import { NextRequest, NextResponse } from "next/server";
import { assertLocalRequest } from "@/lib/api/localOnly";
import { rawDb } from "@/lib/db/client";

export const runtime = "nodejs";
export const dynamic = "force-dynamic";

interface CandidateRow {
  id: number;
  code: string;
  title: string | null;
  thumb_path: string;
}

/**
 * Codes with a playable video but no discoverable subtitle. The user
 * picks from this list when running batch WhisperJAV generation.
 *
 * has_subtitle is the cheap signal — populated by the video index
 * scan (sidecar files / generated subs / library roots).
 */
export async function GET(req: NextRequest) {
  const blocked = assertLocalRequest(req);
  if (blocked) return blocked;

  const limit = Math.min(500, Math.max(1, Number(req.nextUrl.searchParams.get("limit") ?? "200")));
  const offset = Math.max(0, Number(req.nextUrl.searchParams.get("offset") ?? "0"));
  const includeAlreadyHasSubs = req.nextUrl.searchParams.get("all") === "1";

  const where = includeAlreadyHasSubs
    ? `i.has_video = 1 AND i.code IS NOT NULL AND i.deleted_at IS NULL AND i.parent_image_id IS NULL`
    : `i.has_video = 1 AND i.has_subtitle = 0 AND i.code IS NOT NULL AND i.deleted_at IS NULL AND i.parent_image_id IS NULL`;

  const rows = rawDb.prepare(`
    SELECT i.id, i.code, i.title, i.thumb_path
    FROM images i
    WHERE ${where}
    ORDER BY UPPER(i.code) ASC
    LIMIT ? OFFSET ?
  `).all(limit, offset) as CandidateRow[];

  const totalRow = rawDb.prepare(`
    SELECT COUNT(*) AS n FROM images i WHERE ${where}
  `).get() as { n: number };

  return NextResponse.json({
    candidates: rows.map((r) => ({
      id: r.id,
      code: r.code,
      title: r.title,
      thumbPath: r.thumb_path,
    })),
    total: totalRow.n,
  });
}