"use client";

import { AnimatePresence, motion } from "motion/react";
import Link from "next/link";
import { HexCheck } from "@/components/honeycomb";
import { Container, SectionHeading, LinkButton } from "@/components/ui";
import { TrustBadges } from "@/components/trust-badges";
import { CartItemThumbnail } from "@/components/cart-item-thumbnail";
import { QuantityStepper } from "@/components/quantity-stepper";
import { ProductCard } from "@/components/product-card";
import { useCartStore, cartTotalCents, cartPhysicalQuantity, cartDiscountBase } from "@/store/cart-store";
import { SponsorshipLineDetails, SponsorshipThumb } from "@/components/sponsorship-cart-line";
import { getSponsorshipShopStrings } from "@/i18n/sponsorship/shop";
import WarenkorbLoading from "./loading";
import { useCartStock } from "@/hooks/use-cart-stock";
import { formatPrice } from "@/lib/format";
import { resolveShippingCostCents, getNextShippingTier, type ShippingTierLike } from "@/lib/shipping-calc";
import { resolveBulkDiscount, getNextBulkDiscountTier, type BulkDiscountTierLike } from "@/lib/bulk-discount-calc";
import { useI18n } from "@/i18n/i18n-provider";
import type { ProductWithRelations } from "@/lib/data";

const CROSS_SELL_LIMIT = 3;

export function WarenkorbContent({
  tiers,
  availableProducts,
  bulkDiscountTiers,
}: {
  tiers: ShippingTierLike[];
  availableProducts: ProductWithRelations[];
  bulkDiscountTiers: BulkDiscountTierLike[];
}) {
  const { t, locale } = useI18n();
  const sponsorshipStrings = getSponsorshipShopStrings(locale);
  const items = useCartStore((s) => s.items);
  const hasHydrated = useCartStore((s) => s.hasHydrated);
  const setQuantity = useCartStore((s) => s.setQuantity);
  const removeItem = useCartStore((s) => s.removeItem);
  // Live-Bestand je Position — derselbe Hinweis wie auf der Produktkarte/
  // -detailseite, aber hier fuer den ggf. seit dem Hinzufuegen veraenderten
  // aktuellen Bestand (siehe use-cart-stock.ts).
  const stock = useCartStock([...new Set(items.map((item) => item.productId))]);
  const subtotal = cartTotalCents(items);
  // Gesamtmenge ueber alle Positionen hinweg — mehrere verschiedene Artikel
  // werden fuer die Versandstaffel zusammengezaehlt, nicht getrennt bewertet.
  // Nur Glaeser zaehlen: eine Urkunde ohne Paket loest keinen Versand aus
  // (wie physicalQuantity im Checkout-Server).
  const totalQuantity = cartPhysicalQuantity(items);
  const hasPhysical = totalQuantity > 0;
  const shipping = !hasPhysical ? 0 : resolveShippingCostCents(tiers, totalQuantity);
  const nextTier = !hasPhysical ? null : getNextShippingTier(tiers, totalQuantity);
  // Live-Vorschau des serverseitig in api/checkout/route.ts automatisch
  // angewendeten Mengenrabatts — Hoehe/Menge kommen aus den im Admin-Bereich
  // (Gutscheine) gepflegten DiscountCode-Zeilen, nicht mehr aus Konstanten.
  // Basis ohne Patenschaftspakete, wie im Server (discountBase).
  const discountable = cartDiscountBase(items);
  const hasDiscountable = discountable.quantity > 0;
  const activeBulkDiscount = !hasDiscountable ? null : resolveBulkDiscount(bulkDiscountTiers, discountable.quantity);
  const bulkDiscountCents = activeBulkDiscount
    ? Math.round((discountable.subtotalCents * activeBulkDiscount.percent) / 100)
    : 0;
  const nextBulkDiscount = !hasDiscountable ? null : getNextBulkDiscountTier(bulkDiscountTiers, discountable.quantity);

  const cartProductIds = new Set(items.map((item) => item.productId));
  const crossSellProducts = availableProducts
    .filter((product) => !cartProductIds.has(product.id))
    .slice(0, CROSS_SELL_LIMIT);
  // Fuer den leeren Warenkorb: Honig zuerst, sonst was gerade verfuegbar ist.
  const honeyFirst = availableProducts.filter((product) => product.category === "HONIG");
  const emptyCartSuggestions = (honeyFirst.length > 0 ? honeyFirst : availableProducts).slice(0, 2);

  // Siehe checkout-form.tsx: ohne diese Weiche flackert kurz die
  // "leer"-Meldung auf, bevor der Cart-Store aus localStorage nachliest.
  if (!hasHydrated) {
    return <WarenkorbLoading />;
  }

  return (
    <div className="py-16">
      <Container>
        <SectionHeading title={t.cartPage.title} />

        {items.length === 0 ? (
          // Leerer Warenkorb ist kein Endpunkt: daneben stehen die aktuell
          // verfuegbaren Honige, statt nur eines Satzes und eines Knopfs.
          <div className="mt-14 grid gap-12 lg:grid-cols-12 lg:gap-16">
            <div className="lg:col-span-4">
              <p className="font-serif text-2xl leading-snug text-heading">{t.cart.empty}</p>
              <LinkButton href="/shop" variant="secondary" className="mt-6">
                {t.cartPage.goToShop}
              </LinkButton>
            </div>
            {emptyCartSuggestions.length > 0 ? (
              <div className="grid grid-cols-1 gap-x-8 gap-y-14 sm:grid-cols-2 lg:col-span-8">
                {emptyCartSuggestions.map((product, index) => (
                  <ProductCard key={product.id} product={product} index={index} />
                ))}
              </div>
            ) : null}
          </div>
        ) : (
          <div className="mt-14 grid lg:grid-cols-3 gap-14">
            <div className="lg:col-span-2 divide-y divide-ink/10 border-y border-ink/10">
              <AnimatePresence initial={false}>
              {items.map((item) => {
                const itemStock = stock?.[item.productId];
                const sponsorship = item.sponsorship;
                return (
                  <motion.div
                    key={item.key}
                    layout
                    initial={{ opacity: 0, y: 12 }}
                    animate={{ opacity: 1, y: 0 }}
                    exit={{ opacity: 0, x: 40, transition: { duration: 0.2 } }}
                    className="py-6 flex flex-wrap items-center gap-x-6 gap-y-3"
                  >
                    {sponsorship ? (
                      <SponsorshipThumb className="w-20 h-20" />
                    ) : (
                      <CartItemThumbnail image={item.image} className="w-20 h-20 flex-shrink-0 rounded-lg" />
                    )}
                    <div className="flex-1 min-w-[160px]">
                      <Link
                        href={sponsorship ? "/patenschaft" : `/honig/${item.slug}`}
                        className="link-draw pb-0.5 font-serif text-2xl text-heading"
                      >
                        {item.name}
                      </Link>
                      {sponsorship ? (
                        <SponsorshipLineDetails sponsorship={sponsorship} className="mt-1 text-sm text-ink/65" />
                      ) : (
                        <p className="text-sm text-ink/65">{item.weightGrams} g</p>
                      )}
                      {/* Siehe Kommentar im Cart-Drawer (site-chrome.tsx): persistenter
                          aria-live-Wrapper, damit der erst nach dem ersten Rendern
                          eintreffende Live-Bestand als Ansage bei Screenreadern ankommt. */}
                      <div aria-live="polite">
                        {itemStock !== undefined && itemStock === 0 ? (
                          <p className="mt-1 text-xs text-red-700">
                            {sponsorship ? sponsorshipStrings.cart.soldOut : t.product.outOfStock}
                          </p>
                        ) : !sponsorship && itemStock !== undefined && itemStock <= 5 ? (
                          <p className="mt-1 text-xs text-honey-dark">{t.product.onlyLeft(itemStock)}</p>
                        ) : null}
                      </div>
                    </div>
                    <div className="flex items-center gap-4 ml-auto">
                      {/* Patenschaften: Menge fest 1 — jede hat ihre eigene Urkunde. */}
                      {sponsorship ? null : (
                        <QuantityStepper
                          quantity={item.quantity}
                          onChange={(quantity) => setQuantity(item.key, quantity)}
                          max={itemStock ?? 10}
                        />
                      )}
                      <span className="w-24 text-right font-serif text-xl text-heading tabular-nums">
                        {formatPrice(item.priceCents * item.quantity, "EUR", locale)}
                      </span>
                      <button
                        onClick={() => removeItem(item.key)}
                        aria-label={t.cart.remove}
                        className="flex h-11 w-11 items-center justify-center text-ink/55 transition-[color,transform] duration-300 hover:rotate-90 hover:text-red-700"
                      >
                        <svg viewBox="0 0 24 24" className="h-4 w-4" fill="none" stroke="currentColor" strokeWidth="1.6" aria-hidden="true">
                          <path d="M6 6l12 12M18 6L6 18" strokeLinecap="round" />
                        </svg>
                      </button>
                    </div>
                  </motion.div>
                );
              })}
              </AnimatePresence>
            </div>

            <div className="border border-ink/10 bg-background p-8 h-fit lg:sticky lg:top-28">
              <div className="space-y-3 text-sm">
                <div className="flex justify-between">
                  <span>{t.cart.subtotal}</span>
                  <span className="tabular-nums">{formatPrice(subtotal, "EUR", locale)}</span>
                </div>
                <div className="flex justify-between">
                  <span>{hasPhysical ? t.cartPage.shippingLabel(totalQuantity) : sponsorshipStrings.checkout.digitalShipping}</span>
                  <span className="tabular-nums">{shipping === 0 ? t.cartPage.free : formatPrice(shipping, "EUR", locale)}</span>
                </div>
                {nextTier && nextTier.unitsUntilNext <= 2 ? (
                  <p className="text-xs text-ink/70">
                    {t.cartPage.nextTierHint(nextTier.unitsUntilNext, formatPrice(nextTier.priceCents, "EUR", locale))}
                  </p>
                ) : null}
                {activeBulkDiscount ? (
                  <motion.div
                    initial={{ opacity: 0, scale: 0.96 }}
                    animate={{ opacity: 1, scale: 1 }}
                    transition={{ type: "spring", stiffness: 380, damping: 22 }}
                    className="flex items-center justify-between rounded-sm bg-honey/10 px-3 py-2 text-heading"
                  >
                    <span className="flex items-center gap-2">
                      <HexCheck className="h-4 w-4 text-honey-dark" />
                      {t.cartPage.discountLabel} ({activeBulkDiscount.percent}%)
                    </span>
                    <span className="tabular-nums">-{formatPrice(bulkDiscountCents, "EUR", locale)}</span>
                  </motion.div>
                ) : nextBulkDiscount && nextBulkDiscount.unitsUntilNext <= 2 ? (
                  // Der Weg zum Mengenrabatt als Glas, das sich mit jedem
                  // weiteren Stueck fuellt — nicht nur als Kleingedrucktes.
                  <div className="rounded-sm bg-honey/[0.07] px-3 py-3">
                    <p className="text-xs text-ink/75">
                      {t.cartPage.bulkDiscountProgress(nextBulkDiscount.unitsUntilNext, nextBulkDiscount.percent)}
                    </p>
                    <div aria-hidden="true" className="mt-2 h-1.5 overflow-hidden rounded-full bg-ink/10">
                      <motion.div
                        className="h-full rounded-full bg-gradient-to-r from-honey-dark to-honey"
                        initial={false}
                        animate={{
                          width: `${(totalQuantity / (totalQuantity + nextBulkDiscount.unitsUntilNext)) * 100}%`,
                        }}
                        transition={{ type: "spring", stiffness: 120, damping: 20 }}
                      />
                    </div>
                  </div>
                ) : null}
                <div className="flex items-baseline justify-between text-heading pt-4 border-t border-ink/10">
                  <span className="text-base">{t.cartPage.total}</span>
                  <motion.span
                    key={subtotal - bulkDiscountCents + shipping}
                    initial={{ opacity: 0.4, y: -4 }}
                    animate={{ opacity: 1, y: 0 }}
                    className="font-serif text-3xl tabular-nums"
                  >
                    {formatPrice(subtotal - bulkDiscountCents + shipping, "EUR", locale)}
                  </motion.span>
                </div>
              </div>
              <LinkButton href="/checkout" className="w-full mt-6">
                {t.cart.checkout}
              </LinkButton>
              <Link href="/versand-zahlung" className="mt-4 block text-center text-xs text-ink/70 hover:text-heading underline">
                {t.cartPage.pickupHint}
              </Link>
              <TrustBadges className="mt-6 pt-6 border-t border-ink/10" />
            </div>
          </div>
        )}

        {items.length > 0 && crossSellProducts.length > 0 ? (
          <div className="mt-20">
            <h2 className="text-3xl md:text-4xl text-heading mb-10">{t.productPage.relatedProductsHeading}</h2>
            <div className="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-3 gap-x-8 gap-y-14">
              {crossSellProducts.map((product, index) => (
                <ProductCard key={product.id} product={product} index={index} />
              ))}
            </div>
          </div>
        ) : null}
      </Container>
    </div>
  );
}