/**
    * Logback: the reliable, generic, fast and flexible logging framework.
    * Copyright (C) 1999-2015, QOS.ch. All rights reserved.
    *
    * This program and the accompanying materials are dual-licensed under
    * either the terms of the Eclipse Public License v1.0 as published by
    * the Eclipse Foundation
    *
    *   or (per the licensee's choosing)
   *
   * under the terms of the GNU Lesser General Public License version 2.1
   * as published by the Free Software Foundation.
   */
  package ch.qos.logback.core.util;
  
  import ch.qos.logback.core.Context;
  import ch.qos.logback.core.CoreConstants;
  import ch.qos.logback.core.spi.ContextAware;
  import ch.qos.logback.core.spi.LifeCycle;
  import ch.qos.logback.core.status.OnConsoleStatusListener;
  import ch.qos.logback.core.status.OnErrorConsoleStatusListener;
  import ch.qos.logback.core.status.StatusListener;
  
  import static ch.qos.logback.core.CoreConstants.STDOUT;
  import static ch.qos.logback.core.CoreConstants.SYSOUT;
  
  public class StatusListenerConfigHelper {
  
      public static void installIfAsked(Context context) {
          String slClass = OptionHelper.getSystemProperty(CoreConstants.STATUS_LISTENER_CLASS_KEY);
          if (!OptionHelper.isNullOrEmptyOrAllSpaces(slClass)) {
              addStatusListener(context, slClass);
          }
      }
  
      private static void addStatusListener(Context context, String listenerClassName) {
          StatusListener listener = null;
          if (SYSOUT.equalsIgnoreCase(listenerClassName) || STDOUT.equalsIgnoreCase(listenerClassName)) {
              listener = new OnConsoleStatusListener();
          } else {
              listener = createListenerPerClassName(context, listenerClassName);
          }
          initAndAddListener(context, listener);
      }
  
      private static void initAndAddListener(Context context, StatusListener listener) {
          if (listener != null) {
              if (listener instanceof ContextAware) // LOGBACK-767
                  ((ContextAware) listener).setContext(context);
  
              boolean effectivelyAdded = context.getStatusManager().add(listener);
              if (effectivelyAdded && (listener instanceof LifeCycle)) {
                  ((LifeCycle) listener).start(); // LOGBACK-767
              }
          }
      }
  
      private static StatusListener createListenerPerClassName(Context context, String listenerClass) {
          try {
              return (StatusListener) OptionHelper.instantiateByClassName(listenerClass, StatusListener.class, context);
          } catch (Exception e) {
              // printing on the console is the best we can do
              e.printStackTrace();
              return null;
          }
      }
  
      /**
       * This utility method adds a new OnConsoleStatusListener to the context passed
       * as parameter.
       *
       * @param context
       * @since 1.0.1
       */
      static public void addOnConsoleListenerInstance(Context context, OnConsoleStatusListener onConsoleStatusListener) {
          onConsoleStatusListener.setContext(context);
          boolean effectivelyAdded = context.getStatusManager().add(onConsoleStatusListener);
          if (effectivelyAdded) {
              onConsoleStatusListener.start();
          }
      }
  }