// Strapi product thumbnails for picking surfaces — batched (max 5 concurrent), cached
// per product for the whole session, fail-soft (no image = caller shows a placeholder).
//
// The /api/processes/inouts/{docNo} response $expands m_product_id without $select, so
// every shipment line already carries M_Product_ID.Strapi_Product_documentId — no extra
// iDempiere lookups are needed, only the two Strapi gallery calls per product.

const thumbs = ref<Record<string, string>>({})     // productId -> resolved image URL (shared)
const requested = new Set<string>()                // productIds already requested (incl. failures)

export const useProductThumbs = () => {
  const config = useRuntimeConfig()

  const fetchOne = async (strapiDocumentId: string, productId: string) => {
    try {
      const [strapiProductRes, imagesRes]: any[] = await Promise.all([
        $fetch(`/api/materials/products/${strapiDocumentId}/galleries`, { headers: useRequestHeaders(['cookie']) }),
        $fetch(`/api/materials/products/${strapiDocumentId}/galleries/images`, { headers: useRequestHeaders(['cookie']) }),
      ])
      if (!imagesRes?.length) return
      let mainImage = imagesRes[0]
      if (strapiProductRes?.data?.Main_Image && strapiProductRes.data.Main_Image != 0) {
        const foundMain = imagesRes.find((img: any) => img.id == strapiProductRes.data.Main_Image)
        if (foundMain) mainImage = foundMain
      }
      let imageUrl: string | null = null
      if (mainImage?.formats?.small) {
        imageUrl = config.public.strapi + '/files-api/' + mainImage.formats.small.hash + mainImage.formats.small.ext
      } else if (mainImage?.formats?.thumbnail) {
        imageUrl = config.public.strapi + '/files-api/' + mainImage.formats.thumbnail.hash + mainImage.formats.thumbnail.ext
      } else if (mainImage?.url) {
        imageUrl = config.public.strapi + mainImage.url
      }
      if (imageUrl) thumbs.value = { ...thumbs.value, [productId]: imageUrl }
    } catch (err: any) {
      console.error('[useProductThumbs] product image error:', err?.data ?? err)
    }
  }

  // Load thumbnails for every distinct product of the given lines (once per product).
  const fetchForLines = async (lines: any[]) => {
    const unique = new Map<string, string>()
    for (const line of lines || []) {
      const product = line?.M_Product_ID ?? line
      const pid = product?.id != null ? String(product.id) : ''
      const docId = product?.Strapi_Product_documentId
      if (pid && docId && !requested.has(pid) && !unique.has(pid)) unique.set(pid, docId)
    }
    const entries = [...unique.entries()]
    for (let i = 0; i < entries.length; i += 5) {
      await Promise.all(entries.slice(i, i + 5).map(([pid, docId]) => {
        requested.add(pid)
        return fetchOne(docId, pid)
      }))
    }
  }

  // Image source for a product: Strapi first, legacy M_Product.ImageURL fallback.
  const thumbFor = (product: any): string | null => {
    if (!product) return null
    const pid = product.id != null ? String(product.id) : ''
    return (pid && thumbs.value[pid]) || product.ImageURL || null
  }

  return { thumbs, fetchForLines, thumbFor }
}