import { createVNode, render } from 'vue'
import { isClient } from '@vueuse/core'
import {
  debugWarn,
  isElement,
  isFunction,
  isNumber,
  isObject,
  isString,
  isVNode,
} from '@element-plus/utils'
import { useZIndex } from '@element-plus/hooks'
import { messageConfig } from '@element-plus/components/config-provider/src/config-provider'
import MessageConstructor from './message.vue'
import { messageTypes } from './message'

import type { AppContext, ComponentPublicInstance, VNode } from 'vue'
import type { Message, MessageFn, MessageProps, MessageQueue } from './message'

const instances: MessageQueue = []
let seed = 1

// TODO: Since Notify.ts is basically the same like this file. So we could do some encapsulation against them to reduce code duplication.

const message: MessageFn & Partial<Message> & { _context: AppContext | null } =
  function (options = {}, context?: AppContext | null) {
    if (!isClient) return { close: () => undefined }
    if (isNumber(messageConfig.max) && instances.length >= messageConfig.max) {
      return { close: () => undefined }
    }

    if (
      !isVNode(options) &&
      isObject(options) &&
      options.grouping &&
      !isVNode(options.message) &&
      instances.length
    ) {
      const tempVm: any = instances.find(
        (item) =>
          `${item.vm.props?.message ?? ''}` ===
          `${(options as any).message ?? ''}`
      )
      if (tempVm) {
        tempVm.vm.component!.props.repeatNum += 1
        tempVm.vm.component!.props.type = options?.type || 'info'
        return {
          close: () =>
            ((
              vm.component!.proxy as ComponentPublicInstance<{
                visible: boolean
              }>
            ).visible = false),
        }
      }
    }

    if (isString(options) || isVNode(options)) {
      options = { message: options }
    }

    let verticalOffset = options.offset || 20
    instances.forEach(({ vm }) => {
      verticalOffset += (vm.el?.offsetHeight || 0) + 16
    })
    verticalOffset += 16

    const { nextZIndex } = useZIndex()

    const id = `message_${seed++}`
    const userOnClose = options.onClose
    const props: Partial<MessageProps> = {
      zIndex: nextZIndex(),
      ...options,
      offset: verticalOffset,
      id,
      onClose: () => {
        close(id, userOnClose)
      },
    }

    let appendTo: HTMLElement | null = document.body
    if (isElement(options.appendTo)) {
      appendTo = options.appendTo
    } else if (isString(options.appendTo)) {
      appendTo = document.querySelector(options.appendTo)
    }
    // should fallback to default value with a warning
    if (!isElement(appendTo)) {
      debugWarn(
        'ElMessage',
        'the appendTo option is not an HTMLElement. Falling back to document.body.'
      )
      appendTo = document.body
    }

    const container = document.createElement('div')

    container.className = `container_${id}`

    const messageContent = props.message
    const vm = createVNode(
      MessageConstructor,
      props,
      isFunction(messageContent)
        ? { default: messageContent }
        : isVNode(messageContent)
        ? { default: () => messageContent }
        : null
    )

    vm.appContext = context || message._context

    // clean message element preventing mem leak
    vm.props!.onDestroy = () => {
      render(null, container)
      // since the element is destroy, then the VNode should be collected by GC as well
      // we do not want cause any mem leak because we have returned vm as a reference to users
      // so that we manually set it to false.
    }

    render(vm, container)
    // instances will remove this item when close function gets called. So we do not need to worry about it.
    instances.push({ vm })
    appendTo.appendChild(container.firstElementChild!)

    return {
      // instead of calling the onClose function directly, setting this value so that we can have the full lifecycle
      // for out component, so that all closing steps will not be skipped.
      close: () =>
        ((
          vm.component!.proxy as ComponentPublicInstance<{ visible: boolean }>
        ).visible = false),
    }
  }

messageTypes.forEach((type) => {
  message[type] = (options = {}, appContext?: AppContext | null) => {
    if (isString(options) || isVNode(options)) {
      options = {
        message: options,
      }
    }
    return message(
      {
        ...options,
        type,
      },
      appContext
    )
  }
})

export function close(id: string, userOnClose?: (vm: VNode) => void): void {
  const idx = instances.findIndex(({ vm }) => id === vm.component!.props.id)
  if (idx === -1) return

  const { vm } = instances[idx]
  if (!vm) return
  userOnClose?.(vm)

  const removedHeight = vm.el!.offsetHeight
  instances.splice(idx, 1)

  // adjust other instances vertical offset
  const len = instances.length
  if (len < 1) return
  for (let i = idx; i < len; i++) {
    const pos =
      Number.parseInt(instances[i].vm.el!.style['top'], 10) - removedHeight - 16

    instances[i].vm.component!.props.offset = pos
  }
}

export function closeAll(): void {
  for (let i = instances.length - 1; i >= 0; i--) {
    const instance = instances[i].vm.component
    ;(instance?.proxy as any)?.close()
  }
}

message.closeAll = closeAll
message._context = null

export default message as Message