/**
 * Copyright 2014 Netflix, Inc.
 * 
 * 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 rx.internal.operators;

import static org.junit.Assert.*;

import java.util.*;
import java.util.concurrent.*;
import java.util.concurrent.atomic.AtomicInteger;

import org.junit.*;
import org.mockito.*;

import rx.*;
import rx.Observable;
import rx.Observer;
import rx.observers.TestSubscriber;
import rx.schedulers.Schedulers;

public class OperatorMergeMaxConcurrentTest {

    @Mock
    Observer<String> stringObserver;

    @Before
    public void before() {
        MockitoAnnotations.initMocks(this);
    }

    @Test
    public void testWhenMaxConcurrentIsOne() {
        for (int i = 0; i < 100; i++) {
            List<Observable<String>> os = new ArrayList<Observable<String>>();
            os.add(Observable.just("one", "two", "three", "four", "five").subscribeOn(Schedulers.newThread()));
            os.add(Observable.just("one", "two", "three", "four", "five").subscribeOn(Schedulers.newThread()));
            os.add(Observable.just("one", "two", "three", "four", "five").subscribeOn(Schedulers.newThread()));

            List<String> expected = Arrays.asList("one", "two", "three", "four", "five", "one", "two", "three", "four", "five", "one", "two", "three", "four", "five");
            Iterator<String> iter = Observable.merge(os, 1).toBlocking().toIterable().iterator();
            List<String> actual = new ArrayList<String>();
            while (iter.hasNext()) {
                actual.add(iter.next());
            }
            assertEquals(expected, actual);
        }
    }

    @Test
    public void testMaxConcurrent() {
        for (int times = 0; times < 100; times++) {
            int observableCount = 100;
            // Test maxConcurrent from 2 to 12
            int maxConcurrent = 2 + (times % 10);
            AtomicInteger subscriptionCount = new AtomicInteger(0);

            List<Observable<String>> os = new ArrayList<Observable<String>>();
            List<SubscriptionCheckObservable> scos = new ArrayList<SubscriptionCheckObservable>();
            for (int i = 0; i < observableCount; i++) {
                SubscriptionCheckObservable sco = new SubscriptionCheckObservable(subscriptionCount, maxConcurrent);
                scos.add(sco);
                os.add(Observable.create(sco));
            }

            Iterator<String> iter = Observable.merge(os, maxConcurrent).toBlocking().toIterable().iterator();
            List<String> actual = new ArrayList<String>();
            while (iter.hasNext()) {
                actual.add(iter.next());
            }
            //            System.out.println("actual: " + actual);
            assertEquals(5 * observableCount, actual.size());
            for (SubscriptionCheckObservable sco : scos) {
                assertFalse(sco.failed);
            }
        }
    }

    private static class SubscriptionCheckObservable implements Observable.OnSubscribe<String> {

        private final AtomicInteger subscriptionCount;
        private final int maxConcurrent;
        volatile boolean failed = false;

        SubscriptionCheckObservable(AtomicInteger subscriptionCount, int maxConcurrent) {
            this.subscriptionCount = subscriptionCount;
            this.maxConcurrent = maxConcurrent;
        }

        @Override
        public void call(final Subscriber<? super String> t1) {
            new Thread(new Runnable() {

                @Override
                public void run() {
                    if (subscriptionCount.incrementAndGet() > maxConcurrent) {
                        failed = true;
                    }
                    t1.onNext("one");
                    t1.onNext("two");
                    t1.onNext("three");
                    t1.onNext("four");
                    t1.onNext("five");
                    // We could not decrement subscriptionCount in the unsubscribe method
                    // as "unsubscribe" is not guaranteed to be called before the next "subscribe".
                    subscriptionCount.decrementAndGet();
                    t1.onCompleted();
                }

            }).start();
        }

    }
    
    @Test
    public void testMergeALotOfSourcesOneByOneSynchronously() {
        int n = 10000;
        List<Observable<Integer>> sourceList = new ArrayList<Observable<Integer>>(n);
        for (int i = 0; i < n; i++) {
            sourceList.add(Observable.just(i));
        }
        Iterator<Integer> it = Observable.merge(Observable.from(sourceList), 1).toBlocking().getIterator();
        int j = 0;
        while (it.hasNext()) {
            assertEquals((Integer)j, it.next());
            j++;
        }
        assertEquals(j, n);
    }
    @Test
    public void testMergeALotOfSourcesOneByOneSynchronouslyTakeHalf() {
        int n = 10000;
        List<Observable<Integer>> sourceList = new ArrayList<Observable<Integer>>(n);
        for (int i = 0; i < n; i++) {
            sourceList.add(Observable.just(i));
        }
        Iterator<Integer> it = Observable.merge(Observable.from(sourceList), 1).take(n / 2).toBlocking().getIterator();
        int j = 0;
        while (it.hasNext()) {
            assertEquals((Integer)j, it.next());
            j++;
        }
        assertEquals(j, n / 2);
    }
    
    @Test
    public void testSimple() {
        for (int i = 1; i < 100; i++) {
            TestSubscriber<Integer> ts = new TestSubscriber<Integer>();
            List<Observable<Integer>> sourceList = new ArrayList<Observable<Integer>>(i);
            List<Integer> result = new ArrayList<Integer>(i);
            for (int j = 1; j <= i; j++) {
                sourceList.add(Observable.just(j));
                result.add(j);
            }
            
            Observable.merge(sourceList, i).subscribe(ts);
        
            ts.assertNoErrors();
            ts.assertTerminalEvent();
            ts.assertReceivedOnNext(result);
        }
    }
    @Test
    public void testSimpleOneLess() {
        for (int i = 2; i < 100; i++) {
            TestSubscriber<Integer> ts = new TestSubscriber<Integer>();
            List<Observable<Integer>> sourceList = new ArrayList<Observable<Integer>>(i);
            List<Integer> result = new ArrayList<Integer>(i);
            for (int j = 1; j <= i; j++) {
                sourceList.add(Observable.just(j));
                result.add(j);
            }
            
            Observable.merge(sourceList, i - 1).subscribe(ts);
        
            ts.assertNoErrors();
            ts.assertTerminalEvent();
            ts.assertReceivedOnNext(result);
        }
    }
    @Test(timeout = 20000)
    public void testSimpleAsyncLoop() {
        for (int i = 0; i < 200; i++) {
            testSimpleAsync();
        }
    }
    @Test(timeout = 10000)
    public void testSimpleAsync() {
        for (int i = 1; i < 50; i++) {
            TestSubscriber<Integer> ts = new TestSubscriber<Integer>();
            List<Observable<Integer>> sourceList = new ArrayList<Observable<Integer>>(i);
            Set<Integer> expected = new HashSet<Integer>(i);
            for (int j = 1; j <= i; j++) {
                sourceList.add(Observable.just(j).subscribeOn(Schedulers.io()));
                expected.add(j);
            }
            
            Observable.merge(sourceList, i).subscribe(ts);
        
            ts.awaitTerminalEvent(1, TimeUnit.SECONDS);
            ts.assertNoErrors();
            Set<Integer> actual = new HashSet<Integer>(ts.getOnNextEvents());
            
            assertEquals(expected, actual);
        }
    }
    @Test(timeout = 10000)
    public void testSimpleOneLessAsyncLoop() {
        for (int i = 0; i < 200; i++) {
            testSimpleOneLessAsync();
        }
    }
    @Test(timeout = 10000)
    public void testSimpleOneLessAsync() {
        long t = System.currentTimeMillis();
        for (int i = 2; i < 50; i++) {
            if (System.currentTimeMillis() - t > TimeUnit.SECONDS.toMillis(9)) {
                break;
            }
            TestSubscriber<Integer> ts = new TestSubscriber<Integer>();
            List<Observable<Integer>> sourceList = new ArrayList<Observable<Integer>>(i);
            Set<Integer> expected = new HashSet<Integer>(i);
            for (int j = 1; j <= i; j++) {
                sourceList.add(Observable.just(j).subscribeOn(Schedulers.io()));
                expected.add(j);
            }
            
            Observable.merge(sourceList, i - 1).subscribe(ts);
        
            ts.awaitTerminalEvent(1, TimeUnit.SECONDS);
            ts.assertNoErrors();
            Set<Integer> actual = new HashSet<Integer>(ts.getOnNextEvents());
            
            assertEquals(expected, actual);
        }
    }
    @Test(timeout = 5000)
    public void testBackpressureHonored() throws Exception {
        List<Observable<Integer>> sourceList = new ArrayList<Observable<Integer>>(3);
        
        sourceList.add(Observable.range(0, 100000).subscribeOn(Schedulers.io()));
        sourceList.add(Observable.range(0, 100000).subscribeOn(Schedulers.io()));
        sourceList.add(Observable.range(0, 100000).subscribeOn(Schedulers.io()));
        
        final CountDownLatch cdl = new CountDownLatch(5);
        
        TestSubscriber<Integer> ts = new TestSubscriber<Integer>() {
            @Override
            public void onStart() {
                request(0);
            }
            @Override
            public void onNext(Integer t) {
                super.onNext(t);
                cdl.countDown();
            }
        };
        
        Observable.merge(sourceList, 2).subscribe(ts);
        
        ts.requestMore(5);
        
        cdl.await();
        
        ts.assertNoErrors();
        assertEquals(5, ts.getOnNextEvents().size());
        assertEquals(0, ts.getOnCompletedEvents().size());
        
        ts.unsubscribe();
    }
    @Test(timeout = 5000)
    public void testTake() throws Exception {
        List<Observable<Integer>> sourceList = new ArrayList<Observable<Integer>>(3);
        
        sourceList.add(Observable.range(0, 100000).subscribeOn(Schedulers.io()));
        sourceList.add(Observable.range(0, 100000).subscribeOn(Schedulers.io()));
        sourceList.add(Observable.range(0, 100000).subscribeOn(Schedulers.io()));
        
        TestSubscriber<Integer> ts = new TestSubscriber<Integer>();
        
        Observable.merge(sourceList, 2).take(5).subscribe(ts);
        
        ts.awaitTerminalEvent();
        ts.assertNoErrors();
        assertEquals(5, ts.getOnNextEvents().size());
    }
}
