import { watchEffect, nextTick, effectScope } from "vue";
import { diffArrayChange } from './diff'

import type { EffectScope } from 'vue'

// 一次监听
export const onlyWatchEffect: typeof watchEffect = (cb, options) => {
  const stopWatch = watchEffect((...args) => {
    cb(...args);
    nextTick(stopWatch);
  }, options);
  return stopWatch;
};

export const shallowWatchArray = <T extends any[]>(
  getItems: () => T, 
  cb: (newItems: T, oldItems: T) => void
) => {
  let oldItems = [] as unknown as T
  watchEffect(() => {
    const newItems = getItems()
    cb(newItems, oldItems)
    oldItems = [...newItems] as T
  })
}

export const arrayChildEffectScope = <T extends any[]>(
  getItems: () => T, 
  cb: (item: T[number]) => void
) => {
  const scopes = new WeakMap<T, EffectScope>()
  shallowWatchArray(getItems, (newItems, oldItems) => {
    const { added, deleted } = diffArrayChange(newItems, oldItems)
    for (const addItem of added) {
      const scope = effectScope()
      scope.run(() => {
        cb(addItem)
      })
      scopes.set(addItem, scope)
    }
    for (const delItem of deleted) {
      scopes.get(delItem)?.stop()
    }
  })
}