import { on } from '@element-plus/utils/dom'
import isServer from '@element-plus/utils/isServer'
import type { ComponentPublicInstance, DirectiveBinding, ObjectDirective } from 'vue'


type DocumentHandler = <T extends MouseEvent>(mouseup: T, mousedown: T) => void;

type FlushList = Map<
  HTMLElement,
  {
    documentHandler: DocumentHandler
    bindingFn: (...args: unknown[]) => unknown
  }[]
>;

const nodeList: FlushList = new Map()

let startClick: MouseEvent

if (!isServer) {
  on(document, 'mousedown', (e: MouseEvent) => (startClick = e))
  on(document, 'mouseup', (e: MouseEvent) => {
    for (const handlers of nodeList.values()) {
      for (const { documentHandler } of handlers) {
        documentHandler(e, startClick)
      }
    }
  })
}

function createDocumentHandler(
  el: HTMLElement,
  binding: DirectiveBinding,
): DocumentHandler {
  let excludes: HTMLElement[] = []
  if (Array.isArray(binding.arg)) {
    excludes = binding.arg
  } else if (binding.arg as unknown instanceof HTMLElement) {
    // due to current implementation on binding type is wrong the type casting is necessary here
    excludes.push(binding.arg as unknown as HTMLElement)
  }
  return function(mouseup, mousedown) {
    const popperRef = (binding.instance as ComponentPublicInstance<{
      popperRef: Nullable<HTMLElement>
    }>).popperRef
    const mouseUpTarget = mouseup.target as Node
    const mouseDownTarget = mousedown?.target as Node
    const isBound = !binding || !binding.instance
    const isTargetExists = !mouseUpTarget || !mouseDownTarget
    const isContainedByEl = el.contains(mouseUpTarget) || el.contains(mouseDownTarget)
    const isSelf = el === mouseUpTarget

    const isTargetExcluded =
      ( excludes.length &&
        excludes.some(item => item?.contains(mouseUpTarget))
      ) || (
        excludes.length && excludes.includes(mouseDownTarget as HTMLElement)
      )
    const isContainedByPopper = (
      popperRef &&
      (
        popperRef.contains(mouseUpTarget) ||
          popperRef.contains(mouseDownTarget)
      )
    )
    if (
      isBound ||
      isTargetExists ||
      isContainedByEl ||
      isSelf ||
      isTargetExcluded ||
      isContainedByPopper
    ) {
      return
    }
    binding.value(mouseup, mousedown)
  }
}

const ClickOutside: ObjectDirective = {
  beforeMount(el, binding) {
    // there could be multiple handlers on the element
    if (!nodeList.has(el)) {
      nodeList.set(el, [])
    }

    nodeList.get(el).push({
      documentHandler: createDocumentHandler(el, binding),
      bindingFn: binding.value,
    })
  },
  updated(el, binding) {
    if (!nodeList.has(el)) {
      nodeList.set(el, [])
    }

    const handlers = nodeList.get(el)
    const oldHandlerIndex = handlers.findIndex(item => (item.bindingFn === binding.oldValue))
    const newHandler = {
      documentHandler: createDocumentHandler(el, binding),
      bindingFn: binding.value,
    }

    if (oldHandlerIndex >= 0) {
      // replace the old handler to the new handler
      handlers.splice(oldHandlerIndex, 1, newHandler)
    } else {
      handlers.push(newHandler)
    }
  },
  unmounted(el) {
    // remove all listeners when a component unmounted
    nodeList.delete(el)
  },
}

export default ClickOutside