package org.infinispan.eviction.impl;

import static org.testng.AssertJUnit.assertEquals;
import static org.testng.AssertJUnit.assertNotNull;
import static org.testng.AssertJUnit.assertNull;
import static org.testng.AssertJUnit.assertTrue;
import static org.testng.AssertJUnit.fail;

import java.io.Serializable;
import java.util.Arrays;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;

import org.infinispan.Cache;
import org.infinispan.commands.VisitableCommand;
import org.infinispan.commands.read.GetCacheEntryCommand;
import org.infinispan.commands.read.GetKeyValueCommand;
import org.infinispan.commands.write.PutKeyValueCommand;
import org.infinispan.commons.util.Util;
import org.infinispan.configuration.cache.ConfigurationBuilder;
import org.infinispan.container.DataContainer;
import org.infinispan.container.entries.InternalCacheEntry;
import org.infinispan.context.InvocationContext;
import org.infinispan.eviction.EvictionStrategy;
import org.infinispan.eviction.PassivationManager;
import org.infinispan.interceptors.AsyncInterceptor;
import org.infinispan.interceptors.AsyncInterceptorChain;
import org.infinispan.interceptors.base.BaseCustomInterceptor;
import org.infinispan.interceptors.impl.EntryWrappingInterceptor;
import org.infinispan.manager.EmbeddedCacheManager;
import org.infinispan.marshall.core.MarshalledEntry;
import org.infinispan.notifications.Listener;
import org.infinispan.notifications.cachelistener.annotation.CacheEntriesEvicted;
import org.infinispan.notifications.cachelistener.event.CacheEntriesEvictedEvent;
import org.infinispan.persistence.dummy.DummyInMemoryStoreConfigurationBuilder;
import org.infinispan.persistence.spi.CacheLoader;
import org.infinispan.persistence.spi.PersistenceException;
import org.infinispan.test.SingleCacheManagerTest;
import org.infinispan.test.TestingUtil;
import org.infinispan.test.fwk.TestCacheManagerFactory;
import org.testng.annotations.Test;

/**
 * Tests size-based eviction with concurrent read and/or write operation. In this test, we have no passivation.
 *
 * @author Pedro Ruivo
 * @since 6.0
 */
@Test(groups = "functional", testName = "eviction.EvictionWithConcurrentOperationsTest")
public class EvictionWithConcurrentOperationsTest extends SingleCacheManagerTest {

   protected final AtomicInteger storeNamePrefix = new AtomicInteger(0);
   public final String storeName = getClass().getSimpleName();

   public EvictionWithConcurrentOperationsTest() {
      cleanup = CleanupPhase.AFTER_METHOD;
   }

   /**
    * ISPN-3048: this is a simple scenario. a put triggers the eviction while another thread tries to read. the read
    * occurs before the eviction listener is notified (and passivated if enabled). the key still exists in the map
    */
   public void testScenario1() throws Exception {
      final Object key1 = new SameHashCodeKey("key1");
      initializeKeyAndCheckData(key1, "v1");

      final Object key2 = new SameHashCodeKey("key2");
      final Latch latch = new Latch();
      final ControlledPassivationManager controlledPassivationManager = replacePassivationManager(latch);

      //this will trigger the eviction of key1. key1 eviction will be blocked in the latch
      latch.enable();
      Future<Object> put = cache.putAsync(key2, "v2");
      latch.waitToBlock(30, TimeUnit.SECONDS);

      //the eviction was trigger and it blocked before passivation
      assertEquals("Wrong value for key " + key1 + " in get operation.", "v1", cache.get(key1));

      //let the eviction continue and wait for put
      latch.disable();
      put.get();

      assertInMemory(key2, "v2");
      assertNotInMemory(key1, "v1");
   }

   /**
    * ISPN-3048: this is a simple scenario. a put triggers the eviction while another thread tries to read. the read
    * occurs after the eviction listener is notified (if passivation is enabled, it is written to disk). the key still
    * exists in the map
    */
   public void testScenario2() throws Exception {
      final Object key1 = new SameHashCodeKey("key1");
      initializeKeyAndCheckData(key1, "v1");

      final Object key2 = new SameHashCodeKey("key2");
      final Latch latch = new Latch();
      final ControlledPassivationManager controlledPassivationManager = replacePassivationManager(latch);

      //this will trigger the eviction of key1. key1 eviction will be blocked in the latch
      latch.enable();
      Future<Object> put = cache.putAsync(key2, "v2");
      latch.waitToBlock(30, TimeUnit.SECONDS);

      //the eviction was trigger and it blocked before passivation
      assertEquals("Wrong value for key " + key1 + " in get operation.", "v1", cache.get(key1));

      //let the eviction continue and wait for put
      latch.disable();
      put.get();

      assertInMemory(key2, "v2");
      assertNotInMemory(key1, "v1");
   }

   /**
    * ISPN-3048: a put triggers the eviction while another thread tries to read. the read occurs after the eviction
    * listener is notified (if passivation is enabled, it is written to disk) and after the entry is removed from the
    * map. however, it should be able to load it from persistence.
    */
   public void testScenario3() throws Exception {
      final Object key1 = new SameHashCodeKey("key1");
      initializeKeyAndCheckData(key1, "v1");

      final Object key2 = new SameHashCodeKey("key2");
      final Latch latch = new Latch();
      final SyncEvictionListener evictionListener = new SyncEvictionListener() {
         @CacheEntriesEvicted
         @Override
         public void evicted(CacheEntriesEvictedEvent event) {
            if (event.getEntries().containsKey(key1)) {
               latch.blockIfNeeded();
            }
         }
      };
      cache.addListener(evictionListener);

      //this will trigger the eviction of key1. key1 eviction will be blocked in the latch
      latch.enable();
      Future<Object> put = cache.putAsync(key2, "v2");
      latch.waitToBlock(30, TimeUnit.SECONDS);

      //let the eviction continue and wait for put
      latch.disable();
      put.get();

      //the eviction was trigger and the key is no longer in the map
      // This should be after the async put is known to finish.  It is undefined which would
      // win in the case of an entry being activated while it is also being passivated
      // This way it is clear which should be there
      assertEquals("Wrong value for key " + key1 + " in get operation.", "v1", cache.get(key1));

      assertInMemory(key1, "v1");
      assertNotInMemory(key2, "v2");
   }

   /**
    * ISPN-3048: a put triggers the eviction while another thread tries to read. the read occurs after the eviction
    * listener is notified (if passivation is enabled, it is written to disk) and after the entry is removed from the
    * map. however, a concurrent read happens at the same time before the first has time to load it from persistence.
    */
   public void testScenario4() throws Exception {
      final Object key1 = new SameHashCodeKey("key1");
      initializeKeyAndCheckData(key1, "v1");

      final Object key2 = new SameHashCodeKey("key2");
      final Latch readLatch = new Latch();
      final Latch writeLatch = new Latch();
      final AtomicBoolean firstGet = new AtomicBoolean(false);
      final AfterEntryWrappingInterceptor afterEntryWrappingInterceptor = new AfterEntryWrappingInterceptor()
            .injectThis(cache);
      afterEntryWrappingInterceptor.beforeGet = new Runnable() {
         @Override
         public void run() {
            if (firstGet.compareAndSet(false, true)) {
               readLatch.blockIfNeeded();
            }
         }
      };
      final SyncEvictionListener evictionListener = new

            SyncEvictionListener() {
               @CacheEntriesEvicted
               @Override
               public void evicted(CacheEntriesEvictedEvent event) {
                  if (event.getEntries().containsKey(key1)) {
                     writeLatch.blockIfNeeded();
                  }
               }
            };
      cache.addListener(evictionListener);

      //this will trigger the eviction of key1. key1 eviction will be blocked in the latch
      readLatch.enable();
      Future<Object> put = cache.putAsync(key2, "v2");
      writeLatch.waitToBlock(30, TimeUnit.SECONDS);

      //the eviction was trigger and the key is no longer in the map
      Future<Object> get = cache.getAsync(key1);
      readLatch.waitToBlock(30, TimeUnit.SECONDS);

      //the first read is blocked. it has check the data container and it didn't found any value
      //this second get should not block anywhere and it should fetch the value from persistence
      assertEquals("Wrong value for key " + key1 + " in get operation.", "v1", cache.get(key1));

      //let the eviction continue and wait for put
      writeLatch.disable();
      put.get();

      //let the second get continue
      readLatch.disable();
      assertEquals("Wrong value for key " + key1 + " in get operation.", "v1", get.get());

      assertInMemory(key1, "v1");
      assertNotInMemory(key2, "v2");
   }

   /**
    * ISPN-3048: a put triggers the eviction while another thread tries to read. the read occurs after the eviction
    * listener is notified (if passivation is enabled, it is written to disk) and after the entry is removed from the
    * map. however, a concurrent put happens at the same time before the get has time to load it from persistence.
    */
   public void testScenario5() throws Exception {
      final Object key1 = new SameHashCodeKey("key1");
      initializeKeyAndCheckData(key1, "v1");

      final Object key2 = new SameHashCodeKey("key2");
      final Latch readLatch = new Latch();
      final Latch writeLatch = new Latch();
      final AfterEntryWrappingInterceptor afterEntryWrappingInterceptor = new AfterEntryWrappingInterceptor()
            .injectThis(cache);
      afterEntryWrappingInterceptor.beforeGet = new Runnable() {
         @Override
         public void run() {
            readLatch.blockIfNeeded();

         }
      };
      final SyncEvictionListener evictionListener = new

            SyncEvictionListener() {
               @CacheEntriesEvicted
               @Override
               public void evicted(CacheEntriesEvictedEvent event) {
                  if (event.getEntries().containsKey(key1)) {
                     writeLatch.blockIfNeeded();
                  }
               }
            };
      cache.addListener(evictionListener);

      //this will trigger the eviction of key1. key1 eviction will be blocked in the latch
      readLatch.enable();
      Future<Object> put = cache.putAsync(key2, "v2");
      writeLatch.waitToBlock(30, TimeUnit.SECONDS);

      //the eviction was trigger and the key is no longer in the map
      Future<Object> get = cache.getAsync(key1);
      readLatch.waitToBlock(30, TimeUnit.SECONDS);

      //let the eviction continue
      writeLatch.disable();

      //the first read is blocked. it has check the data container and it didn't found any value
      //this second get should not block anywhere and it should fetch the value from persistence
      assertEquals("Wrong value for key " + key1 + " in get operation.", "v1", cache.put(key1, "v3"));

      put.get();

      //let the get continue
      readLatch.disable();
      assertEquals("Wrong value for key " + key1 + " in get operation.", "v3", get.get());

      assertInMemory(key1, "v3");
      assertNotInMemory(key2, "v2");
   }

   /**
    * ISPN-3048: a put triggers the eviction while another thread tries to read. the read occurs after the eviction
    * listener is notified (if passivation is enabled, it is written to disk) and after the entry is removed from the
    * map. however, a concurrent put happens at the same time before the get has time to load it from persistence. The
    * get will occur after the put writes to persistence and before writes to data container
    */
   public void testScenario6() throws Exception {
      final Object key1 = new SameHashCodeKey("key1");
      initializeKeyAndCheckData(key1, "v1");

      final Object key2 = new SameHashCodeKey("key2");
      final Latch readLatch = new Latch();
      final Latch writeLatch = new Latch();
      final Latch writeLatch2 = new Latch();
      final AtomicBoolean firstWriter = new AtomicBoolean(false);
      final AfterEntryWrappingInterceptor afterEntryWrappingInterceptor = new AfterEntryWrappingInterceptor()
            .injectThis(cache);
      afterEntryWrappingInterceptor.beforeGet = new Runnable() {
         @Override
         public void run() {
            readLatch.blockIfNeeded();

         }
      };
      afterEntryWrappingInterceptor.afterPut = new

            Runnable() {
               @Override
               public void run() {
                  if (!firstWriter.compareAndSet(false, true)) {
                     writeLatch2.blockIfNeeded();
                  }
               }
            };
      final SyncEvictionListener evictionListener = new

            SyncEvictionListener() {
               @CacheEntriesEvicted
               @Override
               public void evicted(CacheEntriesEvictedEvent event) {
                  if (event.getEntries().containsKey(key1)) {
                     writeLatch.blockIfNeeded();
                  }
               }
            };
      cache.addListener(evictionListener);

      //this will trigger the eviction of key1. key1 eviction will be blocked in the latch
      readLatch.enable();
      Future<Object> put = cache.putAsync(key2, "v2");
      writeLatch.waitToBlock(30, TimeUnit.SECONDS);

      //the eviction was trigger and the key is no longer in the map
      Future<Object> get = cache.getAsync(key1);
      readLatch.waitToBlock(30, TimeUnit.SECONDS);

      //let the eviction continue
      writeLatch.disable();

      Future<Object> put2 = cache.putAsync(key1, "v3");

      put.get();

      //wait until the 2nd put writes to persistence
      writeLatch2.waitToBlock(30, TimeUnit.SECONDS);

      //let the get continue
      readLatch.disable();
      assertPossibleValues(key1, get.get(), "v1", "v3");

      writeLatch2.disable();
      assertEquals("Wrong value for key " + key1 + " in put operation.", "v1", put2.get());

      assertInMemory(key1, "v3");
      assertNotInMemory(key2, "v2");
   }

   /**
    * ISPN-3854: an entry is evicted. a get operation is performed and loads the entry from the persistence. However,
    * before continue the processing, a put succeeds and updates the key. Check in the end if the key is correctly
    * stored or not.
    */
   public void testScenario7() throws Exception {
      final Object key1 = new SameHashCodeKey("key1");
      initializeKeyAndCheckData(key1, "v1");

      final Latch readLatch = new Latch();
      final AfterActivationOrCacheLoader commandController = new AfterActivationOrCacheLoader()
            .injectThis(cache);
      commandController.afterGet = new Runnable() {
         @Override
         public void run() {
            readLatch.blockIfNeeded();

         }
      };

      cache.evict(key1);

      assertNotInMemory(key1, "v1");

      //perform the get. it will load the entry from cache loader.
      readLatch.enable();
      Future<Object> get = cache.getAsync(key1);
      readLatch.waitToBlock(30, TimeUnit.SECONDS);

      //now, we perform a put.
      assertEquals("Wrong value for key " + key1 + " in put operation.", "v1", cache.put(key1, "v2"));

      //we let the get go...
      readLatch.disable();
      assertPossibleValues(key1, get.get(), "v1");

      assertInMemory(key1, "v2");
   }

   @SuppressWarnings("unchecked")
   protected void initializeKeyAndCheckData(Object key, Object value) {
      assertTrue("A cache store should be configured!", cache.getCacheConfiguration().persistence().usingStores());
      cache.put(key, value);
      DataContainer container = cache.getAdvancedCache().getDataContainer();
      InternalCacheEntry entry = container.get(key);
      CacheLoader<Object, Object> loader = TestingUtil.getFirstLoader(cache);
      assertNotNull("Key " + key + " does not exist in data container.", entry);
      assertEquals("Wrong value for key " + key + " in data container.", value, entry.getValue());
      MarshalledEntry<Object, Object> entryLoaded = loader.load(key);
      assertNotNull("Key " + key + " does not exist in cache loader.", entryLoaded);
      assertEquals("Wrong value for key " + key + " in cache loader.", value, entryLoaded.getValue());
   }

   @SuppressWarnings("unchecked")
   protected void assertInMemory(Object key, Object value) {
      DataContainer container = cache.getAdvancedCache().getDataContainer();
      InternalCacheEntry entry = container.get(key);
      CacheLoader<Object, Object> loader = TestingUtil.getFirstLoader(cache);
      assertNotNull("Key " + key + " does not exist in data container", entry);
      assertEquals("Wrong value for key " + key + " in data container", value, entry.getValue());
      MarshalledEntry<Object, Object> entryLoaded = loader.load(key);
      assertNotNull("Key " + key + " does not exist in cache loader", entryLoaded);
      assertEquals("Wrong value for key " + key + " in cache loader", value, entryLoaded.getValue());
   }

   @SuppressWarnings("unchecked")
   protected void assertNotInMemory(Object key, Object value) {
      DataContainer container = cache.getAdvancedCache().getDataContainer();
      InternalCacheEntry entry = container.get(key);
      CacheLoader<Object, Object> loader = TestingUtil.getFirstLoader(cache);
      assertNull("Key " + key + " exists in data container", entry);
      MarshalledEntry<Object, Object> entryLoaded = loader.load(key);
      assertNotNull("Key " + key + " does not exist in cache loader", entryLoaded);
      assertEquals("Wrong value for key " + key + " in cache loader", value, entryLoaded.getValue());
   }

   @Override
   protected EmbeddedCacheManager createCacheManager() throws Exception {
      ConfigurationBuilder builder = getDefaultStandaloneCacheConfig(false);
      configurePersistence(builder);
      configureEviction(builder);
      return TestCacheManagerFactory.createCacheManager(builder);
   }

   protected void configureEviction(ConfigurationBuilder builder) {
      builder.eviction()
            .maxEntries(1)
            .strategy(EvictionStrategy.LRU);
   }

   protected void configurePersistence(ConfigurationBuilder builder) {
      builder.persistence().passivation(false).addStore(DummyInMemoryStoreConfigurationBuilder.class)
            .storeName(storeName + storeNamePrefix.getAndIncrement());
   }

   protected final ControlledPassivationManager replacePassivationManager(final Latch latch) {
      PassivationManager current = TestingUtil.extractComponent(cache, PassivationManager.class);
      ControlledPassivationManager controlledPassivationManager = new ControlledPassivationManager(current);
      controlledPassivationManager.beforePassivate = new Runnable() {
         @Override
         public void run() {
            latch.blockIfNeeded();
         }
      };
      TestingUtil.replaceComponent(cache, PassivationManager.class, controlledPassivationManager, true);
      return controlledPassivationManager;
   }

   protected void assertPossibleValues(Object key, Object value, Object... expectedValues) {
      for (Object expectedValue : expectedValues) {
         if (value == null ? expectedValue == null : value.equals(expectedValue)) {
            return;
         }
      }
      fail("Wrong value for key " + key + ". value=" + String.valueOf(value) + ", expectedValues=" +
                 Arrays.toString(expectedValues));
   }

   public static class SameHashCodeKey implements Serializable {

      private final String name;

      public SameHashCodeKey(String name) {
         this.name = name;
      }

      @Override
      public boolean equals(Object o) {
         if (this == o) return true;
         if (o == null || getClass() != o.getClass()) return false;

         SameHashCodeKey that = (SameHashCodeKey) o;

         return name.equals(that.name);

      }

      @Override
      public int hashCode() {
         return 0; //same hash code to force the keys to be in the same segment.
      }

      @Override
      public String toString() {
         return name;
      }
   }

   protected class ControlledPassivationManager implements PassivationManager {
      protected final PassivationManager delegate;
      protected volatile Runnable beforePassivate;
      protected volatile Runnable afterPassivate;

      private ControlledPassivationManager(PassivationManager delegate) {
         this.delegate = delegate;
      }

      @Override
      public boolean isEnabled() {
         return delegate.isEnabled();
      }

      @Override
      public void passivate(InternalCacheEntry entry) {
         final Runnable before = beforePassivate;
         if (before != null) {
            before.run();
         }
         delegate.passivate(entry);
         final Runnable after = afterPassivate;
         if (after != null) {
            after.run();
         }
      }

      @Override
      public void passivateAll() throws PersistenceException {
         delegate.passivateAll();
      }

      @Override
      public void skipPassivationOnStop(boolean skip) {
         delegate.skipPassivationOnStop(skip);
      }

      @Override
      public long getPassivations() {
         return delegate.getPassivations();
      }

      @Override
      public boolean getStatisticsEnabled() {
         return delegate.getStatisticsEnabled();
      }

      @Override
      public void setStatisticsEnabled(boolean enabled) {
         delegate.setStatisticsEnabled(enabled);
      }

      @Override
      public void resetStatistics() {
         delegate.resetStatistics();
      }
   }

   @Listener(sync = true)
   protected abstract class SyncEvictionListener {
      @CacheEntriesEvicted
      public abstract void evicted(CacheEntriesEvictedEvent event);
   }

   protected abstract class ControlledCommandInterceptor extends BaseCustomInterceptor {
      volatile Runnable beforeGet;
      volatile Runnable afterGet;
      volatile Runnable beforePut;
      volatile Runnable afterPut;

      @Override
      public Object visitPutKeyValueCommand(InvocationContext ctx, PutKeyValueCommand command) throws Throwable {
         return handle(ctx, command, beforePut, afterPut);
      }

      @Override
      public Object visitGetKeyValueCommand(InvocationContext ctx, GetKeyValueCommand command) throws Throwable {
         return handle(ctx, command, beforeGet, afterGet);
      }

      @Override
      public Object visitGetCacheEntryCommand(InvocationContext ctx, GetCacheEntryCommand command) throws Throwable {
         return handle(ctx, command, beforeGet, afterGet);
      }

      protected final Object handle(InvocationContext ctx, VisitableCommand command, Runnable before, Runnable after)
            throws Throwable {
         if (before != null) {
            before.run();
         }
         Object retVal = invokeNextInterceptor(ctx, command);
         if (after != null) {
            after.run();
         }
         return retVal;
      }
   }

   protected class AfterEntryWrappingInterceptor extends ControlledCommandInterceptor {

      public AfterEntryWrappingInterceptor injectThis(Cache<Object, Object> injectInCache) {
         injectInCache.getAdvancedCache().getAsyncInterceptorChain().addInterceptorAfter(this, EntryWrappingInterceptor.class);
         return this;
      }

   }

   private class AfterActivationOrCacheLoader extends ControlledCommandInterceptor {

      public AfterActivationOrCacheLoader injectThis(Cache<Object, Object> injectInCache) {
         AsyncInterceptorChain chain =
               TestingUtil.extractComponent(injectInCache, AsyncInterceptorChain.class);
         AsyncInterceptor loaderInterceptor =
               chain.findInterceptorExtending(org.infinispan.interceptors.impl.CacheLoaderInterceptor.class);
         injectInCache.getAdvancedCache().getAsyncInterceptorChain().addInterceptorAfter(this, loaderInterceptor.getClass());
         return this;
      }

   }

   protected class Latch {

      private boolean enabled = false;
      private boolean blocked = false;

      public final synchronized void enable() {
         this.enabled = true;
      }

      public final synchronized void disable() {
         this.enabled = false;
         notifyAll();
      }

      public final synchronized void blockIfNeeded() {
         blocked = true;
         notifyAll();
         while (enabled) {
            try {
               wait();
            } catch (InterruptedException e) {
               Thread.currentThread().interrupt();
               return;
            }
         }
      }

      public final synchronized void waitToBlock(long timeout, TimeUnit timeUnit) throws InterruptedException, TimeoutException {
         final long endTime = Util.currentMillisFromNanotime() + timeUnit.toMillis(timeout);
         long waitingTime;
         while (!blocked && (waitingTime = endTime - Util.currentMillisFromNanotime()) > 0) {
            wait(waitingTime);
         }
         if (!blocked) {
            throw new TimeoutException();
         }

      }


   }
}
