import { listSongs, readSong } from "@/lib/browse";
import { allContext, clipCitation, momentCitation, momentsContext, songContext } from "@/lib/context";

export const dynamic = "force-dynamic";

// The paste. Markdown, as text/plain, so `curl` gives you something you can
// read and the UI can drop it straight on the clipboard.
//
//   /api/browse/context?song=metal-slug        one song
//   /api/browse/context                        every song
//   /api/browse/context?song=x&rel=y&t=42.3    one moment, resolved
//   /api/browse/context?song=x&rel=y           every mark on that file
//   /api/browse/context?song=x&clip=<id>       one clip in the arrangement
//
// The moment form is the one that could not exist before: a timestamp on a
// rendered file, turned back into the clip playing there and a link to that
// moment in the archive.

const text = (body: string) =>
  new Response(body, {
    headers: { "content-type": "text/plain; charset=utf-8", "cache-control": "no-store" },
  });

export async function GET(request: Request) {
  const url = new URL(request.url);
  const id = url.searchParams.get("song");
  const rel = url.searchParams.get("rel");
  const t = url.searchParams.get("t");

  if (!id) {
    const songs = await listSongs();
    return text(await allContext(songs.map((s) => s.id)));
  }

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

  const clip = url.searchParams.get("clip");
  if (clip) {
    if (!/^[A-Za-z0-9_-]+@[0-9.]+$/.test(clip)) return new Response("bad clip", { status: 400 });
    return text(await clipCitation(id, clip));
  }

  if (rel) {
    const known = [
      ...song.cuts.flatMap((c) => [c.shipped, ...c.variants]),
      ...song.unattributed,
    ].some((r) => r && r.rel === rel);
    if (!known) return new Response("not a file in this song", { status: 404 });

    // With a `t`, one moment. Without, every mark on that file -- which is what
    // the "copy N marks" button wants, and what citing only the first was
    // quietly doing wrong.
    if (t === null) return text(await momentsContext(id, rel));

    const seconds = Number(t);
    if (!Number.isFinite(seconds) || seconds < 0) return new Response("bad t", { status: 400 });
    return text(await momentCitation(id, rel, seconds, url.searchParams.get("note") ?? undefined));
  }

  return text(await songContext(id));
}