import { NextRequest, NextResponse } from 'next/server';
import { getLocalizedMessage } from '@/lib/i18n-loader';
import enMessages from '@/messages/en.json';
import deMessages from '@/messages/de.json';

// Cache für 5 Minuten
export const revalidate = 300;

const messagesMap = { en: enMessages, de: deMessages };

/**
 * GET /api/i18n/[namespace]?locale=en
 * Lädt alle Keys eines Namespace aus Directus oder JSON
 */
export async function GET(
  req: NextRequest,
  { params }: { params: Promise<{ namespace: string }> }
) {
  const { namespace } = await params;
  const locale = req.nextUrl.searchParams.get('locale') || 'en';

  // Normalize locale (de-DE -> de)
  const normalizedLocale = locale.startsWith('de') ? 'de' : 'en';

  try {
    // Hole alle Keys aus JSON für diesen Namespace
    const jsonData = messagesMap[normalizedLocale as 'en' | 'de'];
    const namespaceData = getNestedValue(jsonData, namespace);

    if (!namespaceData || typeof namespaceData !== 'object') {
      return NextResponse.json({}, { status: 200 });
    }

    // Flatten das Objekt zu flachen Keys
    const flatKeys = flattenObject(namespaceData);
    
    // Lade jeden Key aus Directus (mit Fallback auf JSON)
    const result: Record<string, string> = {};
    
    await Promise.all(
      Object.entries(flatKeys).map(async ([key, jsonValue]) => {
        const fullKey = `${namespace}.${key}`;
        const value = await getLocalizedMessage(fullKey, locale);
        result[key] = value || String(jsonValue);
      })
    );

    return NextResponse.json(result, {
      headers: {
        'Cache-Control': 'public, s-maxage=300, stale-while-revalidate=600',
      },
    });
  } catch (error) {
    console.error('i18n API error:', error);
    return NextResponse.json({ error: 'Failed to load translations' }, { status: 500 });
  }
}

// Helper: Holt verschachtelte Werte aus Objekt
function getNestedValue(obj: any, path: string): any {
  return path.split('.').reduce((current, key) => current?.[key], obj);
}

// Helper: Flatten verschachteltes Objekt zu flachen Keys
function flattenObject(obj: any, prefix = ''): Record<string, string> {
  const result: Record<string, string> = {};

  for (const [key, value] of Object.entries(obj)) {
    const newKey = prefix ? `${prefix}.${key}` : key;
    
    if (value && typeof value === 'object' && !Array.isArray(value)) {
      Object.assign(result, flattenObject(value, newKey));
    } else {
      result[newKey] = String(value);
    }
  }

  return result;
}