import { rangeResponse, resolveReport, videoFor } from "@/lib/report/serve.mjs";

export const dynamic = "force-dynamic";

// A built CUT, to a <video> element: the deliverable (`kind=final`, the
// default) or the short window `--chrome-preview` writes (`kind=preview`).
//
// ?project&variant&kind. Names, never paths: the file is the pipeline's own
// variantPaths() for the manifest's slug and a variant from its list.
//
// The `v` contract is the segment route's: a re-render writes the SAME path, so
// the client passes the mtime it was told about (`x-video-mtime`) as `v`, and
// only a matching one may be cached.
export async function GET(request: Request) {
  const url = new URL(request.url);
  const kind = url.searchParams.get("kind") || "final";
  if (kind !== "final" && kind !== "preview") {
    return new Response("kind must be final or preview", { status: 400 });
  }
  const r = await resolveReport(url.searchParams.get("project") ?? "", url.searchParams.get("variant"));
  if ("error" in r) return new Response(r.error, { status: r.status });

  const video = await videoFor(r.project, r.manifest, r.variant, kind);
  if (!video) {
    // The normal state of a cut nobody has built yet; said in words.
    return new Response(
      kind === "preview" ? "no on-screen preview has been rendered for this cut yet" : "this cut has not been built yet",
      { status: 404 },
    );
  }

  const fresh = url.searchParams.get("v") === String(video.mtimeMs);
  return rangeResponse(request, {
    abs: video.abs,
    size: video.size,
    headers: {
      "content-type": "video/mp4",
      "accept-ranges": "bytes",
      "cache-control": fresh ? "private, max-age=3600, immutable" : "private, no-store",
      "x-video-mtime": String(video.mtimeMs),
      "x-video": video.rel,
    },
  });
}