/*
 * API communication module. Centralizes fetch calls so network details stay
 * out of rendering and state logic. All JSON traffic from the frontend goes
 * through `fetchJson()`, which prepends the versioned base path and unwraps
 * structured error responses into regular thrown errors.
 */

import { API_BASE } from './constants.js';

/*
 * Generic JSON fetcher. Prepends the API base path when the caller passes a
 * relative path, forwards headers, and parses the response body on success.
 * Non-2xx responses raise an `Error` whose message is the server's `message`
 * field when present, otherwise a generic status-code fallback.
 */
export async function fetchJson(path, options = {}) {
  const url = path.startsWith('http') ? path : `${API_BASE}${path}`;

  const requestOptions = {
    ...options,
    headers: {
      Accept: 'application/json',
      ...(options.headers || {})
    }
  };

  const response = await fetch(url, requestOptions);

  if (!response.ok) {
    let message = `Request failed for ${url}: ${response.status}`;

    try {
      const errorPayload = await response.json();

      if (errorPayload?.message) {
        message = errorPayload.message;
      }
    } catch {
      /* Ignore JSON parse errors for non-JSON responses. */
    }

    throw new Error(message);
  }

  return response.json();
}