/*
 * Copyright 2018 mayabot.com authors. All rights reserved.
 *
 * Licensed 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 com.mayabot.nlp.common.logging;

import java.util.logging.Level;
import java.util.logging.LogRecord;
import java.util.logging.Logger;

/**
 * <a href="http://java.sun.com/javase/6/docs/technotes/guides/logging/index.html">java.util.logging</a>
 * logger.
 */
public class JdkLogger extends AbstractInternalLogger {

    private static final long serialVersionUID = -1767272577989225979L;

    final transient Logger logger;

    public static InternalLogLevel defaultLevel = InternalLogLevel.INFO;

    JdkLogger(Logger logger) {
        super(logger.getName());
        this.logger = logger;
        setLogLevel(defaultLevel);
    }

    @Override
    public void setLogLevel(InternalLogLevel level) {
        switch (level) {
            case TRACE:
                logger.setLevel(Level.FINEST);
                break;
            case DEBUG:
                logger.setLevel(Level.FINE);
                break;
            case INFO:
                logger.setLevel(Level.INFO);
                break;
            case WARN:
                logger.setLevel(Level.WARNING);
                break;
            case ERROR:
                logger.setLevel(Level.SEVERE);
                break;
        }
    }

    /**
     * Is this logger instance enabled for the FINEST level?
     *
     * @return True if this Logger is enabled for level FINEST, false otherwise.
     */
    @Override
    public boolean isTraceEnabled() {
        return logger.isLoggable(Level.FINEST);
    }

    /**
     * Log a message object at level FINEST.
     *
     * @param msg - the message object to be logged
     */
    @Override
    public void trace(String msg) {
        if (logger.isLoggable(Level.FINEST)) {
            log(SELF, Level.FINEST, msg, null);
        }
    }

    /**
     * Log a message at level FINEST according to the specified format and
     * argument.
     *
     * <p>
     * This form avoids superfluous object creation when the logger is disabled
     * for level FINEST.
     * </p>
     *
     * @param format the format string
     * @param arg    the argument
     */
    @Override
    public void trace(String format, Object arg) {
        if (logger.isLoggable(Level.FINEST)) {
            FormattingTuple ft = MessageFormatter.format(format, arg);
            log(SELF, Level.FINEST, ft.getMessage(), ft.getThrowable());
        }
    }

    /**
     * Log a message at level FINEST according to the specified format and
     * arguments.
     *
     * <p>
     * This form avoids superfluous object creation when the logger is disabled
     * for the FINEST level.
     * </p>
     *
     * @param format the format string
     * @param argA   the first argument
     * @param argB   the second argument
     */
    @Override
    public void trace(String format, Object argA, Object argB) {
        if (logger.isLoggable(Level.FINEST)) {
            FormattingTuple ft = MessageFormatter.format(format, argA, argB);
            log(SELF, Level.FINEST, ft.getMessage(), ft.getThrowable());
        }
    }

    /**
     * Log a message at level FINEST according to the specified format and
     * arguments.
     *
     * <p>
     * This form avoids superfluous object creation when the logger is disabled
     * for the FINEST level.
     * </p>
     *
     * @param format   the format string
     * @param argArray an array of arguments
     */
    @Override
    public void trace(String format, Object... argArray) {
        if (logger.isLoggable(Level.FINEST)) {
            FormattingTuple ft = MessageFormatter.arrayFormat(format, argArray);
            log(SELF, Level.FINEST, ft.getMessage(), ft.getThrowable());
        }
    }

    /**
     * Log an exception (throwable) at level FINEST with an accompanying message.
     *
     * @param msg the message accompanying the exception
     * @param t   the exception (throwable) to log
     */
    @Override
    public void trace(String msg, Throwable t) {
        if (logger.isLoggable(Level.FINEST)) {
            log(SELF, Level.FINEST, msg, t);
        }
    }

    /**
     * Is this logger instance enabled for the FINE level?
     *
     * @return True if this Logger is enabled for level FINE, false otherwise.
     */
    @Override
    public boolean isDebugEnabled() {
        return logger.isLoggable(Level.FINE);
    }

    /**
     * Log a message object at level FINE.
     *
     * @param msg - the message object to be logged
     */
    @Override
    public void debug(String msg) {
        if (logger.isLoggable(Level.FINE)) {
            log(SELF, Level.FINE, msg, null);
        }
    }

    /**
     * Log a message at level FINE according to the specified format and argument.
     *
     * <p>
     * This form avoids superfluous object creation when the logger is disabled
     * for level FINE.
     * </p>
     *
     * @param format the format string
     * @param arg    the argument
     */
    @Override
    public void debug(String format, Object arg) {
        if (logger.isLoggable(Level.FINE)) {
            FormattingTuple ft = MessageFormatter.format(format, arg);
            log(SELF, Level.FINE, ft.getMessage(), ft.getThrowable());
        }
    }

    /**
     * Log a message at level FINE according to the specified format and
     * arguments.
     *
     * <p>
     * This form avoids superfluous object creation when the logger is disabled
     * for the FINE level.
     * </p>
     *
     * @param format the format string
     * @param argA   the first argument
     * @param argB   the second argument
     */
    @Override
    public void debug(String format, Object argA, Object argB) {
        if (logger.isLoggable(Level.FINE)) {
            FormattingTuple ft = MessageFormatter.format(format, argA, argB);
            log(SELF, Level.FINE, ft.getMessage(), ft.getThrowable());
        }
    }

    /**
     * Log a message at level FINE according to the specified format and
     * arguments.
     *
     * <p>
     * This form avoids superfluous object creation when the logger is disabled
     * for the FINE level.
     * </p>
     *
     * @param format   the format string
     * @param argArray an array of arguments
     */
    @Override
    public void debug(String format, Object... argArray) {
        if (logger.isLoggable(Level.FINE)) {
            FormattingTuple ft = MessageFormatter.arrayFormat(format, argArray);
            log(SELF, Level.FINE, ft.getMessage(), ft.getThrowable());
        }
    }

    /**
     * Log an exception (throwable) at level FINE with an accompanying message.
     *
     * @param msg the message accompanying the exception
     * @param t   the exception (throwable) to log
     */
    @Override
    public void debug(String msg, Throwable t) {
        if (logger.isLoggable(Level.FINE)) {
            log(SELF, Level.FINE, msg, t);
        }
    }

    /**
     * Is this logger instance enabled for the INFO level?
     *
     * @return True if this Logger is enabled for the INFO level, false otherwise.
     */
    @Override
    public boolean isInfoEnabled() {
        return logger.isLoggable(Level.INFO);
    }

    /**
     * Log a message object at the INFO level.
     *
     * @param msg - the message object to be logged
     */
    @Override
    public void info(String msg) {
        if (logger.isLoggable(Level.INFO)) {
            log(SELF, Level.INFO, msg, null);
        }
    }

    /**
     * Log a message at level INFO according to the specified format and argument.
     *
     * <p>
     * This form avoids superfluous object creation when the logger is disabled
     * for the INFO level.
     * </p>
     *
     * @param format the format string
     * @param arg    the argument
     */
    @Override
    public void info(String format, Object arg) {
        if (logger.isLoggable(Level.INFO)) {
            FormattingTuple ft = MessageFormatter.format(format, arg);
            log(SELF, Level.INFO, ft.getMessage(), ft.getThrowable());
        }
    }

    /**
     * Log a message at the INFO level according to the specified format and
     * arguments.
     *
     * <p>
     * This form avoids superfluous object creation when the logger is disabled
     * for the INFO level.
     * </p>
     *
     * @param format the format string
     * @param argA   the first argument
     * @param argB   the second argument
     */
    @Override
    public void info(String format, Object argA, Object argB) {
        if (logger.isLoggable(Level.INFO)) {
            FormattingTuple ft = MessageFormatter.format(format, argA, argB);
            log(SELF, Level.INFO, ft.getMessage(), ft.getThrowable());
        }
    }

    /**
     * Log a message at level INFO according to the specified format and
     * arguments.
     *
     * <p>
     * This form avoids superfluous object creation when the logger is disabled
     * for the INFO level.
     * </p>
     *
     * @param format   the format string
     * @param argArray an array of arguments
     */
    @Override
    public void info(String format, Object... argArray) {
        if (logger.isLoggable(Level.INFO)) {
            FormattingTuple ft = MessageFormatter.arrayFormat(format, argArray);
            log(SELF, Level.INFO, ft.getMessage(), ft.getThrowable());
        }
    }

    /**
     * Log an exception (throwable) at the INFO level with an accompanying
     * message.
     *
     * @param msg the message accompanying the exception
     * @param t   the exception (throwable) to log
     */
    @Override
    public void info(String msg, Throwable t) {
        if (logger.isLoggable(Level.INFO)) {
            log(SELF, Level.INFO, msg, t);
        }
    }

    /**
     * Is this logger instance enabled for the WARNING level?
     *
     * @return True if this Logger is enabled for the WARNING level, false
     * otherwise.
     */
    @Override
    public boolean isWarnEnabled() {
        return logger.isLoggable(Level.WARNING);
    }

    /**
     * Log a message object at the WARNING level.
     *
     * @param msg - the message object to be logged
     */
    @Override
    public void warn(String msg) {
        if (logger.isLoggable(Level.WARNING)) {
            log(SELF, Level.WARNING, msg, null);
        }
    }

    /**
     * Log a message at the WARNING level according to the specified format and
     * argument.
     *
     * <p>
     * This form avoids superfluous object creation when the logger is disabled
     * for the WARNING level.
     * </p>
     *
     * @param format the format string
     * @param arg    the argument
     */
    @Override
    public void warn(String format, Object arg) {
        if (logger.isLoggable(Level.WARNING)) {
            FormattingTuple ft = MessageFormatter.format(format, arg);
            log(SELF, Level.WARNING, ft.getMessage(), ft.getThrowable());
        }
    }

    /**
     * Log a message at the WARNING level according to the specified format and
     * arguments.
     *
     * <p>
     * This form avoids superfluous object creation when the logger is disabled
     * for the WARNING level.
     * </p>
     *
     * @param format the format string
     * @param argA   the first argument
     * @param argB   the second argument
     */
    @Override
    public void warn(String format, Object argA, Object argB) {
        if (logger.isLoggable(Level.WARNING)) {
            FormattingTuple ft = MessageFormatter.format(format, argA, argB);
            log(SELF, Level.WARNING, ft.getMessage(), ft.getThrowable());
        }
    }

    /**
     * Log a message at level WARNING according to the specified format and
     * arguments.
     *
     * <p>
     * This form avoids superfluous object creation when the logger is disabled
     * for the WARNING level.
     * </p>
     *
     * @param format   the format string
     * @param argArray an array of arguments
     */
    @Override
    public void warn(String format, Object... argArray) {
        if (logger.isLoggable(Level.WARNING)) {
            FormattingTuple ft = MessageFormatter.arrayFormat(format, argArray);
            log(SELF, Level.WARNING, ft.getMessage(), ft.getThrowable());
        }
    }

    /**
     * Log an exception (throwable) at the WARNING level with an accompanying
     * message.
     *
     * @param msg the message accompanying the exception
     * @param t   the exception (throwable) to log
     */
    @Override
    public void warn(String msg, Throwable t) {
        if (logger.isLoggable(Level.WARNING)) {
            log(SELF, Level.WARNING, msg, t);
        }
    }

    /**
     * Is this logger instance enabled for level SEVERE?
     *
     * @return True if this Logger is enabled for level SEVERE, false otherwise.
     */
    @Override
    public boolean isErrorEnabled() {
        return logger.isLoggable(Level.SEVERE);
    }

    /**
     * Log a message object at the SEVERE level.
     *
     * @param msg - the message object to be logged
     */
    @Override
    public void error(String msg) {
        if (logger.isLoggable(Level.SEVERE)) {
            log(SELF, Level.SEVERE, msg, null);
        }
    }

    /**
     * Log a message at the SEVERE level according to the specified format and
     * argument.
     *
     * <p>
     * This form avoids superfluous object creation when the logger is disabled
     * for the SEVERE level.
     * </p>
     *
     * @param format the format string
     * @param arg    the argument
     */
    @Override
    public void error(String format, Object arg) {
        if (logger.isLoggable(Level.SEVERE)) {
            FormattingTuple ft = MessageFormatter.format(format, arg);
            log(SELF, Level.SEVERE, ft.getMessage(), ft.getThrowable());
        }
    }

    /**
     * Log a message at the SEVERE level according to the specified format and
     * arguments.
     *
     * <p>
     * This form avoids superfluous object creation when the logger is disabled
     * for the SEVERE level.
     * </p>
     *
     * @param format the format string
     * @param argA   the first argument
     * @param argB   the second argument
     */
    @Override
    public void error(String format, Object argA, Object argB) {
        if (logger.isLoggable(Level.SEVERE)) {
            FormattingTuple ft = MessageFormatter.format(format, argA, argB);
            log(SELF, Level.SEVERE, ft.getMessage(), ft.getThrowable());
        }
    }

    /**
     * Log a message at level SEVERE according to the specified format and
     * arguments.
     *
     * <p>
     * This form avoids superfluous object creation when the logger is disabled
     * for the SEVERE level.
     * </p>
     *
     * @param format    the format string
     * @param arguments an array of arguments
     */
    @Override
    public void error(String format, Object... arguments) {
        if (logger.isLoggable(Level.SEVERE)) {
            FormattingTuple ft = MessageFormatter.arrayFormat(format, arguments);
            log(SELF, Level.SEVERE, ft.getMessage(), ft.getThrowable());
        }
    }

    /**
     * Log an exception (throwable) at the SEVERE level with an accompanying
     * message.
     *
     * @param msg the message accompanying the exception
     * @param t   the exception (throwable) to log
     */
    @Override
    public void error(String msg, Throwable t) {
        if (logger.isLoggable(Level.SEVERE)) {
            log(SELF, Level.SEVERE, msg, t);
        }
    }

    /**
     * Log the message at the specified level with the specified throwable if any.
     * This method creates a LogRecord and fills in caller date before calling
     * this instance's JDK14 logger.
     * <p>
     * See bug report #13 for more details.
     */
    private void log(String callerFQCN, Level level, String msg, Throwable t) {
        // millis and thread are filled by the constructor
        LogRecord record = new LogRecord(level, msg);
        record.setLoggerName(name());
        record.setThrown(t);
        fillCallerData(callerFQCN, record);
        logger.log(record);
    }

    static final String SELF = JdkLogger.class.getName();
    static final String SUPER = AbstractInternalLogger.class.getName();

    /**
     * Fill in caller data if possible.
     *
     * @param record The record to update
     */
    private static void fillCallerData(String callerFQCN, LogRecord record) {
        StackTraceElement[] steArray = new Throwable().getStackTrace();

        int selfIndex = -1;
        for (int i = 0; i < steArray.length; i++) {
            final String className = steArray[i].getClassName();
            if (className.equals(callerFQCN) || className.equals(SUPER)) {
                selfIndex = i;
                break;
            }
        }

        int found = -1;
        for (int i = selfIndex + 1; i < steArray.length; i++) {
            final String className = steArray[i].getClassName();
            if (!(className.equals(callerFQCN) || className.equals(SUPER))) {
                found = i;
                break;
            }
        }

        if (found != -1) {
            StackTraceElement ste = steArray[found];
            // setting the class name has the side effect of setting
            // the needToInferCaller variable to false.
            record.setSourceClassName(ste.getClassName());
            record.setSourceMethodName(ste.getMethodName());
        }
    }
}
