const AUTH_STATE_COOKIE = "magent_logged_in";

export const getApiBase = () => process.env.NEXT_PUBLIC_API_BASE ?? "/api";

const setCookie = (name: string, value: string, maxAgeSeconds: number) => {
  if (typeof document === "undefined") return;
  document.cookie = `${name}=${value}; Max-Age=${maxAgeSeconds}; Path=/; SameSite=Lax`;
};

const clearCookie = (name: string) => {
  if (typeof document === "undefined") return;
  document.cookie = `${name}=; Max-Age=0; Path=/; SameSite=Lax`;
};

export const getToken = () => {
  if (typeof document === "undefined") return null;
  const cookies = document.cookie.split(";").map((entry) => entry.trim());
  const marker = cookies.find((entry) => entry.startsWith(`${AUTH_STATE_COOKIE}=`));
  if (!marker) return null;
  const [, value] = marker.split("=", 2);
  return value || null;
};

export const setToken = (_token: string) => {
  setCookie(AUTH_STATE_COOKIE, "1", 60 * 60 * 12);
};

export const clearToken = () => {
  clearCookie(AUTH_STATE_COOKIE);
  if (typeof window === "undefined") return;
  const baseUrl = getApiBase();
  void fetch(`${baseUrl}/auth/logout`, {
    method: "POST",
    credentials: "include",
    keepalive: true,
  }).catch(() => undefined);
};

export const logout = async () => {
  const baseUrl = getApiBase();
  clearCookie(AUTH_STATE_COOKIE);
  await fetch(`${baseUrl}/auth/logout`, {
    method: "POST",
    credentials: "include",
  });
};

export const authFetch = (input: RequestInfo | URL, init?: RequestInit) => {
  const headers = new Headers(init?.headers || {});
  return fetch(input, { ...init, headers, credentials: "include" });
};

export const getEventStreamToken = async () => {
  const baseUrl = getApiBase();
  const response = await authFetch(`${baseUrl}/auth/stream-token`);
  if (!response.ok) {
    const text = await response.text();
    throw new Error(text || `Stream token request failed: ${response.status}`);
  }
  const data = await response.json();
  const token = typeof data?.stream_token === "string" ? data.stream_token : "";
  if (!token) {
    throw new Error("Stream token not returned");
  }
  return token;
};

export class UnauthorizedError extends Error {
  constructor() {
    super("Unauthorized");
    this.name = "UnauthorizedError";
  }
}

export class ForbiddenError extends Error {
  constructor() {
    super("Forbidden");
    this.name = "ForbiddenError";
  }
}

export const authFetchOrThrow = async (input: RequestInfo | URL, init?: RequestInit) => {
  const response = await authFetch(input, init);
  if (response.status === 401) {
    clearToken();
    throw new UnauthorizedError();
  }
  if (response.status === 403) {
    throw new ForbiddenError();
  }
  return response;
};

export const readResponseText = async (response: Response) => {
  try {
    return (await response.text()).trim();
  } catch {
    return "";
  }
};