/**
 * API utilities for consistent request handling
 */

/**
 * Normalizes a URL to ensure it passes through the Next.js API proxy
 * This ensures all client-side requests go through the Next.js rewrites.
 * 
 * @param url The endpoint URL to normalize 
 * @returns A normalized URL with proper /api prefix
 */
export function normalizeApiUrl(url: string): string {
  if (url.startsWith('/api/')) {
    return url; // Already has /api/ prefix
  } else {
    // Add /api prefix, handling any leading slashes
    const cleanUrl = url.startsWith('/') ? url : `/${url}`;
    return `/api${cleanUrl}`;
  }
}

/**
 * Constructs a server-side API URL for backend requests
 * Used in Server Components and API routes to directly access the backend API
 * 
 * @param endpoint The API endpoint path
 * @returns A complete URL to the backend API
 */
export function getServerApiUrl(endpoint: string): string {
  const apiUrl = process.env.SERVER_API_URL || 'https://internal-api.inboxi.ng/api';
  const cleanEndpoint = endpoint.startsWith('/') ? endpoint.substring(1) : endpoint;
  
  return apiUrl.endsWith('/') 
    ? `${apiUrl}${cleanEndpoint}`
    : `${apiUrl}/${cleanEndpoint}`;
}

/**
 * Get the authentication token from cookies or localStorage
 */
export function getAuthToken(): string | null {
  if (typeof document === 'undefined') return null; // Guard for SSR
  
  return document.cookie
    .split('; ')
    .find(row => row.startsWith('Authorization='))
    ?.split('=')[1] || localStorage.getItem('Authorization');
}

/**
 * Check if the user is logged in
 */
export function isAuthenticated(): boolean {
  return !!getAuthToken();
}

/**
 * Creates standard API request headers with authentication
 * 
 * @param token Optional auth token (fetched automatically if not provided)
 * @param customHeaders Additional headers to include
 * @returns Headers object ready for fetch requests
 */
export function createApiHeaders(token?: string | null, customHeaders: Record<string, string> = {}): Headers {
  const headers = new Headers({
    'Content-Type': 'application/json',
    ...customHeaders
  });

  const authToken = token || getAuthToken();
  if (authToken) {
    headers.set('Authorization', `Bearer ${authToken}`);
  }

  return headers;
}