/** BeatSaver public API — map key / hash resolution for campaign `songid` + `hash`. */

const BEATSAVER_BASE = "https://api.beatsaver.com";

export type BeatSaverMapMeta = {
  id: string;
  name?: string;
  /** Lowercase SHA-1 for latest / selected version */
  hash: string;
  songName?: string;
  songSubName?: string;
  levelAuthorName?: string;
  uploaderName?: string;
  coverURL?: string;
};

function asRecord(v: unknown): Record<string, unknown> | null {
  return v != null && typeof v === "object" && !Array.isArray(v)
    ? (v as Record<string, unknown>)
    : null;
}

async function fetchJson(url: string): Promise<unknown> {
  const res = await fetch(url);
  if (!res.ok) {
    throw new Error(`BeatSaver request failed ${res.status} ${url}`);
  }
  return res.json();
}

function pickLatestVersionHashes(
  versions: unknown,
): { hash: string; coverURL?: string } | null {
  if (!Array.isArray(versions) || versions.length === 0) return null;
  const last = versions[versions.length - 1];
  const vr = asRecord(last);
  if (!vr) return null;
  const h = vr["hash"];
  const coverURL = vr["coverURL"];
  return {
    hash: typeof h === "string" ? h : "",
    coverURL: typeof coverURL === "string" ? coverURL : undefined,
  };
}

export function mapBeatSaverResponseToMeta(
  data: unknown,
): BeatSaverMapMeta | null {
  const r = asRecord(data);
  if (!r) return null;
  const meta = asRecord(r["metadata"]);
  const uid = asRecord(r["uploader"]);
  const vhash = pickLatestVersionHashes(r["versions"]);
  const id = r["id"];
  if (!vhash?.hash || typeof id !== "string") return null;
  return {
    id,
    name: typeof r["name"] === "string" ? r["name"] : undefined,
    hash: vhash.hash,
    songName: meta?.["songName"] as string | undefined,
    songSubName: meta?.["songSubName"] as string | undefined,
    levelAuthorName: meta?.["levelAuthorName"] as string | undefined,
    uploaderName: uid?.["name"] as string | undefined,
    coverURL: vhash.coverURL,
  };
}

export async function fetchBeatSaverByKey(
  key: string,
): Promise<BeatSaverMapMeta | null> {
  const trimmed = key.trim().toLowerCase();
  if (!trimmed) return null;
  const data = await fetchJson(
    `${BEATSAVER_BASE}/maps/id/${encodeURIComponent(trimmed)}`,
  );
  return mapBeatSaverResponseToMeta(data);
}

export async function fetchBeatSaverByHash(
  hash: string,
): Promise<BeatSaverMapMeta | null> {
  const h = hash.trim().toLowerCase();
  if (!h) return null;
  const data = await fetchJson(
    `${BEATSAVER_BASE}/maps/hash/${encodeURIComponent(h)}`,
  );
  return mapBeatSaverResponseToMeta(data);
}

/** Strip Twitch-style `!bsr` prefix when pasting a map key (e.g. `!bsr 43a47` → `43a47`). */
export function normalizeBeatSaverLookupInput(input: string): string {
  return input.trim().replace(/^!bsr\s*/i, "").trim();
}

export async function resolveBeatSaverMeta(
  input: string,
): Promise<BeatSaverMapMeta | null> {
  const s = normalizeBeatSaverLookupInput(input);
  if (!s) return null;
  if (/^[a-f0-9]{40}$/i.test(s)) {
    return await fetchBeatSaverByHash(s);
  }
  return await fetchBeatSaverByKey(s);
}