/*
    * Licensed to the Apache Software Foundation (ASF) under one or more
    * contributor license agreements.  See the NOTICE file distributed with
    * this work for additional information regarding copyright ownership.
    * The ASF licenses this file to You 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
    *
    *     https://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.apache.commons.configuration2.event;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertFalse;
  import static org.junit.jupiter.api.Assertions.assertSame;
  import static org.junit.jupiter.api.Assertions.assertThrows;
  import static org.junit.jupiter.api.Assertions.assertTrue;
  
  import java.util.Collection;
  import java.util.List;
  
  import org.junit.jupiter.api.BeforeEach;
  import org.junit.jupiter.api.Test;
  
  /**
   * Test class for BaseEventSource.
   */
  public class TestEventSource {
  
      /**
       * A specialized event source implementation that counts the number of created event objects. It is used to test whether
       * the {@code fireEvent()} methods only creates event objects if necessary. It also allows testing the clone()
       * operation.
       */
      private static final class CountingEventSource extends BaseEventSource implements Cloneable {
  
          private int eventCount;
  
          private int errorCount;
  
          @Override
          protected ConfigurationErrorEvent createErrorEvent(final EventType<? extends ConfigurationErrorEvent> type, final EventType<?> opType,
              final String propName, final Object propValue, final Throwable ex) {
              errorCount++;
              return super.createErrorEvent(type, opType, propName, propValue, ex);
          }
  
          @Override
          protected <T extends ConfigurationEvent> ConfigurationEvent createEvent(final EventType<T> eventType, final String propName, final Object propValue,
              final boolean before) {
              eventCount++;
              return super.createEvent(eventType, propName, propValue, before);
          }
      }
  
      /** Constant for the event property value. */
      private static final Object TEST_PROPVALUE = "a test property value";
  
      /** Constant for the event property name. */
      private static final String TEST_PROPNAME = "test.property.name";
  
      /** The object under test. */
      private CountingEventSource source;
  
      @BeforeEach
      public void setUp() throws Exception {
          source = new CountingEventSource();
      }
  
      /**
       * Tests registering a new listener.
       */
      @Test
      void testAddEventListener() {
          final EventListenerTestImpl l = new EventListenerTestImpl(this);
          source.addEventListener(ConfigurationEvent.ANY, l);
          final Collection<EventListener<? super ConfigurationEvent>> listeners = source.getEventListeners(ConfigurationEvent.ANY);
          assertEquals(1, listeners.size());
          assertTrue(listeners.contains(l));
      }
  
      /**
       * Tests adding an undefined configuration listener. This should cause an exception.
       */
      @Test
      void testAddNullEventListener() {
          assertThrows(IllegalArgumentException.class, () -> source.addEventListener(ConfigurationEvent.ANY, null));
      }
  
      /**
       * Tests whether all error listeners can be cleared.
       */
      @Test
     void testClearErrorListeners() {
         final EventListener<ConfigurationEvent> cl = new EventListenerTestImpl(null);
         final ErrorListenerTestImpl el1 = new ErrorListenerTestImpl(null);
         final ErrorListenerTestImpl el2 = new ErrorListenerTestImpl(null);
         final ErrorListenerTestImpl el3 = new ErrorListenerTestImpl(null);
         source.addEventListener(ConfigurationErrorEvent.READ, el1);
         source.addEventListener(ConfigurationErrorEvent.ANY, el2);
         source.addEventListener(ConfigurationEvent.ANY, cl);
         source.addEventListener(ConfigurationErrorEvent.WRITE, el3);
 
         source.clearErrorListeners();
         final List<EventListenerRegistrationData<?>> regs = source.getEventListenerRegistrations();
         assertEquals(1, regs.size());
         assertSame(cl, regs.get(0).getListener());
     }
 
     /**
      * Tests whether all event listeners can be removed.
      */
     @Test
     void testClearEventListeners() {
         source.addEventListener(ConfigurationEvent.ANY, new EventListenerTestImpl(source));
         source.addEventListener(ConfigurationEvent.ANY_HIERARCHICAL, new EventListenerTestImpl(source));
 
         source.clearEventListeners();
         assertTrue(source.getEventListeners(ConfigurationEvent.ANY).isEmpty());
         assertTrue(source.getEventListeners(ConfigurationEvent.ANY_HIERARCHICAL).isEmpty());
     }
 
     /**
      * Tests cloning an event source object. The registered listeners should not be registered at the clone.
      */
     @Test
     void testClone() throws CloneNotSupportedException {
         source.addEventListener(ConfigurationEvent.ANY, new EventListenerTestImpl(source));
         final BaseEventSource copy = (BaseEventSource) source.clone();
         assertTrue(copy.getEventListenerRegistrations().isEmpty());
     }
 
     /**
      * Tests whether event listeners can be copied to another source.
      */
     @Test
     void testCopyEventListeners() {
         final EventListenerTestImpl l1 = new EventListenerTestImpl(source);
         final EventListenerTestImpl l2 = new EventListenerTestImpl(source);
         source.addEventListener(ConfigurationEvent.ANY, l1);
         source.addEventListener(ConfigurationEvent.ANY_HIERARCHICAL, l2);
 
         final BaseEventSource source2 = new BaseEventSource();
         source.copyEventListeners(source2);
         Collection<EventListener<? super ConfigurationEvent>> listeners = source2.getEventListeners(ConfigurationEvent.ANY_HIERARCHICAL);
         assertEquals(2, listeners.size());
         assertTrue(listeners.contains(l1));
         assertTrue(listeners.contains(l2));
         listeners = source2.getEventListeners(ConfigurationEvent.ANY);
         assertEquals(1, listeners.size());
         assertTrue(listeners.contains(l1));
     }
 
     /**
      * Tries to copy event listeners to a null source.
      */
     @Test
     void testCopyEventListenersNullSource() {
         assertThrows(IllegalArgumentException.class, () -> source.copyEventListeners(null));
     }
 
     /**
      * Tests delivering an error event to a listener.
      */
     @Test
     void testFireError() {
         final ErrorListenerTestImpl lstRead = new ErrorListenerTestImpl(source);
         final ErrorListenerTestImpl lstWrite = new ErrorListenerTestImpl(source);
         final ErrorListenerTestImpl lstAll = new ErrorListenerTestImpl(source);
         source.addEventListener(ConfigurationErrorEvent.READ, lstRead);
         source.addEventListener(ConfigurationErrorEvent.WRITE, lstWrite);
         source.addEventListener(ConfigurationErrorEvent.ANY, lstAll);
         final Exception testException = new Exception("A test");
 
         source.fireError(ConfigurationErrorEvent.WRITE, ConfigurationEvent.ADD_PROPERTY, TEST_PROPNAME, TEST_PROPVALUE, testException);
         lstRead.done();
         assertEquals(testException,
                 lstWrite.checkEvent(ConfigurationErrorEvent.WRITE, ConfigurationEvent.ADD_PROPERTY, TEST_PROPNAME, TEST_PROPVALUE));
         lstWrite.done();
         assertEquals(testException,
                 lstAll.checkEvent(ConfigurationErrorEvent.WRITE, ConfigurationEvent.ADD_PROPERTY, TEST_PROPNAME, TEST_PROPVALUE));
         lstAll.done();
         assertEquals(1, source.errorCount);
     }
 
     /**
      * Tests firing an error event if there are no error listeners.
      */
     @Test
     void testFireErrorNoListeners() {
         source.fireError(ConfigurationErrorEvent.ANY, ConfigurationEvent.ANY, TEST_PROPNAME, TEST_PROPVALUE, new Exception());
         assertEquals(0, source.errorCount);
     }
 
     /**
      * Tests delivering an event to a listener.
      */
     @Test
     void testFireEvent() {
         final EventListenerTestImpl l = new EventListenerTestImpl(source);
         source.addEventListener(ConfigurationEvent.ANY, l);
         source.fireEvent(ConfigurationEvent.ADD_PROPERTY, TEST_PROPNAME, TEST_PROPVALUE, true);
         l.checkEvent(ConfigurationEvent.ADD_PROPERTY, TEST_PROPNAME, TEST_PROPVALUE, true);
         l.done();
     }
 
     /**
      * Tests generating a detail event if detail events are not allowed.
      */
     @Test
     void testFireEventNoDetails() {
         final EventListenerTestImpl l = new EventListenerTestImpl(source);
         source.addEventListener(ConfigurationEvent.ANY, l);
         source.setDetailEvents(false);
         source.fireEvent(ConfigurationEvent.SET_PROPERTY, TEST_PROPNAME, TEST_PROPVALUE, false);
         assertEquals(0, source.eventCount);
         l.done();
     }
 
     /**
      * Tests firing an event if there are no listeners.
      */
     @Test
     void testFireEventNoListeners() {
         source.fireEvent(ConfigurationEvent.ADD_NODES, TEST_PROPNAME, TEST_PROPVALUE, false);
         assertEquals(0, source.eventCount);
     }
 
     /**
      * Tests that the collection returned by getEventListeners() is really a snapshot. A later added listener must not be
      * visible.
      */
     @Test
     void testGetEventListenersAddNew() {
         final Collection<EventListener<? super ConfigurationEvent>> list = source.getEventListeners(ConfigurationEvent.ANY);
         source.addEventListener(ConfigurationEvent.ANY, new EventListenerTestImpl(null));
         assertTrue(list.isEmpty());
     }
 
     /**
      * Tests whether the listeners list is read only.
      */
     @Test
     void testGetEventListenersUpdate() {
         source.addEventListener(ConfigurationEvent.ANY, new EventListenerTestImpl(null));
         final Collection<EventListener<? super ConfigurationEvent>> list = source.getEventListeners(ConfigurationEvent.ANY);
         assertThrows(UnsupportedOperationException.class, list::clear);
     }
 
     /**
      * Tests a newly created source object.
      */
     @Test
     void testInit() {
         assertTrue(source.getEventListenerRegistrations().isEmpty());
         assertFalse(source.removeEventListener(ConfigurationEvent.ANY, new EventListenerTestImpl(null)));
         assertFalse(source.isDetailEvents());
     }
 
     /**
      * Tests removing a listener.
      */
     @Test
     void testRemoveEventListener() {
         final EventListenerTestImpl l = new EventListenerTestImpl(this);
         assertFalse(source.removeEventListener(ConfigurationEvent.ANY, l));
         source.addEventListener(ConfigurationEvent.ADD_NODES, new EventListenerTestImpl(this));
         source.addEventListener(ConfigurationEvent.ANY, l);
         assertFalse(source.removeEventListener(ConfigurationEvent.ANY, new EventListenerTestImpl(null)));
         assertTrue(source.removeEventListener(ConfigurationEvent.ANY, l));
         assertFalse(source.getEventListeners(ConfigurationEvent.ANY).contains(l));
     }
 
     /**
      * Tests whether an event listener can deregister itself in reaction of a delivered event.
      */
     @Test
     void testRemoveListenerInFireEvent() {
         final EventListener<ConfigurationEvent> lstRemove = new EventListener<ConfigurationEvent>() {
             @Override
             public void onEvent(final ConfigurationEvent event) {
                 source.removeEventListener(ConfigurationEvent.ANY, this);
             }
         };
 
         source.addEventListener(ConfigurationEvent.ANY, lstRemove);
         final EventListenerTestImpl l = new EventListenerTestImpl(source);
         source.addEventListener(ConfigurationEvent.ANY, l);
         source.fireEvent(ConfigurationEvent.ADD_PROPERTY, TEST_PROPNAME, TEST_PROPVALUE, false);
         l.checkEvent(ConfigurationEvent.ADD_PROPERTY, TEST_PROPNAME, TEST_PROPVALUE, false);
         assertEquals(1, source.getEventListeners(ConfigurationEvent.ANY).size());
     }
 
     /**
      * Tests if a null listener can be removed. This should be a no-op.
      */
     @Test
     void testRemoveNullEventListener() {
         source.addEventListener(ConfigurationEvent.ANY, new EventListenerTestImpl(null));
         assertFalse(source.removeEventListener(ConfigurationEvent.ANY, null));
         assertEquals(1, source.getEventListeners(ConfigurationEvent.ANY).size());
     }
 
     /**
      * Tests enabling and disabling the detail events flag.
      */
     @Test
     void testSetDetailEvents() {
         source.setDetailEvents(true);
         assertTrue(source.isDetailEvents());
         source.setDetailEvents(true);
         source.setDetailEvents(false);
         assertTrue(source.isDetailEvents());
         source.setDetailEvents(false);
         assertFalse(source.isDetailEvents());
     }
 }