/*
    * Licensed under the GPL License. You may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    *   https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
    *
    * THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
    * WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
    * PURPOSE.
   */
  package psiprobe.tools.logging.log4j;
  
  import java.lang.reflect.Method;
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.Enumeration;
  import java.util.List;
  
  import org.apache.commons.lang3.reflect.MethodUtils;
  
  import psiprobe.tools.logging.DefaultAccessor;
  
  /**
   * The Class Log4JManagerAccessor.
   */
  public class Log4JManagerAccessor extends DefaultAccessor {
  
    /**
     * Instantiates a new log4 j manager accessor.
     *
     * @param cl the cl
     *
     * @throws ClassNotFoundException the class not found exception
     */
    public Log4JManagerAccessor(ClassLoader cl) throws ClassNotFoundException {
      Class<?> clazz = cl.loadClass("org.apache.log4j.LogManager");
      Method exists = MethodUtils.getAccessibleMethod(clazz, "exists", String.class);
      if (exists == null) {
        throw new RuntimeException("The LogManager is part of the slf4j bridge.");
      }
      setTarget(clazz);
    }
  
    /**
     * Gets the root logger.
     *
     * @return the root logger
     */
    public Log4JLoggerAccessor getRootLogger() {
      try {
        Class<?> clazz = (Class<?>) getTarget();
        Method getRootLogger = MethodUtils.getAccessibleMethod(clazz, "getRootLogger");
  
        Object logger = getRootLogger.invoke(null);
        if (logger == null) {
          throw new NullPointerException(
              getTarget().getClass().getName() + "#getRootLogger() returned null");
        }
        Log4JLoggerAccessor accessor = new Log4JLoggerAccessor();
        accessor.setTarget(logger);
        accessor.setApplication(getApplication());
        return accessor;
      } catch (Exception e) {
        logger.error("{}#getRootLogger() failed", getTarget().getClass().getName(), e);
      }
      return null;
    }
  
    /**
     * Gets the logger.
     *
     * @param name the name
     *
     * @return the logger
     */
    public Log4JLoggerAccessor getLogger(String name) {
      try {
        Class<?> clazz = (Class<?>) getTarget();
        Method getLogger = MethodUtils.getAccessibleMethod(clazz, "getLogger", String.class);
  
        Object logger = getLogger.invoke(null, name);
        if (logger == null) {
          throw new NullPointerException(
              getTarget().getClass().getName() + "#getLogger(\"" + name + "\") returned null");
        }
        Log4JLoggerAccessor accessor = new Log4JLoggerAccessor();
        accessor.setTarget(logger);
        accessor.setApplication(getApplication());
        return accessor;
      } catch (Exception e) {
        logger.error("{}#getLogger('{}') failed", getTarget().getClass().getName(), name, e);
      }
      return null;
    }
  
    /**
     * Gets the appenders.
     *
     * @return the appenders
    */
   @SuppressWarnings("unchecked")
   public List<Log4JAppenderAccessor> getAppenders() {
     List<Log4JAppenderAccessor> appenders = new ArrayList<>();
     try {
       appenders.addAll(getRootLogger().getAppenders());
 
       Class<?> clazz = (Class<?>) getTarget();
       Method getCurrentLoggers = MethodUtils.getAccessibleMethod(clazz, "getCurrentLoggers");
 
       for (Object currentLogger : Collections
           .list((Enumeration<Object>) getCurrentLoggers.invoke(null))) {
         Log4JLoggerAccessor accessor = new Log4JLoggerAccessor();
         accessor.setTarget(currentLogger);
         accessor.setApplication(getApplication());
 
         appenders.addAll(accessor.getAppenders());
       }
     } catch (Exception e) {
       logger.error("{}#getCurrentLoggers() failed", getTarget().getClass().getName(), e);
     }
     return appenders;
   }
 
 }