/*******************************************************************************
 * Copyright (c) 2007, 2010 Association for Decentralized Information Management
 * in Industry THTH ry.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
package org.simantics.utils.threads.logger;

import java.io.DataOutput;
import java.io.DataOutputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class ThreadLogger implements IThreadLogger {

    final private static ITask DUMMY = () -> {};

    public static String LOG_FILE = "threads.log";
    
    public static boolean LOG = false;

    static Object loggerCreationLock = new Object();
    static ThreadLogger logger = null; 

    DataOutput log;

    public ThreadLogger() {
        if(LOG) {
            try {
                FileOutputStream stream = new FileOutputStream(LOG_FILE);
                log = new DataOutputStream(stream);
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            }
        }
    }

    public static ThreadLogger getInstance() {
        if(logger == null) {
            synchronized (loggerCreationLock) {
                if(logger == null)
                    logger = new ThreadLogger();	
            }
        }
        return logger;
    }

    public class Task implements ITask {

        String name;
        long beginTime;
        long endTime;
        long threadId;

        public Task(String name) {			
            this.name = name;
            this.threadId = Thread.currentThread().getId();
            this.beginTime = System.nanoTime();
        }

        @Override
        public void finish() {
            this.endTime = System.nanoTime();
            if(LOG && log != null) {
                
                try {
                    synchronized(log) {
                        log.writeUTF(name);
                        log.writeLong(threadId);
                        log.writeLong(beginTime);
                        log.writeLong(endTime);
                    }
                } catch(IOException e) {
                    e.printStackTrace();
                }

            }
        }

    }

    @Override
    public ITask begin(String taskName) {
        return new Task(taskName);
    }
    
    final public static ITask task(Object taskName) {
        if(LOG)
            return getInstance().begin(taskName.toString());
        else
            return DUMMY;
    }

}