import { readSong } from "@/lib/browse";
import { isTarget, readNotes, setNote, readTrimNotes, setTrimNote, NOTE_LIMIT } from "@/lib/notes";
import { TRIM_SETS } from "@/lib/trim";

export const dynamic = "force-dynamic";

// Notes on anything selectable.
//
// The target is validated for SHAPE but not for existence, deliberately. You
// write a note about `cut:vertical` for a cut that has not been built yet --
// that is precisely when the note is worth having -- and about a clip from a
// plan that is not the one currently selected. Requiring the thing to exist
// first would rule out the most useful notes in the set.

export async function GET(request: Request) {
  const url = new URL(request.url);
  const set = url.searchParams.get("set");
  if (set) {
    if (!TRIM_SETS[set]) return Response.json({ error: "no such trim set" }, { status: 404 });
    return Response.json(
      { notes: await readTrimNotes() },
      { headers: { "cache-control": "no-store" } },
    );
  }

  const id = url.searchParams.get("song") ?? "";
  const song = await readSong(id);
  if (!song) return Response.json({ error: "no such song" }, { status: 404 });
  return Response.json({ notes: await readNotes(id) }, { headers: { "cache-control": "no-store" } });
}

export async function POST(request: Request) {
  let body: { song?: string; set?: string; hook?: string; target?: string; note?: string };
  try {
    body = await request.json();
  } catch {
    return Response.json({ error: "bad json" }, { status: 400 });
  }

  const note = typeof body.note === "string" ? body.note : "";
  if (note.length > NOTE_LIMIT) {
    return Response.json({ error: `notes are capped at ${NOTE_LIMIT} characters` }, { status: 400 });
  }

  // Trim-set notes are not song-scoped: a hook belongs to a catalogue shared
  // across songs, so it cannot live in one song's notes.json.
  if (body.set) {
    const set = TRIM_SETS[body.set];
    if (!set) return Response.json({ error: "no such trim set" }, { status: 404 });
    if (!body.hook || !/^[A-Za-z0-9._-]+$/.test(body.hook)) {
      return Response.json({ error: "hook is required" }, { status: 400 });
    }
    const notes = await setTrimNote(set.id, body.hook, note);
    return Response.json({ ok: true, notes }, { headers: { "cache-control": "no-store" } });
  }

  const id = body.song ?? "";
  const target = body.target ?? "";
  if (!isTarget(target)) return Response.json({ error: `bad target: ${target}` }, { status: 400 });

  const song = await readSong(id);
  if (!song) return Response.json({ error: "no such song" }, { status: 404 });

  const notes = await setNote(id, target, note);
  return Response.json(
    { ok: true, target, entry: notes[target] ?? null, notes },
    { headers: { "cache-control": "no-store" } },
  );
}