// Adapts our actual ProductSummary (apps/user-app/src/api/client.ts) into the
// same output shape legacy's Mixins/product/index.ts `useProduct()` produced.
// The legacy card components it was originally shaped for (ProductHorizontal/
// ProductVertical/ProductVerticalFull) are gone, replaced by the redesigned
// components/product/ProductCard.vue, components/home/ShowcaseCard.vue and
// components/product/CartItem.vue — all of which consume this same contract.
//
// Honest gaps vs. legacy (no backend equivalent exists yet — apps/api was not
// touched to add these):
//   - promotions/discounts: legacy matched a customer's order against admin
//     promotion + ignore-list rules (getCandidPromotions/getPromotion). No such
//     data exists in the new API, so `hasDiscountWage` is always null here —
//     the discount badge and "before/after" price never render, which is
//     correct given there is genuinely nothing to show, not a bug.
//   - `wage` now comes from the server (wageQuoteStore), which adds the
//     customer's own percent and the promotion exactly as legacy did.
//   - `is_exist` (stock) and `has_warranty`: no such fields exist on our
//     ProductVariant model yet — always true / false respectively.
import { computed, ref, unref, type Ref } from 'vue'
import type { ProductSummary, ProductVariantSummary } from '../api/client'
import { useSessionStore } from '../stores/session'
import { useWageQuoteStore } from '../stores/wageQuoteStore'

/** A variant can be ordered when it has stock, or when it is flagged pre-order. */
export function isVariantOrderable(v: ProductVariantSummary): boolean {
  return (v.qty ?? 0) > 0 || Boolean(v.isPreOrder)
}

function getCheapestVariant(variants: ProductVariantSummary[] | undefined): ProductVariantSummary | null {
  if (!variants || variants.length === 0) return null
  // Prefer something the customer can actually order: defaulting to an
  // out-of-stock variant means the page opens on a disabled button even though
  // other weights are available. Falls back to the full list when nothing is
  // orderable, so the page still shows a selection.
  const pool = variants.filter(isVariantOrderable)
  const candidates = pool.length ? pool : variants
  return candidates.reduce((cheapest, v) =>
    parseFloat(v.defaultWagePercent) < parseFloat(cheapest.defaultWagePercent) ? v : cheapest,
  )
}

export function useProduct(productItem: ProductSummary, initialVariant?: ProductVariantSummary) {
  const product = ref<ProductSummary>(productItem)
  const image = computed(() => product.value.images?.[0]?.url)
  const id = computed(() => product.value.id)
  const title = computed(() => product.value.title)
  const variants = computed(() => product.value.variants)
  const selectedVariant: Ref<ProductVariantSummary | null> = ref(initialVariant ?? getCheapestVariant(unref(variants)))
  const min_gram = computed(() => selectedVariant.value ? parseFloat(selectedVariant.value.rashWeightGrams) : 0)
  // The making charge the server will charge (MON-08): variant + the
  // customer's own percent − the best active promotion, by the formula the
  // admin «اجرت» screen controls. Signed in: the server's figure, hidden for
  // the moment it loads rather than flashing a different number. Signed out
  // (no customer, so no customer percent): the variant's own figure.
  const session = useSessionStore()
  const wageQuotes = useWageQuoteStore()
  const wage = computed(() => {
    const v = selectedVariant.value
    if (!v) return null
    if (!session.isLoggedIn) return parseFloat(v.defaultWagePercent)
    wageQuotes.request(v.id)
    return wageQuotes.finalPercent(v.id)
  })
  const hasDiscountWage = ref<number | null>(null) // no promotions backend yet — see file header
  // REAL stock: ProductVariant.qty / isPreOrder exist and are returned by
  // GET /catalog/products. A variant is orderable when it has stock, or when
  // it is flagged pre-order — the same rule the admin cart uses.
  const qty = computed(() => selectedVariant.value?.qty ?? 0)
  const isPreOrder = computed(() => selectedVariant.value?.isPreOrder ?? false)
  const is_exist = computed(() => qty.value > 0 || isPreOrder.value)
  const productCode = computed(() => product.value.productCode ?? null)
  const has_warranty = ref(false) // no warranty field on ProductVariant yet

  return {
    product,
    image,
    id,
    title,
    productCode,
    variants,
    selectedVariant,
    min_gram,
    wage,
    hasDiscountWage,
    qty,
    isPreOrder,
    is_exist,
    has_warranty,
  }
}