(function(window, undefined) {

function addEvent(el, ev, cb) {
  if (el.addEventListener) el.addEventListener(ev, cb, false)
  else if (el.attachEvent) el.attachEvent('on' + ev, cb)}

function removeEvent(el, ev, cb) {
  if (el.removeEventListener) el.removeEventListener(ev, cb, false)
  else if (el.detachEvent) el.detachEvent('on' + ev, cb)}

function getStyle(el, p) {var r
  if (window.getComputedStyle) r = getComputedStyle(el,null).getPropertyValue(p);
  else                         r = el.currentStyle[p]
  return r}

function extend() {var hasOwnProp, p, i, l, r
  hasOwnProp = Object.prototype.hasOwnProperty
  r = {}
  for (i = 0, l = arguments.length; i < l; ++i)
    for (p in arguments[i])
      if (hasOwnProp.call(arguments[i], p))
        r[p] = arguments[i][p]
  return r}

function contains(a, b) {
  return a.contains ? a != b && a.contains(b) : !!(a.compareDocumentPosition(b) & 16)}

function getPos(el) {var x, y
  x = 0, y = 0
  do {
    x += el.offsetLeft
    y += el.offsetTop}
  while (el = el.offsetParent)
  return {x: x, y: y}}

function XHRGet(url, parameters, cb) {var p, req, hasOwnProp
  hasOwnProp = Object.prototype.hasOwnProperty
  if (window.XMLHttpRequest) req = new XMLHttpRequest()
  else if (window.ActiveXObject) {req = new ActiveXObject('Microsoft.XMLHTTP')}
  else alert('This browser does not support Ajax')
  url += '?'
  for (p in parameters) 
    if (hasOwnProp.call(parameters, p))
      url += encodeURIComponent(p) + '=' + encodeURIComponent(parameters[p]) + '&'
  url = url.substring(0, url.length-1)
  req.open('GET', url, true)
  req.onreadystatechange = function(e) {
    if (req.readyState == 4) {
      if (req.status == 200) {
        cb(req)
      }
      else throw new Error('Couldn\'t fetch the data from the server')}}
  req.send()
  return req}

function Autocomplete(input, options) {var suggestBox, timeout, inputValue, xhr, that

  function loadData(string) {
    if (typeof options.onFetch == 'function')
      if (options.onFetch.call(that, string) === false) return false
    if (typeof options.queryURL == "string")
      // Fetch data from an xhr
      xhr = XHRGet(options.queryURL
                  ,extend(options.queryParameters, {'value': string})
                  ,function(e) {var jsonResponse
                     try {jsonResponse = JSON.parse(e.responseText)}
                     catch (error) {
                       if (error.name == 'SyntaxError')
                         alert('Il server ha risposto in modo inaspettato\n\n'
                               + e.responseText)
                       else throw error}
                     updateSuggestBox(jsonResponse)})
    else if (typeof options.data == "object")
      // Fetch data from the provided object
      updateSuggestBox(filterDataSet(options.data, string))}

  function filterDataSet(dataDict, value) {var p, hasOwnProp, ret
    hasOwnProp = Object.prototype.hasOwnProperty
    ret = {}
    if (isNaN(Number(value))) {
      for (p in dataDict)
        if (hasOwnProp.call(dataDict, p) && dataDict[p].toLowerCase().indexOf(value.toLowerCase()) == 0)
          ret[p] = dataDict[p]}
    else {
      for (p in dataDict)
        if (hasOwnProp.call(dataDict, p) && p.indexOf(value) == 0)
          ret[p] = dataDict[p]}
    return ret}

  function updateSuggestBox(dataDict) {var i, fragment, div, hasOwnProp, n
    // this is to catch the case where the user delete every character and we
    // don't manage to catch it in time to stop the xhr callback from firing
    // It's the wrong way to do it (see input.onkeyup handler)
    //if (input.value.length < options.minChars) return
    hasOwnProp = Object.prototype.hasOwnProperty
    n = 0
    options.clearSuggestBox.call(that, suggestBox)
    fragment = document.createDocumentFragment()
    for (i in dataDict)
      if (hasOwnProp.call(dataDict, i)) {
        ++n
        div = that.options.processJSON.call(dataDict[i], i)
        if (typeof that.options.suggestionExtender == 'function')
          div = that.options.suggestionExtender(div)
        if (div !== null) fragment.appendChild(div)}
    suggestBox.appendChild(fragment)
    // If there is at least one element, i is not undefin...NOT!
    // GODDAMN YOU, PROTOTYPE! ROT IN HELL FFS
    //if (i !== undefined) that.showSuggestBox(true)
    if (n > 0 && getStyle(suggestBox, 'display') == 'none')
      that.showSuggestBox(true)
    else if (n === 0 && getStyle(suggestBox, 'display') == 'block')
      that.showSuggestBox(false)

    // Helper functions
    function addHover() {
      this.className += ' hover'}

    function removeHover(e) {
      this.className = this.className.replace(/ ?\bhover\b ?/g, '')}}

  function bringIntoView(el, container, top) {var scroll
    if(!isVisible(el, container)) {
      if (top === undefined) {
        if (el.offsetTop < container.scrollTop) top = true
        else                                    top = false}
      if (top) scroll = el.offsetTop
      else     scroll = el.offsetTop - container.offsetHeight + el.offsetHeight
      container.scrollTop = scroll}

    function isVisible(el, co) {
      return co.scrollTop + co.offsetHeight > el.offsetTop + el.offsetHeight
          && co.scrollTop < el.offsetTop}}

  function singleClickHandler(e) {var t, el, value
    e = e || window.event
    t = e.target || e.srcElement
    if (t.className.indexOf('acsb-element') >= 0) {el = t}
    else if (t.parentNode.className.indexOf('acsb-element') >= 0) {el = t.parentNode}
    else return
    if (typeof options.onPick == 'function') {
      value = el.textContent || el.innerText
      options.onPick.call(that, {'type': 'pick'
                                ,'input': input
                                ,'target': el
                                ,'value': value
                                ,'suggestBox': suggestBox})}
    e.cancelBubble = true
    if (e.stopPropagation) e.stopPropagation()}

  var multipleClicksHandler = singleClickHandler

  function keysNavigationHandler(e) {var sel, value
    e = e || window.event
    if (e.keyCode == 27) {
      select(null)
      that.showSuggestBox(false)
      return false}
    // If the suggestBox is not shown
    if (getStyle(suggestBox, 'display') == 'none') {
      if (e.keyCode == 40) {
        that.showSuggestBox(true)
        if (suggestBox.firstChild) select(suggestBox.firstChild)}}
    // If the suggestBox is shown
    else if (getStyle(suggestBox, 'display') == 'block') {
      sel = getSelected(suggestBox)
      // If there is no selection:
      if (!sel) {
        if (e.keyCode == 40) select(suggestBox.firstChild)
        if (e.keyCode == 38) select(suggestBox.lastChild)}
      // If some suggestion is selected:
      else {
        sel.className = sel.className.replace('hover', '')
        if (e.keyCode == 40) // down arrow
          if (sel.nextSibling) select(sel.nextSibling)
          else                 select(suggestBox.firstChild)
        if (e.keyCode == 38) // up arrow
          if (sel.previousSibling) select(sel.previousSibling)
          else                     select(suggestBox.lastChild)
        if (e.keyCode == 13) { // enter
          if (typeof options.onPick == 'function')
            value = sel.textContent || sel.innerText
            options.onPick.call(that, {'type': 'pick'
                                      ,'input': input
                                      ,'target': sel
                                      ,'value': value
                                      ,'suggestBox': suggestBox})
          return false}}}

  function getSelected(el) {
    for (i = 0, l = el.childNodes.length; i < l; ++i)
      if (/\bhover\b/.exec(el.childNodes[i].className))
        return el.childNodes[i]
    return null}
  
  function select(el, show) {
    if (el === null) {
      el = getSelected(suggestBox)
      if (el) el.className = el.className.replace('hover', '')} // UGH
    else if (typeof el === 'object') {
      el.className = ' hover'
      bringIntoView(el, suggestBox)}}}

  // Constructor
  that = this
  options = extend(defaultOptions, options)
  if (!options.suggestBox) {
    suggestBox = document.createElement('div')
    suggestBox.className = 'acsb'
    suggestBox.style.display = 'none'
    suggestBox.style.position = 'absolute'
    suggestBox.style.zIndex = 999
    suggestBox.style.left = input.offsetLeft + 'px'
    suggestBox.style.top = input.offsetTop + input.offsetHeight + 'px'
    input.parentNode.appendChild(suggestBox)}
  else suggestBox = options.suggestBox
  if (!!options.forceCSSWidth) suggestBox.style.width = input.offsetWidth + 'px'

  // IE
  input.autocomplete = 'off'
  // Other browsers
  input.setAttribute('autocomplete', 'off')

  // Events
  input.onkeyup = function(e) {var last
    // TODO investigate some time
    if (input.value.length < options.minChars) {
      that.showSuggestBox(false)
      if (timeout) window.clearTimeout(timeout)
      // This raises some error, but it would be the right way to do it
      // See the updateSuggestBox function for the "temporary" fix
      /*if (xhr)     {xhr.onreadystatechange = null
                    xhr.abort()
                    xhr = undefined}*/
    }
    if (input.value == inputValue) return false
    inputValue = input.value
    last = inputValue.split(options.fieldSeparator).pop()
    if (timeout) window.clearTimeout(timeout)
    if (last.length >= options.minChars) 
                 timeout = setTimeout(function(){loadData(last)}
                                     ,options.updateTimeout)}
  if(options.keyboard)
    input.onkeydown = keysNavigationHandler

  if (!options.multiclickAsDefault) {
    suggestBox.onclick = singleClickHandler
  /*  document.body.onkeydown = function(e) {
      e = e || window.event
      // 17 is the control key
      if (e.keyCode == 17) suggestBox.onclick = multipleClicksHandler}
    document.body.onkeyup = function(e) {
      e = e || window.event
      if (e.keyCode == 17) suggestBox.onclick = singleClickHandler}*/}
  else suggestBox.onclick = multipleClickHandler

  // API
  that.options = options
  that.forceUpdate = function(s) {loadData(arguments.length > 0 ? s : input.value)}
  that.showSuggestBox = (function() {
      function keyHandler(e) {
        e = e || window.event
        if (e.keyCode == 27) that.showSuggestBox(false)} // 27 is esc

      function clickHandler(e) {
        e = e || window.event
        that.showSuggestBox(false)}

      return function(bool) {
        options.showHide.call(suggestBox, bool)
        if (bool) { addEvent(document, 'keydown', keyHandler)
                    addEvent(document, 'click', clickHandler)}
        else      { removeEvent(document, 'keydown', keyHandler)
                    removeEvent(document, 'click', clickHandler)}}})()
}

// EXPORTS
window.Autocomplete = Autocomplete

// DEFAULTS
defaultOptions = 
   {minChars: 3
   ,updateTimeout: 100
   ,data: {}
   ,queryURL: undefined
   ,queryParameters: undefined
   ,onFetch: undefined
   ,multiclickAsDefault: false
   ,forceCSSWidth: true
   ,keyboard: true
   ,fieldSeparator: ", "
   ,onPick: function(e) {
      e.input.value = e.input.value.replace(/(, )?[^,]*$/, '$1' + e.value + ', ')
      this.showSuggestBox(false)}
   ,showHide: function(bool) {
      if (bool) this.style.display = 'block'
      else      this.style.display = 'none'}
   ,processJSON: function(i) {var div, p
      div = document.createElement('div')
      div.className = 'acsb-element'
      div.id = i
      div.onmouseover = addHover
      div.onmouseout = removeHover
      p = document.createElement('p')
      p.className = 'acsb-p'
      p.appendChild(document.createTextNode(this))
      div.appendChild(p)
      return div

      // Helper functions
      function addHover() {
        this.className += ' hover'}

      function removeHover(e) {
        this.className = this.className.replace(/ ?\bhover\b ?/g, '')}}
   ,suggestionExtender: undefined
   ,clearSuggestBox: function(suggestBox) {suggestBox.innerHTML = ''}}
})(this)