/**
    * SpamSchutz - simple way to protect your mail addresses from naïve spammers
    * Copyright (C) 2011, Aiki IT
    * <p/>
    * This program is free software: you can redistribute it and/or modify
    * it under the terms of the GNU General Public License as published by
    * the Free Software Foundation, either version 3 of the License, or
    * (at your option) any later version.
    * <p/>
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   * <p/>
   * You should have received a copy of the GNU General Public License
   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
   */
  package de.aikiit.spamprotector.util;
  
  import com.google.common.base.Strings;
  import lombok.AccessLevel;
  import lombok.NoArgsConstructor;
  import org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  
  import java.text.MessageFormat;
  import java.util.Arrays;
  import java.util.Locale;
  import java.util.MissingResourceException;
  import java.util.ResourceBundle;
  
  /**
   * Helper to deal with localizations and ease the usage of
   * resource bundles within spamschutz.
   */
  @NoArgsConstructor(access = AccessLevel.PRIVATE)
  public final class LocalizationHelper {
  
      /**
       * Logger.
       */
      private static final Logger LOG =
              LogManager.getLogger(LocalizationHelper.class);
  
      /**
       * ResourceBundle used for this application.
       */
      private static final String BASE_NAME = "spamprotector";
      private static final Locale FALLBACK_LOCALE = Locale.GERMANY;
  
      private static ResourceBundle BUNDLE;
      private static Locale LOCALE;
      private static MessageFormat FORMAT;
  
      static {
          setLocale();
      }
  
      /**
       * Set locale depending on system properties, in case of errors fallback is Locale.GERMANY.
       */
      public static void setLocale() {
          String userLanguage = System.getProperty("user.language");
          String userCountry = System.getProperty("user.country");
  
          LOG.info(String.format("Your system emits the following l10n-properties: language=%s, country=%s", userLanguage, userCountry));
  
          if (Strings.isNullOrEmpty(userLanguage) || Strings.isNullOrEmpty(userCountry)) {
              LOCALE = FALLBACK_LOCALE;
              LOG.info("Falling back to locale " + LOCALE);
          } else {
              LOCALE = new Locale(userLanguage, userCountry);
              LOG.info("Setting locale to " + LOCALE);
          }
  
          BUNDLE = ResourceBundle.getBundle(BASE_NAME, LOCALE);
          FORMAT = new MessageFormat("");
          FORMAT.setLocale(LOCALE);
      }
  
      /**
       * @return the currently set Locale of this application. Fallback is Locale.GERMANY.
       */
      public static Locale getLocale() {
          if (LOCALE == null) {
              LOG.warn("Returning fallback Locale for Germany - please make sure you've configured your environment correctly via system properties 'user.country'/'user.language'.");
              return FALLBACK_LOCALE;
          }
          return LOCALE;
      }
  
      /**
       * @return the currently set language
       */
      public static String getLanguage() {
          return getLocale().getLanguage();
      }
  
      /**
      * Helper function to retrieve a given key
      * from the underlying resource bundle.
      *
      * @param key Key to retrieve from the bundle,
      *            e.g. <i>spamprotector.foo.title</i>
      * @return Returns the value from the bundle.
      */
     public static String getBundleString(final String key) {
         LOG.debug("Retrieving key " + key);
         try {
             return BUNDLE.getString(key);
         } catch (MissingResourceException mre) {
             LOG.error("Retrieving unknown key " + key + ". Please fix your property files.");
             return key;
         }
     }
 
     /**
      * Helper function to retrieve a given key
      * from the underlying resource bundle while
      * applying localization parameters.
      *
      * @param key        Key to retrieve from the bundle,
      *                   e.g. <i>spamprotector.foo.title</i>
      * @param parameters Object array with all parameters.
      * @return Returns the value from the bundle
      * with the given parameters applied.
      * @see <a href="https://docs.oracle.com/javase/tutorial/i18n/format/messageFormat.html">
      * I18N-tutorial</a>
      */
     public static String getParameterizedBundleString(final String key, final Object... parameters) {
         LOG.debug("Applying " + ((parameters == null) ? null : Arrays.toString(parameters)) + " parameters to " + key);
         FORMAT.applyPattern(getBundleString(key));
         return FORMAT.format(parameters);
     }
 
 }