// Author:Devolux
// Author URI:http://devolux.org/

$(document).ready(function(){

  var currentPosition = 0;
  var slideWidth = 400;
  var slides = $('.gr_slide');
  var numberOfSlides = slides.length;
  
  // nasconde gli eventi successivi
  $('#slide_container').css('overflow', 'hidden');

  //crea un div dove  inserire tutti i div 
  slides.wrapAll('<div id="bw_slideInner"></div>')
  // imposta la dimensione di tutte le slide 
  slides.css({
      'float' : 'left',
      'width' : slideWidth
    });

  // aumenta la dimensione di tutte le slide
  $('#bw_slideInner').css('width', slideWidth * numberOfSlides);

  // Inserisce le freccie
  $('#slide_container')
    .prepend('<div class="control" id="leftControl">&nbsp;</div>')
    .append('<div class="control" id="rightControl">&nbsp;</div>');
  // Mostra o nasconde le freccie
  manageControls(currentPosition);

  // Listener per le freccie
  $('.control')
    .bind('click', function(){
	currentPosition = ($(this).attr('id')=='rightControl') ? currentPosition+1 : currentPosition-1; 
   manageControls(currentPosition);
    $('#bw_slideInner').animate({
      'marginLeft' : slideWidth*(-currentPosition)
    });
  });

  // manageControls: mostra o nasconde le freccie a seconda del ost visualizzato
  function manageControls(position){
	if(position==0){ $('#leftControl').hide() } else{ $('#leftControl').show() }
    if(position==numberOfSlides-1){ $('#rightControl').hide() } else{ $('#rightControl').show() }
  }


 });