import { API_URL } from '../config';

/** Errore restituito dal server nella forma { error: { code, message } }. */
export class ApiError extends Error {
  constructor(
    public readonly status: number,
    public readonly code: string,
    message: string,
  ) {
    super(message);
    this.name = 'ApiError';
  }
}

let accessToken: string | null = null;

export function setAccessToken(token: string | null): void {
  accessToken = token;
}

type RequestOptions = {
  method?: 'GET' | 'POST';
  body?: unknown;
};

export async function request<T>(path: string, options: RequestOptions = {}): Promise<T> {
  const headers: Record<string, string> = {};
  if (options.body !== undefined) headers['Content-Type'] = 'application/json';
  if (accessToken) headers['Authorization'] = `Bearer ${accessToken}`;

  let response: Response;
  try {
    response = await fetch(`${API_URL}/api/v1${path}`, {
      method: options.method ?? 'GET',
      headers,
      body: options.body !== undefined ? JSON.stringify(options.body) : undefined,
    });
  } catch {
    throw new ApiError(0, 'NETWORK_ERROR', 'Server non raggiungibile');
  }

  if (!response.ok) {
    let code = 'REQUEST_ERROR';
    let message = `Errore ${response.status}`;
    try {
      const payload = (await response.json()) as { error?: { code?: string; message?: string } };
      code = payload.error?.code ?? code;
      message = payload.error?.message ?? message;
    } catch {
      // risposta non JSON: si tengono i default
    }
    throw new ApiError(response.status, code, message);
  }

  return (await response.json()) as T;
}