export const dynamic = "force-dynamic";

import Link from "next/link";
import { notFound } from "next/navigation";
import { getSvaMeta, getSvaIntroSegments } from "@/lib/sva";
import { PageHeader } from "@/components/page-header";
import { Card, CardContent } from "@/components/ui/card";

export default async function SvaPage() {
  const meta = await getSvaMeta();
  if (!meta) notFound();

  const introSegments = await getSvaIntroSegments();

  // Split intro segments into front matter (before chapters) and back matter (after)
  const frontMatter = introSegments.filter((seg) => seg.order < 99);
  const backMatter = introSegments.filter((seg) => seg.order >= 99);

  return (
    <div className="min-h-screen bg-background">
      <PageHeader>
        <Link
          href="/books"
          className="text-sm text-muted-foreground hover:text-foreground transition-colors"
        >
          &larr; Books
        </Link>
        <h1 className="mt-3 text-3xl font-bold text-foreground">
          {meta.title}
        </h1>
        <p className="mt-1 text-muted-foreground">{meta.author}</p>
      </PageHeader>

      <main className="max-w-5xl mx-auto px-6 py-8 space-y-8">
        {/* Description */}
        {meta.description && (
          <p className="text-muted-foreground">{meta.description}</p>
        )}

        {/* Front Matter */}
        {frontMatter.length > 0 && (
          <div>
            <h2 className="text-sm font-bold uppercase tracking-wider text-muted-foreground mb-3">
              Front Matter
            </h2>
            <Card className="divide-y divide-border">
              <CardContent className="p-0">
                <ul className="divide-y divide-border">
                  {frontMatter.map((seg) => (
                    <li key={seg.slug}>
                      <Link
                        href={`/books/sva/${seg.slug.startsWith("intro-") ? seg.slug : `intro-${seg.slug}`}`}
                        className="flex flex-col sm:flex-row sm:items-center sm:justify-between px-5 py-4 gap-1 sm:gap-0 hover:bg-muted transition-colors"
                      >
                        <div>
                          <p className="font-medium text-foreground">
                            {seg.title}
                          </p>
                        </div>
                        <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
                          {seg.paragraphs.length} paragraphs
                        </span>
                      </Link>
                    </li>
                  ))}
                </ul>
              </CardContent>
            </Card>
          </div>
        )}

        {/* Parts — hierarchical parent → song (sub-chapter) structure */}
        {meta.chapters.map((ch) => (
          <div key={ch.number}>
            <h2 className="text-sm font-bold uppercase tracking-wider text-muted-foreground mb-3">
              Part {ch.number}: {ch.title}
            </h2>
            <Card className="divide-y divide-border">
              <CardContent className="p-0">
                <ul className="divide-y divide-border">
                  {ch.subChapters.map((sub) => (
                    <li key={sub.slug}>
                      <Link
                        href={`/books/sva/${sub.slug}`}
                        className="flex flex-col sm:flex-row sm:items-center sm:justify-between px-5 py-4 gap-1 sm:gap-0 hover:bg-muted transition-colors"
                      >
                        <p className="font-medium text-foreground">
                          {sub.title}
                        </p>
                      </Link>
                    </li>
                  ))}
                </ul>
              </CardContent>
            </Card>
          </div>
        ))}

        {/* Back Matter */}
        {backMatter.length > 0 && (
          <div>
            <h2 className="text-sm font-bold uppercase tracking-wider text-muted-foreground mb-3">
              Back Matter
            </h2>
            <Card className="divide-y divide-border">
              <CardContent className="p-0">
                <ul className="divide-y divide-border">
                  {backMatter.map((seg) => (
                    <li key={seg.slug}>
                      <Link
                        href={`/books/sva/${seg.slug.startsWith("intro-") ? seg.slug : `intro-${seg.slug}`}`}
                        className="flex flex-col sm:flex-row sm:items-center sm:justify-between px-5 py-4 gap-1 sm:gap-0 hover:bg-muted transition-colors"
                      >
                        <div>
                          <p className="font-medium text-foreground">
                            {seg.title}
                          </p>
                        </div>
                        <span className="text-sm text-muted-foreground sm:shrink-0 sm:ml-4">
                          {seg.paragraphs.length} paragraphs
                        </span>
                      </Link>
                    </li>
                  ))}
                </ul>
              </CardContent>
            </Card>
          </div>
        )}
      </main>
    </div>
  );
}