package org.apidesign.reentrant;

import java.util.ArrayList;

import java.util.Iterator;

import java.util.List;

import org.junit.Test;

import static org.junit.Assert.*;

public abstract class CriticalSectionBase {

    protected abstract CriticalSection<Integer> create();

    protected boolean reentrantJustOnce() {

        return false;

    }

    // BEGIN: reentrant.ok.call

    @Test

    public void testCriticalSectionWith15() {

        final CriticalSection<Integer> cs = create();

        testFor15(cs);

    }

    // END: reentrant.ok.call

    final void testFor15(CriticalSection<Integer> cs) {

        cs.assignPilot(15);

        List<Integer> ints = new ArrayList<Integer>();

        ints.add(8);

        ints.add(11);

        ints.add(10);

        ints.add(5);

        ints.add(12);

        ints.add(18);

        ints.add(13);

        ints.add(7);

        int cnt = cs.sumBigger(ints);

        assertEquals("18 is bigger than 15", 1, cnt);

    }

    @Test 

    public void teaseCriticalSectionWithReentrantCalls() {

        final CriticalSection<Integer> cs = create();

        cs.assignPilot(10);

        class ChangePilotTo15 implements Runnable {

            // BEGIN: reentrant.forbidden.call

            // if this runnable is called from inside the critical section,

            // and the locks are non-reentrant then it throws an exception

            public void run() {

                testFor15(cs);

            }

            // END: reentrant.forbidden.call

        }

        List<Integer> ints = new MyCollection(new ChangePilotTo15(), 3);

        ints.add(8);

        ints.add(11);

        ints.add(10);

        ints.add(5);

        ints.add(12);

        ints.add(18);

        ints.add(13);

        ints.add(7);

        int cnt = cs.sumBigger(ints);

        assertEquals("11, 12, 18, 13 are bigger than 10", 4, cnt);

        assertEquals("Global count is sum of ints(e.g. 4) plus result of testFor15(e.g. 1)", 5, cs.getCount());

    }

    class MyCollection extends ArrayList<Integer> {

        private Runnable callback;

        private final int callbackBeforeIndex;

        public MyCollection(Runnable callback, int callbackAtIndex) {

            this.callback = callback;

            this.callbackBeforeIndex = callbackAtIndex;

        }

        @Override

        public Iterator<Integer> iterator() {

            final Iterator<Integer> delegate = super.iterator();

            class It implements Iterator<Integer> {

                private int index;

                public boolean hasNext() {

                    return delegate.hasNext();

                }

                public Integer next() {

                    if (index++ == callbackBeforeIndex) {

                        if (callback != null) {

                            callback.run();

                        }

                        if (reentrantJustOnce()) {

                            callback = null;

                        }

                    }

                    return delegate.next();

                }

                public void remove() {

                    delegate.remove();

                }

            } // end of It

            return new It();

        }

    }

}