import type { ArticleSummary, Category, Paginated } from '#shared/types/blog'
import type { Locale } from '#shared/utils/locale'

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

interface RawArticleSummary {
  id: string
  title: string
  titleEn: string | null
  slug: string
  publishedAt: string
  cover: string
  coverAlt: string | null
  coverAltEn: string | null
  expand?: { category?: RawCategory }
}

function toSummary(raw: RawArticleSummary, lang: Locale): ArticleSummary {
  const title = lang === 'en' ? raw.titleEn || raw.title : raw.title
  const coverAlt = lang === 'en' ? raw.coverAltEn || raw.coverAlt : raw.coverAlt
  const category = raw.expand?.category
    ? {
        name: lang === 'en' ? raw.expand.category.nameEn || raw.expand.category.name : raw.expand.category.name,
        slug: raw.expand.category.slug,
      }
    : null

  return {
    title,
    slug: raw.slug,
    publishedAt: raw.publishedAt,
    cover: toMediaImage('articles', raw.id, raw.cover, coverAlt),
    category,
  }
}

export default defineEventHandler(async (event): Promise<Paginated<ArticleSummary>> => {
  const query = getQuery(event)
  const page = pageParam(query.page)
  const lang = langParam(query.lang)
  const category = typeof query.category === 'string' ? query.category : null

  const filters = []
  if (category) filters.push(`category.slug = ${quote(category)}`)
  // An English listing only ever shows articles that have actually been
  // translated — never a partial/fallback entry, see docs/content-model.md.
  if (lang === 'en') filters.push(`titleEn != ''`)
  const filter = filters.length ? `&filter=${encodeURIComponent(filters.join(' && '))}` : ''

  const response = await pbFetch<PbList<RawArticleSummary>>(
    `/api/collections/articles/records?fields=${ARTICLE_SUMMARY_FIELDS}&expand=category&sort=-publishedAt&${pagination(page)}${filter}`
  )

  return {
    items: response.items.map((raw) => toSummary(raw, lang)),
    page: response.page,
    pageCount: response.totalPages,
    total: response.totalItems,
  }
})