import type { Ref } from 'vue'
import { onBeforeUnmount, onMounted, ref } from 'vue'

import useState from '../../../_util/hooks/useState'

type TouchEventHandler = (e: TouchEvent) => void
type WheelEventHandler = (e: WheelEvent) => void

const MIN_SWIPE_DISTANCE = 0.1
const STOP_SWIPE_DISTANCE = 0.01
const REFRESH_INTERVAL = 20
const SPEED_OFF_MULTIPLE = 0.995 ** REFRESH_INTERVAL
// ================================= Hook =================================
export default function useTouchMove(
  domRef: Ref<HTMLDivElement>,
  onOffset: (offsetX: number, offsetY: number) => boolean,
) {
  const [touchPosition, setTouchPosition] = useState<{ x: number; y: number }>()
  const [lastTimestamp, setLastTimestamp] = useState<number>(0)
  const [lastTimeDiff, setLastTimeDiff] = useState<number>(0)
  const [lastOffset, setLastOffset] = useState<{ x: number; y: number }>()
  const motionInterval = ref<any>()

  // ========================= Events =========================
  // >>> Touch events
  function onTouchStart(e: TouchEvent) {
    const { screenX, screenY } = e.touches[0]
    setTouchPosition({ x: screenX, y: screenY })
    clearInterval(motionInterval.value)
  }

  function onTouchMove(e: TouchEvent) {
    if (!touchPosition.value) return

    e.preventDefault()
    const { screenX, screenY } = e.touches[0]
    const offsetX = screenX - touchPosition.value.x
    const offsetY = screenY - touchPosition.value.y
    onOffset(offsetX, offsetY)
    setTouchPosition({ x: screenX, y: screenY })
    const now = Date.now()
    setLastTimeDiff(now - lastTimestamp.value)
    setLastTimestamp(now)
    setLastOffset({ x: offsetX, y: offsetY })
  }

  function onTouchEnd() {
    if (!touchPosition.value) return
    const lastOffsetValue = lastOffset.value
    setTouchPosition(null)
    setLastOffset(null)

    // Swipe if needed
    if (lastOffsetValue) {
      const distanceX = lastOffsetValue.x / lastTimeDiff.value
      const distanceY = lastOffsetValue.y / lastTimeDiff.value
      const absX = Math.abs(distanceX)
      const absY = Math.abs(distanceY)

      // Skip swipe if low distance
      if (Math.max(absX, absY) < MIN_SWIPE_DISTANCE) return

      let currentX = distanceX
      let currentY = distanceY

      motionInterval.value = setInterval(() => {
        if (Math.abs(currentX) < STOP_SWIPE_DISTANCE && Math.abs(currentY) < STOP_SWIPE_DISTANCE) {
          clearInterval(motionInterval.value)
          return
        }

        currentX *= SPEED_OFF_MULTIPLE
        currentY *= SPEED_OFF_MULTIPLE
        onOffset(currentX * REFRESH_INTERVAL, currentY * REFRESH_INTERVAL)
      }, REFRESH_INTERVAL)
    }
  }

  // >>> Wheel event
  const lastWheelDirectionRef = ref<'x' | 'y'>()

  function onWheel(e: WheelEvent) {
    const { deltaX, deltaY } = e

    // Convert both to x & y since wheel only happened on PC
    let mixed = 0
    const absX = Math.abs(deltaX)
    const absY = Math.abs(deltaY)
    if (absX === absY) {
      mixed = lastWheelDirectionRef.value === 'x' ? deltaX : deltaY
    } else if (absX > absY) {
      mixed = deltaX
      lastWheelDirectionRef.value = 'x'
    } else {
      mixed = deltaY
      lastWheelDirectionRef.value = 'y'
    }

    if (onOffset(-mixed, -mixed)) {
      e.preventDefault()
    }
  }

  // ========================= Effect =========================
  const touchEventsRef = ref<{
    onTouchStart: TouchEventHandler
    onTouchMove: TouchEventHandler
    onTouchEnd: TouchEventHandler
    onWheel: WheelEventHandler
  }>({
    onTouchStart,
    onTouchMove,
    onTouchEnd,
    onWheel,
  })
  function onProxyTouchStart(e: TouchEvent) {
    touchEventsRef.value.onTouchStart(e)
  }
  function onProxyTouchMove(e: TouchEvent) {
    touchEventsRef.value.onTouchMove(e)
  }
  function onProxyTouchEnd(e: TouchEvent) {
    touchEventsRef.value.onTouchEnd(e)
  }
  function onProxyWheel(e: WheelEvent) {
    touchEventsRef.value.onWheel(e)
  }
  onMounted(() => {
    document.addEventListener('touchmove', onProxyTouchMove, { passive: false })
    document.addEventListener('touchend', onProxyTouchEnd, { passive: false })

    // No need to clean up since element removed
    domRef.value?.addEventListener('touchstart', onProxyTouchStart, { passive: false })
    domRef.value?.addEventListener('wheel', onProxyWheel, { passive: false })
  })

  onBeforeUnmount(() => {
    document.removeEventListener('touchmove', onProxyTouchMove)
    document.removeEventListener('touchend', onProxyTouchEnd)
  })
}
