const hasProp = (instance, prop) => {
  const $options = instance.$options || {}
  const propsData = $options.propsData || {}
  return prop in propsData
}
const slotHasProp = (slot, prop) => {
  const $options = slot.componentOptions || {}
  const propsData = $options.propsData || {}
  return prop in propsData
}
const filterProps = (props, propsData = {}) => {
  const res = {}
  Object.keys(props).forEach((k) => {
    if (k in propsData || props[k] !== undefined) {
      res[k] = props[k]
    }
  })
  return res
}
const getSlotOptions = (ele) => {
  let componentOptions = ele.componentOptions
  if (ele.$vnode) {
    componentOptions = ele.$vnode.componentOptions
  }
  return componentOptions ? componentOptions.Ctor.options || {} : {}
}
const getOptionProps = (instance) => {
  const { $options = {}, $props = {}} = instance
  return filterProps($props, $options.propsData)
}

const getComponentFromProp = (instance, prop) => {
  if (instance.$createElement) {
    const h = instance.$createElement
    const temp = instance[prop]
    if (temp !== undefined) {
      return typeof temp === 'function' ? temp(h) : temp
    }
    return instance.$slots[prop]
  } else {
    const h = instance.context.$createElement
    const temp = getPropsData(instance)[prop]
    if (temp !== undefined) {
      return typeof temp === 'function' ? temp(h) : temp
    }
    const slotsProp = []
    const componentOptions = instance.componentOptions || {};
    (componentOptions.children || []).forEach((child) => {
      if (child.data && child.data.slot === prop) {
        slotsProp.push(child)
      }
    })
    return slotsProp.length ? slotsProp : undefined
  }
}

const getPropsData = (ele) => {
  let componentOptions = ele.componentOptions
  if (ele.$vnode) {
    componentOptions = ele.$vnode.componentOptions
  }
  return componentOptions ? componentOptions.propsData || {} : {}
}
const getValueByProp = (ele, prop) => {
  return getPropsData(ele)[prop]
}

const getAttrs = (ele) => {
  let data = ele.data
  if (ele.$vnode) {
    data = ele.$vnode.data
  }
  return data ? data.attrs || {} : {}
}

const getKey = (ele) => {
  let key = ele.key
  if (ele.$vnode) {
    key = ele.$vnode.key
  }
  return key
}

export function getEvents (child) {
  let events = {}
  if (child.componentOptions && child.componentOptions.listeners) {
    events = child.componentOptions.listeners
  } else if (child.data && child.data.on) {
    events = child.data.on
  }
  return { ...events }
}
export function getClass (ele) {
  let data = {}
  if (ele.data) {
    data = ele.data
  } else if (ele.$vnode && ele.$vnode.data) {
    data = ele.$vnode.data
  }
  return data.class || data.staticClass
}
export function getStyle (ele) {
  let data = {}
  if (ele.data) {
    data = ele.data
  } else if (ele.$vnode && ele.$vnode.data) {
    data = ele.$vnode.data
  }
  return data.style || data.staticStyle
}

export function getComponentName (opts) {
  return opts && (opts.Ctor.options.name || opts.tag)
}

export function isValidElement (ele) {
  return !!ele.tag
}

export function isEmptyElement (ele) {
  return !(ele.tag || ele.text.trim() !== '')
}

export function filterEmpty (children = []) {
  return children.filter(c => c.tag || c.text.trim() !== '')
}
export {
  hasProp,
  filterProps,
  getOptionProps,
  getComponentFromProp,
  getSlotOptions,
  slotHasProp,
  getPropsData,
  getKey,
  getAttrs,
  getValueByProp,
}
export default hasProp