/*
 * 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.karaf.main.util;

import java.io.BufferedOutputStream;
import java.io.Closeable;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import org.apache.felix.utils.properties.Properties;
import org.apache.felix.utils.properties.InterpolationHelper;

import java.util.logging.Handler;
import java.util.logging.LogRecord;
import java.util.logging.StreamHandler;

/**
 * Convenience class for configuring java.util.logging to append to
 * the configured log4j log.  This could be used for bootstrap logging
 * prior to start of the framework.
 * 
 */
public class BootstrapLogManager {
	private static final String KARAF_BOOTSTRAP_LOG = "karaf.bootstrap.log";
    private static final String LOG4J_APPENDER_FILE = "log4j.appender.out.file";
    private static BootstrapLogManager instance;
	private Handler handler;
    private Properties configProps;
	private String log4jConfigPath;
    
    public BootstrapLogManager(Properties configProps, String log4jConfigPath) {
		this.configProps = configProps;
		this.log4jConfigPath = log4jConfigPath;
		this.handler = null;
	}

    public static synchronized Handler getDefaultHandler() {
    	if (instance == null) {
        	throw new IllegalStateException("Properties must be set before calling getDefaultHandler");
        }
    	return instance.getDefaultHandlerInternal();
    }
    
    public static void setProperties(Properties configProps) {
        setProperties(configProps, null);
    }
    
	public static void setProperties(Properties configProps, String log4jConfigPath) {
		instance = new BootstrapLogManager(configProps, log4jConfigPath);
	}

    private Handler getDefaultHandlerInternal() {
        if (handler != null) {
            return handler;
        }
        
        String filename = getLogFilePath();
        filename = InterpolationHelper.substVars(filename, LOG4J_APPENDER_FILE, null, configProps);
        File logFile = new File(filename);
        try {
			return new SimpleFileHandler(logFile);
		} catch (IOException e) {
			throw new RuntimeException(e.getMessage(), e);
		}
	}

	private Properties loadPaxLoggingConfig() {
    	Properties props = new Properties();
        FileInputStream fis = null;
        try {
            fis = new FileInputStream(log4jConfigPath);
            props.load(fis);
        } catch (Exception e) {
        	// Ignore
		} finally {
        	close(fis);
        }
        return props;
    }

	private static void close(Closeable closeable) {
		try {
			if (closeable != null) {
				closeable.close();
			}
		} catch (IOException e) {
		    // Ignore
		}
	}
    
    String getLogFilePath() {
    	String filename = configProps == null ? null : configProps.getProperty(KARAF_BOOTSTRAP_LOG);
    	if (filename != null) {
    		return filename;
    	}
    	Properties props = loadPaxLoggingConfig();
  		// Make a best effort to log to the default file appender configured for log4j
  		return props.getProperty(LOG4J_APPENDER_FILE, "${karaf.data}/log/karaf.log");
    }

    /**
     * Implementation of java.util.logging.Handler that does simple appending
     * to a named file.  Should be able to use this for bootstrap logging
     * via java.util.logging prior to startup of pax logging.
     */
    public static class SimpleFileHandler extends StreamHandler {

        public SimpleFileHandler (File file) throws IOException {
            open(file, true);
        }

        private void open (File logfile, boolean append) throws IOException {
            if (!logfile.getParentFile().exists()) {
                try {
                    logfile.getParentFile().mkdirs();
                } catch (SecurityException se) {
                    throw new IOException(se.getMessage());
                }
            }
            FileOutputStream fout = new FileOutputStream(logfile, append);
            BufferedOutputStream out = new BufferedOutputStream(fout);
            setOutputStream(out);
        }

        public synchronized void publish (LogRecord record) {
            if (!isLoggable(record)) {
                return;
            }
            super.publish(record);
            flush();
        }
    }


}
