import type { Article, Category } from '#shared/types/blog'

interface RawCategory extends Category {
  nameEn?: string | null
}

interface RawArticle {
  id: string
  title: string
  titleEn: string | null
  slug: string
  publishedAt: string
  content: string | null
  contentEn: string | null
  cover: string
  coverAlt: string | null
  coverAltEn: string | null
  authorName: string | null
  expand?: { category?: RawCategory }
}

export default defineEventHandler(async (event): Promise<Article> => {
  const slug = getRouterParam(event, 'slug')

  if (!slug) {
    throw createError({ statusCode: 400, statusMessage: 'Missing article slug' })
  }

  const lang = langParam(getQuery(event).lang)

  const response = await pbFetch<PbList<RawArticle>>(
    `/api/collections/articles/records?fields=${ARTICLE_DETAIL_FIELDS}&expand=category&filter=${encodeURIComponent(`slug = ${quote(slug)}`)}&${pagination(1, 1)}`
  )

  const article = response.items[0]

  if (!article) {
    throw createError({ statusCode: 404, statusMessage: 'Article not found' })
  }

  const hasTranslation = Boolean(article.titleEn && article.contentEn)

  // An /en/ request for an article with no translation yet 404s cleanly,
  // rather than silently falling back to Italian text on an English URL —
  // see docs/content-model.md.
  if (lang === 'en' && !hasTranslation) {
    throw createError({ statusCode: 404, statusMessage: 'Article not found' })
  }

  const title = lang === 'en' ? article.titleEn! : article.title
  const content = lang === 'en' ? article.contentEn : article.content
  const coverAlt = lang === 'en' ? article.coverAltEn || article.coverAlt : article.coverAlt
  const category = article.expand?.category
    ? {
        name:
          lang === 'en'
            ? article.expand.category.nameEn || article.expand.category.name
            : article.expand.category.name,
        slug: article.expand.category.slug,
      }
    : null

  return {
    title,
    slug: article.slug,
    publishedAt: article.publishedAt,
    cover: toMediaImage('articles', article.id, article.cover, coverAlt),
    category,
    html: renderMarkdown(content),
    summary: summarise(content),
    author: article.authorName || null,
    hasTranslation,
  }
})