Intial i18n messages support

Send different languages of messages based on player's client setting

src/main/java/fr/xephi/authme/message/AbstractMessageFileHandler.java

@@ -14,6 +14,7 @@ import org.bukkit.configuration.file.YamlConfiguration;
 import javax.annotation.PostConstruct;
 import javax.inject.Inject;
 import java.io.File;
+import java.util.concurrent.ConcurrentHashMap;
 
 import static fr.xephi.authme.message.MessagePathHelper.DEFAULT_LANGUAGE;
 
@@ -33,6 +34,7 @@ public abstract class AbstractMessageFileHandler implements Reloadable {
 
     private String filename;
     private FileConfiguration configuration;
+    private ConcurrentHashMap<String, FileConfiguration> i18nConfiguration;
     private final String defaultFile;
 
     protected AbstractMessageFileHandler() {
@@ -46,6 +48,7 @@ public abstract class AbstractMessageFileHandler implements Reloadable {
         filename = createFilePath(language);
         File messagesFile = initializeFile(filename);
         configuration = YamlConfiguration.loadConfiguration(messagesFile);
+        i18nConfiguration = null;
     }
 
     protected String getLanguage() {
@@ -83,6 +86,24 @@ public abstract class AbstractMessageFileHandler implements Reloadable {
             : message;
     }
 
+    /**
+     * Returns the i18n message for the given key and given locale.
+     *
+     * @param key the key to retrieve the message for
+     * @param locale the locale that player client setting uses
+     * @return the message
+     */
+    public String getMessageByLocale(String key, String locale) {
+        if (locale == null || !settings.getProperty(PluginSettings.I18N_MESSAGES)) {
+            return getMessage(key);
+        }
+
+        String message = getI18nConfiguration(locale).getString(key);
+        return message == null
+            ? "Error retrieving message '" + key + "'"
+            : message;
+    }
+
     /**
      * Returns the message for the given key only if it exists,
      * i.e. without falling back to the default file.
@@ -94,6 +115,25 @@ public abstract class AbstractMessageFileHandler implements Reloadable {
         return configuration.getString(key);
     }
 
+    public FileConfiguration getI18nConfiguration(String locale) {
+        if (i18nConfiguration == null) {
+            i18nConfiguration = new ConcurrentHashMap<>();
+        }
+
+        if (i18nConfiguration.containsKey(locale)) {
+            return i18nConfiguration.get(locale);
+        } else {
+            // Sync with reload();
+            String i18nFilename = createFilePath(locale);
+            File i18nMessagesFile = initializeFile(i18nFilename);
+            FileConfiguration config = YamlConfiguration.loadConfiguration(i18nMessagesFile);
+
+            i18nConfiguration.put(locale, config);
+
+            return config;
+        }
+    }
+
     /**
      * Creates the path to the messages file for the given language code.
      *

src/main/java/fr/xephi/authme/message/Messages.java

@@ -4,6 +4,7 @@ import com.google.common.collect.ImmutableMap;
 import fr.xephi.authme.ConsoleLogger;
 import fr.xephi.authme.mail.EmailService;
 import fr.xephi.authme.output.ConsoleLoggerFactory;
+import fr.xephi.authme.util.PlayerUtils;
 import fr.xephi.authme.util.expiring.Duration;
 import org.bukkit.ChatColor;
 import org.bukkit.command.CommandSender;
@@ -120,7 +121,8 @@ public class Messages {
      * @return The message from the file
      */
     private String retrieveMessage(MessageKey key, CommandSender sender) {
-        String message = messagesFileHandler.getMessage(key.getKey());
+        String locale = PlayerUtils.getLocale(sender);
+        String message = messagesFileHandler.getMessageByLocale(key.getKey(), locale);
         String displayName = sender.getName();
         if (sender instanceof Player) {
             displayName = ((Player) sender).getDisplayName();