/*
 * Copyright 2002-2015 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.springframework.messaging.simp.broker;

import java.util.Arrays;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicReference;

import org.junit.Test;

import org.springframework.messaging.Message;
import org.springframework.messaging.simp.SimpMessageHeaderAccessor;
import org.springframework.messaging.simp.SimpMessageType;
import org.springframework.messaging.support.MessageBuilder;
import org.springframework.util.AntPathMatcher;
import org.springframework.util.MultiValueMap;
import org.springframework.util.PathMatcher;

import static org.junit.Assert.*;

/**
 * Test fixture for
 * {@link org.springframework.messaging.simp.broker.DefaultSubscriptionRegistry}.
 *
 * @author Rossen Stoyanchev
 * @author Sebastien Deleuze
 */
public class DefaultSubscriptionRegistryTests {

	private final DefaultSubscriptionRegistry registry = new DefaultSubscriptionRegistry();


	@Test
	public void registerSubscriptionInvalidInput() {
		String sessId = "sess01";
		String subsId = "subs01";
		String dest = "/foo";

		this.registry.registerSubscription(subscribeMessage(null, subsId, dest));
		MultiValueMap<String, String> actual = this.registry.findSubscriptions(createMessage(dest));
		assertNotNull(actual);
		assertEquals(0, actual.size());

		this.registry.registerSubscription(subscribeMessage(sessId, null, dest));
		actual = this.registry.findSubscriptions(createMessage(dest));
		assertNotNull(actual);
		assertEquals(0, actual.size());

		this.registry.registerSubscription(subscribeMessage(sessId, subsId, null));
		actual = this.registry.findSubscriptions(createMessage(dest));
		assertNotNull(actual);
		assertEquals(0, actual.size());
	}

	@Test
	public void registerSubscription() {
		String sessId = "sess01";
		String subsId = "subs01";
		String dest = "/foo";

		this.registry.registerSubscription(subscribeMessage(sessId, subsId, dest));

		MultiValueMap<String, String> actual = this.registry.findSubscriptions(createMessage(dest));
		assertNotNull(actual);
		assertEquals("Expected one element " + actual, 1, actual.size());
		assertEquals(Collections.singletonList(subsId), actual.get(sessId));
	}

	@Test
	public void registerSubscriptionOneSession() {
		String sessId = "sess01";
		List<String> subscriptionIds = Arrays.asList("subs01", "subs02", "subs03");
		String dest = "/foo";

		for (String subId : subscriptionIds) {
			this.registry.registerSubscription(subscribeMessage(sessId, subId, dest));
		}

		MultiValueMap<String, String> actual = this.registry.findSubscriptions(createMessage(dest));
		assertNotNull(actual);
		assertEquals(1, actual.size());
		assertEquals(subscriptionIds, sort(actual.get(sessId)));
	}

	@Test
	public void registerSubscriptionMultipleSessions() {
		List<String> sessIds = Arrays.asList("sess01", "sess02", "sess03");
		List<String> subscriptionIds = Arrays.asList("subs01", "subs02", "subs03");
		String dest = "/foo";

		for (String sessId : sessIds) {
			for (String subsId : subscriptionIds) {
				this.registry.registerSubscription(subscribeMessage(sessId, subsId, dest));
			}
		}

		MultiValueMap<String, String> actual = this.registry.findSubscriptions(createMessage(dest));
		assertNotNull(actual);
		assertEquals(3, actual.size());
		assertEquals(subscriptionIds, sort(actual.get(sessIds.get(0))));
		assertEquals(subscriptionIds, sort(actual.get(sessIds.get(1))));
		assertEquals(subscriptionIds, sort(actual.get(sessIds.get(2))));
	}

	@Test
	public void registerSubscriptionWithDestinationPattern() {
		String sessId = "sess01";
		String subsId = "subs01";
		String destPattern = "/topic/PRICE.STOCK.*.IBM";
		String dest = "/topic/PRICE.STOCK.NASDAQ.IBM";
		this.registry.registerSubscription(subscribeMessage(sessId, subsId, destPattern));

		MultiValueMap<String, String> actual = this.registry.findSubscriptions(createMessage(dest));
		assertNotNull(actual);
		assertEquals("Expected one element " + actual, 1, actual.size());
		assertEquals(Collections.singletonList(subsId), actual.get(sessId));
	}

	@Test  // SPR-11657
	public void registerSubscriptionsWithSimpleAndPatternDestinations() {
		String sess1 = "sess01";
		String sess2 = "sess02";

		String subs1 = "subs01";
		String subs2 = "subs02";
		String subs3 = "subs03";

		String destNasdaqIbm = "/topic/PRICE.STOCK.NASDAQ.IBM";
		Message<?> destNasdaqIbmMessage = createMessage(destNasdaqIbm);

		this.registry.registerSubscription(subscribeMessage(sess1, subs2, destNasdaqIbm));
		this.registry.registerSubscription(subscribeMessage(sess1, subs1, "/topic/PRICE.STOCK.*.IBM"));

		MultiValueMap<String, String> actual = this.registry.findSubscriptions(destNasdaqIbmMessage);
		assertNotNull(actual);
		assertEquals(1, actual.size());
		assertEquals(Arrays.asList(subs2, subs1), actual.get(sess1));

		this.registry.registerSubscription(subscribeMessage(sess2, subs1, destNasdaqIbm));
		this.registry.registerSubscription(subscribeMessage(sess2, subs2, "/topic/PRICE.STOCK.NYSE.IBM"));
		this.registry.registerSubscription(subscribeMessage(sess2, subs3, "/topic/PRICE.STOCK.NASDAQ.GOOG"));

		actual = this.registry.findSubscriptions(destNasdaqIbmMessage);
		assertNotNull(actual);
		assertEquals(2, actual.size());
		assertEquals(Arrays.asList(subs2, subs1), actual.get(sess1));
		assertEquals(Collections.singletonList(subs1), actual.get(sess2));

		this.registry.unregisterAllSubscriptions(sess1);

		actual = this.registry.findSubscriptions(destNasdaqIbmMessage);
		assertNotNull(actual);
		assertEquals(1, actual.size());
		assertEquals(Collections.singletonList(subs1), actual.get(sess2));

		this.registry.registerSubscription(subscribeMessage(sess1, subs1, "/topic/PRICE.STOCK.*.IBM"));
		this.registry.registerSubscription(subscribeMessage(sess1, subs2, destNasdaqIbm));

		actual = this.registry.findSubscriptions(destNasdaqIbmMessage);
		assertNotNull(actual);
		assertEquals(2, actual.size());
		assertEquals(Arrays.asList(subs1, subs2), actual.get(sess1));
		assertEquals(Collections.singletonList(subs1), actual.get(sess2));

		this.registry.unregisterSubscription(unsubscribeMessage(sess1, subs2));

		actual = this.registry.findSubscriptions(destNasdaqIbmMessage);
		assertNotNull(actual);
		assertEquals(2, actual.size());
		assertEquals(Collections.singletonList(subs1), actual.get(sess1));
		assertEquals(Collections.singletonList(subs1), actual.get(sess2));

		this.registry.unregisterSubscription(unsubscribeMessage(sess1, subs1));

		actual = this.registry.findSubscriptions(destNasdaqIbmMessage);
		assertNotNull(actual);
		assertEquals(1, actual.size());
		assertEquals(Collections.singletonList(subs1), actual.get(sess2));

		this.registry.unregisterSubscription(unsubscribeMessage(sess2, subs1));

		actual = this.registry.findSubscriptions(destNasdaqIbmMessage);
		assertNotNull(actual);
		assertEquals(0, actual.size());
	}

	@Test  // SPR-11755
	public void registerAndUnregisterMultipleDestinations() {
		String sess1 = "sess01";
		String sess2 = "sess02";

		String subs1 = "subs01";
		String subs2 = "subs02";
		String subs3 = "subs03";
		String subs4 = "subs04";
		String subs5 = "subs05";

		this.registry.registerSubscription(subscribeMessage(sess1, subs1, "/topic/PRICE.STOCK.NASDAQ.IBM"));
		this.registry.registerSubscription(subscribeMessage(sess1, subs2, "/topic/PRICE.STOCK.NYSE.IBM"));
		this.registry.registerSubscription(subscribeMessage(sess1, subs3, "/topic/PRICE.STOCK.NASDAQ.GOOG"));

		this.registry.findSubscriptions(createMessage("/topic/PRICE.STOCK.NYSE.IBM"));
		this.registry.findSubscriptions(createMessage("/topic/PRICE.STOCK.NASDAQ.GOOG"));
		this.registry.findSubscriptions(createMessage("/topic/PRICE.STOCK.NASDAQ.IBM"));

		this.registry.unregisterSubscription(unsubscribeMessage(sess1, subs1));
		this.registry.unregisterSubscription(unsubscribeMessage(sess1, subs2));
		this.registry.unregisterSubscription(unsubscribeMessage(sess1, subs3));

		this.registry.registerSubscription(subscribeMessage(sess1, subs1, "/topic/PRICE.STOCK.NASDAQ.IBM"));
		this.registry.registerSubscription(subscribeMessage(sess1, subs2, "/topic/PRICE.STOCK.NYSE.IBM"));
		this.registry.registerSubscription(subscribeMessage(sess1, subs3, "/topic/PRICE.STOCK.NASDAQ.GOOG"));
		this.registry.registerSubscription(subscribeMessage(sess1, subs4, "/topic/PRICE.STOCK.NYSE.IBM"));
		this.registry.registerSubscription(subscribeMessage(sess2, subs5, "/topic/PRICE.STOCK.NASDAQ.GOOG"));

		this.registry.unregisterAllSubscriptions(sess1);
		this.registry.unregisterAllSubscriptions(sess2);
	}

	@Test
	public void registerSubscriptionWithDestinationPatternRegex() {
		String sessId = "sess01";
		String subsId = "subs01";
		String destPattern = "/topic/PRICE.STOCK.*.{ticker:(IBM|MSFT)}";

		this.registry.registerSubscription(subscribeMessage(sessId, subsId, destPattern));
		Message<?> message = createMessage("/topic/PRICE.STOCK.NASDAQ.IBM");
		MultiValueMap<String, String> actual = this.registry.findSubscriptions(message);
		assertNotNull(actual);
		assertEquals("Expected one element " + actual, 1, actual.size());
		assertEquals(Collections.singletonList(subsId), actual.get(sessId));

		message = createMessage("/topic/PRICE.STOCK.NASDAQ.MSFT");
		actual = this.registry.findSubscriptions(message);
		assertNotNull(actual);
		assertEquals("Expected one element " + actual, 1, actual.size());
		assertEquals(Collections.singletonList(subsId), actual.get(sessId));

		message = createMessage("/topic/PRICE.STOCK.NASDAQ.VMW");
		actual = this.registry.findSubscriptions(message);
		assertNotNull(actual);
		assertEquals("Expected no elements " + actual, 0, actual.size());
	}

	@Test
	public void registerSubscriptionWithSelector() throws Exception {
		String sessionId = "sess01";
		String subscriptionId = "subs01";
		String destination = "/foo";
		String selector = "headers.foo == 'bar'";

		this.registry.registerSubscription(subscribeMessage(sessionId, subscriptionId, destination, selector));

		SimpMessageHeaderAccessor accessor = SimpMessageHeaderAccessor.create();
		accessor.setDestination(destination);
		accessor.setNativeHeader("foo", "bar");
		Message<?> message = MessageBuilder.createMessage("", accessor.getMessageHeaders());

		MultiValueMap<String, String> actual = this.registry.findSubscriptions(message);
		assertNotNull(actual);
		assertEquals(1, actual.size());
		assertEquals(Collections.singletonList(subscriptionId), actual.get(sessionId));

		actual = this.registry.findSubscriptions(createMessage(destination));
		assertNotNull(actual);
		assertEquals(0, actual.size());
	}

	@Test  // SPR-11931
	public void registerSubscriptionTwiceAndUnregister() {
		this.registry.registerSubscription(subscribeMessage("sess01", "subs01", "/foo"));
		this.registry.registerSubscription(subscribeMessage("sess01", "subs02", "/foo"));

		MultiValueMap<String, String> actual = this.registry.findSubscriptions(createMessage("/foo"));
		assertNotNull(actual);
		assertEquals("Expected 1 element", 1, actual.size());
		assertEquals(Arrays.asList("subs01", "subs02"), actual.get("sess01"));

		this.registry.unregisterSubscription(unsubscribeMessage("sess01", "subs01"));

		actual = this.registry.findSubscriptions(createMessage("/foo"));
		assertNotNull(actual);
		assertEquals("Expected 1 element", 1, actual.size());
		assertEquals(Collections.singletonList("subs02"), actual.get("sess01"));

		this.registry.unregisterSubscription(unsubscribeMessage("sess01", "subs02"));

		actual = this.registry.findSubscriptions(createMessage("/foo"));
		assertNotNull(actual);
		assertEquals("Expected no element", 0, actual.size());
	}

	@Test
	public void unregisterSubscription() {
		List<String> sessIds = Arrays.asList("sess01", "sess02", "sess03");
		List<String> subscriptionIds = Arrays.asList("subs01", "subs02", "subs03");
		String dest = "/foo";

		for (String sessId : sessIds) {
			for (String subsId : subscriptionIds) {
				this.registry.registerSubscription(subscribeMessage(sessId, subsId, dest));
			}
		}

		this.registry.unregisterSubscription(unsubscribeMessage(sessIds.get(0), subscriptionIds.get(0)));
		this.registry.unregisterSubscription(unsubscribeMessage(sessIds.get(0), subscriptionIds.get(1)));
		this.registry.unregisterSubscription(unsubscribeMessage(sessIds.get(0), subscriptionIds.get(2)));

		MultiValueMap<String, String> actual = this.registry.findSubscriptions(createMessage(dest));
		assertNotNull(actual);
		assertEquals("Expected two elements: " + actual, 2, actual.size());
		assertEquals(subscriptionIds, sort(actual.get(sessIds.get(1))));
		assertEquals(subscriptionIds, sort(actual.get(sessIds.get(2))));
	}

	@Test
	public void unregisterAllSubscriptions() {
		List<String> sessIds = Arrays.asList("sess01", "sess02", "sess03");
		List<String> subscriptionIds = Arrays.asList("subs01", "subs02", "subs03");
		String dest = "/foo";

		for (String sessId : sessIds) {
			for (String subsId : subscriptionIds) {
				this.registry.registerSubscription(subscribeMessage(sessId, subsId, dest));
			}
		}

		this.registry.unregisterAllSubscriptions(sessIds.get(0));
		this.registry.unregisterAllSubscriptions(sessIds.get(1));

		MultiValueMap<String, String> actual = this.registry.findSubscriptions(createMessage(dest));
		assertNotNull(actual);
		assertEquals("Expected one element: " + actual, 1, actual.size());
		assertEquals(subscriptionIds, sort(actual.get(sessIds.get(2))));
	}

	@Test
	public void unregisterAllSubscriptionsNoMatch() {
		this.registry.unregisterAllSubscriptions("bogus");
		// no exceptions
	}

	@Test
	public void findSubscriptionsNoMatches() {
		MultiValueMap<String, String> actual = this.registry.findSubscriptions(createMessage("/foo"));
		assertNotNull(actual);
		assertEquals("Expected no elements " + actual, 0, actual.size());
	}

	@Test  // SPR-12665
	public void findSubscriptionsReturnsMapSafeToIterate() throws Exception {
		this.registry.registerSubscription(subscribeMessage("sess1", "1", "/foo"));
		this.registry.registerSubscription(subscribeMessage("sess2", "1", "/foo"));

		MultiValueMap<String, String> subscriptions = this.registry.findSubscriptions(createMessage("/foo"));
		assertNotNull(subscriptions);
		assertEquals(2, subscriptions.size());

		Iterator<Map.Entry<String, List<String>>> iterator = subscriptions.entrySet().iterator();
		iterator.next();

		this.registry.registerSubscription(subscribeMessage("sess3", "1", "/foo"));

		iterator.next();
		// no ConcurrentModificationException
	}

	@Test  // SPR-13185
	public void findSubscriptionsReturnsMapSafeToIterateIncludingValues() throws Exception {
		this.registry.registerSubscription(subscribeMessage("sess1", "1", "/foo"));
		this.registry.registerSubscription(subscribeMessage("sess1", "2", "/foo"));

		MultiValueMap<String, String> allSubscriptions = this.registry.findSubscriptions(createMessage("/foo"));
		assertNotNull(allSubscriptions);
		assertEquals(1, allSubscriptions.size());

		Iterator<String> iteratorValues = allSubscriptions.get("sess1").iterator();
		iteratorValues.next();

		this.registry.unregisterSubscription(unsubscribeMessage("sess1", "2"));

		iteratorValues.next();
		// no ConcurrentModificationException
	}

	@Test  // SPR-13204
	public void findSubscriptionsWithConcurrentUnregisterAllSubscriptions() throws Exception {
		final CountDownLatch iterationPausedLatch = new CountDownLatch(1);
		final CountDownLatch iterationResumeLatch = new CountDownLatch(1);
		final CountDownLatch iterationDoneLatch = new CountDownLatch(1);

		PathMatcher pathMatcher = new PausingPathMatcher(iterationPausedLatch, iterationResumeLatch);
		this.registry.setPathMatcher(pathMatcher);
		this.registry.registerSubscription(subscribeMessage("sess1", "1", "/foo"));
		this.registry.registerSubscription(subscribeMessage("sess2", "1", "/foo"));

		AtomicReference<MultiValueMap<String, String>> subscriptions = new AtomicReference<>();
		new Thread(() -> {
			subscriptions.set(registry.findSubscriptions(createMessage("/foo")));
			iterationDoneLatch.countDown();
		}).start();

		assertTrue(iterationPausedLatch.await(10, TimeUnit.SECONDS));

		this.registry.unregisterAllSubscriptions("sess1");
		this.registry.unregisterAllSubscriptions("sess2");

		iterationResumeLatch.countDown();
		assertTrue(iterationDoneLatch.await(10, TimeUnit.SECONDS));

		MultiValueMap<String, String> result = subscriptions.get();
		assertNotNull(result);
		assertEquals(0, result.size());
	}


	private Message<?> createMessage(String destination) {
		SimpMessageHeaderAccessor accessor = SimpMessageHeaderAccessor.create();
		accessor.setDestination(destination);
		return MessageBuilder.createMessage("", accessor.getMessageHeaders());
	}

	private Message<?> subscribeMessage(String sessionId, String subscriptionId, String destination) {
		return subscribeMessage(sessionId, subscriptionId, destination, null);
	}

	private Message<?> subscribeMessage(String sessionId, String subscriptionId, String dest, String selector) {
		SimpMessageHeaderAccessor accessor = SimpMessageHeaderAccessor.create(SimpMessageType.SUBSCRIBE);
		accessor.setSessionId(sessionId);
		accessor.setSubscriptionId(subscriptionId);
		if (dest != null) {
			accessor.setDestination(dest);
		}
		if (selector != null) {
			accessor.setNativeHeader("selector", selector);
		}
		return MessageBuilder.createMessage("", accessor.getMessageHeaders());
	}

	private Message<?> unsubscribeMessage(String sessionId, String subscriptionId) {
		SimpMessageHeaderAccessor accessor = SimpMessageHeaderAccessor.create(SimpMessageType.UNSUBSCRIBE);
		accessor.setSessionId(sessionId);
		accessor.setSubscriptionId(subscriptionId);
		return MessageBuilder.createMessage("", accessor.getMessageHeaders());
	}

	private List<String> sort(List<String> list) {
		Collections.sort(list);
		return list;
	}


	/**
	 * An extension of AntPathMatcher with a pair of CountDownLatches to pause
	 * while matching, allowing another thread to something, and resume when the
	 * other thread signals it's okay to do so.
	 */
	private static class PausingPathMatcher extends AntPathMatcher {

		private final CountDownLatch iterationPausedLatch;

		private final CountDownLatch iterationResumeLatch;

		public PausingPathMatcher(CountDownLatch iterationPausedLatch, CountDownLatch iterationResumeLatch) {
			this.iterationPausedLatch = iterationPausedLatch;
			this.iterationResumeLatch = iterationResumeLatch;
		}

		@Override
		public boolean match(String pattern, String path) {
			try {
				this.iterationPausedLatch.countDown();
				assertTrue(this.iterationResumeLatch.await(10, TimeUnit.SECONDS));
				return super.match(pattern, path);
			}
			catch (InterruptedException ex) {
				ex.printStackTrace();
				return false;
			}
		}
	}

}
