/**
 * Mixin to add touch handlers.
 * @mixin ApTouchMixin
 */

'use strict'

import React, {PropTypes as types} from 'react'
import ReactDOM from 'react-dom'

const TOUCH_HAMMER_KEY = '_apTouchHammer'

function createTouchHammer (node, props, getData) {
  if (!node) {
    return
  }
  let Hammer = require('hammerjs')
  let hammer = new Hammer(node)
  if (props.touchOptions) {
    hammer.set(props.touchOptions)
  }
  Object.keys(ApTouchMixin.propTypes)
    .filter((key) => !!props[ key ])
    .forEach((key) => {
      if (/^on/.test(key)) {
        let event = key.replace(/^on/, '').toLowerCase()
        let handler = props[ key ]
        hammer.on(event, (e) => {
          e.data = getData() // Set touching data.
          handler(e)
        })
      }
      if (/Direction$/.test(key)) {
        let gesture = key.replace(/Direction$/, '')
        hammer.get(gesture).set({ direction: Hammer[ 'DIRECTION_' + props[ key ] ] })
      }
      if (/Threshold$/.test(key)) {
        let threshold = key.replace(/Threshold$/, '')
        hammer.get(threshold).set({ threshold: props[ key ] })
      }
    })
  return hammer
}

function destroyTouchHammer (hammer) {
  if (!hammer) {
    return
  }
  hammer.stop()
  hammer.destroy()
}

function supportsTouch (props) {
  let touchableKey = Object.keys(ApTouchMixin.propTypes)
  for (let key of Object.keys(props)) {
    let hit = !!~touchableKey.indexOf(key)
    if (hit) {
      return true
    }
  }
  return false
}

/** Enum for touching */
const touchEnums = {
  directions: [
    'NONE',
    'LEFT',
    'RIGHT',
    'UP',
    'DOWN',
    'HORIZONTAL',
    'VERTICAL',
    'ALL'
  ]
}

/** @lends ApTouchMixin */
let ApTouchMixin = {

  // --------------------
  // Custom
  // --------------------

  [TOUCH_HAMMER_KEY]: null,

  // --------------------
  // Specs
  // --------------------

  propTypes: {
    onTap: types.func,
    onDoubleTap: types.func,
    onPan: types.func,
    onPanStart: types.func,
    onPanMove: types.func,
    onPanEnd: types.func,
    onPanCancel: types.func,
    onSwipe: types.func,
    onPress: types.func,
    onPressUp: types.func,
    onPinch: types.func,
    onPinchStart: types.func,
    onPinchMove: types.func,
    onPinchEnd: types.func,
    onPinchCancel: types.func,
    onRotate: types.func,
    onRotateStart: types.func,
    onRotateMove: types.func,
    onRotateEnd: types.func,
    onRotateCancel: types.func,
    touchOptions: types.object,
    panThreshold: types.number,
    panDirection: types.oneOf(touchEnums.directions),
    swipeDirection: types.oneOf(touchEnums.directions)
  },

  statics: {},

  // --------------------
  // Lifecycle
  // --------------------

  componentWillMount () {
    const s = this
    s.getTouchData = s.getTouchData || (() => undefined)
  },

  componentDidMount () {
    const s = this
    let touchable = supportsTouch(s.props)
    let getData = () => s.getTouchData()
    if (touchable) {
      s[ TOUCH_HAMMER_KEY ] = createTouchHammer(ReactDOM.findDOMNode(s), s.props, getData)
    }
  },

  componentWillUnmount () {
    const s = this
    let hammer = s[ TOUCH_HAMMER_KEY ]
    if (hammer) {
      destroyTouchHammer(hammer)
    }
    delete s[ TOUCH_HAMMER_KEY ]
  }
}

export default Object.freeze(ApTouchMixin)