import { cookies } from 'next/headers';
import { redirect } from 'next/navigation';

/**
 * Gets the base URL for server API requests with proper fallbacks
 */
function getBaseUrl() {
  // For server components, we normally would use environment variables
  // But we need to be careful with how they're accessed
  
  // Try to get the API URL from environment variables
  const apiUrl = process.env.NEXT_PUBLIC_API_URL;
  
  // We need to get the host from somewhere to construct the URL
  // In production, we can rely on the VERCEL_URL or similar
  if (process.env.VERCEL_URL) {
    return `https://${process.env.VERCEL_URL}/api`;
  }
  
  // If we have a configured API URL, use that
  if (apiUrl) {
    // If it's already an absolute URL, use it
    if (apiUrl.startsWith('http')) {
      return apiUrl;
    }
    // Otherwise, it's likely a relative path like /api
    return `http://localhost:3000${apiUrl.startsWith('/') ? apiUrl : `/${apiUrl}`}`;
  }
  
  // Last resort fallback for development
  return 'http://localhost:3000/api';
}

/**
 * Server-side fetch wrapper with authentication.
 */
export async function fetchServer<T = unknown>(
  endpoint: string,
  options: RequestInit = {}
): Promise<T> {
  const cookieStore = cookies();
  const authToken = cookieStore.get('Authorization')?.value;

  if (!authToken) redirect('/login');

  try {
    const baseUrl = getBaseUrl();
    
    // Ensure endpoint doesn't start with a slash if baseUrl ends with one
    const normalizedEndpoint = endpoint.startsWith('/') ? endpoint.substring(1) : endpoint;
    
    // Ensure baseUrl ends with a slash if it doesn't already
    const normalizedBaseUrl = baseUrl.endsWith('/') ? baseUrl : `${baseUrl}/`;
    
    // Combine them to get a complete URL
    const url = `${normalizedBaseUrl}${normalizedEndpoint}`;
    
    console.log(`Server fetch to: ${url}`);
    
    const res = await fetch(url, {
      ...options,
      headers: {
        'Content-Type': 'application/json',
        Authorization: `Bearer ${authToken}`,
        ...options.headers,
      },
      cache: 'no-store',
    });

    if (res.status === 401) redirect('/login');
    if (!res.ok) throw new Error(`Request failed: ${res.statusText}`);

    return res.json();
  } catch (error) {
    console.error(`Server request to ${endpoint} failed:`, error);
    throw error;
  }
}