import { notFound } from 'next/navigation';
import Link from 'next/link';
import Header from '@/components/Header';
import Footer from '@/components/Footer';
import ReadingProgress from '@/components/ReadingProgress';
import ScrollToTop from '@/components/ScrollToTop';
import ShareButton from '@/components/ShareButton';
import ArticleCard from '@/components/ArticleCard';
import { getArticle, listArticles } from '@/lib/engine';
import { renderMarkdown, formatDate } from '@/lib/markdown';
import { Clock, ArrowLeft } from 'lucide-react';

export const dynamic = 'force-dynamic';

export async function generateMetadata({ params }) {
  const { slug } = await params;
  const article = await getArticle(slug);
  if (!article) return { title: 'Статья не найдена' };
  return {
    title: article.seo_title || article.title,
    description: article.seo_descr || article.excerpt,
    openGraph: {
      title: article.title,
      description: article.excerpt,
      type: 'article',
      publishedTime: article.published_at,
      tags: article.tags || [],
      images: article.cover_url ? [{ url: article.cover_url }] : undefined,
    },
  };
}

async function loadRelated(article) {
  // ищем статьи с пересекающимися тегами, исключая текущую
  if (!article.tags?.length) return [];
  const all = await listArticles({ limit: 20 });
  const scored = all
    .filter(a => a.id !== article.id)
    .map(a => ({
      ...a,
      score: (a.tags || []).filter(t => article.tags.includes(t)).length,
    }))
    .filter(a => a.score > 0)
    .sort((a, b) => b.score - a.score)
    .slice(0, 3);
  return scored;
}

export default async function ArticlePage({ params }) {
  const { slug } = await params;
  const article = await getArticle(slug);
  if (!article) notFound();

  const related = await loadRelated(article);
  const contentWithoutH1 = article.content.replace(/^#\s+.+$/m, '').trim();
  const html = renderMarkdown(contentWithoutH1);

  return (
    <>
      <Header />
      <ReadingProgress />

      <article className="container-narrow pt-6 sm:pt-10 pb-12">
        <Link href="/" className="btn btn-ghost text-sm mb-4 sm:mb-6 -ml-2">
          <ArrowLeft className="w-4 h-4" /> Все статьи
        </Link>

        <div className="flex flex-wrap items-center gap-2 mb-3">
          {(article.tags || []).map(t => (
            <Link key={t} href={`/tag/${encodeURIComponent(t)}`} className="tag">#{t}</Link>
          ))}
        </div>

        <h1 className="font-serif text-2xl sm:text-4xl lg:text-5xl font-bold leading-[1.15] mb-4 sm:mb-5 tracking-tight ink">
          {article.title}
        </h1>

        <div className="flex items-center flex-wrap gap-x-3 gap-y-2 text-xs sm:text-sm mute pb-6 sm:pb-8 mb-6 sm:mb-8 border-b-soft">
          <span>{article.author}</span>
          <span aria-hidden>·</span>
          <span>{formatDate(article.published_at)}</span>
          {article.reading_time && (
            <>
              <span aria-hidden>·</span>
              <span className="inline-flex items-center gap-1">
                <Clock className="w-3.5 h-3.5" /> {article.reading_time} мин чтения
              </span>
            </>
          )}
          <span className="ml-auto">
            <ShareButton title={article.title} />
          </span>
        </div>

        {article.cover_url && (
          <div className="mb-8 sm:mb-10 -mx-4 sm:mx-0">
            <img
              src={article.cover_url}
              alt={article.title}
              className="w-full sm:rounded-xl"
              style={{ aspectRatio: '16/9', objectFit: 'cover' }}
            />
          </div>
        )}

        <div
          className="prose prose-base sm:prose-lg max-w-none font-serif prose-headings:font-sans prose-p:leading-relaxed prose-img:rounded-xl"
          dangerouslySetInnerHTML={{ __html: html }}
        />

        <div className="mt-12 pt-6 border-t-soft text-center">
          <p className="mute text-sm">Статья сгенерирована ИИ под редакторским присмотром.</p>
        </div>
      </article>

      {related.length > 0 && (
        <section className="container-wide pb-12 sm:pb-16">
          <h2 className="text-xs sm:text-sm font-medium uppercase tracking-widest mute mb-4 sm:mb-5">
            Похожее
          </h2>
          <div className="grid sm:grid-cols-2 lg:grid-cols-3 gap-4 sm:gap-5">
            {related.map(a => <ArticleCard key={a.id} article={a} />)}
          </div>
        </section>
      )}

      <ScrollToTop />
      <Footer />
    </>
  );
}