export const dynamic = "force-dynamic";

import type { Metadata } from "next";
import { redirect } from "next/navigation";
import { notFound } from "next/navigation";
import Link from "next/link";
import { getChapterVerseIndex, getProseChapter } from "@/lib/api";
import { buildOgMeta } from "@/lib/og";
import { BOOK_NAMES } from "@/lib/constants";
import { Card, CardContent } from "@/components/ui/card";
import { PageHeader } from "@/components/layout/page-header";
import { FindInPage } from "@/components/layout/find-in-page";

export async function generateMetadata({
  params,
}: {
  params: Promise<{ chapter: string }>;
}): Promise<Metadata> {
  const { chapter } = await params;
  // Non-numeric segments are front matter (dedication, foreword, …).
  if (isNaN(parseInt(chapter))) {
    const segment = await getProseChapter("bg", 0, chapter);
    return buildOgMeta({
      title: BOOK_NAMES["bg"],
      detail: segment?.title ?? "Front Matter",
    });
  }
  return buildOgMeta({ title: BOOK_NAMES["bg"], detail: `Chapter ${chapter}` });
}

export default async function ChapterPage({
  params,
}: {
  params: Promise<{ chapter: string }>;
}) {
  const { chapter } = await params;

  // Front matter — non-numeric slugs (dedication, foreword, preface,
  // introduction, disciplic-succession) resolve to prose intro-segments.
  if (isNaN(parseInt(chapter))) {
    const segment = await getProseChapter("bg", 0, chapter);
    if (!segment) notFound();

    return (
      <div className="min-h-screen bg-background">
        <PageHeader sticky>
          <Link
            href="/books/bg"
            className="text-sm text-muted-foreground hover:text-foreground transition-colors"
          >
            &larr; {BOOK_NAMES["bg"]}
          </Link>
          <div className="mt-3 flex items-start justify-between gap-3">
            <h1 className="text-2xl font-bold text-foreground">
              {segment.title}
            </h1>
            <FindInPage targetId="book-content" className="shrink-0 mt-0.5" />
          </div>
        </PageHeader>

        <main className="max-w-5xl mx-auto px-6 py-8">
          <Card id="book-content">
            <CardContent className="py-8 px-6 sm:px-8">
              <div className="space-y-4">
                {segment.paragraphs.map((paragraph, i) => (
                  <div
                    key={i}
                    className="text-base text-foreground leading-relaxed"
                    dangerouslySetInnerHTML={{ __html: paragraph }}
                  />
                ))}
              </div>
            </CardContent>
          </Card>
        </main>
      </div>
    );
  }

  // Numeric chapters — redirect to the first verse.
  const verseIndex = await getChapterVerseIndex("bg", null, parseInt(chapter));
  if (verseIndex.length === 0) {
    notFound();
  }
  redirect(`/books/bg/${chapter}/${verseIndex[0].verse}`);
}