package top.infra.localization;
   
   import org.reflections.Reflections;
   import org.springframework.context.i18n.LocaleContextHolder;
   
   import java.util.HashMap;
   import java.util.Locale;
   import java.util.Map;
   import java.util.Set;
  
  import top.infra.core.ErrorMessage;
  
  /**
   * Created by zhuowan on 2018/3/30 18:04.
   * Description:
   */
  public class LocalizedMessages {
  
    private transient static final Map<MessageLocale, Map<String, String>> messageCache;
    private static boolean initialized = false;
  
    static {
      messageCache = new HashMap<>();
      init();
    }
  
    /**
     * 1. 第一步加载所有的locales及所有的messages
     * 2. 获取message优先级：
     * priority 1: Forced 强制加载的类型message
     * priority 2: 指定类型的message类型
     * priority 3: 默认的message类型 （目前把US当作默认类型）
     * priority 4: 抛出异常
     */
    public static String getMessageByLocale(final ErrorMessage message, final Locale locale) {
      String resultMsg = getMessageByLocaleAndMessage(message, getLocale(locale));
      if (resultMsg != null) {
        return resultMsg;
      }
      throw new RuntimeException("Invalid common locale message usage");
    }
  
    /**
     * 初始化所有message信息
     */
    private static void init() {
      if (!initialized) {
        final Reflections reflections = new Reflections();
        final Set<Class<?>> bundles = reflections.getTypesAnnotatedWith(LocalizedMessageBundle.class);
        for (final MessageLocale locale : MessageLocale.values()) { // all locales
          final Map<String, String> enumConstants = new HashMap<>();
          for (final Class bundle : bundles) {
            final LocalizedMessageBundle annotation = (LocalizedMessageBundle) bundle.getAnnotation(LocalizedMessageBundle.class);
            final MessageLocale bundleLocale = annotation.value();
            if (locale == bundleLocale) {
              arrayToMap(enumConstants, bundle.getEnumConstants());
            }
          }
          messageCache.putIfAbsent(locale, enumConstants);
        }
        initialized = true;
      }
    }
  
    private static void arrayToMap(final Map<String, String> map, final Object[] enums) {
      if (map != null && enums != null) {
        for (final Object enu : enums) {
          final ErrorMessage message = (ErrorMessage) enu;
          map.putIfAbsent(message.getName(), message.getText());
        }
      }
    }
  
    private static MessageLocale getLocale(final Locale locale) {
      final String country = locale != null ? locale.getCountry() : LocaleContextHolder.getLocale().getCountry();
      return MessageLocale.of(country);
    }
  
    private static String getMessageByLocaleAndMessage(ErrorMessage message, MessageLocale messageLocale) {
      //priority 1 Forced messageLocale Message
      String finalMessage = messageCache.get(MessageLocale.FORCED).get(message.getName());
      if (finalMessage == null) {
        //priority 2 Specific messageLocale message
        finalMessage = messageCache.get(messageLocale).get(message.getName());
        if (finalMessage == null) {
          //priority 3 Default message
          finalMessage = messageCache.get(MessageLocale.DEFAULT).get(message.getName());
        }
      }
      return finalMessage;
    }
  }