"use client";

import { useEffect, useMemo, useState } from "react";
import Link from "next/link";
import { ProductImage } from './ProductImage';
import PlatformSwitcher from "./PlatformSwitcher";

const API_BASE_URL = process.env.NEXT_PUBLIC_API_BASE_URL ?? "";

type ProductDetailDto = {
  id: string;
  name: string;
  brand: string;
  platform: string;
  partRole: string;
  categoryKey: string | null;
  price: number | null;
  buyUrl: string | null;
  imageUrl: string | null;
};

function parseIdFromProductSlug(productSlug: string): string | null {
  // Expected: "1217-some-slug"
  const m = /^(\d+)(?:-|$)/.exec(productSlug ?? "");
  return m?.[1] ?? null;
}

/**
 * Attempts to fetch a product detail.
 * If you don't have a dedicated endpoint yet, it falls back to list + filter by id.
 */
async function fetchProductDetail(params: {
  platform: string;
  partRole: string;
  productSlug: string;
}): Promise<ProductDetailDto> {
  const { platform, partRole, productSlug } = params;
  const id = parseIdFromProductSlug(productSlug);

  if (!id) throw new Error(`Invalid product URL slug: '${productSlug}' (could not parse id)`);

  // ---- Preferred (if you add it): GET /api/v1/products/{id}
  // If it 404s, we fall back.
  try {
    const res = await fetch(`/api/catalog/products/${encodeURIComponent(id)}`, {
      headers: { Accept: "application/json" },
      credentials: 'include',
    });

    if (res.ok) {
      return await res.json();
    }
  } catch {
    // ignore and fall back
  }

  // ---- Fallback: use list endpoint + find by id (works right now with your current API)
  const listRes = await fetch(
    `/api/catalog/products?platform=${encodeURIComponent(platform)}&partRoles=${encodeURIComponent(partRole)}`,
    { headers: { Accept: "application/json" }, credentials: 'include' }
  );

  if (!listRes.ok) {
    const txt = await listRes.text().catch(() => "");
    throw new Error(`Failed to load product (fallback) (${listRes.status}): ${txt}`);
  }

  const list: ProductDetailDto[] = await listRes.json();
  const found = list.find((p) => String(p.id) === String(id));

  if (!found) {
    throw new Error(`Product id=${id} not found in ${platform}/${partRole} list`);
  }

  return found;
}

export default function ProductDetailPageClient(props: {
  platform: string;
  partRole: string;
  productSlug: string;
}) {
  const { platform, partRole, productSlug } = props;

  const [p, setP] = useState<ProductDetailDto | null>(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);

  const id = useMemo(() => parseIdFromProductSlug(productSlug), [productSlug]);

  useEffect(() => {
    let cancelled = false;

    async function load() {
      try {
        setLoading(true);
        setError(null);

        const data = await fetchProductDetail({ platform, partRole, productSlug });

        if (!cancelled) setP(data);
      } catch (e: any) {
        if (!cancelled) setError(e?.message ?? "Failed to load product");
      } finally {
        if (!cancelled) setLoading(false);
      }
    }

    load();
    return () => { cancelled = true; };
  }, [platform, partRole, productSlug]);

  return (
    <main className="min-h-screen bg-black text-zinc-50">
      <div className="mx-auto max-w-5xl px-4 py-6 lg:py-10">
        <header className="mb-6 flex flex-col gap-3">
          <div className="flex items-center justify-between gap-4">
            <div>
              <p className="text-xs font-semibold tracking-[0.2em] uppercase text-zinc-500">
                Battl Builders
              </p>
              <h1 className="mt-1 text-2xl md:text-3xl font-semibold tracking-tight">
                Part: <span className="text-amber-300">{partRole}</span>
              </h1>
            </div>

            {/* temp disabling while I rework the routing.  */}
            {/* <PlatformSwitcher currentPlatform={platform} partRole={partRole} /> */}
          </div>

          <div className="flex items-center gap-2 text-xs text-zinc-500">
            <Link className="hover:text-amber-200" href={`/parts/p/${encodeURIComponent(platform)}/${encodeURIComponent(partRole)}`}>
              ← Back to list
            </Link>
            <span>•</span>
            <span>id: {id ?? "—"}</span>
          </div>
        </header>

        {loading && <p className="text-sm text-zinc-500">Loading product…</p>}

        {error && (
          <div className="rounded-md border border-red-500/40 bg-red-500/10 px-3 py-2 text-sm text-red-200">
            {error}
          </div>
        )}

        {!loading && !error && p && (
          <section className="rounded-lg border border-zinc-800 bg-zinc-950/70 p-4 md:p-6">
            <div className="flex flex-col gap-6 md:flex-row">
              <div className="w-full md:w-72">
                <div className="aspect-square overflow-hidden rounded-lg border border-zinc-800 bg-black/30">
                  <ProductImage
                    src={p.imageUrl}
                    alt={p.name}
                    className="h-full w-full object-cover"
                  />
                </div>
              </div>

              <div className="flex-1">
                <p className="text-xs uppercase tracking-[0.14em] text-zinc-500">
                  {p.brand} • {p.platform}
                </p>
                <h2 className="mt-2 text-xl md:text-2xl font-semibold text-zinc-100">
                  {p.name}
                </h2>

                <div className="mt-4 grid grid-cols-1 gap-3 text-sm">
                  <div className="rounded-md border border-zinc-800 bg-black/30 p-3">
                    <p className="text-xs uppercase tracking-[0.14em] text-zinc-500">Category</p>
                    <p className="mt-1 text-zinc-200">{p.categoryKey ?? "—"}</p>
                  </div>

                  <div className="rounded-md border border-zinc-800 bg-black/30 p-3">
                    <p className="text-xs uppercase tracking-[0.14em] text-zinc-500">Best price</p>
                    <p className="mt-1 text-zinc-200">
                      {typeof p.price === "number" ? `$${p.price.toFixed(2)}` : "—"}
                    </p>
                  </div>
                </div>

                <div className="mt-5 flex items-center gap-3">
                  {p.buyUrl ? (
                    <a
                      href={p.buyUrl}
                      target="_blank"
                      rel="noreferrer"
                      className="rounded-md bg-amber-400 px-4 py-2 text-sm font-semibold text-black hover:bg-amber-300"
                    >
                      Buy / View offer
                    </a>
                  ) : (
                    <span className="text-sm text-zinc-500">No buy link</span>
                  )}
                </div>
              </div>
            </div>
          </section>
        )}
      </div>
    </main>
  );
}