// ***************************************************************************************************************************
// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements.  See the NOTICE file *
// * distributed with this work for additional information regarding copyright ownership.  The ASF licenses this file        *
// * to you under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance            *
// * with the License.  You may obtain a copy of the License at                                                              *
// *                                                                                                                         *
// *  http://www.apache.org/licenses/LICENSE-2.0                                                                             *
// *                                                                                                                         *
// * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an  *
// * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.  See the License for the        *
// * specific language governing permissions and limitations under the License.                                              *
// ***************************************************************************************************************************
package org.apache.juneau.microservice;

import static java.util.logging.Level.*;
import java.util.logging.*;

import org.apache.juneau.internal.*;
import org.eclipse.jetty.util.log.AbstractLogger;

/**
 * Implementation of Jetty {@link Logger} based on {@link java.util.logging.Logger}.
 * 
 * <p>
 * Allows Jetty to log to the Java Util logging framework (and thus to the main log file defined in the 
 * <cc>[Logging]</cc> section).
 * 
 * <p>
 * Can be used by setting the following system property in the microservice config file.
 * 
 * <p class='bcode'>
 *    <cs>[SystemProperties]</cs>
 *    
 *    <cc># Configure Jetty to log using java-util logging</cc>
 *    <ck>org.eclipse.jetty.util.log.class</ck> = org.apache.juneau.microservice.JettyLogger
 * </p>
 * 
 */
public class JettyLogger extends AbstractLogger {
   private static final boolean SHOW_SOURCE = SystemUtils.getFirstBoolean(true, "org.eclipse.jetty.util.log.SOURCE", "org.eclipse.jetty.util.log.javautil.SOURCE");

   private Level configuredLevel;
   private Logger logger;

   /**
    * Default constructor.
    * 
    * <p>
    * Returns the logger with name <js>"org.eclipse.jetty.util.log.javautil"</js>.
    */
   public JettyLogger() {
      this("org.eclipse.jetty.util.log.javautil");
   }

   /**
    * Normal constructor.
    * 
    * @param name The logger name.
    */
   public JettyLogger(String name) {
      logger = Logger.getLogger(name);
      configuredLevel = logger.getLevel();
   }

   @Override
   public String getName() {
      return logger.getName();
   }

   @Override
   public void warn(String msg, Object... args) {
      if (isLoggable(WARNING))
         log(WARNING, format(msg, args), null);
   }

   @Override
   public void warn(Throwable thrown) {
      if (isLoggable(WARNING))
         log(WARNING, "", thrown);
   }

   @Override
   public void warn(String msg, Throwable thrown) {
      if (isLoggable(WARNING))
         log(WARNING, msg, thrown);
   }

   @Override
   public void info(String msg, Object... args) {
      if (isLoggable(INFO))
         log(INFO, format(msg, args), null);
   }

   @Override
   public void info(Throwable thrown) {
      if (isLoggable(INFO))
         log(INFO, "", thrown);
   }

   @Override
   public void info(String msg, Throwable thrown) {
      if (isLoggable(INFO))
         log(INFO, msg, thrown);
   }

   @Override
   public boolean isDebugEnabled() {
      return isLoggable(FINE);
   }

   @Override
   public void setDebugEnabled(boolean enabled) {
      if (enabled) {
         configuredLevel = logger.getLevel();
         logger.setLevel(FINE);
      } else {
         logger.setLevel(configuredLevel);
      }
   }

   @Override
   public void debug(String msg, Object... args) {
      if (isLoggable(FINE))
         log(FINE, format(msg, args), null);
   }

   @Override
   public void debug(String msg, long arg) {
      if (isLoggable(FINE))
         log(FINE, format(msg, arg), null);
   }

   @Override
   public void debug(Throwable thrown) {
      if (isLoggable(FINE))
         log(FINE, "", thrown);
   }

   @Override
   public void debug(String msg, Throwable thrown) {
      if (isLoggable(FINE))
         log(FINE, msg, thrown);
   }

   @Override
   protected org.eclipse.jetty.util.log.Logger newLogger(String fullname) {
      return new JettyLogger(fullname);
   }

   @Override
   public void ignore(Throwable ignored) {
      if (isLoggable(FINEST))
         log(FINEST, org.eclipse.jetty.util.log.Log.IGNORED, ignored);
   }

   private static String format(String msg, Object... args) {
      msg = String.valueOf(msg); 
      if (args.length == 0)
         return msg;
      StringBuilder sb = new StringBuilder();
      int start = 0;
      for (Object arg : args) {
         int bi = msg.indexOf("{}", start);
         if (bi < 0) {
            sb.append(msg.substring(start)).append(" ").append(arg);
            start = msg.length();
         } else {
            sb.append(msg.substring(start, bi)).append(String.valueOf(arg));
            start = bi + 2;
         }
      }
      sb.append(msg.substring(start));
      return sb.toString();
   }

   private void log(Level level, String msg, Throwable thrown) {
      LogRecord r = new LogRecord(level, msg);
      if (thrown != null)
         r.setThrown(thrown);
      r.setLoggerName(logger.getName());
      if (SHOW_SOURCE) {
         StackTraceElement[] stack = new Throwable().getStackTrace();
         for (int i = 0; i < stack.length; i++) {
            StackTraceElement e = stack[i];
            if (!e.getClassName().equals(getClass().getName())) {
               r.setSourceClassName(e.getClassName());
               r.setSourceMethodName(e.getMethodName());
               break;
            }
         }
      }
      logger.log(r);
   }
   
   private boolean isLoggable(Level level) {
      return logger.isLoggable(level);
   }
}