/*
    * 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
    *
    *     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.apache.commons.configuration2.reloading;
  
  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 static org.mockito.ArgumentMatchers.any;
  import static org.mockito.Mockito.doAnswer;
  import static org.mockito.Mockito.mock;
  import static org.mockito.Mockito.verify;
  import static org.mockito.Mockito.verifyNoMoreInteractions;
  import static org.mockito.Mockito.when;
  
  import org.apache.commons.configuration2.event.Event;
  import org.apache.commons.configuration2.event.EventListener;
  import org.apache.commons.lang3.mutable.MutableObject;
  import org.junit.jupiter.api.BeforeEach;
  import org.junit.jupiter.api.Test;
  
  /**
   * Test class for {@code ReloadingController}.
   */
  public class TestReloadingController {
      /**
       * Creates a mock event listener.
       *
       * @return the mock listener
       */
      @SuppressWarnings("unchecked")
      private static EventListener<ReloadingEvent> createListenerMock() {
          return mock(EventListener.class);
      }
  
      /** A mock for the detector. */
      private ReloadingDetector detector;
  
      /**
       * Creates a default test instance.
       *
       * @return the test instance
       */
      private ReloadingController createController() {
          return new ReloadingController(detector);
      }
  
      /**
       * Prepares the given event listener mock to expect an event notification. The event received is stored in the given
       * mutable object.
       *
       * @param l the listener mock
       * @param evRef the reference where to store the event
       */
      private void setupEvent(final EventListener<ReloadingEvent> l, final MutableObject<ReloadingEvent> evRef) {
          doAnswer(invocation -> {
              evRef.setValue(invocation.getArgument(0, ReloadingEvent.class));
              return null;
          }).when(l).onEvent(any());
      }
  
      /**
       * Verifies that an invocation has occurred on the given event listener for an event notification.
       *
       * @param l the listener mock
       */
      private void verifyEvent(final EventListener<ReloadingEvent> l) {
          verify(l).onEvent(any());
      }
  
      @BeforeEach
      public void setUp() throws Exception {
          detector = mock(ReloadingDetector.class);
      }
  
      /**
       * Tests a reloading check with a negative result.
       */
      @Test
      public void testCheckForReloadingFalse() {
          final EventListener<ReloadingEvent> l = createListenerMock();
  
          when(detector.isReloadingRequired()).thenReturn(Boolean.FALSE);
  
         final ReloadingController ctrl = createController();
         ctrl.addEventListener(ReloadingEvent.ANY, l);
         assertFalse(ctrl.checkForReloading(null));
         assertFalse(ctrl.isInReloadingState());
 
         verify(detector).isReloadingRequired();
         verifyNoMoreInteractions(detector, l);
     }
 
     /**
      * Tests that no further checks are performed when already in reloading state.
      */
     @Test
     public void testCheckForReloadingInReloadingState() {
         final EventListener<ReloadingEvent> l = createListenerMock();
 
         when(detector.isReloadingRequired()).thenReturn(Boolean.TRUE);
         // No need to setup the event; the event is not captured
 
         final ReloadingController ctrl = createController();
         ctrl.addEventListener(ReloadingEvent.ANY, l);
         assertTrue(ctrl.checkForReloading(1));
         assertTrue(ctrl.checkForReloading(2));
 
         verify(detector).isReloadingRequired();
         verifyEvent(l);
         verifyNoMoreInteractions(detector, l);
     }
 
     /**
      * Tests a reloading check with a positive result.
      */
     @Test
     public void testCheckForReloadingTrue() {
         final EventListener<ReloadingEvent> l = createListenerMock();
         final EventListener<ReloadingEvent> lRemoved = createListenerMock();
         final MutableObject<ReloadingEvent> evRef = new MutableObject<>();
 
         setupEvent(l, evRef);
         when(detector.isReloadingRequired()).thenReturn(Boolean.TRUE);
 
         final ReloadingController ctrl = createController();
         ctrl.addEventListener(ReloadingEvent.ANY, lRemoved);
         ctrl.addEventListener(ReloadingEvent.ANY, l);
         assertTrue(ctrl.removeEventListener(ReloadingEvent.ANY, lRemoved));
         final Object testData = "Some test data";
         assertTrue(ctrl.checkForReloading(testData));
         assertTrue(ctrl.isInReloadingState());
         assertSame(ctrl, evRef.getValue().getSource());
         assertSame(ctrl, evRef.getValue().getController());
         assertEquals(testData, evRef.getValue().getData());
 
         verifyEvent(l);
         verify(detector).isReloadingRequired();
         verifyNoMoreInteractions(l, lRemoved, detector);
     }
 
     /**
      * Tries to create an instance without a detector.
      */
     @Test
     public void testInitNoDetector() {
         assertThrows(IllegalArgumentException.class, () -> new ReloadingController(null));
     }
 
     /**
      * Tests the event type of the reloading event.
      */
     @Test
     public void testReloadingEventType() {
         assertEquals(Event.ANY, ReloadingEvent.ANY.getSuperType());
     }
 
     /**
      * Tests that a newly created instance is not in reloading state.
      */
     @Test
     public void testReloadingStateAfterInit() {
         assertFalse(createController().isInReloadingState());
     }
 
     /**
      * Tests that resetReloadingState() has no effect if the controller is not in reloading state.
      */
     @Test
     public void testResetReloadingNotInReloadingState() {
         createController().resetReloadingState();
     }
 
     /**
      * Tests that the reloading state can be reset.
      */
     @Test
     public void testResetReloadingState() {
         when(detector.isReloadingRequired()).thenReturn(Boolean.TRUE);
 
         final ReloadingController ctrl = createController();
         ctrl.checkForReloading(null);
         ctrl.resetReloadingState();
         assertFalse(ctrl.isInReloadingState());
 
         verify(detector).isReloadingRequired();
         verify(detector).reloadingPerformed();
         verifyNoMoreInteractions(detector);
     }
 }