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

export async function fetchJson<T = unknown>(path: string, init?: RequestInit): Promise<T> {
  const res = await fetch(path, {
    ...init,
    headers: {
      ...(init?.body ? { 'Content-Type': 'application/json' } : {}),
      ...init?.headers,
    },
  });
  const body = await res.json().catch(() => null);
  if (!res.ok) {
    const message = Array.isArray(body?.message)
      ? body.message.join('; ')
      : body?.message || `Request failed (${res.status})`;
    throw new ApiError(res.status, message);
  }
  return body as T;
}

export const api = {
  get: <T = unknown>(path: string) => fetchJson<T>(path),
  post: <T = unknown>(path: string, data: unknown) =>
    fetchJson<T>(path, { method: 'POST', body: JSON.stringify(data) }),
  patch: <T = unknown>(path: string, data: unknown) =>
    fetchJson<T>(path, { method: 'PATCH', body: JSON.stringify(data) }),
  delete: <T = unknown>(path: string) => fetchJson<T>(path, { method: 'DELETE' }),
};