import ResizeObserver from 'resize-observer-polyfill'

import contains from '../vc-util/Dom/contains'
import type { TargetPoint } from './interface'

export function isSamePoint(prev: TargetPoint, next: TargetPoint) {
  if (prev === next) return true
  if (!prev || !next) return false

  if ('pageX' in next && 'pageY' in next) {
    return prev.pageX === next.pageX && prev.pageY === next.pageY
  }

  if ('clientX' in next && 'clientY' in next) {
    return prev.clientX === next.clientX && prev.clientY === next.clientY
  }

  return false
}

export function restoreFocus(activeElement, container) {
  // Focus back if is in the container
  if (
    activeElement !== document.activeElement &&
    contains(container, activeElement) &&
    typeof activeElement.focus === 'function'
  ) {
    activeElement.focus()
  }
}

export function monitorResize(element: HTMLElement, callback: Function) {
  let prevWidth: number = null
  let prevHeight: number = null

  function onResize([{ target }]: ResizeObserverEntry[]) {
    if (!document.documentElement.contains(target)) return
    const { width, height } = target.getBoundingClientRect()
    const fixedWidth = Math.floor(width)
    const fixedHeight = Math.floor(height)

    if (prevWidth !== fixedWidth || prevHeight !== fixedHeight) {
      // https://webkit.org/blog/9997/resizeobserver-in-webkit/
      Promise.resolve().then(() => {
        callback({ width: fixedWidth, height: fixedHeight })
      })
    }

    prevWidth = fixedWidth
    prevHeight = fixedHeight
  }

  const resizeObserver = new ResizeObserver(onResize)
  if (element) {
    resizeObserver.observe(element)
  }

  return () => {
    resizeObserver.disconnect()
  }
}
