/* @flow */

import { callHook } from 'core/instance/lifecycle'

import { getFirstComponentChild } from 'core/vdom/helpers/index'

const patternTypes = [String, RegExp]

function matches (pattern: string | RegExp, name: string): boolean {

  if (typeof pattern === 'string') {

    return pattern.split(',').indexOf(name) > -1

  } else {

    return pattern.test(name)

  }

}

export default {

  name: 'keep-alive',

  abstract: true,

  props: {

    include: patternTypes,

    exclude: patternTypes

  },

  created () {

    this.cache = Object.create(null)

  },

  render () {

    const vnode: VNode = getFirstComponentChild(this.$slots.default)

    if (vnode && vnode.componentOptions) {

      const opts: VNodeComponentOptions = vnode.componentOptions

      // check pattern

      const name = opts.Ctor.options.name || opts.tag

      if (name && (

        (this.include && !matches(this.include, name)) ||

        (this.exclude && matches(this.exclude, name))

      )) {

        return vnode

      }

      const key = vnode.key == null

        // same constructor may get registered as different local components

        // so cid alone is not enough (#3269)

        ? opts.Ctor.cid + (opts.tag ? `::${opts.tag}` : '')

        : vnode.key

      if (this.cache[key]) {

        vnode.child = this.cache[key].child

      } else {

        this.cache[key] = vnode

      }

      vnode.data.keepAlive = true

    }

    return vnode

  },

  destroyed () {

    for (const key in this.cache) {

      const vnode = this.cache[key]

      callHook(vnode.child, 'deactivated')

      vnode.child.$destroy()

    }

  }

}