/**
 *
 * Copyright
 * 2009-2015 Jayway Products AB
 * 2016-2017 Föreningen Sambruk
 *
 * Licensed under AGPL, Version 3.0 (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.gnu.org/licenses/agpl.txt
 *
 * 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 se.streamsource.infrastructure.circuitbreaker;

import org.hamcrest.CoreMatchers;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;
import java.beans.PropertyVetoException;
import java.beans.VetoableChangeListener;
import java.io.IOException;

/**
 * JAVADOC
 */
public class CircuitBreakerTest
{
   private CircuitBreaker cb;

   @Before
   public void createCircuitBreaker()
   {
      cb = new CircuitBreaker(3, 250, CircuitBreakers.in( IllegalArgumentException.class ));

      cb.addPropertyChangeListener( new PropertyChangeListener()
      {

         public void propertyChange( PropertyChangeEvent evt )
         {
            System.out.println(evt.getSource()+":"+evt.getPropertyName()+"="+evt.getOldValue()+" -> "+evt.getNewValue());
         }
      });
   }

   @Test
   public void GivenCBWhenTripWithExceptionsAndTurnOnThenStatusIsOn() throws PropertyVetoException
   {

      Assert.assertThat( cb.getStatus(), CoreMatchers.equalTo(CircuitBreaker.Status.on ));

      // Service levels goes down but does not cause a trip
      cb.throwable( new IOException() );

      Assert.assertThat( cb.getStatus(), CoreMatchers.equalTo(CircuitBreaker.Status.on ));

      // Service level goes down and causes a trip
      cb.throwable( new IOException() );
      cb.throwable( new IOException() );

      Assert.assertThat( cb.getStatus(), CoreMatchers.equalTo(CircuitBreaker.Status.off ));

      // Turn on the CB again
      cb.turnOn();

      Assert.assertThat( cb.getStatus(), CoreMatchers.equalTo(CircuitBreaker.Status.on ));
   }

   @Test
   public void GivenCBWhenAllowedExceptionsThenServiceLevelIsNormal() throws PropertyVetoException
   {

      Assert.assertThat( cb.getStatus(), CoreMatchers.equalTo(CircuitBreaker.Status.on ));

      // Service level goes down
      cb.throwable( new IOException() );

      // Service levels goes up
      cb.throwable( new IllegalArgumentException() );

      Assert.assertThat( cb.getServiceLevel(), CoreMatchers.equalTo(1.0 ));
   }

   @Test
   public void GivenCBWhenTripCBWithExceptionsAndTimeoutThenStatusIsOn() throws PropertyVetoException
   {
      Assert.assertThat( cb.getStatus(), CoreMatchers.equalTo(CircuitBreaker.Status.on ));

      // Service levels goes down and causes a trip
      cb.throwable( new IOException() );
      cb.throwable( new IOException() );
      cb.throwable( new IOException() );

      Assert.assertThat( cb.getStatus(), CoreMatchers.equalTo(CircuitBreaker.Status.off ));

      // Wait until timeout
      Assert.assertThat( cb.getStatus(), CoreMatchers.equalTo(CircuitBreaker.Status.off ));
      try
      {
         System.out.println("Wait...");
         Thread.sleep( 300 );
      } catch (InterruptedException e)
      {
         // Ignore
      }

      Assert.assertThat( cb.getStatus(), CoreMatchers.equalTo(CircuitBreaker.Status.on ));
   }

   @Test
   public void GivenCBWhenExceptionsAndSuccessesThenStatusIsOn() throws PropertyVetoException
   {
      Assert.assertThat( cb.getStatus(), CoreMatchers.equalTo(CircuitBreaker.Status.on ));

      // Service levels goes down and causes a trip
      cb.throwable( new IOException() );
      cb.throwable( new IOException() );
      cb.success();
      cb.success();
      cb.throwable( new IOException() );
      cb.throwable( new IOException() );

      Assert.assertThat( cb.getStatus(), CoreMatchers.equalTo(CircuitBreaker.Status.on ));
   }

   @Test
   public void GivenCBWhenTripCBWithExceptionsAndSuccessesThenStatusIsOff() throws PropertyVetoException
   {
      Assert.assertThat( cb.getStatus(), CoreMatchers.equalTo(CircuitBreaker.Status.on ));

      // Service levels goes down and causes a trip
      cb.throwable( new IOException() );
      cb.throwable( new IOException() );
      cb.throwable( new IOException() );
      cb.success();

      Assert.assertThat( cb.getStatus(), CoreMatchers.equalTo(CircuitBreaker.Status.off ));
   }

   @Test
   public void GivenCBWhenTripCBWithExceptionsAndGetStatusWithFailureThenStatusIsOff() throws PropertyVetoException
   {
      Assert.assertThat( cb.getStatus(), CoreMatchers.equalTo(CircuitBreaker.Status.on ));

      cb.addVetoableChangeListener( new VetoableChangeListener()
      {
         public void vetoableChange( PropertyChangeEvent evt ) throws PropertyVetoException
         {
            if (evt.getNewValue() == CircuitBreaker.Status.on)
               throw new PropertyVetoException("Service is down", evt);
         }
      });

      // Service levels goes down and causes a trip
      cb.throwable( new IOException() );
      cb.throwable( new IOException() );
      cb.throwable( new IOException() );

      try
      {
         System.out.println("Wait...");
         Thread.sleep( 300 );
      } catch (InterruptedException e)
      {
         // Ignore
      }

      Assert.assertThat( cb.getStatus(), CoreMatchers.equalTo(CircuitBreaker.Status.off ));
      Assert.assertThat( cb.getLastThrowable().getMessage(), CoreMatchers.equalTo("Service is down"));
   }
}