import { NextResponse } from "next/server";
import { prisma } from "@/lib/db";

const DEFAULT_PAGE_SIZE = 20;

export async function GET(
  req: Request,
  { params }: { params: Promise<{ book: string }> },
) {
  const { book } = await params;
  const url = new URL(req.url);
  const division = url.searchParams.get("division");
  const chapterStr = url.searchParams.get("chapter");
  const indexOnly = url.searchParams.get("indexOnly") === "true";
  const pageStr = url.searchParams.get("page");
  const limitStr = url.searchParams.get("limit");

  if (!chapterStr) {
    return NextResponse.json(
      { error: "chapter query param is required" },
      { status: 400 },
    );
  }

  const chapter = parseInt(chapterStr);
  const where: Record<string, unknown> = { book, chapter };

  if (book === "bg") {
    where.division = null;
  } else if (division) {
    where.division = division;
  }

  // --- Index-only mode: return lightweight verse list for the sidebar ---
  // Returns all verses but only the fields needed for navigation
  if (indexOnly) {
    const verses = await prisma.verse.findMany({
      where,
      orderBy: { verse: "asc" },
      select: {
        verse: true,
        verseEnd: true,
        reference: true,
      },
    });

    return NextResponse.json({ verses, total: verses.length });
  }

  // --- Paginated mode: return full verse data in pages ---
  const page = Math.max(1, parseInt(pageStr || "1"));
  const limit = Math.min(
    100,
    Math.max(1, parseInt(limitStr || String(DEFAULT_PAGE_SIZE))),
  );
  const skip = (page - 1) * limit;

  const [verses, total] = await Promise.all([
    prisma.verse.findMany({
      where,
      orderBy: { verse: "asc" },
      skip,
      take: limit,
    }),
    prisma.verse.count({ where }),
  ]);

  return NextResponse.json({
    verses,
    total,
    page,
    limit,
    totalPages: Math.ceil(total / limit),
    hasMore: skip + verses.length < total,
  });
}