api.ts

const API_URL = process.env.NEXT_PUBLIC_API_URL ?? 'http://localhost:3000';
const TOKEN_KEY = 'stellartickets.token';

export class ApiError extends Error {
  constructor(
    message: string,
    public readonly status: number,
  ) {
    super(message);
    this.name = 'ApiError';
  }
}

export function getToken(): string | null {
  if (typeof window === 'undefined') return null;
  return window.localStorage.getItem(TOKEN_KEY);
}

export function setToken(token: string) {
  window.localStorage.setItem(TOKEN_KEY, token);
}

export function clearToken() {
  window.localStorage.removeItem(TOKEN_KEY);
}

interface RequestOptions {
  method?: 'GET' | 'POST' | 'PATCH' | 'DELETE';
  body?: unknown;
  auth?: boolean;
}

/** Backend BigInt fields (prices, chain ids) arrive as JSON strings/numbers depending on Nest's serializer; kept as strings end-to-end. */
export async function apiFetch<T>(path: string, options: RequestOptions = {}): Promise<T> {
  const { method = 'GET', body, auth = true } = options;
  const headers: Record<string, string> = { 'Content-Type': 'application/json' };

  if (auth) {
    const token = getToken();
    if (token) headers.Authorization = `Bearer ${token}`;
  }

  const res = await fetch(`${API_URL}${path}`, {
    method,
    headers,
    body: body !== undefined ? JSON.stringify(body) : undefined,
  });

  if (!res.ok) {
    const payload = await res.json().catch(() => null);
    const message = Array.isArray(payload?.message)
      ? payload.message.join(', ')
      : (payload?.message ?? res.statusText);
    throw new ApiError(message, res.status);
  }

  if (res.status === 204) return undefined as T;
  return res.json() as Promise<T>;
}