/** 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 ReviewItem = {
  id: string;
  artist: string;
  title: string;
  album: string | null;
  year: string | null;
  cover: string | null;
  /** 0..1. Below the auto threshold, which is why this is here at all. */
  confidence: number | null;
  /** Human-readable reasons behind the score, semicolon-joined. */
  why: string | null;
  /** Basename of the file sitting in downloads, awaiting a decision. */
  file: string;
  path: string | null;
  size: number | null;
  requested_by: string | null;
  created_at: string;
};

export type Discover = {
  seeds: string[];
  artists: {
    id: number;
    name: string;
    picture: string | null;
    fans: number | null;
  }[];
};

export type Recap = {
  days: number;
  tracks: number;
  bytes: number;
  artists: { name: string; n: number }[];
  genres: { name: string; n: number }[];
  decades: { decade: string; n: number }[];
  busiest_day: { date: string; n: number } | null;
};

export type Job = {
  id: string;
  state: "queued" | "searching" | "downloading" | "review" | "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 Usage = { requests: number; storage: number };

export type Me = {
  user: string | null;
  auth: string;
  role?: string | null;
  display?: string | null;
  avatar?: string | null;
  provider?: string;
  quota?: number;
  storage_quota?: number;
  usage?: Usage;
  providers?: string[];
  email?: string | null;
  notify?: boolean;
  /** SMTP is configured server-side; without it the settings are inert. */
  mail_configured?: boolean;
};

export type AdminUser = {
  username: string;
  provider: string;
  role: string;
  display: string | null;
  avatar: string | null;
  quota: number;
  storage_quota: number;
  disabled: boolean;
  created_at: string;
  last_seen: string | null;
  invited_by: string | null;
  usage: Usage;
  email: string | null;
  notify: boolean;
  /** In MUSE_ALLOWED_USERS — cannot actually be locked out by disabling. */
  bootstrap: boolean;
};

export type DiskStat = { total: number; used: number; free: number; pct: number | null };

export type SystemStats = {
  system: {
    cpu_pct: number | null;
    cpus: number | null;
    mem_total: number | null;
    mem_used: number | null;
    mem_pct: number | null;
    load: number[] | null;
    disks: Record<string, DiskStat | null>;
  };
  workers: number;
  pending: number;
  jobs: Record<string, number>;
  library: { tracks: number; bytes: number };
  users: number;
  sessions: number;
  slskd: {
    ok: boolean;
    connected?: boolean;
    logged_in?: boolean;
    version?: string;
    shared_files?: number | null;
    error?: string;
  };
};

export type Activity = {
  days: number;
  series: { date: string; n: number; imported: number; failed: number }[];
  per_user: { u: string; n: number; bytes: number }[];
  top_artists: { artist: string; n: 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) {
    // FastAPI puts the useful part in `detail` — quota messages, "only active
    // admin", and so on. Surfacing "HTTP 429" instead would throw away the
    // only text that tells the user what to do about it.
    let msg = `HTTP ${r.status}`;
    try {
      const body = await r.json();
      if (typeof body?.detail === "string") msg = body.detail;
      else if (typeof body?.error === "string") msg = body.error;
    } catch {
      /* not JSON */
    }
    throw new ApiError(r.status, msg);
  }
  return (await r.json()) as T;
}

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

const post = <T,>(path: string, body?: unknown) => send<T>("POST", path, 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/${id}`),
  settings: (s: { email?: string | null; notify?: boolean }) =>
    send<{ ok: boolean; mail_configured: boolean }>("PATCH", "/api/me", s),
  review: () =>
    get<{
      items: ReviewItem[];
      thresholds: { auto: number; review: number };
    }>("/api/review"),
  decide: (id: string, action: "approve" | "reject") =>
    post<{ ok: boolean; state: string }>(`/api/review/${id}`, { action }),
  discover: () => get<Discover>("/api/discover"),
  recap: () => get<Recap>("/api/recap"),
  importList: (text: string) =>
    post<{
      queued: { id: string; line: string; matched: string; cover: string | null }[];
      skipped: { line: string; why: string }[];
      pending: number;
    }>("/api/import", { text }),

  admin: {
    users: () => get<{ users: AdminUser[]; roles: string[] }>("/api/admin/users"),
    resend: (username: string) =>
      post<{ ok: boolean; sent_to: string }>(
        `/api/admin/users/${encodeURIComponent(username)}/resend`,
      ),
    addUser: (u: {
      username: string;
      provider: string;
      role: string;
      quota: number;
      storage_quota_gb: number;
      email?: string;
    }) =>
      post<AdminUser & { invite_sent: boolean; invite_why: string | null }>(
        "/api/admin/users",
        u,
      ),
    patchUser: (
      username: string,
      patch: Partial<{
        role: string;
        quota: number;
        storage_quota_gb: number;
        disabled: boolean;
      }>,
    ) => send<AdminUser>("PATCH", `/api/admin/users/${encodeURIComponent(username)}`, patch),
    deleteUser: (username: string) =>
      send<{ ok: boolean }>("DELETE", `/api/admin/users/${encodeURIComponent(username)}`),
    system: () => get<SystemStats>("/api/admin/system"),
    activity: (days = 30) => get<Activity>(`/api/admin/activity?days=${days}`),
  },
};

/** Bytes → human. Binary units, because that's what df and the OS report. */
export function bytes(n: number | null | undefined): string {
  if (!n) return "0 B";
  const u = ["B", "KB", "MB", "GB", "TB"];
  let i = 0;
  let v = n;
  while (v >= 1024 && i < u.length - 1) {
    v /= 1024;
    i++;
  }
  return `${v.toFixed(v < 10 && i > 0 ? 1 : 0)} ${u[i]}`;
}

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")}`;
};