/**
 * i18n Loader with Directus + JSON Fallback
 * - Fetches from Directus first
 * - Falls back to JSON files if not found
 * - Caches results (5 min TTL)
 */

import { getMessage, getContentPage } from './directus';
import enMessages from '@/messages/en.json';
import deMessages from '@/messages/de.json';

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

// Simple in-memory cache
const cache = new Map<string, { value: any; expires: number }>();

function setCached(key: string, value: any, ttlSeconds = 300) {
  cache.set(key, { value, expires: Date.now() + ttlSeconds * 1000 });
}

function getCached(key: string): any | null {
  const hit = cache.get(key);
  if (!hit) return null;
  if (Date.now() > hit.expires) {
    cache.delete(key);
    return null;
  }
  return hit.value;
}

/**
 * Get a localized message by key
 * Tries: Directus (requested locale) → Directus (EN) → JSON (requested locale) → JSON (EN)
 */
export async function getLocalizedMessage(
  key: string,
  locale: string
): Promise<string> {
  const cacheKey = `msg:${key}:${locale}`;
  const cached = getCached(cacheKey);
  if (cached !== null) return cached;

  // Try Directus with requested locale
  const dbValue = await getMessage(key, locale);
  if (dbValue) {
    setCached(cacheKey, dbValue);
    return dbValue;
  }

  // Fallback to EN in Directus if not EN already
  if (locale !== 'en') {
    const dbValueEn = await getMessage(key, 'en');
    if (dbValueEn) {
      setCached(cacheKey, dbValueEn);
      return dbValueEn;
    }
  }

  // Fallback to JSON file (normalize locale to 'en' or 'de')
  const normalizedLocale = locale.startsWith('de') ? 'de' : 'en';
  const jsonValue = getNestedValue(jsonFallback[normalizedLocale as 'en' | 'de'], key);
  if (jsonValue) {
    setCached(cacheKey, jsonValue);
    return jsonValue;
  }

  // Fallback to EN JSON
  if (normalizedLocale !== 'en') {
    const jsonValueEn = getNestedValue(jsonFallback['en'], key);
    if (jsonValueEn) {
      setCached(cacheKey, jsonValueEn);
      return jsonValueEn;
    }
  }

  // Fallback: return the key itself
  return key;
}

/**
 * Get a localized content page by slug
 * Tries: Directus (requested locale) → Directus (EN)
 */
export async function getLocalizedContent(
  slug: string,
  locale: string
): Promise<any | null> {
  const cacheKey = `page:${slug}:${locale}`;
  const cached = getCached(cacheKey);
  if (cached !== null) return cached;
  if (cached === null && cache.has(cacheKey)) return null; // Already checked, not found

  // Try Directus with requested locale
  const dbPage = await getContentPage(slug, locale);
  if (dbPage) {
    setCached(cacheKey, dbPage);
    return dbPage;
  }

  // Fallback to EN in Directus
  if (locale !== 'en') {
    const dbPageEn = await getContentPage(slug, 'en');
    if (dbPageEn) {
      setCached(cacheKey, dbPageEn);
      return dbPageEn;
    }
  }

  // Not found
  setCached(cacheKey, null);
  return null;
}

/**
 * Helper: Get nested value from object
 * Example: "nav.home" → obj.nav.home
 */
function getNestedValue(obj: any, path: string): any {
  const keys = path.split('.');
  let value = obj;
  for (const key of keys) {
    value = value?.[key];
    if (value === undefined) return null;
  }
  return value;
}

/**
 * Clear cache (useful for webhooks/revalidation)
 */
export function clearI18nCache() {
  cache.clear();
}