const baseUrl = import.meta.env.VITE_API_URL ?? 'http://localhost:3000';

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

type ApiOptions = RequestInit & {
  token?: string;
};

export function getApiToken(): string | null {
  return localStorage.getItem('montime_access_token');
}

export async function api<T>(path: string, options: ApiOptions = {}): Promise<T> {
  const token = options.token ?? getApiToken() ?? undefined;
  const headers: Record<string, string> = {
    'Content-Type': 'application/json',
    ...(options.headers as Record<string, string> | undefined),
  };

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

  const { token: _token, ...fetchOptions } = options;

  const res = await fetch(`${baseUrl}${path}`, {
    ...fetchOptions,
    headers,
  });

  if (!res.ok) {
    const body = (await res.json().catch(() => null)) as
      | { message?: string | string[] }
      | null;
    let msg: string;
    if (Array.isArray(body?.message)) {
      const lines = body.message.map(String);
      const timeErrors = lines.filter((l) =>
        /startTime|endTime/.test(l) && /regular expression|HH:mm/i.test(l),
      );
      msg =
        timeErrors.length > 0
          ? 'فرمت ساعت نامعتبر است. لطفاً دوباره بازه را اضافه و ذخیره کنید.'
          : lines.join(' · ');
    } else {
      msg = body?.message ?? res.statusText;
    }
    throw new ApiError(res.status, msg);
  }

  if (res.status === 204) {
    return undefined as T;
  }

  return res.json() as Promise<T>;
}