNews('next');    
  });
  $('nextArrowButton').observe('click', function(event) {
    slideNews('next');    
  });
  
  $('prevSlideButton').observe('click', function(event) {
    slideNews('prev');    
  });
  $('prevArrowButton').observe('click', function(event) {
    slideNews('prev');    
  });
});

function slideNews(action){
  
  if(action == 'next'){
    if($('nextSlideButton').getStyle('display') == 'none') alert('non faccio nulla');
  }
   
  $('nextSlideButton').stopObserving('click');
  $('prevSlideButton').stopObserving('click');
  
  var maxElements = $$('#scrollContainer div.panel').length;
  var activeElement = String($$('#scrollContainer div.active').pluck('id'));
  var activeElement = parseInt(activeElement.replace("panel_",""));
  var moveOk = true;
  
  if(action == 'next'){         
    var x_move = 293;
    var id_next = activeElement + 1;
    var xmove = - x_move;      
    
    if(id_next == maxElements){
      $('nextSlideButton').setStyle({'display':'none'});
      $('nextArrowButton').setStyle({'display':'none'});
    }       
    if($('prevSlideButton').getStyle('display') == 'none'){
      $('prevSlideButton').appear();
      $('prevArrowButton').appear();
    }
                
    if($('panel_'+id_next)){
      $('panel_'+id_next).addClassName('active');
      if($('panel_'+activeElement)) $('panel_'+activeElement).removeClassName('active');
    } else moveOk = false;
  }else{
    var id_next = activeElement; 
    var xmove = 293;          
    
    if((id_next-1) == 1){
      $('prevSlideButton').setStyle({'display':'none'});
      $('prevArrowButton').setStyle({'display':'none'});
    }         
    if($('nextSlideButton').getStyle('display') == 'none'){
      $('nextSlideButton').appear();
      $('nextArrowButton').appear();
    } 
    
    if($('panel_'+(id_next-1))){
      $('panel_'+(id_next-1)).addClassName('active');
      $('panel_'+activeElement).removeClassName('active');
    } else moveOk = false;
  }  
  
  if(moveOk){
    new Effect.Move('scrollContainer', {
      afterFinish : function() {
        $('nextSlideButton').observe('click', function(event) {
          slideNews('next');
        });
        
        $('prevSlideButton').observe('click', function(event) {
          slideNews('prev');
        });          
     },
     x: xmove, 
     mode: 'relative',
     duration: 0.3, 
     transition: Effect.Transitions.sinoidal 
   });  
 }  
}