import { readSong } from "@/lib/browse";
import { readSpec, writeSpec, validateSpec, operationsFor, type Spec } from "@/lib/spec";

export const dynamic = "force-dynamic";

// Read and write one song's spec sheet.
//
// The other writer is song/spec.mjs on the CLI, which is the whole point --
// the sheet is meant to be something both sides edit. So this re-reads on every
// request and writes through withStateLock + writeJsonAtomic, exactly as the
// clip state does for the same reason.

export async function GET(request: Request) {
  const id = new URL(request.url).searchParams.get("song") ?? "";
  const song = await readSong(id);
  if (!song) return Response.json({ error: "no such song" }, { status: 404 });
  const spec = await readSpec(id);
  return Response.json(
    { spec, problems: await validateSpec(spec), operations: operationsFor(spec, song) },
    { headers: { "cache-control": "no-store" } },
  );
}

export async function PUT(request: Request) {
  let body: { song?: string; spec?: Spec };
  try {
    body = await request.json();
  } catch {
    return Response.json({ error: "bad json" }, { status: 400 });
  }
  const id = body.song ?? "";
  const song = await readSong(id);
  if (!song) return Response.json({ error: "no such song" }, { status: 404 });
  if (!body.spec || typeof body.spec !== "object") {
    return Response.json({ error: "spec is required" }, { status: 400 });
  }

  // Problems are REPORTED, not refused. A half-finished sheet is a normal state
  // to save from -- you point the background at a file you are about to render,
  // and it does not exist yet. Refusing the write would mean the only way to
  // author one is to get it right in a single pass.
  const spec = await writeSpec(id, body.spec);
  return Response.json(
    { ok: true, spec, problems: await validateSpec(spec), operations: operationsFor(spec, song) },
    { headers: { "cache-control": "no-store" } },
  );
}