import type { Metadata } from 'next';
import Link from 'next/link';
import { notFound } from 'next/navigation';
import { getArticleFull, getRelatedArticles } from '@/lib/queries';
import RelatedArticles from '@/components/RelatedArticles';
import { InArticleAd, SidebarAd } from '@/components/ads/placements';
import { categoryCover, ogImageUrl, resolveCoverImage } from '@/lib/cover';
import { CoverImage } from '@/components/CoverImage';
import { env } from '@/lib/env';
import { formatFull } from '@/lib/format';
import { safeParse } from '@/lib/llm/parse';
import { SECTIONS } from '@/data/feeds';

export const dynamic = 'force-dynamic';

interface ArticleData {
  id: string;
  slug: string;
  title: string;
  headline: string | null;
  body: string | null;
  takeaways: string | null;
  tags: string | null;
  siteName: string;
  category: string;
  author: string | null;
  publishedAt: Date | null;
  synthesizedAt: Date | null;
  sourceUrl: string;
  canonicalUrl: string;
  image: string | null;
  sources: string | null;
  originalText: string | null;
  llmProvider: string | null;
}

export async function generateMetadata({
  params,
}: {
  params: { slug: string };
}): Promise<Metadata> {
  const a = await getArticleFull(params.slug);
  if (!a) return { title: 'Briefing not found' };
  const title = a.headline ?? a.title;
  const description = a.body?.split('\n\n')[0]?.slice(0, 160) ?? '';
  const sectionLabel = SECTIONS.find((s) => s.slug === a.category)?.label ?? 'Briefing';
  return {
    title,
    description,
    alternates: { canonical: a.canonicalUrl },
    openGraph: {
      type: 'article',
      title,
      description,
      url: a.canonicalUrl,
      siteName: env.siteName,
      publishedTime: a.publishedAt?.toISOString(),
      modifiedTime: a.synthesizedAt?.toISOString(),
      section: sectionLabel,
      tags: a.tags ? safeParse<string[]>(a.tags).slice(0, 5) : undefined,
      images: [{
        url: ogImageUrl(a.image, a.category),
        width: 1200,
        height: 630,
        alt: title,
      }],
    },
    twitter: {
      card: 'summary_large_image',
      title,
      description,
      images: [ogImageUrl(a.image, a.category)],
    },
  };
}

export default async function ArticlePage({
  params,
}: {
  params: { slug: string };
}) {
  const a = await getArticleFull(params.slug);
  if (!a || !a.body) notFound();

  const paragraphs = a.body.split('\n\n').map((p) => p.trim()).filter(Boolean);
  const takeaways = a.takeaways ? safeParse<string[]>(a.takeaways) : [];
  const tags = a.tags ? safeParse<string[]>(a.tags) : [];
  const relatedItems = await getRelatedArticles(a.slug, 6);
  const title = a.headline ?? a.title;

  return (
    <div className="mx-auto max-w-6xl px-4 py-6 sm:px-6">
      <div className="grid gap-10 lg:grid-cols-3">
        {/* Article column */}
        <article className="lg:col-span-2">
          <header>
            <p className="mb-3 flex flex-wrap items-center gap-2 text-sm">
              <span className="rounded bg-maple-600/10 px-2 py-0.5 text-xs font-bold uppercase tracking-wide text-maple-700">
                {SECTIONS.find((s) => s.slug === a.category)?.label ?? 'Briefing'}
              </span>
              {a.publishedAt && (
                <span className="text-ink-400">· {formatFull(a.publishedAt.toISOString())}</span>
              )}
            </p>
            <h1 className="font-display text-3xl font-bold leading-tight text-ink-950 sm:text-4xl">
              {title}
            </h1>
          </header>

          <CoverImage
            src={resolveCoverImage(a.image, a.category)}
            category={a.category}
            alt={title}
            loading="eager"
            className="mt-6 aspect-[16/8] w-full rounded-2xl object-cover"
          />

          {takeaways.length > 0 && (
            <section className="mt-8 rounded-xl border-l-4 border-maple-600 bg-maple-50 p-5">
              <h2 className="text-xs font-bold uppercase tracking-wider text-maple-800">
                Key takeaways
              </h2>
              <ul className="mt-3 grid gap-2 sm:grid-cols-1">
                {takeaways.map((t, i) => (
                  <li key={i} className="flex gap-2 text-[15px] leading-snug text-ink-800">
                    <span aria-hidden className="mt-0.5 font-bold text-maple-600">•</span>
                    {t}
                  </li>
                ))}
              </ul>
            </section>
          )}

          <div className="article-prose mt-8">
            {paragraphs.slice(0, 1).map((p, i) => (
              <p key={i}>{p}</p>
            ))}

            {/* In-article ad: between rewritten paragraphs 1 and 2 */}
            <InArticleAd />

            {paragraphs.slice(1).map((p, i) => (
              <p key={i}>{p}</p>
            ))}
          </div>

          {tags.length > 0 && (
            <div className="mt-8 flex flex-wrap gap-2">
              {tags.map((t) => (
                <Link
                  key={t}
                  href={`/tag/${t}`}
                  className="rounded-full bg-ink-100 px-3 py-1 text-sm text-ink-700 hover:bg-maple-100 hover:text-maple-800"
                >
                  #{t}
                </Link>
              ))}
            </div>
          )}

          <RelatedArticles items={relatedItems} />
        </article>

        {/* Sidebar */}
        <aside aria-label="Sidebar" className="space-y-8">
          <SidebarAd tall />
        </aside>
      </div>
    </div>
  );
}