package pp;

import java.util.concurrent.locks.Condition;
import java.util.concurrent.locks.Lock;

public class Philosopher extends Thread implements IPhilosopher {
    static final int MAX_THINKING_DURATION_MS = 1000; //aus Vorlesungsbeispiel
    static final int MAX_EATING_DURATION_MS = 3000; //aus Vorlesungsbeispiel
    boolean stop = false;
    private int seat;
    private Lock table;
    private Condition cond;
    private Philosopher left;
    private Philosopher right;
    private boolean essen;
    private int gegessen = 0;

    @Override
    public void setLeft(IPhilosopher left) {
        // TODO Auto-generated method stub
        // Cast auf Philosopher erforderlich
        this.left = (Philosopher) left;
    }

    @Override
    public void setRight(IPhilosopher right) {
        // TODO Auto-generated method stub
        // Cast auf Philosopher erforderlich
        this.right = (Philosopher) right;
    }

    @Override
    public void setSeat(int seat) {
        this.seat = seat;
    }

    @Override
    public void setTable(Lock table) {
        // TODO Auto-generated method stub
        this.table = table;
        this.cond = table.newCondition();
    }

    @Override
    public void stopPhilosopher() {
        // TODO Auto-generated method stub
        log(seat, "stopping");
        this.stop = true;
        interrupt();
    }

    @Override
    public void run() {
        try {
            while (!stop) {
                log(seat, "überlegen");
                Thread.sleep(MAX_THINKING_DURATION_MS);
                try {
                    startEating();
                    log(seat, "essen");
                    Thread.sleep(MAX_EATING_DURATION_MS);
                    gegessen = gegessen + 1;
                    log(seat, "gegessen " + gegessen);
                } finally {
                    stopEating();
                }
            }
        } catch (InterruptedException e) {
            //Hier ist eine Exception gefunden worden
            System.out.println("Hier ist ein Thread unterbrochen worden");
        }
    }

    private void startEating() throws InterruptedException {
        table.lock();
        try {
            while (left.essen || right.essen) {
                cond.await();
            }
            essen = true;
        } finally {
            table.unlock();
        }
    }

    private void stopEating() throws InterruptedException {
        table.lock();
        try {
            essen = false;
            left.cond.signal();
            right.cond.signal();
        } finally {
            table.unlock();
        }
    }
}