yt/src/lib/i18n.ts

import type { AstroGlobal, Request } from 'astro';
import enTranslations from '../i18n/en.json';
import deTranslations from '../i18n/de.json';

type Translations = typeof enTranslations;

const translations: Record<string, Translations> = {
  en: enTranslations,
  de: deTranslations,
};

/**
 * Get the current locale from Astro
 */
export function getLocale(astro: AstroGlobal): string {
  // Check environment variable first (for Docker/container environments)
  const envLocale = process.env.LOCALE;
  if (envLocale && (envLocale === 'de' || envLocale === 'en')) {
    return envLocale;
  }
  return astro.locale || 'de';
}

/**
 * Get locale from Request (for API routes)
 */
export function getLocaleFromRequest(request: Request): string {
  // Check environment variable first (for Docker/container environments)
  const envLocale = process.env.LOCALE;
  if (envLocale && (envLocale === 'de' || envLocale === 'en')) {
    return envLocale;
  }
  
  // Try to get locale from Accept-Language header
  const acceptLanguage = request.headers.get('accept-language');
  if (acceptLanguage) {
    if (acceptLanguage.includes('de')) return 'de';
    if (acceptLanguage.includes('en')) return 'en';
  }
  return 'de'; // Default to German
}

/**
 * Get translation for a key
 * Supports nested keys like "common.download"
 * Supports interpolation with {{variable}}
 */
function getTranslation(locale: string, key: string, params?: Record<string, string>): string {
  const translation = translations[locale] || translations.de;
  
  // Navigate through nested keys
  const keys = key.split('.');
  let value: any = translation;
  
  for (const k of keys) {
    if (value && typeof value === 'object' && k in value) {
      value = value[k];
    } else {
      // Fallback to German if key not found
      value = deTranslations;
      for (const k2 of keys) {
        if (value && typeof value === 'object' && k2 in value) {
          value = value[k2];
        } else {
          return key; // Return key if translation not found
        }
      }
      break;
    }
  }
  
  if (typeof value !== 'string') {
    return key;
  }
  
  // Replace placeholders like {{variable}}
  if (params) {
    return value.replace(/\{\{(\w+)\}\}/g, (match, paramKey) => {
      return params[paramKey] || match;
    });
  }
  
  return value;
}

/**
 * Get translation in Astro component
 */
export function t(astro: AstroGlobal, key: string, params?: Record<string, string>): string {
  const locale = getLocale(astro);
  return getTranslation(locale, key, params);
}

/**
 * Get translation in API route
 */
export function tApi(request: Request, key: string, params?: Record<string, string>): string {
  const locale = getLocaleFromRequest(request);
  return getTranslation(locale, key, params);
}