# WHY IS THIS FILE HERE? ReactCSSTransitionGroup is causing
# inconsitency exceptions when you hammer on the animations and don't let them
# finish. This is from http://khan.github.io/react-components/#timeout-transition-group
# and uses timeouts to clean up elements rather than listeners on CSS events, which
# don't always seem to fire.

# https://github.com/facebook/react/issues/1707

###*
# The CSSTransitionGroup component uses the 'transitionend' event, which
# browsers will not send for any number of reasons, including the
# transitioning node not being painted or in an unfocused tab.
#
# This TimeoutTransitionGroup instead uses a user-defined timeout to determine
# when it is a good time to remove the component. Currently there is only one
# timeout specified, but in the future it would be nice to be able to specify
# separate timeouts for enter and leave, in case the timeouts for those
# animations differ. Even nicer would be some sort of inspection of the CSS to
# automatically determine the duration of the animation or transition.
#
# This is adapted from Facebook's CSSTransitionGroup which is in the React
# addons and under the Apache 2.0 License.
###

React = require('react/addons')
PriorityUICoordinator = require('../priority-ui-coordinator')
ReactTransitionGroup = React.addons.TransitionGroup
TICK = 17

endEvents = ['webkitTransitionEnd', 'webkitAnimationEnd']

animationSupported = => true

###*
# Functions for element class management to replace dependency on jQuery
# addClass, removeClass and hasClass
###

addClass = (element, className) =>
  if element.classList
    element.classList.add className
  else if !hasClass(element, className)
    element.className = element.className + ' ' + className
  element

removeClass = (element, className) =>
  if hasClass(className)
    if element.classList
      element.classList.remove className
    else
      element.className = (' ' + element.className + ' ').replace(' ' + className + ' ', ' ').trim()
  element

hasClass = (element, className) =>
  if element.classList
    element.classList.contains className
  else
    (' ' + element.className + ' ').indexOf(' ' + className + ' ') > -1


class TimeoutTransitionGroupChild extends React.Component

  transition: (animationType, finishCallback) =>
    node = React.findDOMNode(@)
    className = @props.name + '-' + animationType
    activeClassName = className + '-active'

    # If you animate back and forth fast enough, you can call `transition`
    # before a previous transition has finished. Make sure we cancel the
    # old timeout.
    if @animationTimeout
      clearTimeout(@animationTimeout)
      @animationTimeout = null

    if @animationTaskId
      PriorityUICoordinator.endPriorityTask(@animationTaskId)
      @animationTaskId = null

    # Block database responses, JSON parsing while we are in flight
    @animationTaskId = PriorityUICoordinator.beginPriorityTask()

    endListener = =>
      removeClass(node, className)
      removeClass(node, activeClassName)
      # Usually this optional callback is used for informing an owner of
      # a leave animation and telling it to remove the child.
      finishCallback and finishCallback()

      if @animationTaskId
        PriorityUICoordinator.endPriorityTask(@animationTaskId)
        @animationTaskId = null
      @animationTimeout = null
      return

    if !animationSupported()
      endListener()
    else
      if animationType == 'enter'
        @animationTimeout = setTimeout(endListener, @props.enterTimeout)
      else if animationType == 'leave'
        @animationTimeout = setTimeout(endListener, @props.leaveTimeout)

    addClass(node, className)

    # Need to do this to actually trigger a transition.
    @queueClass activeClassName
    return

  queueClass: (className) =>
    @classNameQueue.push className
    if !@timeout
      @timeout = setTimeout(@flushClassNameQueue, TICK)
    return
  
  flushClassNameQueue: =>
    @classNameQueue.forEach ((name) =>
      addClass(React.findDOMNode(@), name)
      return
    ).bind(this)
    @classNameQueue.length = 0
    @timeout = null
    return

  componentWillMount: =>
    @classNameQueue = []
    @animationTimeout = null
    @animationTaskId = null
    return

  componentWillUnmount: =>
    if @timeout
      clearTimeout(@timeout)
    if @animationTimeout
      clearTimeout(@animationTimeout)
      @animationTimeout = null
    if @animationTaskId
      PriorityUICoordinator.endPriorityTask(@animationTaskId)
      @animationTaskId = null
    return

  componentWillEnter: (done) =>
    if @props.enter
      @transition 'enter', done
    else
      done()
    return

  componentWillLeave: (done) =>
    if @props.leave
      @transition 'leave', done
    else
      done()
    return

  render: =>
    React.Children.only @props.children

class TimeoutTransitionGroup extends React.Component
  @propTypes =
    enterTimeout: React.PropTypes.number.isRequired
    leaveTimeout: React.PropTypes.number.isRequired
    transitionName: React.PropTypes.string.isRequired
    transitionEnter: React.PropTypes.bool
    transitionLeave: React.PropTypes.bool

  @defaultProps =
    transitionEnter: true
    transitionLeave: true

  _wrapChild: (child) =>
    <TimeoutTransitionGroupChild
      enterTimeout={@props.enterTimeout}
      leaveTimeout={@props.leaveTimeout}
      name={@props.transitionName}
      enter={@props.transitionEnter}
      leave={@props.transitionLeave}>
        {child}
    </TimeoutTransitionGroupChild>

  render: =>
    <ReactTransitionGroup
        {...@props}
        childFactory={@_wrapChild} />


module.exports = TimeoutTransitionGroup