/** Types mirror what app.py's track_row() and endpoints actually return. */

export type Track = {
  deezer_id: number;
  title: string;
  artist: string;
  artist_id: number | null;
  artist_pic: string | null;
  album: string;
  album_id: number | null;
  cover: string | null;
  cover_big: string | null;
  length: number;
  preview: string | null;
  explicit: boolean;
  isrc: string | null;
  rank: number;
  year: string | null;
  genre: string | null;
  track: number | null;
  disc?: number | null;
};

export type AlbumHeader = {
  album_id: number;
  title: string;
  artist: string;
  artist_id: number | null;
  cover: string | null;
  cover_big: string | null;
  year: string | null;
  genres: string[];
  label: string | null;
  nb_tracks: number | null;
  record_type: string | null;
  duration: number | null;
};

export type ArtistHeader = {
  artist_id: number;
  name: string;
  picture: string | null;
  nb_fan: number | null;
  nb_album: number | null;
};

export type AlbumCard = {
  album_id: number;
  title: string;
  cover: string | null;
  cover_big: string | null;
  year: string | null;
  record_type: string | null;
  nb_tracks: number | null;
};

export type Suggestions = {
  tracks: {
    deezer_id: number;
    title: string;
    artist: string;
    cover: string | null;
    preview: string | null;
  }[];
  albums: {
    album_id: number;
    title: string;
    artist: string;
    cover: string | null;
    nb_tracks: number | null;
  }[];
  artists: {
    artist_id: number;
    name: string;
    cover: string | null;
    nb_album: number | null;
  }[];
};

export type Job = {
  id: string;
  state: "queued" | "searching" | "downloading" | "imported" | "failed";
  detail: string | null;
  artist: string;
  title: string;
  album: string | null;
  year: string | null;
  cover: string | null;
  genre: string | null;
  duration: number | null;
  requested_by: string | null;
  created_at: string;
};

export type Me = {
  user: string | null;
  auth: string;
  role?: string;
  display?: string | null;
  avatar?: string | null;
  quota?: number;
};

/**
 * Every response goes through here so a 401 is a typed failure rather than a
 * JSON parse error thirty lines away. Sessions expire, and when one does the
 * UI should say "signed out", not "Unexpected token < in JSON".
 */
export class ApiError extends Error {
  constructor(
    public status: number,
    message: string,
  ) {
    super(message);
  }
}

async function get<T>(path: string, init?: RequestInit): Promise<T> {
  const r = await fetch(path, { credentials: "same-origin", ...init });
  if (r.status === 401) throw new ApiError(401, "signed out");
  if (!r.ok) throw new ApiError(r.status, `HTTP ${r.status}`);
  return (await r.json()) as T;
}

function post<T>(path: string, body?: unknown): Promise<T> {
  return get<T>(path, {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: body === undefined ? undefined : JSON.stringify(body),
  });
}

export const api = {
  me: () => get<Me>("/api/me"),
  search: (q: string) =>
    get<{ results: Track[] }>(`/api/search?q=${encodeURIComponent(q)}`),
  suggest: (q: string, signal?: AbortSignal) =>
    get<Suggestions>(`/api/suggest?q=${encodeURIComponent(q)}`, { signal }),
  album: (id: number | string) =>
    get<{ album: AlbumHeader; tracks: Track[] }>(
      `/api/album/${encodeURIComponent(String(id))}`,
    ),
  artist: (id: number | string) =>
    get<{ artist: ArtistHeader; tracks: Track[]; albums: AlbumCard[] }>(
      `/api/artist/${encodeURIComponent(String(id))}`,
    ),
  request: (t: Track) => post<{ id: string }>("/api/request", t),
  requestBatch: (tracks: Track[]) =>
    post<{ queued: number; ids: string[]; pending: number }>(
      "/api/request/batch",
      { tracks },
    ),
  jobs: () =>
    get<{ jobs: Job[]; counts: Record<string, number>; pending: number }>(
      "/api/jobs",
    ),
  retry: (id: string) => post<{ ok: boolean }>(`/api/retry/${id}`),
  importList: (text: string) =>
    post<{
      queued: { id: string; line: string; matched: string; cover: string | null }[];
      skipped: { line: string; why: string }[];
      pending: number;
    }>("/api/import", { text }),
};

export const mmss = (ms: number | null | undefined) => {
  const t = Math.round((ms || 0) / 1000);
  return `${Math.floor(t / 60)}:${String(t % 60).padStart(2, "0")}`;
};