import { createReadStream, statSync } from "node:fs";
import { Readable } from "node:stream";
import { finishDownloadJob, getDownloadJob, jsonError, requireDownloadAccess } from "../helpers/downloadJobs";

function contentDisposition(fileName: string) {
  const ascii = fileName.replace(/[^\x20-\x7e]/g, "_").replace(/["\\]/g, "_");
  return `attachment; filename="${ascii}"; filename*=UTF-8''${encodeURIComponent(fileName)}`;
}

export async function handle(request: Request) {
  try {
    const access = await requireDownloadAccess(request);
    if (access.error) return access.error;

    const jobId = new URL(request.url).searchParams.get("jobId") || "";
    const job = getDownloadJob(jobId, access.userId);
    if (!job || job.status !== "ready" || !job.filePath || !job.fileName) {
      return jsonError("This download is not ready or has already been collected.", 404);
    }

    const size = statSync(job.filePath).size;
    const stream = createReadStream(job.filePath);
    stream.on("close", () => finishDownloadJob(job));

    return new Response(Readable.toWeb(stream) as ReadableStream, {
      headers: {
        "Content-Type": job.kind === "playlist" ? "application/zip" : "audio/mpeg",
        "Content-Length": String(size),
        "Content-Disposition": contentDisposition(job.fileName),
        "Cache-Control": "no-store",
      },
    });
  } catch (error) {
    return jsonError(error instanceof Error ? error.message : "Unable to send the file.", 500);
  }
}