"use client";

import { useEffect, useMemo, useState } from "react";
import Link from "next/link";
import { useParams } from "next/navigation";
import { CATEGORIES } from "@/data/gunbuilderParts";
import type { CategoryId } from "@/types/gunbuilder";
import {
  getRetailerOffers,
  type RetailerOffer,
} from "./data";

type GunbuilderProductFromApi = {
  id: string; // backend UUID string
  name: string;
  brand: string;
  platform: string;
  partRole: string;
  price: number | null;
  imageUrl: string | null;
  buyUrl: string | null;
};

const API_BASE_URL =
  process.env.NEXT_PUBLIC_API_BASE_URL ?? "http://localhost:8080";

export default function PartDetailPage() {
  const params = useParams();
  const categoryId = params.categoryId as CategoryId;
  const partId = params.partId as string; // this is the UUID we passed in the link

  const [product, setProduct] = useState<GunbuilderProductFromApi | null>(null);
  const [loading, setLoading] = useState(true);
  const [error, setError] = useState<string | null>(null);

  const [offers, setOffers] = useState<RetailerOffer[]>([]);
  const [offersLoading, setOffersLoading] = useState(true);
  const [offersError, setOffersError] = useState<string | null>(null);

  const category = useMemo(
    () => CATEGORIES.find((c) => c.id === categoryId),
    [categoryId],
  );

  // 1) Load product (same as before)
  useEffect(() => {
    if (!partId) return;

    const controller = new AbortController();

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

        // For now, pull the full AR-15 list and find by UUID.
        // We can optimize with a dedicated /api/products/{uuid} later.
        const url = `${API_BASE_URL}/api/products/gunbuilder/products/${partId}`;
        const res = await fetch(url, { signal: controller.signal });

        if (!res.ok) {
          throw new Error(`Failed to load product (${res.status})`);
        }

        const data: GunbuilderProductFromApi = await res.json();

        if (!data) {
          setError("Product not found");
        }

        setProduct(data);
      } catch (err: any) {
        if (err.name === "AbortError") return;
        setError(err.message ?? "Failed to load product");
      } finally {
        setLoading(false);
      }
    }
    
    fetchProduct();

    return () => controller.abort();
  }, [partId]);

  // 2) Load offers for this product from Ballistic backend
  useEffect(() => {
    if (!partId) return;

    let cancelled = false;

    async function fetchOffers() {
      try {
        setOffersLoading(true);
        setOffersError(null);

        const data = await getRetailerOffers(partId);

        if (!cancelled) {
          setOffers(data);
        }
      } catch (err: any) {
        if (!cancelled) {
          setOffersError(err.message ?? "Failed to load retailer offers");
        }
      } finally {
        if (!cancelled) {
          setOffersLoading(false);
        }
      }
    }

    fetchOffers();

    return () => {
      cancelled = true;
    };
  }, [partId]);

  // Best price: prefer live offers, fall back to summary product.price
  const bestPrice = useMemo(() => {
    if (offers.length > 0) {
      return offers[0].price;
    }
    return product?.price ?? null;
  }, [offers, product]);

  if (!category) {
    return (
      <main className="min-h-screen bg-black text-zinc-50">
        <div className="mx-auto max-w-6xl px-4 py-6 lg:py-10">
          <h1 className="text-2xl font-semibold mb-4">Category Not Found</h1>
          <Link
            href="/builder"
            className="text-amber-300 hover:text-amber-200 underline"
          >
            Return to Builder
          </Link>
        </div>
      </main>
    );
  }

  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">
        {/* Breadcrumbs */}
        <nav className="mb-4 text-xs text-zinc-500">
          <Link
            href="/builder"
            className="hover:text-zinc-300 transition-colors"
          >
            Builder
          </Link>
          <span className="mx-1">/</span>
          <Link
            href={`/builder/${categoryId}`}
            className="hover:text-zinc-300 transition-colors"
          >
            {category.name}
          </Link>
          {product && (
            <>
              <span className="mx-1">/</span>
              <span className="text-zinc-300">{product.name}</span>
            </>
          )}
        </nav>

        {loading ? (
          <p className="text-sm text-zinc-500">Loading product…</p>
        ) : error || !product ? (
          <div>
            <h1 className="text-xl font-semibold mb-2">Product Unavailable</h1>
            <p className="text-sm text-zinc-500 mb-4">
              {error ?? "We couldn’t find this product."}
            </p>
            <Link
              href={`/builder/${categoryId}`}
              className="text-amber-300 hover:text-amber-200 underline text-sm"
            >
              Back to {category.name} parts
            </Link>
          </div>
        ) : (
          <>
            <div className="grid gap-6 md:grid-cols-[minmax(0,2fr)_minmax(0,1.3fr)] items-start">
              {/* Left: image + meta */}
              <div className="space-y-4">
                {product.imageUrl && (
                  <div className="overflow-hidden rounded-lg border border-zinc-800 bg-zinc-950">
                    {/* eslint-disable-next-line @next/next/no-img-element */}
                    <img
                      src={product.imageUrl}
                      alt={product.name}
                      className="w-full object-contain max-h-80 bg-zinc-950"
                    />
                  </div>
                )}
                <div className="text-xs font-semibold tracking-[0.2em] uppercase text-zinc-500">
                  {product.brand}
                </div>
                <h1 className="text-2xl md:text-3xl font-semibold tracking-tight">
                  {product.name}
                </h1>

                <div className="grid grid-cols-2 gap-3 text-xs">
                  <p className="text-zinc-500">
                    Platform:{" "}
                    <span className="text-zinc-300">{product.platform}</span>
                  </p>
                  <p className="text-zinc-500">
                    Role:{" "}
                    <span className="text-zinc-300">{product.partRole}</span>
                  </p>
                  <p className="text-zinc-500">
                    Category:{" "}
                    <span className="text-zinc-300">{category.name}</span>
                  </p>
                  <p className="text-zinc-500">
                    Offers:{" "}
                    <span className="text-zinc-300">
                      {offers.length > 0
                        ? `${offers.length} live offer${
                            offers.length === 1 ? "" : "s"
                          }`
                        : "No live offers yet"}
                    </span>
                  </p>
                </div>

                {/* Placeholder content until long-form fields are wired up */}
                <section className="mt-4 space-y-3 text-sm text-zinc-300">
                  <h2 className="text-xs font-semibold tracking-[0.2em] uppercase text-zinc-500">
                    Product Overview
                  </h2>
                  <p className="text-zinc-400">
                    This is placeholder copy for the product overview. Once
                    the Ballistic backend exposes richer metadata (short
                    description, feature bullets, etc.), we&apos;ll swap this
                    text out and surface the real content here.
                  </p>
                  <p className="text-zinc-500 text-xs">
                    Use this section to highlight what makes this part worth
                    a slot in your build: materials, intended use
                    (duty/range/competition), and any standout features.
                  </p>
                </section>

                <section className="mt-4 rounded-lg border border-zinc-800 bg-zinc-950/70 p-3">
                  <h2 className="text-xs font-semibold tracking-[0.2em] uppercase text-zinc-500 mb-2">
                    Quick Specs (Placeholder)
                  </h2>
                  <dl className="grid grid-cols-2 gap-x-4 gap-y-2 text-xs text-zinc-400">
                    <div>
                      <dt className="text-zinc-500">Configuration</dt>
                      <dd className="text-zinc-200">
                        TBD (Stripped / Complete / Kit)
                      </dd>
                    </div>
                    <div>
                      <dt className="text-zinc-500">Caliber</dt>
                      <dd className="text-zinc-200">TBD from feed</dd>
                    </div>
                    <div>
                      <dt className="text-zinc-500">Finish</dt>
                      <dd className="text-zinc-200">TBD from merchant data</dd>
                    </div>
                    <div>
                      <dt className="text-zinc-500">Weight</dt>
                      <dd className="text-zinc-200">TBD (oz)</dd>
                    </div>
                  </dl>
                  <p className="mt-2 text-[11px] text-zinc-500">
                    Specs are placeholders for now. As we normalize more
                    structured attributes in the importer, this block will
                    auto-populate per product.
                  </p>
                </section>
              </div>

              {/* Right: pricing + actions */}
              <aside className="rounded-lg border border-zinc-800 bg-zinc-950/70 p-4 space-y-4">
                <div>
                  <p className="text-xs uppercase tracking-[0.2em] text-zinc-500 mb-1">
                    Price
                  </p>
                  <p className="text-2xl font-semibold text-amber-300">
                    {bestPrice && bestPrice > 0
                      ? `$${bestPrice.toFixed(2)}`
                      : "—"}
                  </p>
                  {!bestPrice && (
                    <p className="mt-1 text-xs text-zinc-500">
                      Pricing not available yet. Live pricing will appear once
                      offers are imported.
                    </p>
                  )}
                  {offers.length > 0 && (
                    <p className="mt-1 text-[11px] text-zinc-500">
                      Showing the best available price across all live
                      offers for this part.
                    </p>
                  )}
                  {offers.length > 1 && (
                    <p className="mt-1 text-[11px] text-zinc-500">
                      Price range across retailers:{" "}
                      <span className="text-zinc-300">
                        ${Math.min(...offers.map(o => o.price)).toFixed(2)} – ${Math.max(...offers.map(o => o.price)).toFixed(2)}
                      </span>
                    </p>
                  )}
                </div>

                {/* Offers list */}
                <div className="space-y-2">
                  {offersLoading && (
                    <p className="text-xs text-zinc-500">Loading offers…</p>
                  )}
                  {offersError && (
                    <p className="text-xs text-red-400">{offersError}</p>
                  )}
                  {!offersLoading && !offersError && offers.length > 0 && (
                    <div className="space-y-1">
                      {offers.map((offer) => (
                        <a
                          key={offer.id}
                          href={offer.affiliateUrl}
                          target="_blank"
                          rel="noreferrer"
                          className="flex items-center justify-between rounded-md border border-zinc-700 bg-zinc-900 px-3 py-1.5 text-xs hover:bg-zinc-800 transition-colors"
                        >
                          <span className="text-zinc-200">
                            {offer.retailerName}
                          </span>
                          <span className="font-semibold text-amber-300">
                            ${offer.price.toFixed(2)}
                          </span>
                        </a>
                      ))}
                    </div>
                  )}
                  {!offersLoading &&
                    !offersError &&
                    offers.length === 0 && (
                      <p className="text-xs text-zinc-500">
                        No live retailer offers yet. As feeds are imported,
                        merchants and pricing will show up here.
                      </p>
                    )}
                </div>

                <div className="space-y-2">
                  <Link
                    href={`/builder?select=${categoryId}:${product.id}`}
                    className="block w-full rounded-md bg-amber-400 text-black text-sm font-semibold text-center py-2.5 hover:bg-amber-300 transition-colors"
                  >
                    Add to Build
                  </Link>

                  {product.buyUrl ? (
                    <a
                      href={product.buyUrl}
                      target="_blank"
                      rel="noreferrer"
                      className="block w-full rounded-md border border-zinc-700 bg-zinc-900 text-xs font-medium text-zinc-200 text-center py-2 hover:bg-zinc-800 transition-colors"
                    >
                      View on Merchant Site
                    </a>
                  ) : (
                    <button
                      type="button"
                      disabled
                      className="block w-full rounded-md border border-zinc-800 bg-zinc-900/60 text-xs font-medium text-zinc-500 text-center py-2 cursor-not-allowed"
                    >
                      External link coming soon
                    </button>
                  )}
                </div>
              </aside>
            </div>

            {/* Lower content: builder-focused helper copy (placeholder) */}
            <section className="mt-10 grid gap-6 md:grid-cols-3 text-sm md:grid-cols-4">
              <div className="space-y-2">
                <h2 className="text-xs font-semibold tracking-[0.2em] uppercase text-zinc-500">
                  Why We Like This Part
                </h2>
                <p className="text-zinc-400">
                  Drop in a short blurb here about what makes this part
                  worth picking over similar options — think reliability,
                  track record, and value for the money.
                </p>
              </div>
              <div className="space-y-2">
                <h2 className="text-xs font-semibold tracking-[0.2em] uppercase text-zinc-500">
                  Best For
                </h2>
                <p className="text-zinc-400">
                  Use this block to call out ideal use cases:{" "}
                  <span className="text-zinc-200">
                    duty rifle, home defense, range toy, competition, night
                    work
                  </span>
                  , etc.
                </p>
              </div>
              <div className="space-y-2">
                <h2 className="text-xs font-semibold tracking-[0.2em] uppercase text-zinc-500">
                  Builder Notes
                </h2>
                <p className="text-zinc-400">
                  Add any compatibility quirks or install tips here once
                  the compatibility engine is wired up — gas system length,
                  buffer recommendations, known fitment notes, and more.
                </p>
              </div>
              <div className="space-y-2">
                <h2 className="text-xs font-semibold tracking-[0.2em] uppercase text-zinc-500">
                  Compatibility
                </h2>
                <div className="inline-flex items-center gap-2 rounded-md border border-amber-400/30 bg-amber-400/10 px-2 py-1 text-[11px] text-amber-300">
                  <span className="inline-block h-2 w-2 rounded-full bg-amber-300 animate-pulse"></span>
                  Compatibility engine coming online soon
                </div>
                <p className="text-zinc-500 text-xs">
                  Fitment checks, caliber validation, buffer/gas system logic, and platform rules will appear here once the engine is active.
                </p>
              </div>
            </section>
          </>
        )}
      </div>
    </main>
  );
}