class GitLabDropdownFilter
  BLUR_KEYCODES = [27, 40]
  ARROW_KEY_CODES = [38, 40]
  HAS_VALUE_CLASS = "has-value"

  constructor: (@input, @options) ->
    {
      @filterInputBlur = true
    } = @options

    $inputContainer = @input.parent()
    $clearButton = $inputContainer.find('.js-dropdown-input-clear')

    @indeterminateIds = []

    # Clear click
    $clearButton.on 'click', (e) =>
      e.preventDefault()
      e.stopPropagation()
      @input
        .val('')
        .trigger('keyup')
        .focus()

    # Key events
    timeout = ""
    @input.on "keyup", (e) =>
      keyCode = e.which

      return if ARROW_KEY_CODES.indexOf(keyCode) >= 0

      if @input.val() isnt "" and !$inputContainer.hasClass HAS_VALUE_CLASS
        $inputContainer.addClass HAS_VALUE_CLASS
      else if @input.val() is "" and $inputContainer.hasClass HAS_VALUE_CLASS
        $inputContainer.removeClass HAS_VALUE_CLASS

      if keyCode is 13
        return false

      # Only filter asynchronously only if option remote is set
      if @options.remote
        clearTimeout timeout
        timeout = setTimeout =>
          blur_field = @shouldBlur keyCode

          if blur_field and @filterInputBlur
            @input.blur()

          @options.query @input.val(), (data) =>
            @options.callback(data)
        , 250
      else
        @filter @input.val()

  shouldBlur: (keyCode) ->
    return BLUR_KEYCODES.indexOf(keyCode) >= 0

  filter: (search_text) ->
    @options.onFilter(search_text) if @options.onFilter
    data = @options.data()

    if data? and not @options.filterByText
      results = data

      if search_text isnt ''
        # When data is an array of objects therefore [object Array] e.g.
        # [
        #   { prop: 'foo' },
        #   { prop: 'baz' }
        # ]
        if _.isArray(data)
          results = fuzzaldrinPlus.filter(data, search_text,
            key: @options.keys
          )
        else
          # If data is grouped therefore an [object Object]. e.g.
          # {
          #   groupName1: [
          #     { prop: 'foo' },
          #     { prop: 'baz' }
          #   ],
          #   groupName2: [
          #     { prop: 'abc' },
          #     { prop: 'def' }
          #   ]
          # }
          if gl.utils.isObject data
            results = {}
            for key, group of data
              tmp = fuzzaldrinPlus.filter(group, search_text,
                key: @options.keys
              )

              if tmp.length
                results[key] = tmp.map (item) -> item

      @options.callback results
    else
      elements = @options.elements()

      if search_text
        elements.each ->
          $el = $(@)
          matches = fuzzaldrinPlus.match($el.text().trim(), search_text)

          unless $el.is('.dropdown-header')
            if matches.length
              $el.show()
            else
              $el.hide()
      else
        elements.show()

class GitLabDropdownRemote
  constructor: (@dataEndpoint, @options) ->

  execute: ->
    if typeof @dataEndpoint is "string"
      @fetchData()
    else if typeof @dataEndpoint is "function"
      if @options.beforeSend
        @options.beforeSend()

      # Fetch the data by calling the data funcfion
      @dataEndpoint "", (data) =>
        if @options.success
          @options.success(data)

        if @options.beforeSend
          @options.beforeSend()

  # Fetch the data through ajax if the data is a string
  fetchData: ->
    $.ajax(
      url: @dataEndpoint,
      dataType: @options.dataType,
      beforeSend: =>
        if @options.beforeSend
          @options.beforeSend()
      success: (data) =>
        if @options.success
          @options.success(data)
    )

class GitLabDropdown
  LOADING_CLASS = "is-loading"
  PAGE_TWO_CLASS = "is-page-two"
  ACTIVE_CLASS = "is-active"
  INDETERMINATE_CLASS = "is-indeterminate"
  currentIndex = -1

  FILTER_INPUT = '.dropdown-input .dropdown-input-field'

  constructor: (@el, @options) ->
    self = @
    selector = $(@el).data "target"
    @dropdown = if selector? then $(selector) else $(@el).parent()

    # Set Defaults
    {
      # If no input is passed create a default one
      @filterInput = @getElement(FILTER_INPUT)
      @highlight = false
      @filterInputBlur = true
    } = @options

    self = @

    # If selector was passed
    if _.isString(@filterInput)
      @filterInput = @getElement(@filterInput)

    searchFields = if @options.search then @options.search.fields else [];

    if @options.data
      # If we provided data
      # data could be an array of objects or a group of arrays
      if _.isObject(@options.data) and not _.isFunction(@options.data)
        @fullData = @options.data
        @parseData @options.data
      else
        # Remote data
        @remote = new GitLabDropdownRemote @options.data, {
          dataType: @options.dataType,
          beforeSend: @toggleLoading.bind(@)
          success: (data) =>
            @fullData = data

            @parseData @fullData

            @filter.input.trigger('keyup') if @options.filterable and @filter and @filter.input
        }

    # Init filterable
    if @options.filterable
      @filter = new GitLabDropdownFilter @filterInput,
        filterInputBlur: @filterInputBlur
        filterByText: @options.filterByText
        onFilter: @options.onFilter
        remote: @options.filterRemote
        query: @options.data
        keys: searchFields
        elements: =>
          selector = '.dropdown-content li:not(.divider)'

          if @dropdown.find('.dropdown-toggle-page').length
            selector = ".dropdown-page-one #{selector}"

          return $(selector)
        data: =>
          return @fullData
        callback: (data) =>
          @parseData data

          unless @filterInput.val() is ''
            selector = '.dropdown-content li:not(.divider):visible'

            if @dropdown.find('.dropdown-toggle-page').length
              selector = ".dropdown-page-one #{selector}"

            if not $(@el).is('input')
              $(selector, @dropdown)
                .first()
                .find('a')
                .addClass('is-focused')

              currentIndex = 0
            else
              currentIndex = -1


    # Event listeners

    @dropdown.on "shown.bs.dropdown", @opened
    @dropdown.on "hidden.bs.dropdown", @hidden
    $(@el).on "update.label", @updateLabel
    @dropdown.on "click", ".dropdown-menu, .dropdown-menu-close", @shouldPropagate
    @dropdown.on 'keyup', (e) =>
      if e.which is 27 # Escape key
        $('.dropdown-menu-close', @dropdown).trigger 'click'
    @dropdown.on 'blur', 'a', (e) =>
      if e.relatedTarget?
        $relatedTarget = $(e.relatedTarget)
        $dropdownMenu = $relatedTarget.closest('.dropdown-menu')

        if $dropdownMenu.length is 0
          @dropdown.removeClass('open')

    if @dropdown.find(".dropdown-toggle-page").length
      @dropdown.find(".dropdown-toggle-page, .dropdown-menu-back").on "click", (e) =>
        e.preventDefault()
        e.stopPropagation()

        @togglePage()

    if @options.selectable
      selector = ".dropdown-content a"

      if @dropdown.find(".dropdown-toggle-page").length
        selector = ".dropdown-page-one .dropdown-content a"

      @dropdown.on "click", selector, (e) ->
        $el = $(@)
        selected = self.rowClicked $el

        if self.options.clicked
          self.options.clicked(selected, $el, e)

        $el.trigger('blur')

  # Finds an element inside wrapper element
  getElement: (selector) ->
    @dropdown.find selector

  toggleLoading: ->
    $('.dropdown-menu', @dropdown).toggleClass LOADING_CLASS

  togglePage: ->
    menu = $('.dropdown-menu', @dropdown)

    if menu.hasClass(PAGE_TWO_CLASS)
      if @remote
        @remote.execute()

    menu.toggleClass PAGE_TWO_CLASS

    # Focus first visible input on active page
    @dropdown.find('[class^="dropdown-page-"]:visible :text:visible:first').focus()

  parseData: (data) ->
    @renderedData = data

    if @options.filterable and data.length is 0
      # render no matching results
      html = [@noResults()]
    else
      # Handle array groups
      if gl.utils.isObject data
        html = []
        for name, groupData of data
          # Add header for each group
          html.push(@renderItem(header: name, name))

          @renderData(groupData, name)
            .map (item) ->
              html.push item
      else
        # Render each row
        html = @renderData(data)

    # Render the full menu
    full_html = @renderMenu(html)

    @appendMenu(full_html)

  renderData: (data, group = false) ->
    data.map (obj, index) =>
      return @renderItem(obj, group, index)

  shouldPropagate: (e) =>
    if @options.multiSelect
      $target = $(e.target)

      if not $target.hasClass('dropdown-menu-close') and not $target.hasClass('dropdown-menu-close-icon') and not $target.data('is-link')
        e.stopPropagation()
        return false
      else
        return true

  opened: =>
    @addArrowKeyEvent()

    if @options.setIndeterminateIds
      @options.setIndeterminateIds.call(@)

    if @options.setActiveIds
      @options.setActiveIds.call(@)

    # Makes indeterminate items effective
    if @fullData and @dropdown.find('.dropdown-menu-toggle').hasClass('js-filter-bulk-update')
      @parseData @fullData

    contentHtml = $('.dropdown-content', @dropdown).html()
    if @remote && contentHtml is ""
      @remote.execute()

    if @options.filterable
      @filterInput.focus()

    @dropdown.trigger('shown.gl.dropdown')

  hidden: (e) =>
    @removeArrayKeyEvent()

    $input = @dropdown.find(".dropdown-input-field")

    if @options.filterable
      $input
        .blur()
        .val("")

    # Triggering 'keyup' will re-render the dropdown which is not always required
    # specially if we want to keep the state of the dropdown needed for bulk-assignment
    if not @options.persistWhenHide
      $input.trigger("keyup")

    if @dropdown.find(".dropdown-toggle-page").length
      $('.dropdown-menu', @dropdown).removeClass PAGE_TWO_CLASS

    if @options.hidden
      @options.hidden.call(@,e)

    @dropdown.trigger('hidden.gl.dropdown')


  # Render the full menu
  renderMenu: (html) ->
    menu_html = ""

    if @options.renderMenu
      menu_html = @options.renderMenu(html)
    else
      menu_html = $('<ul />')
        .append(html)

    return menu_html

  # Append the menu into the dropdown
  appendMenu: (html) ->
    selector = '.dropdown-content'
    if @dropdown.find(".dropdown-toggle-page").length
      selector = ".dropdown-page-one .dropdown-content"
    $(selector, @dropdown)
      .empty()
      .append(html)

  # Render the row
  renderItem: (data, group = false, index = false) ->
    html = ""

    # Divider
    return "<li class='divider'></li>" if data is "divider"

    # Separator is a full-width divider
    return "<li class='separator'></li>" if data is "separator"

    # Header
    return "<li class='dropdown-header'>#{data.header}</li>" if data.header?

    if @options.renderRow
      # Call the render function
      html = @options.renderRow.call(@options, data, @)
    else
      if not selected
        value = if @options.id then @options.id(data) else data.id
        fieldName = @options.fieldName
        field = @dropdown.parent().find("input[name='#{fieldName}'][value='#{value}']")
        if field.length
          selected = true

      # Set URL
      if @options.url?
        url = @options.url(data)
      else
        url = if data.url? then data.url else '#'

      # Set Text
      if @options.text?
        text = @options.text(data)
      else
        text = if data.text? then data.text else ''

      cssClass = "";

      if selected
        cssClass = "is-active"

      if @highlight
        text = @highlightTextMatches(text, @filterInput.val())

      if group
        groupAttrs = "data-group='#{group}' data-index='#{index}'"
      else
        groupAttrs = ''

      html = "<li>
        <a href='#{url}' #{groupAttrs} class='#{cssClass}'>
          #{text}
        </a>
      </li>"

    return html

  highlightTextMatches: (text, term) ->
    occurrences = fuzzaldrinPlus.match(text, term)
    text.split('').map((character, i) ->
      if i in occurrences then "<b>#{character}</b>" else character
    ).join('')

  noResults: ->
    html = "<li class='dropdown-menu-empty-link'>
      <a href='#' class='is-focused'>
        No matching results.
      </a>
    </li>"

  highlightRow: (index) ->
    if @filterInput.val() isnt ""
      selector = '.dropdown-content li:first-child a'
      if @dropdown.find(".dropdown-toggle-page").length
        selector = ".dropdown-page-one .dropdown-content li:first-child a"

      @getElement(selector).addClass 'is-focused'

  rowClicked: (el) ->
    fieldName = @options.fieldName
    isInput = $(@el).is('input')

    if @renderedData
      groupName = el.data('group')
      if groupName
        selectedIndex = el.data('index')
        selectedObject = @renderedData[groupName][selectedIndex]
      else
        selectedIndex = el.closest('li').index()
        selectedObject = @renderedData[selectedIndex]

    value = if @options.id then @options.id(selectedObject, el) else selectedObject.id

    if isInput
      field = $(@el)
    else
      field = @dropdown.parent().find("input[name='#{fieldName}'][value='#{value}']")

    if el.hasClass(ACTIVE_CLASS)
      el.removeClass(ACTIVE_CLASS)

      if isInput
        field.val('')
      else
        field.remove()

      # Toggle the dropdown label
      if @options.toggleLabel
        @updateLabel(selectedObject, el, @)
      else
        selectedObject
    else if el.hasClass(INDETERMINATE_CLASS)
      el.addClass ACTIVE_CLASS
      el.removeClass INDETERMINATE_CLASS

      if not value?
        field.remove()

      if not field.length and fieldName
        @addInput(fieldName, value)

      return selectedObject
    else
      if not @options.multiSelect or el.hasClass('dropdown-clear-active')
        @dropdown.find(".#{ACTIVE_CLASS}").removeClass ACTIVE_CLASS

        unless isInput
          @dropdown.parent().find("input[name='#{fieldName}']").remove()

      if !value?
        field.remove()

      # Toggle active class for the tick mark
      el.addClass ACTIVE_CLASS

      # Toggle the dropdown label
      if @options.toggleLabel
        @updateLabel(selectedObject, el, @)
      if value?
        if !field.length and fieldName
          @addInput(fieldName, value)
        else
          field
            .val value
            .trigger 'change'

      return selectedObject

  addInput: (fieldName, value)->
    # Create hidden input for form
    $input = $('<input>').attr('type', 'hidden')
                         .attr('name', fieldName)
                        .val(value)

    if @options.inputId?
      $input.attr('id', @options.inputId)

    @dropdown.before $input

  selectRowAtIndex: (e, index) ->
    selector = ".dropdown-content li:not(.divider,.dropdown-header,.separator):eq(#{index}) a"

    if @dropdown.find(".dropdown-toggle-page").length
      selector = ".dropdown-page-one #{selector}"

    # simulate a click on the first link
    $el = $(selector, @dropdown)

    if $el.length and currentIndex > -1
      e.preventDefault()
      e.stopImmediatePropagation()
      $first = $el.first()
      $firstEl = $first.get(0)

      if $firstEl.click
        $firstEl.click()
      else
        $first.trigger('click')

  addArrowKeyEvent: ->
    ARROW_KEY_CODES = [38, 40]
    $input = @dropdown.find(".dropdown-input-field")

    selector = '.dropdown-content li:not(.divider,.dropdown-header,.separator)'
    if @dropdown.find(".dropdown-toggle-page").length
      selector = ".dropdown-page-one #{selector}"

    $('body').on 'keydown', (e) =>
      currentKeyCode = e.which

      if ARROW_KEY_CODES.indexOf(currentKeyCode) >= 0
        e.preventDefault()
        e.stopImmediatePropagation()

        PREV_INDEX = currentIndex
        $listItems = $(selector, @dropdown)

        # if @options.filterable
        #   $input.blur()

        if currentKeyCode is 40
          # Move down
          currentIndex += 1 if currentIndex < ($listItems.length - 1)
        else if currentKeyCode is 38
          # Move up
          currentIndex -= 1 if currentIndex > 0

        @highlightRowAtIndex($listItems, currentIndex) if currentIndex isnt PREV_INDEX

        return false

      if currentKeyCode is 13 and currentIndex isnt -1
        @selectRowAtIndex e, currentIndex

  removeArrayKeyEvent: ->
    $('body').off 'keydown'

  highlightRowAtIndex: ($listItems, index) ->
    # Remove the class for the previously focused row
    $('.is-focused', @dropdown).removeClass 'is-focused'

    # Update the class for the row at the specific index
    $listItem = $listItems.eq(index)
    $listItem.find('a:first-child').addClass "is-focused"

    # Dropdown content scroll area
    $dropdownContent = $listItem.closest('.dropdown-content')
    dropdownScrollTop = $dropdownContent.scrollTop()
    dropdownContentHeight = $dropdownContent.outerHeight()
    dropdownContentTop = $dropdownContent.prop('offsetTop')
    dropdownContentBottom = dropdownContentTop + dropdownContentHeight

    # Get the offset bottom of the list item
    listItemHeight = $listItem.outerHeight()
    listItemTop = $listItem.prop('offsetTop')
    listItemBottom = listItemTop + listItemHeight

    if listItemBottom > dropdownContentBottom + dropdownScrollTop
      # Scroll the dropdown content down
      $dropdownContent.scrollTop(listItemBottom - dropdownContentBottom)
    else if listItemTop < dropdownContentTop + dropdownScrollTop
      # Scroll the dropdown content up
      $dropdownContent.scrollTop(listItemTop - dropdownContentTop)

  updateLabel: (selected = null, el = null, instance = null) =>
    $(@el).find(".dropdown-toggle-text").text @options.toggleLabel(selected, el, instance)

$.fn.glDropdown = (opts) ->
  return @.each ->
    if (!$.data @, 'glDropdown')
      $.data(@, 'glDropdown', new GitLabDropdown @, opts)