jQuery.autocomplete = function(input, options) {
  // Create a link to self
  var me = this;

  // Create jQuery object for input element
  var $input = $(input).attr("autocomplete", "off");

  // Apply inputClass if necessary
  if (options.inputClass) $input.addClass(options.inputClass);

  // Create results
  var results = document.createElement("div");
  // Create jQuery object for results
  var $results = $(results);
  $results.hide().addClass(options.resultsClass).css("position", "absolute");
  if( options.width > 0 ) $results.css("width", options.width);

  // Add to body element
  $("body").append(results);

  input.autocompleter = me;

  var timeout = null;
  var prev = "";
  var active = -1;
  var cache = {};
  var keyb = false;
  var hasFocus = false;
  var lastKeyPressCode = null;

  // flush cache
  function flushCache(){
    cache = {};
    cache.data = {};
    cache.length = 0;
  };

  // flush cache
  flushCache();

  // if there is a data array supplied
  if( options.data != null ){
    var sFirstChar = "", stMatchSets = {}, row = [];

    // no url was specified, we need to adjust the cache length to make sure it fits the local data store
    if( typeof options.url != "string" ) options.cacheLength = 1;

    // loop through the array and create a lookup structure
    for( var i=0; i < options.data.length; i++ ){
      // if row is a string, make an array otherwise just reference the array
      row = ((typeof options.data[i] == "string") ? [options.data[i]] : options.data[i]);

      // if the length is zero, don't add to list
      if( row[0].length > 0 ){
	// get the first character
	sFirstChar = row[0].substring(0, 1).toLowerCase();
	// if no lookup array for this character exists, look it up now
	if( !stMatchSets[sFirstChar] ) stMatchSets[sFirstChar] = [];
	// if the match is a string
	stMatchSets[sFirstChar].push(row);
      }
    }

    // add the data items to the cache
    for( var k in stMatchSets ){
      // increase the cache size
      options.cacheLength++;
      // add to the cache
      addToCache(k, stMatchSets[k]);
    }
  }

  $input
  .keydown(function(e) {
	     // track last key pressed
	     lastKeyPressCode = e.keyCode;
	     switch(e.keyCode) {
	     case 38: // up
	       e.preventDefault();
	       moveSelect(-1);
	       break;
	     case 40: // down
	       e.preventDefault();
	       moveSelect(1);
	       break;
	     case 9:  // tab
	     case 13: // return
	       if( selectCurrent() ){
		 // make sure to blur off the current field
		 $input.get(0).blur();
		 e.preventDefault();
	       }
	       break;
	     default:
	       active = -1;
	       if (timeout) clearTimeout(timeout);
	       timeout = setTimeout(function(){onChange();}, options.delay);
	       break;
	     }
	   })
  .focus(function(){
	   // track whether the field has focus, we shouldn't process any results if the field no longer has focus
	   hasFocus = true;
	 })
  .blur(function() {
	  // track whether the field has focus
	  hasFocus = false;
	  hideResults();
	});

  hideResultsNow();

  function onChange() {
    // ignore if the following keys are pressed: [del] [shift] [capslock]
    if( lastKeyPressCode == 46 || (lastKeyPressCode > 8 && lastKeyPressCode < 32) ) return $results.hide();
    var v = $input.val();
    if (v == prev) return;
    prev = v;
    if (v.length >= options.minChars) {
      $input.addClass(options.loadingClass);
      requestData(v);
    } else {
      $input.removeClass(options.loadingClass);
      $results.hide();
    }
  };

  function moveSelect(step) {

    var lis = $("li", results);
    if (!lis) return;

    active += step;

    if (active < 0) {
      active = 0;
    } else if (active >= lis.size()) {
      active = lis.size() - 1;
    }

    lis.removeClass("ac_over");

    $(lis[active]).addClass("ac_over");

    // Weird behaviour in IE
    // if (lis[active] && lis[active].scrollIntoView) {
    // 	lis[active].scrollIntoView(false);
    // }

  };

  function selectCurrent() {
    var li = $("li.ac_over", results)[0];
    if (!li) {
      var $li = $("li", results);
      if (options.selectOnly) {
	if ($li.length == 1) li = $li[0];
      } else if (options.selectFirst) {
	li = $li[0];
      }
    }
    if (li) {
      selectItem(li);
      return true;
    } else {
      return false;
    }
  };

  function selectItem(li) {
    if (!li) {
      li = document.createElement("li");
      li.extra = [];
      li.selectValue = "";
    }
    var v = $.trim(li.selectValue ? li.selectValue : li.innerHTML);
    input.lastSelected = v;
    prev = v;
    $results.html("");
    $input.val(v);
    hideResultsNow();
    if (options.onItemSelect) setTimeout(function() { options.onItemSelect(li) }, 1);
  };

  // selects a portion of the input string
  function createSelection(start, end){
    // get a reference to the input element
    var field = $input.get(0);
    if( field.createTextRange ){
      var selRange = field.createTextRange();
      selRange.collapse(true);
      selRange.moveStart("character", start);
      selRange.moveEnd("character", end);
      selRange.select();
    } else if( field.setSelectionRange ){
      field.setSelectionRange(start, end);
    } else {
      if( field.selectionStart ){
	field.selectionStart = start;
	field.selectionEnd = end;
      }
    }
    field.focus();
  };

  // fills in the input box w/the first match (assumed to be the best match)
  function autoFill(sValue){
    // if the last user key pressed was backspace, don't autofill
    if( lastKeyPressCode != 8 ){
      // fill in the value (keep the case the user has typed)
      $input.val($input.val() + sValue.substring(prev.length));
      // select the portion of the value not typed by the user (so the next character will erase)
      createSelection(prev.length, sValue.length);
    }
  };

  function showResults() {
    // get the position of the input field right now (in case the DOM is shifted)
    var pos = findPos(input);
    // either use the specified width, or autocalculate based on form element
    var iWidth = (options.width > 0) ? options.width : $input.width();
    // reposition
    $results.css({
      width: parseInt(iWidth) + "px",
	  top: (pos.y + input.offsetHeight) + "px",
	  left: pos.x + "px"
	  }).show();
  };

  function hideResults() {
    if (timeout) clearTimeout(timeout);
    timeout = setTimeout(hideResultsNow, 200);
  };

  function hideResultsNow() {
    if (timeout) clearTimeout(timeout);
    $input.removeClass(options.loadingClass);
    if ($results.is(":visible")) {
      $results.hide();
    }
    if (options.mustMatch) {
      var v = $input.val();
      if (v != input.lastSelected) {
	selectItem(null);
      }
    }
  };

  function receiveData(q, data) {
    if (data) {
      $input.removeClass(options.loadingClass);
      results.innerHTML = "";

      // if the field no longer has focus or if there are no matches, do not display the drop down
      if( !hasFocus || data.length == 0 ) return hideResultsNow();

      if ($.browser.msie) {
	// we put a styled iframe behind the calendar so HTML SELECT elements don't show through
	$results.append(document.createElement('iframe'));
      }
      results.appendChild(dataToDom(data));
      // autofill in the complete box w/the first match as long as the user hasn't entered in more data
      if( options.autoFill && ($input.val().toLowerCase() == q.toLowerCase()) ) autoFill(data[0][0]);
      showResults();
    } else {
      hideResultsNow();
    }
  };

  function parseData(data) {
    if (!data) return null;
    var parsed = [];
    var rows = data.split(options.lineSeparator);
    for (var i=0; i < rows.length; i++) {
      var row = $.trim(rows[i]);
      if (row) {
	parsed[parsed.length] = row.split(options.cellSeparator);
      }
    }
    return parsed;
  };

  function dataToDom(data) {
    var ul = document.createElement("ul");
    var num = data.length;

    // limited results to a max number
    if( (options.maxItemsToShow > 0) && (options.maxItemsToShow < num) ) num = options.maxItemsToShow;

    for (var i=0; i < num; i++) {
      var row = data[i];
      if (!row) continue;
      var li = document.createElement("li");
      if (options.formatItem) {
	li.innerHTML = options.formatItem(row, i, num);
	li.selectValue = row[0];
      } else {
	li.innerHTML = row[0];
	li.selectValue = row[0];
      }
      var extra = null;
      if (row.length > 1) {
	extra = [];
	for (var j=1; j < row.length; j++) {
	  extra[extra.length] = row[j];
	}
      }
      li.extra = extra;
      ul.appendChild(li);
      $(li).hover(
		  function() { $("li", ul).removeClass("ac_over"); $(this).addClass("ac_over"); active = $("li", ul).indexOf($(this).get(0)); },
		  function() { $(this).removeClass("ac_over"); }
		  ).click(function(e) { e.preventDefault(); e.stopPropagation(); selectItem(this) });
    }
    return ul;
  };

  function requestData(q) {
    if (!options.matchCase) q = q.toLowerCase();
    var data = options.cacheLength ? loadFromCache(q) : null;
    // recieve the cached data
    if (data) {
      receiveData(q, data);
      // if an AJAX url has been supplied, try loading the data now
    } else if( (typeof options.url == "string") && (options.url.length > 0) ){
      $.get(makeUrl(q), function(data) {
	      data = parseData(data);
	      addToCache(q, data);
	      receiveData(q, data);
	    });
      // if there's been no data found, remove the loading class
    } else {
      $input.removeClass(options.loadingClass);
    }
  };

  function makeUrl(q) {
    var url = options.url + "?q=" + encodeURI(q);
    for (var i in options.extraParams) {
      url += "&" + i + "=" + encodeURI(options.extraParams[i]);
    }
    return url;
  };

  function loadFromCache(q) {
    if (!q) return null;
    if (cache.data[q]) return cache.data[q];
    if (options.matchSubset) {
      for (var i = q.length - 1; i >= options.minChars; i--) {
	var qs = q.substr(0, i);
	var c = cache.data[qs];
	if (c) {
	  var csub = [];
	  for (var j = 0; j < c.length; j++) {
	    var x = c[j];
	    var x0 = x[0];
	    if (matchSubset(x0, q)) {
	      csub[csub.length] = x;
	    }
	  }
	  return csub;
	}
      }
    }
    return null;
  };

  function matchSubset(s, sub) {
    if (!options.matchCase) s = s.toLowerCase();
    var i = s.indexOf(sub);
    if (i == -1) return false;
    return i == 0 || options.matchContains;
  };

  this.flushCache = function() {
    flushCache();
  };

  this.setExtraParams = function(p) {
    options.extraParams = p;
  };

  this.findValue = function(){
    var q = $input.val();

    if (!options.matchCase) q = q.toLowerCase();
    var data = options.cacheLength ? loadFromCache(q) : null;
    if (data) {
      findValueCallback(q, data);
    } else if( (typeof options.url == "string") && (options.url.length > 0) ){
      $.get(makeUrl(q), function(data) {
	      data = parseData(data)
		addToCache(q, data);
	      findValueCallback(q, data);
	    });
    } else {
      // no matches
      findValueCallback(q, null);
    }
  }

  function findValueCallback(q, data){
    if (data) $input.removeClass(options.loadingClass);

    var num = (data) ? data.length : 0;
    var li = null;

    for (var i=0; i < num; i++) {
      var row = data[i];

      if( row[0].toLowerCase() == q.toLowerCase() ){
	li = document.createElement("li");
	if (options.formatItem) {
	  li.innerHTML = options.formatItem(row, i, num);
	  li.selectValue = row[0];
	} else {
	  li.innerHTML = row[0];
	  li.selectValue = row[0];
	}
	var extra = null;
	if( row.length > 1 ){
	  extra = [];
	  for (var j=1; j < row.length; j++) {
	    extra[extra.length] = row[j];
	  }
	}
	li.extra = extra;
      }
    }

    if( options.onFindValue ) setTimeout(function() { options.onFindValue(li) }, 1);
  }

  function addToCache(q, data) {
    if (!data || !q || !options.cacheLength) return;
    if (!cache.length || cache.length > options.cacheLength) {
      flushCache();
      cache.length++;
    } else if (!cache[q]) {
      cache.length++;
    }
    cache.data[q] = data;
  };

  function findPos(obj) {
    var curleft = obj.offsetLeft || 0;
    var curtop = obj.offsetTop || 0;
    while (obj = obj.offsetParent) {
      curleft += obj.offsetLeft
	curtop += obj.offsetTop
	}
    return {x:curleft,y:curtop};
  }
}

jQuery.fn.autocomplete = function(url, options, data) {
	// Make sure options exists
	options = options || {};
	// Set url as option
	options.url = url;
	// set some bulk local data
	options.data = ((typeof data == "object") && (data.constructor == Array)) ? data : null;

	// Set default values for required options
	options.inputClass = options.inputClass || "ac_input";
	options.resultsClass = options.resultsClass || "ac_results";
	options.lineSeparator = options.lineSeparator || "\n";
	options.cellSeparator = options.cellSeparator || "|";
	options.minChars = options.minChars || 1;
	options.delay = options.delay || 400;
	options.matchCase = options.matchCase || 0;
	options.matchSubset = options.matchSubset || 1;
	options.matchContains = options.matchContains || 0;
	options.cacheLength = options.cacheLength || 1;
	options.mustMatch = options.mustMatch || 0;
	options.extraParams = options.extraParams || {};
	options.loadingClass = options.loadingClass || "ac_loading";
	options.selectFirst = options.selectFirst || false;
	options.selectOnly = options.selectOnly || false;
	options.maxItemsToShow = options.maxItemsToShow || -1;
	options.autoFill = options.autoFill || false;
	options.width = parseInt(options.width, 10) || 0;

	this.each(function() {
		var input = this;
		new jQuery.autocomplete(input, options);
	});

	// Don't break the chain
	return this;
}

jQuery.fn.autocompleteArray = function(data, options) {
	return this.autocomplete(null, options, data);
}

jQuery.fn.indexOf = function(e){
	for( var i=0; i<this.length; i++ ){
		if( this[i] == e ) return i;
	}
	return -1;
};