/*
    * 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.logback;
  
  import com.google.common.collect.Iterators;
  
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Collections;
  import java.util.Iterator;
  import java.util.List;
  
  import org.apache.commons.lang3.reflect.MethodUtils;
  
  import psiprobe.tools.logging.DefaultAccessor;
  
  /**
   * A wrapper for a Logback logger.
   */
  public class LogbackLoggerAccessor extends DefaultAccessor {
  
    /**
     * Returns all appenders of this logger.
     *
     * @return a list of {@link LogbackAppenderAccessor}s
     */
    @SuppressWarnings("unchecked")
    public List<LogbackAppenderAccessor> getAppenders() {
      List<LogbackAppenderAccessor> appenders = new ArrayList<>();
      try {
        for (Object appender : Collections.list(Iterators.asEnumeration(
            (Iterator<Object>) MethodUtils.invokeMethod(getTarget(), "iteratorForAppenders")))) {
          List<Object> siftedAppenders = getSiftedAppenders(appender);
          if (!siftedAppenders.isEmpty()) {
            for (Object siftedAppender : siftedAppenders) {
              wrapAndAddAppender(siftedAppender, appenders);
            }
          } else {
            wrapAndAddAppender(appender, appenders);
          }
        }
      } catch (NoClassDefFoundError e) {
        logger.error("{}#getAppenders() failed, To see this logger, upgrade slf4j to 1.7.21+",
            getTarget().getClass().getName(), e);
      } catch (Exception e) {
        logger.error("{}#getAppenders() failed", getTarget().getClass().getName(), e);
      }
      return appenders;
    }
  
    /**
     * Returns the appender of this logger with the given name.
     *
     * @param name the name of the appender to return
     *
     * @return the appender with the given name, or null if no such appender exists for this logger
     */
    public LogbackAppenderAccessor getAppender(String name) {
      try {
        Object appender = MethodUtils.invokeMethod(getTarget(), "getAppender", name);
        if (appender == null) {
          List<LogbackAppenderAccessor> appenders = getAppenders();
          for (LogbackAppenderAccessor wrappedAppender : appenders) {
            if (wrappedAppender.getIndex().equals(name)) {
              return wrappedAppender;
            }
          }
        }
        return wrapAppender(appender);
      } catch (Exception e) {
        logger.error("{}#getAppender() failed", getTarget().getClass().getName(), e);
      }
      return null;
    }
  
    /**
     * Checks if is context.
     *
     * @return true, if is context
     */
    public boolean isContext() {
      return false;
    }
  
    /**
     * Checks if is root.
     *
     * @return true, if is root
     */
    public boolean isRoot() {
      return "ROOT".equals(getName());
   }
 
   /**
    * Gets the name.
    *
    * @return the name
    */
   public String getName() {
     return (String) getProperty(getTarget(), "name", null);
   }
 
   /**
    * Gets the log level of this logger.
    *
    * @return the level of this logger
    */
   public String getLevel() {
     try {
       Object level = MethodUtils.invokeMethod(getTarget(), "getLevel");
       return (String) MethodUtils.invokeMethod(level, "toString");
     } catch (Exception e) {
       logger.error("{}#getLevel() failed", getTarget().getClass().getName(), e);
     }
     return null;
   }
 
   /**
    * Sets the log level of this logger.
    *
    * @param newLevelStr the name of the new level
    */
   public void setLevel(String newLevelStr) {
     try {
       Object level = MethodUtils.invokeMethod(getTarget(), "getLevel");
       Object newLevel = MethodUtils.invokeMethod(level, "toLevel", newLevelStr);
       MethodUtils.invokeMethod(getTarget(), "setLevel", newLevel);
     } catch (Exception e) {
       logger.error("{}#setLevel('{}') failed", getTarget().getClass().getName(), newLevelStr, e);
     }
   }
 
   /**
    * Gets the sifted appenders.
    *
    * @param appender the appender
    *
    * @return the sifted appenders
    *
    * @throws Exception the exception
    */
   @SuppressWarnings("unchecked")
   private List<Object> getSiftedAppenders(Object appender) throws Exception {
     if ("ch.qos.logback.classic.sift.SiftingAppender".equals(appender.getClass().getName())) {
       Object tracker = MethodUtils.invokeMethod(appender, "getAppenderTracker");
       if (tracker != null) {
         return (List<Object>) MethodUtils.invokeMethod(tracker, "allComponents");
       }
     }
     return Collections.emptyList();
   }
 
   /**
    * Wrap and add appender.
    *
    * @param appender the appender
    * @param appenders the appenders
    */
   private void wrapAndAddAppender(Object appender, Collection<LogbackAppenderAccessor> appenders) {
     LogbackAppenderAccessor appenderAccessor = wrapAppender(appender);
     if (appenderAccessor != null) {
       appenders.add(appenderAccessor);
     }
   }
 
   /**
    * Wrap appender.
    *
    * @param appender the appender
    *
    * @return the logback appender accessor
    */
   private LogbackAppenderAccessor wrapAppender(Object appender) {
     try {
       if (appender == null) {
         throw new IllegalArgumentException("appender is null");
       }
       LogbackAppenderAccessor appenderAccessor = new LogbackAppenderAccessor();
       appenderAccessor.setTarget(appender);
       appenderAccessor.setLoggerAccessor(this);
       appenderAccessor.setApplication(getApplication());
       return appenderAccessor;
     } catch (Exception e) {
       logger.error("Could not wrap appender: '{}'", appender, e);
     }
     return null;
   }
 
 }