/*
 * Copyright 2005-2010 the original author or authors.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */ 
package org.wamblee.observer;

import junit.framework.TestCase;

import org.mockito.InOrder;
import static org.mockito.Mockito.*;

import java.util.ArrayList;
import java.util.List;

/**
 * Test of the observer pattern implementation.
 * 
 * @author Erik Brakkee
 */
public class ObservableTest extends TestCase {
    private static final int SUBSCRIBER_COUNT = 100;
    private static final String UPDATE = "send";
    private Integer observed;
    private Observable<Integer, String> observable;

    /*
     * (non-Javadoc)
     * 
     * @see junit.framework.TestCase#setUp()
     */
    @Override
    protected void setUp() throws Exception {
        super.setUp();
        observed = new Integer(1);
        observable = new Observable<Integer, String>(observed,
            new DefaultObserverNotifier());
    }

    /**
     * Tests subscription and notification of one subscriber.
     */
    public void testOneObserver() {
        final Observer mockObserver = mock(Observer.class);
        InOrder order = inOrder(mockObserver);

        long subscription = observable.subscribe(mockObserver);

        assertEquals(1, observable.getObserverCount());

        final String message = "hallo";
        observable.send(message);

        order.verify(mockObserver).send(observed, message);
        verifyNoMoreInteractions(mockObserver);

        observable.unsubscribe(subscription);
        assertEquals(0, observable.getObserverCount());

        observable.send(message);
        verifyNoMoreInteractions(mockObserver);
    }

    /**
     * Subscribes many susbcribers and sends notifications to subscribers.
     * Verifies that unique subscription number are returned. Also verifies that
     * the correct subscribers are notfied.
     */
    public void testManySubscribers() {
        final int nsubscribers = SUBSCRIBER_COUNT;
        final Observer[] mocks = new Observer[nsubscribers];
        final InOrder[] order = new InOrder[nsubscribers];

        List<Long> subscriptions = new ArrayList<Long>();

        for (int i = 0; i < nsubscribers; i++) {
            mocks[i] = mock(Observer.class);
            order[i] = inOrder(mocks[i]);

            long subscription = observable.subscribe(mocks[i]);
            assertTrue(subscriptions.add(subscription));
        }

        assertEquals(nsubscribers, observable.getObserverCount());

        final String message = "hallo";

        observable.send(message);

        for (int i = 0; i < nsubscribers; i++) {
            order[i].verify(mocks[i]).send(observed, message);
        }

        for (int i = nsubscribers / 2; i < nsubscribers; i++) {
            observable.unsubscribe(subscriptions.get(i));
        }

        assertEquals(nsubscribers - (nsubscribers - (nsubscribers / 2)),
            observable.getObserverCount());

        final String message2 = "blabla";

        observable.send(message2);

        for (int i = 0; i < (nsubscribers / 2); i++) {
            order[i].verify(mocks[i]).send(observed, message2);
        }

        for (int i = nsubscribers / 2; i < nsubscribers; i++) {
            verifyNoMoreInteractions(mocks[i]);
        }
    }

    /**
     * Subscribes and then unsubscribes with a wrong id. Verifies that
     * IllegalArgumentException is thrown.
     * 
     */
    public void testUnsubscribeWithWrongSubscription() {
        Observer<Integer, String> observer = mock(Observer.class);

        long subscription = observable.subscribe(observer);

        assertEquals(1, observable.getObserverCount());

        try {
            observable.unsubscribe(subscription + 1);
        } catch (IllegalArgumentException e) {
            return; // ok
        }

        fail();
    }
}