/**
 * Utility function for making HTTP requests with timeout
 * 
 * This is a critical production utility to prevent hanging requests
 * that can exhaust server resources.
 */

export interface FetchWithTimeoutOptions extends RequestInit {
  timeout?: number; // Timeout in milliseconds (default: 30000)
}

/**
 * Fetch with automatic timeout handling
 * 
 * @param url - The URL to fetch
 * @param options - Fetch options including optional timeout
 * @returns Promise<Response>
 * @throws Error if timeout is exceeded or request fails
 * 
 * @example
 * ```typescript
 * const response = await fetchWithTimeout('https://api.example.com/data', {
 *   method: 'GET',
 *   timeout: 10000, // 10 seconds
 *   headers: { 'Authorization': 'Bearer token' }
 * });
 * ```
 */
export async function fetchWithTimeout(
  url: string,
  options: FetchWithTimeoutOptions = {}
): Promise<Response> {
  const { timeout = 30000, ...fetchOptions } = options;

  // Create AbortController for timeout
  const controller = new AbortController();
  const timeoutId = setTimeout(() => {
    controller.abort();
  }, timeout);

  try {
    const response = await fetch(url, {
      ...fetchOptions,
      signal: controller.signal,
    });

    clearTimeout(timeoutId);
    return response;
  } catch (error) {
    clearTimeout(timeoutId);

    if (error instanceof Error && error.name === 'AbortError') {
      throw new Error(`Request timeout after ${timeout}ms: ${url}`);
    }

    throw error;
  }
}

/**
 * Fetch with timeout and automatic JSON parsing
 * 
 * @param url - The URL to fetch
 * @param options - Fetch options including optional timeout
 * @returns Promise<T> - Parsed JSON response
 * 
 * @example
 * ```typescript
 * const data = await fetchJsonWithTimeout('https://api.example.com/data', {
 *   method: 'GET',
 *   timeout: 10000,
 * });
 * ```
 */
export async function fetchJsonWithTimeout<T = any>(
  url: string,
  options: FetchWithTimeoutOptions = {}
): Promise<T> {
  const response = await fetchWithTimeout(url, options);

  if (!response.ok) {
    const errorText = await response.text().catch(() => 'Unknown error');
    throw new Error(
      `HTTP ${response.status} ${response.statusText}: ${errorText.substring(0, 200)}`
    );
  }

  const contentType = response.headers.get('content-type');
  if (!contentType || !contentType.includes('application/json')) {
    throw new Error(`Expected JSON response, got ${contentType}`);
  }

  return response.json();
}