/*
 * ToroDB
 * Copyright © 2014 8Kdata Technology (www.8kdata.com)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

package com.torodb.packaging.util;

import com.torodb.core.exceptions.SystemException;
import com.torodb.packaging.config.model.generic.LogLevel;
import com.torodb.packaging.config.model.generic.log4j.Log4jLevelToLogLevelMapper;
import org.apache.logging.log4j.Level;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.core.Appender;
import org.apache.logging.log4j.core.Layout;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.Logger;
import org.apache.logging.log4j.core.LoggerContext;
import org.apache.logging.log4j.core.appender.AbstractAppender;
import org.apache.logging.log4j.core.appender.FileAppender;
import org.apache.logging.log4j.core.config.Configuration;
import org.apache.logging.log4j.core.config.LoggerConfig;
import org.apache.logging.log4j.core.layout.PatternLayout;

import java.io.File;
import java.io.Serializable;
import java.util.Map;

public class Log4jUtils {

  public static void appendToLogFile(String logFile) {
    LoggerContext coreContext = (LoggerContext) LogManager.getContext(false);
    Configuration configuration = coreContext.getConfiguration();
    final Layout<? extends Serializable> layout = PatternLayout.newBuilder()
        .withConfiguration(configuration)
        .withPattern("%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n")
        .build();
    final Appender appender = FileAppender.createAppender(logFile, "false", "false", "File", "true",
        "false", null, null, layout, null, "false", null, configuration);
    appender.start();
    for (LoggerConfig loggerConfig : configuration.getLoggers().values()) {
      configuration.addLoggerAppender(coreContext.getLogger(loggerConfig.getName()), appender);
    }
  }

  public static void reconfigure(String configurationFile) {
    try {
      LoggerContext coreContext = (LoggerContext) LogManager.getContext(false);
      coreContext.setConfigLocation(new File(configurationFile).toURI());
    } catch (Exception ex) {
      throw new SystemException(ex);
    }
  }

  public static void setLogPackages(Map<String, LogLevel> logPackages) {
    for (Map.Entry<String, LogLevel> logPackage : logPackages.entrySet()) {
      LoggerContext coreContext = (LoggerContext) LogManager.getContext(false);
      Logger logger = coreContext.getLogger(logPackage.getKey());
      setLevel(logger, logPackage.getValue());
    }
  }

  public static void setRootLevel(LogLevel logLevel) {
    LoggerContext coreContext = (LoggerContext) LogManager.getContext(false);
    Configuration configuration = coreContext.getConfiguration();
    for (LoggerConfig loggerConfig : configuration.getLoggers().values()) {
      setLevel(loggerConfig, logLevel);
    }
  }

  private static void setLevel(LoggerConfig loggerConfig, LogLevel logLevel) {
    Level log4jLevel = Log4jLevelToLogLevelMapper.map(logLevel);
    loggerConfig.setLevel(log4jLevel);
  }

  private static void setLevel(Logger logger, LogLevel logLevel) {
    Level log4jLevel = Log4jLevelToLogLevelMapper.map(logLevel);
    logger.setLevel(log4jLevel);
  }

  public static void addRootAppenderListener(AppenderListener appenderListener) {
    org.apache.logging.log4j.Logger logger = org.apache.logging.log4j.LogManager
        .getRootLogger();
    org.apache.logging.log4j.core.Logger coreLogger = (org.apache.logging.log4j.core.Logger) logger;

    InternalAppenderListener internalAppenderListener = new InternalAppenderListener(
        appenderListener);
    internalAppenderListener.start();
    coreLogger.addAppender(internalAppenderListener);
  }

  public interface AppenderListener {

    void listen(String text, Throwable throwable);
  }

  private static class InternalAppenderListener extends AbstractAppender {

    private final AppenderListener appenderListener;

    protected InternalAppenderListener(AppenderListener appenderListener) {
      super("APPNEDER_LISTENER", null, null);
      this.appenderListener = appenderListener;
    }

    @Override
    public void append(LogEvent event) {
      appenderListener.listen(event.getMessage().getFormattedMessage(), event.getThrown());
    }
  }
}