package com.abc.handoff;

import com.abc.pp.stringhandoff.*;
import com.programix.thread.*;


public class StringHandoffImpl implements StringHandoff {


    private boolean isShutdown = false;

    private String message = null;

    private boolean isReceiving = false;


    @Override
    public synchronized void pass(String msg, long msTimeout)
        throws InterruptedException, TimedOutException, ShutdownException, IllegalStateException {

        throwIfShutdownOrPassing();
        passAndNotify(msg);

        long messagesend = System.currentTimeMillis() + msTimeout;
        while ( message != null ) {
            long messagewait = messagesend - System.currentTimeMillis();
            if ( messagewait <= 0 ) {
                throw new TimedOutException();
            }

            wait(messagewait);

            if ( isShutdown ) {
                throw new ShutdownException();
            }
        }

    }


    @Override
    public synchronized void pass(String msg) throws InterruptedException, ShutdownException, IllegalStateException {

        throwIfShutdownOrPassing();
        passAndNotify(msg);

        while ( message != null ) {
            wait();

            if ( isShutdown ) {
                throw new ShutdownException();
            }
        }
    }


    @Override
    public synchronized String receive(long msTimeout)
        throws InterruptedException, TimedOutException, ShutdownException, IllegalStateException {

        throwIfShutdownOrReceiving();

        long messagesend = System.currentTimeMillis() + msTimeout;
        while ( message == null ) {
            long messagewait = messagesend - System.currentTimeMillis();
            if ( messagewait <= 0 ) {
                throw new TimedOutException();
            }

            wait(messagewait);

            if ( isShutdown ) {
                throw new ShutdownException();
            }
        }

        return receiveAndNotify();
    }


    @Override
    public synchronized String receive() throws InterruptedException, ShutdownException, IllegalStateException {

        throwIfShutdownOrReceiving();

        // while there is no message, wait.
        while ( message == null ) {
            wait();

            if ( isShutdown ) {
                throw new ShutdownException();
            }
        }

        return receiveAndNotify();
    }


    @Override
    public synchronized void shutdown() {
        isShutdown = true;
        message = null;
        isReceiving = false;

        notifyAll();
    }

    @Override
    public Object getLockObject() {
        return this;
    }


    private synchronized void passAndNotify(String msg) {
        if (msg == "orange") {
            System.out.println(isReceiving);
        }
        message = msg;
        notifyAll();
    }


    private synchronized String receiveAndNotify() {
        String msg = message;
        message = null;
        isReceiving = false;

        notifyAll();

        return msg;
    }


    private synchronized void throwIfShutdownOrReceiving() throws ShutdownException, IllegalStateException {
        if ( isShutdown ) {
            throw new ShutdownException();
        }

        if ( isReceiving ) {
            throw new IllegalStateException();
        }

        isReceiving = true;
    }

    private synchronized void throwIfShutdownOrPassing() throws ShutdownException, IllegalStateException {
        if ( isShutdown ) {
            throw new ShutdownException();
        }

        if ( message != null ) {
            throw new IllegalStateException();
        }
    }
}