$q = null

LAYERS = []
LAYERS_BY_ID = {}
CALLBACKS = {}
INSTANCE = {}

App.factory('Layers', ['$q',(q)->
  $q = q

  createId = (->
    possible = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
    _id = ''
    _id += possible.charAt(Math.floor(Math.random() * possible.length)) for i in [0..20]
    return _id
  )

  addLayer = (($element, should_fade_body)->
    _id = createId()
    layer = {
      _id: _id,
      $element: $element,
      onRemove: ((callback)->
        addLayerCallback(_id, callback)
        return layer
      )
      remove: ((args...)->
        removeLayer(_id, args...)
        return layer
      )
      should_fade_body: should_fade_body
    }
    setTimeout(-> finishAddLayer(layer))
    return layer
  )

  addLayerCallback = ((_id, callback)->
    CALLBACKS[_id] ||= []
    CALLBACKS[_id].push(callback) if callback
  )

  finishAddLayer = ((layer)->
    LAYERS.unshift(layer)
    LAYERS_BY_ID[layer._id] = layer
    $('body').addClass('locked-scroll') if layer.should_fade_body
    layer.$element.attr('is-active-layer', 'true')
  )

  removeLayer = ((_id, args...)->
    layer = LAYERS_BY_ID[_id]
    return if !layer
    callbacks = CALLBACKS[_id] || []
    callback(args...) for callback in callbacks
    delete CALLBACKS[_id]
    delete LAYERS_BY_ID[_id]
    for layer, i in LAYERS
      return if layer._id != _id
      layer_i_to_remove = i
      break
    LAYERS.splice(layer_i_to_remove, 1)
    $('body').removeClass('locked-scroll') if layer.should_fade_body
    layer.$element.attr('is-active-layer', 'false')
  )

  removeAll = (->
    removeLayer(layer._id) while layer = LAYERS.shift()
  )

  ######################################################################################################################

  $('body').on('click', (e)->
    layer = LAYERS[0]
    return if !layer
    return if $(e.target).hasClass('dropdown-toggle')

    $target = $(e.target)
    return if !$.contains(document, $target[0])

    $element = $target if $target.attr('is-active-layer')
    $element ||= $target.closest('[is-active-layer="true"]')
    return if ($element and $element.length and $element[0] == layer.$element[0])

    layer.remove()
  )

  $('body').on('keydown', (e)->
    return if e.keyCode != 27

    layer = LAYERS[0]
    return if !layer

    layer.remove()
  )

  ######################################################################################################################

  INSTANCE.add = ((element, should_fade_body=false)->
    return addLayer($(element), should_fade_body)
  )
  INSTANCE.removeAll = removeAll
  return INSTANCE;
]);