const maxField = 8192
const maxSummary = 16384
const maxDescription = 16384
const boundedString = (x: string | undefined, length: number) =>
  x ? (x.length > length ? x.substring(0, length) : x) : x

function scraper(
  url: string,
  item: FeedParser.Item,
  context: ScraperContext,
) {
  const meta: { [key: string]: any } = item.meta
  let locale = item.language
  if (locale) locale = locale.toLowerCase()
  if (context.options?.debugRSS) {
    console.log('FeedParser.Item:')
    console.log(item)
  }

  const props: Props = {}
  if (item.title) props.title = boundedString(item.title, maxField)
  if (item.author) props.author = boundedString(item.author, maxField)
  if (item.summary) props.summary = boundedString(item.summary, maxSummary)
  if (item.description) props.description = boundedString(item.description, maxDescription)
  if (item.image?.title) props.imageTitle = boundedString(item.image.title, maxField)
  if (item.image?.url) props.imageUrl = boundedString(item.image.url, maxField)
  if (item.comments) props.commentsUrl = boundedString(item.comments, maxField)
  if (item.enclosures) {
    for (const enclosure of item.enclosures) {
      if (enclosure.url && enclosure.type?.startsWith('video') && !props.videoUrl) {
        props.videoUrl = boundedString(enclosure.url, maxField)
      } else if (enclosure.url && enclosure.type?.startsWith('audio') && !props.audioUrl) {
        props.audioUrl = boundedString(enclosure.url, maxField)
      } else if (enclosure.url && enclosure.type?.startsWith('image') && !props.imageUrl) {
        props.imageUrl = boundedString(enclosure.url, maxField)
      }
    }
  }

  const news = {
    date: item.pubdate || item.date || new Date(),
    link: boundedString(item.link ?? props.videoUrl ?? props.audioUrl, maxField),
    feed: boundedString(url, maxField),
    guid: boundedString(item.guid || item.link, maxField) || '',
    props,
    tags: {
      ...context.options?.tags,
      locale: boundedString(context.options?.tags?.locale || locale, maxField),
      category: boundedString(context.options?.tags?.category || '', maxField),
    },
  }
  if ((item.categories?.length ?? 0) > 0) {
    news.tags.topics = [ ...item.categories ]
  }
  if (!news.props.imageUrl) {
    news.props.imageUrl = scanHtmlForImage(news.props.description || '')
  }
  if (!news.props.imageUrl) {
    news.props.imageUrl = scanHtmlForImage(news.props.summary || '')
  }
  if (!news.props.imageUrl) delete news.props.imageUrl
  if (context.options?.props?.imageUrl) {
    news.props.feedImageUrl = context.options.props.imageUrl
  }
  if (context.options?.props?.name) {
    news.props.feedName = context.options.props.name
  }

  const feedProps = context.options?.props
  if (feedProps) {
    if (!feedProps.name && meta?.title) feedProps.name = meta.title
    if (!feedProps.description && meta?.description) feedProps.description = meta.description
    if (!feedProps.imageUrl && meta?.image?.url) feedProps.imageUrl = meta.image.url
    if (!feedProps.site && meta?.link) feedProps.site = meta.link
  }

  if (!context.functions) throw new Error('Expected context functions')
  return context.functions.prepare(news, context.options)
}