/**
 * 
 */
function TandemSlideshow(container_id,parameters) {  

  //Default-Werte
  var options = {
    duration: 5,
    transition_speed: 1.5,
    random: false,
    overlap: 0
  };
  
	Object.extend(options,parameters);

  	var self = this;
  	var slides = null;
  	var current_slide_index = 0;
	var periodical_executer = null;
	  
	  
	this.start = function() {
  	  initSlides();

      if(slides.length <= 1)
      {
        console.log('Diashow wurde nicht gestartet. Es wurden nur ' + slides.length + ' Einträge gefunden.');
      }
      else
      {
        periodical_executer = new PeriodicalExecuter(next,options.duration);
      }
	}
	
	this.stop = function() {
    periodical_executer.stop();
	}

	var initSlides = function() {

    //Alle divs ermitteln, die direkt in angegebenen Container liegen
    slides = $$('#'+container_id+' > div');
    
    if(slides.length>0)
    {
      slides.each(function(e) { e.style.display='none'});
      if(options.random)
        for(var j, x, i = slides.length; i; j = parseInt(Math.random() * i), x = slides[--i], slides[i] = slides[j], slides[j] = x);
      slides[0].style.display='block';      
    }
	}

	var next = function() {
	      
	  if(current_slide_index < slides.length-1)
	    var next_slide_index = current_slide_index+1;
	  else
	    var next_slide_index = 0;
	 
	  Effect.Fade(slides[current_slide_index],{delay:options.overlap,duration:options.transition_speed});
  	  Effect.Appear(slides[next_slide_index],{duration:options.transition_speed});
  	  current_slide_index = next_slide_index;
	}
	
	//start();
};