var Effect = {
  DefaultOptions: {
    duration:   1.0,   // seconds
    fps:        100,   // 100= assume 66fps max.
    sync:       false, // true for combining
    from:       0.0,
    to:         1.0,
    delay:      0.0,
    queue:      'parallel'
  }
};

/* ------------- core effects ------------- */

Effect.ScopedQueue = Class.create(Enumerable, {
  initialize: function() {
    this.effects  = [];
    this.interval = null;    
  },
  _each: function(iterator) {
    this.effects._each(iterator);
  },
  add: function(effect) {
    var timestamp = new Date().getTime();
    
    var position = Object.isString(effect.options.queue) ? 
      effect.options.queue : effect.options.queue.position;
    
    switch(position) {
      case 'front':
        // move unstarted effects after this effect  
        this.effects.findAll(function(e){ return e.state=='idle' }).each( function(e) {
            e.startOn  += effect.finishOn;
            e.finishOn += effect.finishOn;
          });
        break;
      case 'with-last':
        timestamp = this.effects.pluck('startOn').max() || timestamp;
        break;
      case 'end':
        // start effect after last queued effect has finished
        timestamp = this.effects.pluck('finishOn').max() || timestamp;
        break;
    }
    
    effect.startOn  += timestamp;
    effect.finishOn += timestamp;

    if (!effect.options.queue.limit || (this.effects.length < effect.options.queue.limit))
      this.effects.push(effect);
    
    if (!this.interval)
      this.interval = setInterval(this.loop.bind(this), 15);
  },
  remove: function(effect) {
    this.effects = this.effects.reject(function(e) { return e==effect });
    if (this.effects.length == 0) {
      clearInterval(this.interval);
      this.interval = null;
    }
  },
  loop: function() {
    var timePos = new Date().getTime();
    for(var i=0, len=this.effects.length;i<len;i++) 
      this.effects[i] && this.effects[i].loop(timePos);
  }
});

Effect.Queues = {
  instances: $H(),
  get: function(queueName) {
    if (!Object.isString(queueName)) return queueName;    
    return this.instances.get(queueName) ||
      this.instances.set(queueName, new Effect.ScopedQueue());
  }
};
Effect.Queue = Effect.Queues.get('global');

Effect.Base = Class.create({
  position: null,
  start: function(options) {
    function codeForEvent(options,eventName){
      return (
        (options[eventName+'Internal'] ? 'this.options.'+eventName+'Internal(this);' : '') +
        (options[eventName] ? 'this.options.'+eventName+'(this);' : '')
      );
    }
    this.options      = Object.extend(Object.extend({ },Effect.DefaultOptions), options || { });
    this.currentFrame = 0;
    this.state        = 'idle';
    this.startOn      = this.options.delay*1000;
    this.finishOn     = this.startOn+(this.options.duration*1000);
    this.fromToDelta  = this.options.to-this.options.from;
    this.totalTime    = this.finishOn-this.startOn;
    this.totalFrames  = this.options.fps*this.options.duration;
    
    eval('this.render = function(pos){ '+
      'if (this.state=="idle"){this.state="running";'+
      codeForEvent(this.options,'beforeSetup')+
      (this.setup ? 'this.setup();':'')+ 
      codeForEvent(this.options,'afterSetup')+
      '};if (this.state=="running"){'+
      this.fromToDelta+'+'+this.options.from+';'+
      'this.position=pos;'+
      codeForEvent(this.options,'beforeUpdate')+
      (this.update ? 'this.update(pos);':'')+
      codeForEvent(this.options,'afterUpdate')+
      '}}');
    
    this.event('beforeStart');
    if (!this.options.sync)
      Effect.Queues.get(Object.isString(this.options.queue) ? 
        'global' : this.options.queue.scope).add(this);
  },
  loop: function(timePos) {
    if (timePos >= this.startOn) {
      if (timePos >= this.finishOn) {
        this.render(1.0);
        this.cancel();
        this.event('beforeFinish');
        if (this.finish) this.finish(); 
        this.event('afterFinish');
        return;  
      }
      var pos   = (timePos - this.startOn) / this.totalTime,
          frame = (pos * this.totalFrames).round();
      if (frame > this.currentFrame) {
        this.render(pos);
        this.currentFrame = frame;
      }
    }
  },
  cancel: function() {
    if (!this.options.sync)
      Effect.Queues.get(Object.isString(this.options.queue) ? 
        'global' : this.options.queue.scope).remove(this);
    this.state = 'finished';
  },
  event: function(eventName) {
    if (this.options[eventName + 'Internal']) this.options[eventName + 'Internal'](this);
    if (this.options[eventName]) this.options[eventName](this);
  },
  inspect: function() {
    var data = $H();
    for(property in this)
      if (!Object.isFunction(this[property])) data.set(property, this[property]);
    return '#<Effect:' + data.inspect() + ',options:' + $H(this.options).inspect() + '>';
  }
});


Effect.Opacity = Class.create(Effect.Base, {
  initialize: function(element) {
    this.element = $(element);
    //if (!this.element) throw(Effect._elementDoesNotExistError);
    // make this work on IE on elements without 'layout'
    if (Prototype.Browser.IE && (!this.element.currentStyle.hasLayout))
      this.element.setStyle({zoom: 1});
    var options = Object.extend({
      from: this.element.getOpacity() || 0.0,
      to:   1.0
    }, arguments[1] || { });
    this.start(options);
  },
  update: function(position) {
    this.element.setOpacity(position);
  }
});


var cuef = [null,null,null,null];
var lh   = 0;
var zidx = 0;
var thisFrame=1;

function btns(n,total){
	highlight(n,total);
	thisFrame=n;
}

function highlight(ann,total){
	if(lh==ann) return;
	if(cuef[ann]) cuef[ann].cancel();
	cuef[ann] = null;
	
	$('fin-img'+ann).setOpacity(0.0);
	$('fin-img'+ann).setStyle({zIndex:(++zidx)});
	
	new Effect.Opacity('fin-img'+ann,{duration:1.0,from:0.0,to:1.0,queue:{scope:'ann',position:'end'}});
	for(i=1;i<total+1;i++){
		lowlight(i);
	}
	var e = $('ann'+ann);
	e.addClassName('highlight');
	lh = ann;
}

function lowlight(ann){
	var e = $('ann'+ann);
	e.removeClassName('highlight');
}