import React, { useState, useEffect } from "react"
import { Helmet } from "react-helmet"

const Seo = ({location}) => {
  const [refreshContent, setRefreshContent] = useState()

  useEffect(() => {
    if (location.host.endsWith("gatsbyjs.io")) {
      const urlRedirect = `http://example.com${location.pathname}${location.search}`

      setRefreshContent(`0;URL="${urlRedirect}"`)
    } else {
      setRefreshContent(undefined)
    }
  }, [location])

  let metaDatas = [
    {
      property: "og:site_name",
      content: "xxxxx",
    },
    {
      property: "og:locale",
      content: "ja",
    },
    中略
  ]

  if (refreshContent !== undefined) {
    metaDatas = metaDatas.concat([
      {
        "http-equiv": "refresh",
        content: refreshContent,
      },
    ])
  }

  return (
    <Helmet
      htmlAttributes={{
        lang: "ja",
        prefix: "og: http://ogp.me/ns#",
      }}
      title="xxxxx"
      meta={metaDatas}
    >
    </Helmet>
  )
}
export default Seo