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);
  } else {
    $results.css("width",'');
  }

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

  input.autocompleter = me;

  var timeout = null;
  var prev = "";
  var original = ""; // the typed text
  var active = -1;
  var cache = {};
  var keyb = false;
  var hasFocus = false;
  var lastKeyPressCode = null;
  var inList = false;

  // 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);
        return;
      case 40: // down
        e.preventDefault();
        moveSelect(1);
        return;
      case 9:  // tab
        e.preventDefault();
        break;
      case 13: // return
        selectCurrent();
        return;
      case 32: // space
        if (inList) {
          selectCurrent();
        }
        break;
      case 37: // left
        return;
      case 39: // right
        return;
      default:
        // do nothing
        break;
    }
    inList = false;
    active = -1;
    if (timeout) {
      clearTimeout(timeout);
    }
    timeout = setTimeout(function() {onChange();}, options.delay);
  })
  .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();
    }
    lis.removeClass("ac_over");
    inList = false;
  };

  function moveSelect(step) {
    var lis = $("li", results);
    if (!lis) {
      return;
    }

    active += step;

    if ((active == -1 && inList) || active >= lis.size()) {
      active = -1;
      inList = false;
      // reset styles
      lis.removeClass("ac_over");

      // reset value
      $input.val(original);
      return;
    } else {
      if (active < -1) {
        active = lis.size() - 1;
      }
      if (!inList) {
        original = $input.val();
        inList = true;
      }

      lis.removeClass("ac_over");

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

      $input.val(itemToText(lis[active]));
    }
    // 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 = "";
    }
    $input.val(itemToText(li));
    prev = $input.val();
    input.lastSelected = prev;
    $results.html("");
    hideResultsNow();
    if (options.onItemSelect) {
      setTimeout(function() { options.onItemSelect(li) }, 1);
    }
  };

  function itemToText(li) {
    if (!!li) {
      return $.trim(li.selectValue ? li.selectValue : li.innerHTML);
    }
    return "";
  }

  // 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(sValue.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 : ((options.width < 0) ? '' : $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;
    var data = 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;

    var lower_q = q.toLowerCase();

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

      if (row[0].toLowerCase() == lower_q) {
        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;
};