import { ArrowLeft, BookHeart } from "lucide-react";
import type { Metadata } from "next";
import Link from "next/link";
import { notFound } from "next/navigation";
import { Suspense, ViewTransition } from "react";
import { AddToPlanControl } from "@/app/components/AddToPlanControl";
import { RecipeMeta } from "@/app/components/RecipeDetail";
import { RecipeServings } from "@/app/components/RecipeServings";
import { SiteHeader } from "@/app/components/SiteHeader";
import { PANTRY_STAPLE_IDS } from "@/app/lib/catalog";
import { buildGroceryList } from "@/app/lib/grocery";
import { CUISINES } from "@/app/lib/plan";
import { RECIPES, RECIPES_BY_ID } from "@/app/lib/recipes";
import { formatUsd } from "@/app/lib/units";

export function generateStaticParams() {
  return RECIPES.map((r) => ({ id: r.id }));
}

export async function generateMetadata({
  params,
}: {
  params: Promise<{ id: string }>;
}): Promise<Metadata> {
  const recipe = RECIPES_BY_ID.get((await params).id);
  return recipe
    ? {
        title: recipe.title,
        description: recipe.description,
      }
    : {};
}

/**
 * URL-independent App Shell renders instantly; everything reading `params`
 * lives inside <Suspense> so Next 16 Partial Prefetching never blocks navigation.
 */
export default function RecipePage({
  params,
}: {
  params: Promise<{ id: string }>;
}) {
  return (
    <div className="min-h-dvh">
      <SiteHeader active="recipes" />
      <main className="mx-auto max-w-5xl px-4 py-10 sm:px-6">
        <Suspense fallback={<RecipeSkeleton />}>
          <RecipeContent params={params} />
        </Suspense>
      </main>
    </div>
  );
}

async function RecipeContent({ params }: { params: Promise<{ id: string }> }) {
  const recipe = RECIPES_BY_ID.get((await params).id);
  if (!recipe) notFound();

  const cost = buildGroceryList([recipe.id], {
    householdSize: recipe.servings,
    onHandItems: PANTRY_STAPLE_IDS,
  });
  const cuisineLabel = CUISINES.find((c) => c.id === recipe.cuisine)?.label;
  const isFamily = recipe.styles.includes("caydens_corner");
  const related = RECIPES.filter(
    (r) =>
      r.id !== recipe.id &&
      r.kind === recipe.kind &&
      (isFamily
        ? r.styles.includes("caydens_corner")
        : r.cuisine === recipe.cuisine && !r.styles.includes("caydens_corner")),
  ).slice(0, 4);

  return (
    <>
      <Link
        href={isFamily ? "/caydens-corner" : "/recipes"}
        className="inline-flex items-center gap-1.5 text-sm font-medium text-ink-muted transition-colors hover:text-brand-300"
      >
        <ArrowLeft className="size-4" aria-hidden />
        {isFamily ? "Cayden's Corner" : "All recipes"}
      </Link>

      {isFamily && (
        <p className="mt-4 inline-flex items-center gap-1.5 font-mono text-xs font-semibold tracking-wider text-brand-300 uppercase">
          <BookHeart className="size-3.5" strokeWidth={2} aria-hidden />
          Heirloom Family Recipe
        </p>
      )}

      <ViewTransition name={`recipe-title-${recipe.id}`}>
        <h1 className="mt-3 font-serif text-3xl font-semibold tracking-tight text-balance sm:text-4xl lg:text-5xl">
          {recipe.title}
        </h1>
      </ViewTransition>

      <p className="mt-3 max-w-2xl text-lg leading-relaxed text-ink-muted">{recipe.description}</p>

      <div className="mt-4">
        <RecipeMeta recipe={recipe} />
      </div>

      {/* Cost ledger + Add to Plan action bar */}
      <div className="mt-6 flex flex-wrap items-center justify-between gap-4 rounded-xl border border-line bg-surface p-4 sm:px-5">
        <dl className="flex flex-wrap items-center gap-6 sm:gap-10">
          <div>
            <dt className="text-xs text-ink-faint">Cost eaten / serving</dt>
            <dd className="mt-0.5 font-mono text-lg font-semibold text-brand-300 tabular-nums">
              {formatUsd(cost.usedTotal / recipe.servings)}
            </dd>
          </div>
          <div className="border-l border-line pl-6 sm:pl-10">
            <dt className="text-xs text-ink-faint">Full packages new</dt>
            <dd className="mt-0.5 font-mono text-lg font-semibold text-ink tabular-nums">
              {formatUsd(cost.checkoutTotal)}
            </dd>
          </div>
        </dl>

        <AddToPlanControl recipeId={recipe.id} recipeTitle={recipe.title} />
      </div>

      <div className="mt-8 rounded-xl border border-line bg-surface p-5 sm:p-8">
        <RecipeServings recipe={recipe} />
      </div>

      {related.length > 0 && (
        <section className="mt-12 border-t border-line pt-8">
          <h2 className="font-serif text-xl font-semibold">
            More {isFamily ? "from Cayden's Corner" : cuisineLabel}
          </h2>
          <ul className="mt-4 grid gap-3.5 sm:grid-cols-2">
            {related.map((r) => (
              <li key={r.id}>
                <Link
                  href={`/recipes/${r.id}`}
                  className="group block rounded-xl border border-line bg-surface p-4 transition-colors hover:border-line-strong hover:bg-raised/60"
                >
                  <span className="font-serif text-lg font-semibold text-ink group-hover:text-brand-300">{r.title}</span>
                  <span className="mt-1 block text-sm text-ink-muted">{r.description}</span>
                </Link>
              </li>
            ))}
          </ul>
        </section>
      )}
    </>
  );
}

function RecipeSkeleton() {
  return (
    <div className="animate-pulse space-y-4" aria-busy="true" aria-label="Loading recipe">
      <div className="h-4 w-28 rounded bg-raised" />
      <div className="h-11 w-2/3 rounded bg-raised" />
      <div className="h-5 w-1/2 rounded bg-raised" />
      <div className="mt-6 h-20 rounded-xl bg-raised" />
      <div className="mt-8 h-96 rounded-xl bg-raised" />
    </div>
  );
}