import type { Metadata } from "next";
import Link from "next/link";
import Image from "next/image";
import { Reveal, RevealGroup, RevealItem } from "../components/Reveal";
import { Newsletter } from "../components/Newsletter";
import { Footer } from "../components/Footer";
import { getBlogPosts } from "../lib/payload";
import { formatDate } from "../lib/format";

export const metadata: Metadata = {
  title: "Blog",
  description: "Gedanken, Methoden und Impulse für einen leichteren und klareren Alltag.",
  alternates: { canonical: "/blog" },
  openGraph: {
    title: "Blog | einfach produktiv.",
    description: "Gedanken, Methoden und Impulse für einen leichteren und klareren Alltag.",
    url: "/blog",
    type: "website",
    images: ["/blog-featured.jpg"],
  },
};

// Every distinct category name in DOM order — Payload's `categories` field
// stores related docs, no separate slug on this side, but since this page
// already fetches every published post (limit 100, no pagination), a
// plain client-agnostic array filter is enough; no separate Payload query
// per category needed.
function distinctCategories(posts: { categories: string[] }[]): string[] {
  const seen = new Set<string>();
  for (const post of posts) for (const c of post.categories) seen.add(c);
  return Array.from(seen);
}

function buildCategoryHref(active: string[], category: string): string {
  const next = active.includes(category) ? active.filter((c) => c !== category) : [...active, category];
  return next.length > 0 ? `/blog?categories=${next.map(encodeURIComponent).join(",")}` : "/blog";
}

export default async function BlogOverviewPage({
  searchParams,
}: {
  searchParams: Promise<{ categories?: string }>;
}) {
  const allPosts = await getBlogPosts(100);
  const { categories: categoriesParam } = await searchParams;
  const activeCategories = categoriesParam ? categoriesParam.split(",").filter(Boolean) : [];
  const allCategories = distinctCategories(allPosts);
  const posts =
    activeCategories.length === 0 ? allPosts : allPosts.filter((post) => post.categories.some((c) => activeCategories.includes(c)));
  const [featured, ...rest] = posts;

  return (
    <>
      <main className="flex flex-col flex-1 bg-bg-base">
        {/* Header — copy left, photo bleeds to the viewport edge on the
            right with a left-edge fade into bg-base, matching Figma's
            hero-fade-left/hero-fade-bottom overlays (node 4577:330). */}
        <Reveal className="relative flex flex-col sm:flex-row items-center w-full min-h-[20rem] sm:min-h-[27.5rem] border-b border-border overflow-hidden">
          <div className="relative z-10 flex flex-col gap-4 items-start px-[var(--layout-padding-x)] py-10 sm:py-0 w-full sm:w-auto sm:max-w-[26rem]">
            <p
              className="font-semibold text-display text-text-primary"
              style={{ fontFamily: "var(--font-lora)" }}
            >
              Blog
            </p>
            <p className="text-body text-text-muted">
              Gedanken, Methoden und Impulse für einen leichteren und klareren Alltag.
            </p>
          </div>
          <div className="relative w-full sm:absolute sm:inset-y-0 sm:right-0 sm:w-[68%] h-56 sm:h-full">
            <Image alt="" src="/hero.png" fill sizes="(min-width: 640px) 68vw, 100vw" className="object-cover object-top" />
            <div className="hidden sm:block absolute inset-y-0 left-0 w-72 bg-gradient-to-r from-bg-base to-transparent" />
            <div className="absolute inset-x-0 bottom-0 h-16 bg-gradient-to-t from-bg-base to-transparent" />
          </div>
        </Reveal>

        {allCategories.length > 1 && (
          <Reveal className="flex flex-wrap gap-2 w-full max-w-[80rem] mx-auto px-[var(--layout-padding-x)] pt-6">
            {allCategories.map((category) => {
              const active = activeCategories.includes(category);
              return (
                <Link
                  key={category}
                  href={buildCategoryHref(activeCategories, category)}
                  className={`inline-flex items-center px-3 py-1.5 rounded-full text-body-sm font-semibold whitespace-nowrap border transition-colors ${
                    active
                      ? "bg-brand border-brand text-text-primary"
                      : "bg-bg-base border-border text-text-muted hover:border-brand hover:text-brand"
                  }`}
                >
                  {category}
                </Link>
              );
            })}
            {activeCategories.length > 0 && (
              <Link
                href="/blog"
                className="inline-flex items-center px-3 py-1.5 text-body-sm font-semibold text-text-muted underline hover:text-brand transition-colors"
              >
                Zurücksetzen
              </Link>
            )}
          </Reveal>
        )}

        {posts.length === 0 && (
          <p className="text-body text-text-muted w-full max-w-[80rem] mx-auto px-[var(--layout-padding-x)] pt-10">
            Keine Beiträge in dieser Kategorie gefunden.
          </p>
        )}

        {featured && (
          // -mt-8, not pt-10 — pulls the card up to slightly overlap the
          // hero section's bottom edge instead of sitting flush below it.
          // relative z-10 keeps it stacked above the hero's own photo.
          <Reveal delay={0.1} className="relative z-10 w-full px-[var(--layout-padding-x)] -mt-8 pb-4">
            <Link
              href={`/blog/${featured.slug}`}
              className="group grid grid-cols-1 sm:grid-cols-2 w-full max-w-[80rem] mx-auto rounded-md overflow-hidden bg-bg-muted transition-transform duration-300 hover:-translate-y-1"
            >
              <div className="relative w-full aspect-video sm:aspect-auto sm:h-full bg-bg-muted">
                {featured.thumbnail && (
                  <Image alt="" src={featured.thumbnail} fill sizes="(min-width: 640px) 40rem, 100vw" className="object-cover" />
                )}
              </div>
              <div className="flex flex-col justify-center gap-3 p-8 sm:p-12 min-w-0">
                <div className="flex items-center gap-2 font-semibold text-text-muted text-body-sm uppercase tracking-wide">
                  <span>{featured.categories.join(", ")}</span>
                  <span>•</span>
                  <span>{featured.readTime} Min</span>
                  <span>•</span>
                  <span className="uppercase">{formatDate(featured.publishedAt)}</span>
                </div>
                <p
                  className="font-semibold text-h-section text-text-primary"
                  style={{ fontFamily: "var(--font-lora)" }}
                >
                  {featured.title}
                </p>
                <p className="text-body text-text-muted line-clamp-3">{featured.excerpt}</p>
                <span className="flex items-center gap-1.5 font-bold text-body text-text-primary mt-1">
                  Zum Beitrag
                  <svg
                    viewBox="0 0 20 20"
                    className="size-4 transition-transform duration-200 group-hover:translate-x-1"
                    fill="none"
                    aria-hidden="true"
                  >
                    <path d="M4 10h12m0 0-5-5m5 5-5 5" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round" />
                  </svg>
                </span>
              </div>
            </Link>
          </Reveal>
        )}

        {rest.length > 0 && (
          <RevealGroup className="flex flex-col w-full max-w-[80rem] mx-auto px-[var(--layout-padding-x)] py-6 divide-y divide-border">
            {rest.map((post) => (
              <RevealItem key={post.id} className="py-8 first:pt-0 last:pb-0">
                <Link href={`/blog/${post.slug}`} className="group flex flex-col sm:flex-row gap-6 items-start">
                  <div className="relative w-full sm:w-[18.75rem] aspect-video sm:aspect-[300/192] shrink-0 rounded-md overflow-hidden bg-bg-muted">
                    {post.thumbnail && (
                      <Image alt="" src={post.thumbnail} fill sizes="(min-width: 640px) 18.75rem, 100vw" className="object-cover" />
                    )}
                  </div>
                  <div className="flex flex-col gap-2 min-w-0 flex-1">
                    <div className="flex items-center gap-2 font-semibold text-text-muted text-body-sm uppercase tracking-wide">
                      <span>{post.categories.join(", ")}</span>
                      <span>•</span>
                      <span>{post.readTime} Min</span>
                      <span>•</span>
                      <span className="uppercase">{formatDate(post.publishedAt)}</span>
                    </div>
                    <p
                      className="font-semibold text-h-small text-text-primary"
                      style={{ fontFamily: "var(--font-lora)" }}
                    >
                      {post.title}
                    </p>
                    <p className="text-body text-text-muted">{post.excerpt}</p>
                    <span className="flex items-center gap-1.5 font-bold text-body-sm text-text-primary mt-1">
                      Zum Beitrag
                      <svg
                        viewBox="0 0 20 20"
                        className="size-3.5 transition-transform duration-200 group-hover:translate-x-1"
                        fill="none"
                        aria-hidden="true"
                      >
                        <path d="M4 10h12m0 0-5-5m5 5-5 5" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round" />
                      </svg>
                    </span>
                  </div>
                </Link>
              </RevealItem>
            ))}
          </RevealGroup>
        )}

        <Newsletter
          title="Neue Impulse im richtigen Moment."
          description="Melde dich zum Newsletter an und erhalte regelmäßig Gedanken, Methoden und praktische Tipps."
        />
      </main>
      <Footer />
    </>
  );
}