/**
    * Copyright 2011, Aiki IT, FotoRenamer
    * <p/>
    * Licensed under the Apache License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    * <p/>
    * http://www.apache.org/licenses/LICENSE-2.0
    * <p/>
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package de.aikiit.fotorenamer.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.Locale;
  import java.util.MissingResourceException;
  import java.util.ResourceBundle;
  
  /**
   * Helper to deal with localizations and ease the usage of
   * resource bundles within fotorenamer.
   *
   * @author hirsch
   * @version 23.08.11
   */
  @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 = "fotorenamer";
      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 {@code Locale.GERMANY}.
       */
      public static void setLocale() {
          String userLanguage = System.getProperty("user.language");
          String userCountry = System.getProperty("user.country");
  
          LOG.info("Your system emits the following l10n-properties: language={}, country={}", 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);
      }
  
      /**
       * Returns the application's locale.
       * @return the currently set Locale of this application. Fallback is {@code 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;
      }
  
      /**
       * Returns the currently set language.
       * @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>fotorenamer.foo.title</i>
      * @return 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 {}. Please fix your property files.", key);
             return key;
         }
         // l18n basics:
         // http://www.kodejava.org/examples/220.html
         // l18n buttons:
         // http://www.java2s.com/Code/Java/I18N/Createonebuttoninternationalizedly.htm
         // l18n with parameters:
         // http://www.java2s.com/Code/Java/I18N/ResourceBundlewithparameterposition.htm
         // parameters are a bit uneasier than with grails -
         // http://download.oracle.com/javase/tutorial/i18n/format/messageFormat.html
         // encoding issues / eclipse plugin:
         // http://stackoverflow.com/questions/863838/problem-with-java-properties-utf8-encoding-in-eclipse
     }
 
     /**
      * 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>fotorenamer.foo.parameteredtitle</i>.
      * @param parameters Object array with all parameters.
      * @return 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 to {}", (parameters == null) ? null : parameters
                 .length, key);
         FORMAT.applyPattern(getBundleString(key));
         return FORMAT.format(parameters);
     }
 
     /**
      * Helper method to prevent CRLF injection in logs.
      *
      * @param input any input
      * @return input without CRLF.
      */
     public static String removeCrLf(final String input) {
         if (!Strings.isNullOrEmpty(input)) {
             return input.replaceAll("[\r\n]", "");
         }
         return input;
     }
 }