import React, { useState, useEffect, useCallback } from 'react'
import { useTheme } from 'next-themes'

import siteMetadata from '@/data/siteMetadata'

interface Props {
  mapping: string
}

const Giscus = ({ mapping }: Props) => {
  const [enableLoadComments, setEnabledLoadComments] = useState(true)
  const { theme, resolvedTheme } = useTheme()
  const commentsTheme =
    siteMetadata.comment.giscusConfig.themeURL === ''
      ? theme === 'dark' || resolvedTheme === 'dark'
        ? siteMetadata.comment.giscusConfig.darkTheme
        : siteMetadata.comment.giscusConfig.theme
      : siteMetadata.comment.giscusConfig.themeURL

  const COMMENTS_ID = 'comments-container'

  const LoadComments = useCallback(() => {
    setEnabledLoadComments(false)
    const script = document.createElement('script')
    script.src = 'https://giscus.app/client.js'
    script.setAttribute('data-repo', siteMetadata.comment.giscusConfig.repo)
    script.setAttribute('data-repo-id', siteMetadata.comment.giscusConfig.repositoryId)
    script.setAttribute('data-category', siteMetadata.comment.giscusConfig.category)
    script.setAttribute('data-category-id', siteMetadata.comment.giscusConfig.categoryId)
    script.setAttribute('data-mapping', mapping)
    script.setAttribute('data-reactions-enabled', siteMetadata.comment.giscusConfig.reactions)
    script.setAttribute('data-emit-metadata', siteMetadata.comment.giscusConfig.metadata)
    script.setAttribute('data-theme', commentsTheme)
    script.setAttribute('crossorigin', 'anonymous')
    script.async = true

    const comments = document.getElementById(COMMENTS_ID)
    if (comments) comments.appendChild(script)

    return () => {
      const comments = document.getElementById(COMMENTS_ID)
      if (comments) comments.innerHTML = ''
    }
  }, [commentsTheme, mapping])

  // Reload on theme change
  useEffect(() => {
    const iframe = document.querySelector('iframe.giscus-frame')
    if (!iframe) return
    LoadComments()
  }, [LoadComments])

  return (
    <div className="pt-6 pb-6 text-center text-gray-700 dark:text-gray-300">
      {enableLoadComments && <button onClick={LoadComments}>Load Comments</button>}
      <div className="giscus" id={COMMENTS_ID} />
    </div>
  )
}

export default Giscus