async function api(method, path, body) {
  const opts = {
    method,
    headers: { "Content-Type": "application/json" },
    credentials: "include",
  };
  if (body !== undefined) opts.body = JSON.stringify(body);
  const res = await fetch(apiURL(path), opts);
  if (res.status === 204) return null;
  let data = null;
  const text = await res.text();
  if (text) {
    try { data = JSON.parse(text); } catch (e) { data = text; }
  }
  if (!res.ok) {
    const err = new Error((data && data.error) || res.statusText);
    err.status = res.status;
    err.data = data;
    throw err;
  }
  return data;
}

const API = {
  login: (u, p) => api("POST", "/api/login", { username: String(u || "").toLowerCase().trim(), password: p }),
  logout: () => api("POST", "/api/logout"),
  me: () => api("GET", "/api/me"),
  updateMe: (b) => api("PATCH", "/api/me", b),

  listUsers: () => api("GET", "/api/users"),
  createUser: (b) => api("POST", "/api/users", b),
  updateUser: (id, b) => api("PATCH", `/api/users/${id}`, b),
  deleteUser: (id) => api("DELETE", `/api/users/${id}`),

  listCompetitions: () => api("GET", "/api/competitions"),
  createCompetition: (b) => api("POST", "/api/competitions", b),
  getCompetition: (id) => api("GET", `/api/competitions/${id}`),
  updateCompetition: (id, b) => api("PATCH", `/api/competitions/${id}`, b),
  deleteCompetition: (id) => api("DELETE", `/api/competitions/${id}`),

  listMembers: (id) => api("GET", `/api/competitions/${id}/members`),
  addMember: (id, b) => api("POST", `/api/competitions/${id}/members`, b),
  removeMember: (id, uid) => api("DELETE", `/api/competitions/${id}/members/${uid}`),

  listPilots: (id) => api("GET", `/api/competitions/${id}/pilots`),
  createPilot: (id, b) => api("POST", `/api/competitions/${id}/pilots`, b),
  updatePilot: (id, pid, b) => api("PATCH", `/api/competitions/${id}/pilots/${pid}`, b),
  deletePilot: (id, pid) => api("DELETE", `/api/competitions/${id}/pilots/${pid}`),
  importPilots: async (id, csv) => {
    const res = await fetch(apiURL(`/api/competitions/${id}/pilots/import`), {
      method: "POST",
      headers: { "Content-Type": "text/csv" },
      body: csv,
      credentials: "include",
    });
    if (!res.ok) throw new Error("import_failed");
    return res.json();
  },

  listPenalties: (id) => api("GET", `/api/competitions/${id}/penalties`),
  createPenalty: (id, b) => api("POST", `/api/competitions/${id}/penalties`, b),
  updatePenalty: (id, pid, b) => api("PATCH", `/api/competitions/${id}/penalties/${pid}`, b),
  deletePenalty: (id, pid) => api("DELETE", `/api/competitions/${id}/penalties/${pid}`),
  applyPenalties: (id, b) => api("POST", `/api/competitions/${id}/penalties/apply`, b),
  exportPenaltiesCSV: async (id) => {
    const res = await fetch(apiURL(`/api/competitions/${id}/penalties.csv`), { credentials: "include" });
    if (!res.ok) throw new Error("export_failed");
    return res.blob();
  },

  listRules: (lang) => api("GET", `/api/rules${lang ? "?lang=" + encodeURIComponent(lang) : ""}`),
  listRuleLanguages: () => api("GET", "/api/rules/languages"),
};

function openCompetitionWS(id, handlers) {
  const url = wsURL(`/api/competitions/${id}/ws`);
  let ws = null;
  let closed = false;
  let backoff = 1000;

  function connect() {
    ws = new WebSocket(url);
    ws.onopen = () => { backoff = 1000; if (handlers.onopen) handlers.onopen(); };
    ws.onmessage = (e) => {
      try {
        const msg = JSON.parse(e.data);
        if (handlers.onmessage) handlers.onmessage(msg);
      } catch (err) {}
    };
    ws.onclose = () => {
      if (handlers.onclose) handlers.onclose();
      if (!closed) {
        setTimeout(connect, backoff);
        backoff = Math.min(backoff * 2, 15000);
      }
    };
    ws.onerror = () => { try { ws.close(); } catch (e) {} };
  }
  connect();
  return {
    close: () => { closed = true; try { ws && ws.close(); } catch (e) {} }
  };
}