// CHECKSTYLE:OFF

/*
 * 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.
 */

// Contributors: Kitching Simon <Simon.Kitching@orange.ch>
// Nicholas Wolff

package org.apache.log4j;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.ObjectStreamException;
import java.io.Serializable;

/**
 * Defines the minimum set of levels recognized by the system, that is <code>OFF</code>, <code>FATAL</code>,
 * <code>ERROR</code>, <code>WARN</code>, <code>INFO</code>, <code>DEBUG</code> and <code>ALL</code>.
 *
 * <p>
 * The <code>Level</code> class may be subclassed to define a larger level set.
 * </p>
 *
 * @author Ceki G&uuml;lc&uuml;
 */
public class Level extends Priority implements Serializable {

	/**
	 * TRACE level integer value.
	 *
	 * @since 1.2.12
	 */
	public static final int TRACE_INT = 5000;

	/**
	 * The <code>OFF</code> has the highest possible rank and is intended to turn off logging.
	 */
	final static public Level OFF = new Level(OFF_INT, "OFF", 0);

	/**
	 * The <code>FATAL</code> level designates very severe error events that will presumably lead the application to
	 * abort.
	 */
	final static public Level FATAL = new Level(FATAL_INT, "FATAL", 0);

	/**
	 * The <code>ERROR</code> level designates error events that might still allow the application to continue running.
	 */
	final static public Level ERROR = new Level(ERROR_INT, "ERROR", 3);

	/**
	 * The <code>WARN</code> level designates potentially harmful situations.
	 */
	final static public Level WARN = new Level(WARN_INT, "WARN", 4);

	/**
	 * The <code>INFO</code> level designates informational messages that highlight the progress of the application at
	 * coarse-grained level.
	 */
	final static public Level INFO = new Level(INFO_INT, "INFO", 6);

	/**
	 * The <code>DEBUG</code> Level designates fine-grained informational events that are most useful to debug an
	 * application.
	 */
	final static public Level DEBUG = new Level(DEBUG_INT, "DEBUG", 7);

	/**
	 * The <code>TRACE</code> Level designates finer-grained informational events than the <code>DEBUG</code> level.
	 *
	 * @since 1.2.12
	 */
	public static final Level TRACE = new Level(TRACE_INT, "TRACE", 7);

	/**
	 * The <code>ALL</code> has the lowest possible rank and is intended to turn on all logging.
	 */
	final static public Level ALL = new Level(ALL_INT, "ALL", 7);

	/**
	 * Serialization version id.
	 */
	static final long serialVersionUID = 3491141966387921974L;

	/**
	 * Instantiate a Level object.
	 */
	protected Level(final int level, final String levelStr, final int syslogEquivalent) {
		super(level, levelStr, syslogEquivalent);
	}

	/**
	 * Convert the string passed as argument to a level. If the conversion fails, then this method returns
	 * {@link #DEBUG}.
	 */
	public static Level toLevel(final String sArg) {
		return toLevel(sArg, Level.DEBUG);
	}

	/**
	 * Convert an integer passed as argument to a level. If the conversion fails, then this method returns
	 * {@link #DEBUG}.
	 */
	public static Level toLevel(final int val) {
		return toLevel(val, Level.DEBUG);
	}

	/**
	 * Convert an integer passed as argument to a level. If the conversion fails, then this method returns the specified
	 * default.
	 */
	public static Level toLevel(final int val, final Level defaultLevel) {
		switch (val) {
			case ALL_INT:
				return ALL;
			case DEBUG_INT:
				return Level.DEBUG;
			case INFO_INT:
				return Level.INFO;
			case WARN_INT:
				return Level.WARN;
			case ERROR_INT:
				return Level.ERROR;
			case FATAL_INT:
				return Level.FATAL;
			case OFF_INT:
				return OFF;
			case TRACE_INT:
				return Level.TRACE;
			default:
				return defaultLevel;
		}
	}

	/**
	 * Convert the string passed as argument to a level. If the conversion fails, then this method returns the value of
	 * <code>defaultLevel</code>.
	 */
	public static Level toLevel(final String sArg, final Level defaultLevel) {
		if (sArg == null) {
			return defaultLevel;
		}

		String s = sArg.toUpperCase();

		if (s.equals("ALL")) {
			return Level.ALL;
		}
		if (s.equals("DEBUG")) {
			return Level.DEBUG;
		}
		if (s.equals("INFO")) {
			return Level.INFO;
		}
		if (s.equals("WARN")) {
			return Level.WARN;
		}
		if (s.equals("ERROR")) {
			return Level.ERROR;
		}
		if (s.equals("FATAL")) {
			return Level.FATAL;
		}
		if (s.equals("OFF")) {
			return Level.OFF;
		}
		if (s.equals("TRACE")) {
			return Level.TRACE;
		}
		//
		// For Turkish i problem, see bug 40937
		//
		if (s.equals("\u0130NFO")) {
			return Level.INFO;
		}
		return defaultLevel;
	}

	/**
	 * Custom deserialization of Level.
	 *
	 * @param s
	 *            serialization stream.
	 * @throws IOException
	 *             if IO exception.
	 * @throws ClassNotFoundException
	 *             if class not found.
	 */
	private void readObject(final ObjectInputStream s) throws IOException, ClassNotFoundException {
		s.defaultReadObject();
		level = s.readInt();
		syslogEquivalent = s.readInt();
		levelStr = s.readUTF();
	}

	/**
	 * Serialize level.
	 *
	 * @param s
	 *            serialization stream.
	 * @throws IOException
	 *             if exception during serialization.
	 */
	private void writeObject(final ObjectOutputStream s) throws IOException {
		s.defaultWriteObject();
		s.writeInt(level);
		s.writeInt(syslogEquivalent);
		s.writeUTF(levelStr);
	}

	/**
	 * Resolved deserialized level to one of the stock instances. May be overridden in classes derived from Level.
	 *
	 * @return resolved object.
	 * @throws ObjectStreamException
	 *             if exception during resolution.
	 */
	private Object readResolve() throws ObjectStreamException {
		//
		// if the deserizalized object is exactly an instance of Level
		//
		if (getClass() == Level.class) {
			return toLevel(level);
		}
		//
		// extension of Level can't substitute stock item
		//
		return this;
	}

}
