/*
 *     This file is part of the MapleSolaxiaV2 Maple Story Server
 *
 * Copyright (C) 2017 RonanLana
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package tools.locks;

import constants.ServerConstants;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.TimeZone;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.locks.ReentrantReadWriteLock;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import java.util.concurrent.ScheduledFuture;
import server.TimerManager;
import net.server.Server;
import net.server.audit.ThreadTracker;
import tools.FilePrinter;

/**
 *
 * @author RonanLana
 */
public class MonitoredWriteLock extends ReentrantReadWriteLock.WriteLock {
    private ScheduledFuture<?> timeoutSchedule = null;
    private StackTraceElement[] deadlockedState = null;
    private final MonitoredEnums id;
    private final int hashcode;
    private final Lock state = new ReentrantLock(true);
    private final AtomicInteger reentrantCount = new AtomicInteger(0);

    public MonitoredWriteLock(MonitoredReentrantReadWriteLock lock) {
        super(lock);
        this.id = lock.id;
        hashcode = this.hashCode();
    }
    
    @Override
    public void lock() {
        super.lock();
        if(ServerConstants.USE_THREAD_TRACKER) {
            if(deadlockedState != null) {
                DateFormat dateFormat = new SimpleDateFormat("dd-MM-yyyy HH:mm:ss");
                dateFormat.setTimeZone(TimeZone.getTimeZone(ServerConstants.TIMEZONE));

                //FilePrinter.printError(FilePrinter.DEADLOCK_ERROR, "[CRITICAL] " + dateFormat.format(new Date()) + " Deadlock occurred when trying to use the '" + id.name() + "' lock resources:\r\n" + printStackTrace(deadlockedState) + "\r\n\r\n");
                ThreadTracker.getInstance().accessThreadTracker(true, true, id, hashcode);
                deadlockedState = null;
            }

            registerLocking();
        }
    }
    
    @Override
    public void unlock() {
        if(ServerConstants.USE_THREAD_TRACKER) {
            unregisterLocking();
        }
        super.unlock();
    }
    
    @Override
    public boolean tryLock() {
        if(super.tryLock()) {
            if(ServerConstants.USE_THREAD_TRACKER) {
                if(deadlockedState != null) {
                    //FilePrinter.printError(FilePrinter.DEADLOCK_ERROR, "Deadlock occurred when trying to use the '" + id.name() + "' lock resources:\r\n" + printStackTrace(deadlockedState) + "\r\n\r\n");
                    ThreadTracker.getInstance().accessThreadTracker(true, true, id, hashcode);
                    deadlockedState = null;
                }

                registerLocking();
            }
            return true;
        } else {
            return false;
        }
    }
    
    private void registerLocking() {
        state.lock();
        try {
            ThreadTracker.getInstance().accessThreadTracker(false, true, id, hashcode);
        
            if(reentrantCount.incrementAndGet() == 1) {
                final Thread t = Thread.currentThread();
                timeoutSchedule = TimerManager.getInstance().schedule(new Runnable() {
                    @Override
                    public void run() {
                        issueDeadlock(t);
                    }
                }, ServerConstants.LOCK_MONITOR_TIME);
            }
        } finally {
            state.unlock();
        }
    }
    
    private void unregisterLocking() {
        state.lock();
        try {
            if(reentrantCount.decrementAndGet() == 0) {
                if(timeoutSchedule != null) {
                    timeoutSchedule.cancel(false);
                    timeoutSchedule = null;
                }
            }
            
            ThreadTracker.getInstance().accessThreadTracker(false, false, id, hashcode);
        } finally {
            state.unlock();
        }
    }
    
    private void issueDeadlock(Thread t) {
        deadlockedState = t.getStackTrace();
        //super.unlock();
    }
    
    private static String printStackTrace(StackTraceElement[] list) {
        String s = "";
        for(int i = 0; i < list.length; i++) {
            s += ("    " + list[i].toString() + "\r\n");
        }
        
        return s;
    }
}