var Autocompleter = { };

Autocompleter.Base = Class.create({
  baseInitialize: function(element, update, options) {
    element          = _(element)
    this.element     = element; 
    this.update      = _(update);  
    this.hasFocus    = false; 
    this.changed     = false; 
    this.active      = false; 
    this.index       = 0;     
    this.entryCount  = 0;
    this.oldElementValue = this.element.value;

    if(this.setOptions)
      this.setOptions(options);
    else
      this.options = options || { };

    this.options.paramName    = this.options.paramName || this.element.name;
    this.options.tokens       = this.options.tokens || [];
    this.options.frequency    = this.options.frequency || 0.4;
    this.options.minChars     = this.options.minChars || 1;
    this.options.onShow       = this.options.onShow || 
      function(element, update){ 
        if(!update.style.position || update.style.position=='absolute') {
          update.style.position = 'absolute';
          Position.clone(element, update, {
            setHeight: false, 
            offsetTop: element.offsetHeight
          });
        }
        new FX.Appear(update,{duration:0.15});
      };
    this.options.onHide = this.options.onHide || 
      function(element, update){ new FX.Disappear(update,{duration:0.15}) };

    if(typeof(this.options.tokens) == 'string') 
      this.options.tokens = new Array(this.options.tokens);
    // Force carriage returns as token delimiters anyway
    if (this.options.tokens.indexOf('\n') === -1)
      this.options.tokens.push('\n');

    this.observer = null;
    
    this.element.setAttribute('autocomplete','off');

    _hide(this.update);

    Event.bind(this.element, 'blur', this.onBlur.bind(this));
    Event.bind(this.element, 'keyup', this.onKeyPress.bind(this));
  },

  show: function() {
    if(_getStyle(this.update, 'display')=='none') this.options.onShow(this.element, this.update);
    if(!this.iefix && 
      (P.Browser.IE) &&
      (_getStyle(this.update, 'position')=='absolute')) {
      	var d = this.update.parentNode.insertBefore(document.createElement('div'), this.update);
      d.innerHTML = '<iframe id="' + this.update.id + '_iefix" '+
       'style="display:none;position:absolute;filter:progid:DXImageTransform.Microsoft.Alpha(opacity=0);" ' +
       'src="javascript:false;" frameborder="0" scrolling="no"></iframe>';
      _hide(d);
      this.iefix = _(this.update.id+'_iefix');
    }
    if(this.iefix) setTimeout(this.fixIEOverlapping.bind(this), 50);
  },
  
  fixIEOverlapping: function() {
    Position.clone(this.update, this.iefix, {setTop:(!this.update.style.height)});
    this.iefix.style.zIndex = 1;
    this.update.style.zIndex = 2;
    _show(this.iefix);
  },

  hide: function() {
    this.stopIndicator();
    if(_getStyle(this.update, 'display')!='none') this.options.onHide(this.element, this.update);
    if(this.iefix) _hide(this.iefix);
  },

  startIndicator: function() {
    if(this.options.indicator) _show(this.options.indicator);
  },

  stopIndicator: function() {
    if(this.options.indicator) _hide(this.options.indicator);
  },

  onKeyPress: function(event) {
    if(this.active)
      switch(event.keyCode) {
       case Event.KEY_TAB:
       case Event.KEY_RETURN:
         this.selectEntry();
         Event.stop(event);
       case Event.KEY_ESC:
         this.hide();
         this.active = false;
         Event.stop(event);
         return;
       case Event.KEY_LEFT:
       case Event.KEY_RIGHT:
         return;
       case Event.KEY_UP:
         this.markPrevious();
         this.render();
         if(P.Browser.WebKit) Event.stop(event);
         return;
       case Event.KEY_DOWN:
         this.markNext();
         this.render();
         if(P.Browser.WebKit) Event.stop(event);
         return;
      }
     else
       if(event.keyCode==Event.KEY_TAB || event.keyCode==Event.KEY_RETURN || 
         (P.Browser.WebKit > 0 && event.keyCode == 0)) return;

    this.changed = true;
    this.hasFocus = true;

    if(this.observer) clearTimeout(this.observer);
      this.observer = 
        setTimeout(this.onObserverEvent.bind(this), this.options.frequency*1000);
  },

  activate: function() {
    this.changed = false;
    this.hasFocus = true;
    this.getUpdatedChoices();
  },

  onHover: function(event) {
  	var element = Event.element(event);
    element = element.nodeName.toUpperCase() == 'LI' ? element : _findParent(Event.element(event), 'LI');
    if(this.index != element.autocompleteIndex) 
    {
        this.index = element.autocompleteIndex;
        this.render();
    }
    Event.stop(event);
  },
  
  onClick: function(event) {
    var element = Event.element(event);
    element = element.nodeName.toUpperCase() == 'LI' ? element : _findParent(Event.element(event), 'LI');
    this.index = element.autocompleteIndex;
    this.selectEntry();
    this.hide();
  },
  
  onBlur: function(event) {
    // needed to make click events working
    setTimeout(this.hide.bind(this), 250);
    this.hasFocus = false;
    this.active = false;     
  }, 
  
  render: function() {
    if(this.entryCount > 0) {
      for (var i = 0; i < this.entryCount; i++)
        this.index==i ? 
          _addClassName(this.getEntry(i),"selected") : 
          _removeClassName(this.getEntry(i),"selected");
      if(this.hasFocus) { 
        this.show();
        this.active = true;
      }
    } else {
      this.active = false;
      this.hide();
    }
  },
  
  markPrevious: function() {
    if(this.index > 0) this.index--
      else this.index = this.entryCount-1;
    //this.getEntry(this.index).scrollIntoView(true);
  },
  
  markNext: function() {
    if(this.index < this.entryCount-1) this.index++
      else this.index = 0;
    //this.getEntry(this.index).scrollIntoView(false);
  },
  
  getEntry: function(index) {
    return this.update.firstChild.childNodes[index];
  },
  
  getCurrentEntry: function() {
    return this.getEntry(this.index);
  },
  
  selectEntry: function() {
    this.active = false;
    this.updateElement(this.getCurrentEntry());
  },

  updateElement: function(selectedElement) {
    if (this.options.updateElement) {
      this.options.updateElement(selectedElement);
      return;
    }
    var value = '';
    if (this.options.select) {
      var nodes = _(selectedElement).select('.' + this.options.select) || [];
      if(nodes.length>0) value = _collectTextNodes(nodes[0], this.options.select);
    } else
      value = _collectTextNodesIgnoreClass(selectedElement, 'informal');
    
    /*
    var bounds = this.getTokenBounds();
    if (bounds[0] != -1) {
      var newValue = this.element.value.substr(0, bounds[0]);
      var whitespace = this.element.value.substr(bounds[0]).match(/^\s+/);
      if (whitespace)
        newValue += whitespace[0];
      this.element.value = newValue + value + this.element.value.substr(bounds[1]);
    } else {*/
      this.element.value = value;
    /*}*/
    this.oldElementValue = this.element.value;
    this.element.focus();
    
    if (this.options.afterUpdateElement)
      this.options.afterUpdateElement(this.element, selectedElement);
  },

  updateChoices: function(choices) {
    if(!this.changed && this.hasFocus) {
      this.update.innerHTML = choices;
      _cleanWhitespace(this.update);
      _cleanWhitespace(this.update.firstChild);

      if(this.update.firstChild && this.update.firstChild.childNodes) {
        this.entryCount = 
          this.update.firstChild.childNodes.length;
        for (var i = 0; i < this.entryCount; i++) {
          var entry = this.getEntry(i);
          entry.autocompleteIndex = i;
          this.addObservers(entry);
        }
      } else { 
        this.entryCount = 0;
      }

      this.stopIndicator();
      this.index = 0;
      
      if(this.entryCount==1 && this.options.autoSelect) {
        this.selectEntry();
        this.hide();
      } else {
        this.render();
      }
    }
  },

  addObservers: function(element) {
    Event.bind(element, "mouseover", this.onHover.bind(this));
    Event.bind(element, "click", this.onClick.bind(this));
  },

  onObserverEvent: function() {
    this.changed = false;   
    this.tokenBounds = null;
    if(this.getToken().length>=this.options.minChars) {
      this.getUpdatedChoices();
    } else {
      this.active = false;
      this.hide();
    }
    this.oldElementValue = this.element.value;
  },

  getToken: function() {
    var bounds = this.getTokenBounds();
    return this.element.value.substring(bounds[0], bounds[1]).trim();
  },

  getTokenBounds: function() {
    if (null != this.tokenBounds) return this.tokenBounds;
    var value = this.element.value;
    if (value.trim() == '') return [-1, 0];
    var diff = arguments.callee.getFirstDifferencePos(value, this.oldElementValue);
    var offset = (diff == this.oldElementValue.length ? 1 : 0);
    var prevTokenPos = -1, nextTokenPos = value.length;
    var tp;
    for (var index = 0, l = this.options.tokens.length; index < l; ++index) {
      tp = value.lastIndexOf(this.options.tokens[index], diff + offset - 1);
      if (tp > prevTokenPos) prevTokenPos = tp;
      tp = value.indexOf(this.options.tokens[index], diff + offset);
      if (-1 != tp && tp < nextTokenPos) nextTokenPos = tp;
    }
    return (this.tokenBounds = [prevTokenPos + 1, nextTokenPos]);
  }
});

Autocompleter.Base.prototype.getTokenBounds.getFirstDifferencePos = function(newS, oldS) {
  var boundary = Math.min(newS.length, oldS.length);
  for (var index = 0; index < boundary; ++index)
    if (newS[index] != oldS[index])
      return index;
  return boundary;
};

Ajax.Autocompleter = Class.create(Autocompleter.Base, {
  initialize: function(element, update, url, options) {
    this.baseInitialize(element, update, options);
    this.options.asynchronous  = true;
    this.options.onComplete    = this.onComplete.bind(this);
    this.options.defaultParams = this.options.parameters || null;
    this.url                   = url;
  },

  getUpdatedChoices: function() {
    this.startIndicator();
    
    var entry = this.options.paramName.encode() + '=' + 
      this.getToken().encode();

    this.options.parameters = this.options.callback ?
      this.options.callback(this.element, entry) : entry;

    if(this.options.defaultParams) 
      this.options.parameters += '&' + this.options.defaultParams;
    
    new Ajax.Request(this.url, this.options);
  },

  onComplete: function(request) {
    this.updateChoices(request.responseText);
  }
});