/*
    * 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;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertFalse;
  import static org.junit.jupiter.api.Assertions.assertNotNull;
  import static org.junit.jupiter.api.Assertions.assertNotSame;
  import static org.junit.jupiter.api.Assertions.assertNull;
  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.Mockito.mock;
  
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.List;
  import java.util.Map;
  
  import org.apache.commons.configuration2.builder.XMLBuilderParametersImpl;
  import org.apache.commons.configuration2.convert.DefaultListDelimiterHandler;
  import org.apache.commons.configuration2.event.ConfigurationErrorEvent;
  import org.apache.commons.configuration2.event.ConfigurationEvent;
  import org.apache.commons.configuration2.event.EventListener;
  import org.apache.commons.configuration2.event.EventSource;
  import org.apache.commons.configuration2.ex.ConfigurationRuntimeException;
  import org.apache.commons.configuration2.sync.NoOpSynchronizer;
  import org.apache.commons.configuration2.tree.DefaultExpressionEngine;
  import org.apache.commons.configuration2.tree.DefaultExpressionEngineSymbols;
  import org.apache.commons.configuration2.tree.ExpressionEngine;
  import org.apache.commons.configuration2.tree.ImmutableNode;
  import org.junit.jupiter.api.AfterEach;
  import org.junit.jupiter.api.BeforeEach;
  import org.junit.jupiter.api.Test;
  
  /**
   * Tests the ConfigurationUtils class
   */
  public class TestConfigurationUtils {
      /**
       * A test Synchronizer implementation which can be cloned.
       */
      private static final class CloneableSynchronizer extends NonCloneableSynchronizer implements Cloneable {
          /** A flag whether clone() was called. */
          private final boolean cloned;
  
          /**
           * Creates a new instance of {@code CloneableSynchronizer} and sets the clone flag.
           *
           * @param clone the clone flag
           */
          public CloneableSynchronizer(final boolean clone) {
              cloned = clone;
          }
  
          @Override
          public Object clone() {
              return new CloneableSynchronizer(true);
          }
  
          /**
           * Returns a flag whether this object was cloned.
           *
           * @return the clone flag
           */
          public boolean isCloned() {
              return cloned;
          }
      }
  
      /**
       * A test Synchronizer implementation which cannot be cloned.
       */
      private static class NonCloneableSynchronizer extends SynchronizerTestImpl {
      }
  
      /** Constant for the name of a class to be loaded. */
      private static final String CLS_NAME = "org.apache.commons.configuration2.PropertiesConfiguration";
  
      /** Stores the CCL. */
      private ClassLoader ccl;
  
      @BeforeEach
      public void setUp() throws Exception {
         ccl = Thread.currentThread().getContextClassLoader();
     }
 
     @AfterEach
     public void tearDown() throws Exception {
         Thread.currentThread().setContextClassLoader(ccl);
     }
 
     @Test
     void testAppend() {
         // create the source configuration
         final Configuration conf1 = new BaseConfiguration();
         conf1.addProperty("key1", "value1");
         conf1.addProperty("key2", "value2");
 
         // create the target configuration
         final Configuration conf2 = new BaseConfiguration();
         conf2.addProperty("key1", "value3");
         conf2.addProperty("key2", "value4");
 
         // append the source configuration to the target configuration
         ConfigurationUtils.append(conf1, conf2);
 
         List<Object> expected = new ArrayList<>();
         expected.add("value3");
         expected.add("value1");
         assertEquals(expected, conf2.getList("key1"));
 
         expected = new ArrayList<>();
         expected.add("value4");
         expected.add("value2");
         assertEquals(expected, conf2.getList("key2"));
     }
 
     /**
      * Tests asEventSource() if an exception is expected.
      */
     @Test
     void testAsEventSourceNonSupportedEx() {
         assertThrows(ConfigurationRuntimeException.class, () -> ConfigurationUtils.asEventSource(this, false));
     }
 
     /**
      * Tests asEventSource() if the passed in object implements this interface.
      */
     @Test
     void testAsEventSourceSupported() {
         final XMLConfiguration src = new XMLConfiguration();
         assertSame(src, ConfigurationUtils.asEventSource(src, true));
     }
 
     /**
      * Tests asEventSource() if a mock object has to be returned.
      */
     @Test
     void testAsEventSourceUnsupportedMock() {
         @SuppressWarnings("unchecked")
         final EventListener<ConfigurationEvent> cl = mock(EventListener.class);
         final EventSource source = ConfigurationUtils.asEventSource(this, true);
         source.addEventListener(ConfigurationEvent.ANY, cl);
         assertFalse(source.removeEventListener(ConfigurationEvent.ANY, cl));
         source.addEventListener(ConfigurationEvent.ANY, null);
     }
 
     /**
      * Tests cloning a configuration that supports this operation.
      */
     @Test
     void testCloneConfiguration() {
         final BaseHierarchicalConfiguration conf = new BaseHierarchicalConfiguration();
         conf.addProperty("test", "yes");
         final BaseHierarchicalConfiguration copy = (BaseHierarchicalConfiguration) ConfigurationUtils.cloneConfiguration(conf);
         assertNotSame(conf, copy);
         assertEquals("yes", copy.getString("test"));
     }
 
     /**
      * Tests cloning a configuration that does not support this operation. This should cause an exception.
      */
     @Test
     void testCloneConfigurationNotSupported() {
         final Configuration myNonCloneableConfig = new NonCloneableConfiguration();
         assertThrows(ConfigurationRuntimeException.class, () -> ConfigurationUtils.cloneConfiguration(myNonCloneableConfig));
     }
 
     /**
      * Tests cloning a <strong>null</strong> configuration.
      */
     @Test
     void testCloneConfigurationNull() {
         assertNull(ConfigurationUtils.cloneConfiguration(null));
     }
 
     /**
      * Tests whether errors are handled correctly by cloneIfPossible().
      */
     @Test
     void testCloneIfPossibleError() {
         final XMLBuilderParametersImpl params = new XMLBuilderParametersImpl() {
             @Override
             public XMLBuilderParametersImpl clone() {
                 throw new ConfigurationRuntimeException();
             }
         };
         assertSame(params, ConfigurationUtils.cloneIfPossible(params));
     }
 
     /**
      * Tests cloneIfPossible() if the passed in object does not support cloning.
      */
     @Test
     void testCloneIfPossibleNotSupported() {
         final Long value = 20130116221714L;
         assertSame(value, ConfigurationUtils.cloneIfPossible(value));
     }
 
     /**
      * Tests whether cloneIfPossible() can handle null parameters.
      */
     @Test
     void testCloneIfPossibleNull() {
         assertNull(ConfigurationUtils.cloneIfPossible(null));
     }
 
     /**
      * Tests whether an object can be cloned which supports cloning.
      */
     @Test
     void testCloneIfPossibleSupported() {
         final XMLBuilderParametersImpl params = new XMLBuilderParametersImpl();
         params.setPublicID("testID");
         params.setSchemaValidation(true);
         final XMLBuilderParametersImpl clone = (XMLBuilderParametersImpl) ConfigurationUtils.cloneIfPossible(params);
         assertNotSame(params, clone);
         final Map<String, Object> map = clone.getParameters();
         for (final Map.Entry<String, Object> e : params.getParameters().entrySet()) {
             if (!e.getKey().startsWith("config-")) {
                 assertEquals(e.getValue(), map.get(e.getKey()), "Wrong value for field " + e.getKey());
             }
         }
     }
 
     /**
      * Tests whether a Synchronizer can be cloned using its clone() method.
      */
     @Test
     void testCloneSynchronizerClone() {
         final CloneableSynchronizer sync = new CloneableSynchronizer(false);
         final CloneableSynchronizer sync2 = (CloneableSynchronizer) ConfigurationUtils.cloneSynchronizer(sync);
         assertTrue(sync2.isCloned());
     }
 
     /**
      * Tests cloneSynchronizer() if the argument cannot be cloned.
      */
     @Test
     void testCloneSynchronizerFailed() {
         final NonCloneableSynchronizer synchronizer = new NonCloneableSynchronizer();
         assertThrows(ConfigurationRuntimeException.class, () -> ConfigurationUtils.cloneSynchronizer(synchronizer));
     }
 
     /**
      * Tests whether a new Synchronizer can be created using reflection.
      */
     @Test
     void testCloneSynchronizerNewInstance() {
         final SynchronizerTestImpl sync = new SynchronizerTestImpl();
         final SynchronizerTestImpl sync2 = (SynchronizerTestImpl) ConfigurationUtils.cloneSynchronizer(sync);
         assertNotNull(sync2);
         assertNotSame(sync, sync2);
     }
 
     /**
      * Tests whether the NoOpSyhnchronizer can be cloned.
      */
     @Test
     void testCloneSynchronizerNoOp() {
         assertSame(NoOpSynchronizer.INSTANCE, ConfigurationUtils.cloneSynchronizer(NoOpSynchronizer.INSTANCE));
     }
 
     /**
      * Tries to clone a null Synchronizer.
      */
     @Test
     void testCloneSynchronizerNull() {
         assertThrows(IllegalArgumentException.class, () -> ConfigurationUtils.cloneSynchronizer(null));
     }
 
     /**
      * Tests converting a configuration into a hierarchical one that is already hierarchical.
      */
     @Test
     void testConvertHierarchicalToHierarchical() {
         final Configuration conf = new BaseHierarchicalConfiguration();
         conf.addProperty("test", "yes");
         assertSame(conf, ConfigurationUtils.convertToHierarchical(conf));
     }
 
     /**
      * Tests converting an already hierarchical configuration using an expression engine. The new engine should be set.
      */
     @Test
     void testConvertHierarchicalToHierarchicalEngine() {
         final BaseHierarchicalConfiguration hc = new BaseHierarchicalConfiguration();
         final ExpressionEngine engine = new DefaultExpressionEngine(DefaultExpressionEngineSymbols.DEFAULT_SYMBOLS);
         assertSame(hc, ConfigurationUtils.convertToHierarchical(hc, engine));
         assertSame(engine, hc.getExpressionEngine());
     }
 
     /**
      * Tests converting an already hierarchical configuration using a null expression engine. In this case the expression
      * engine of the configuration should not be touched.
      */
     @Test
     void testConvertHierarchicalToHierarchicalNullEngine() {
         final BaseHierarchicalConfiguration hc = new BaseHierarchicalConfiguration();
         final ExpressionEngine engine = new DefaultExpressionEngine(DefaultExpressionEngineSymbols.DEFAULT_SYMBOLS);
         hc.setExpressionEngine(engine);
         assertSame(hc, ConfigurationUtils.convertToHierarchical(hc, null));
         assertSame(engine, hc.getExpressionEngine());
     }
 
     /**
      * Tests converting a null configuration to a hierarchical one. The result should be null, too.
      */
     @Test
     void testConvertNullToHierarchical() {
         assertNull(ConfigurationUtils.convertToHierarchical(null));
     }
 
     /**
      * Tests converting a configuration into a hierarchical one.
      */
     @Test
     void testConvertToHierarchical() {
         final Configuration conf = new BaseConfiguration();
         for (int i = 0; i < 10; i++) {
             conf.addProperty("test" + i, "value" + i);
             conf.addProperty("test.list", "item" + i);
         }
         final BaseHierarchicalConfiguration hc = (BaseHierarchicalConfiguration) ConfigurationUtils.convertToHierarchical(conf);
         for (final Iterator<String> it = conf.getKeys(); it.hasNext();) {
             final String key = it.next();
             assertEquals(conf.getProperty(key), hc.getProperty(key), "Wrong value for key " + key);
         }
     }
 
     /**
      * Tests converting a configuration into a hierarchical one if some of its properties contain escaped list delimiter
      * characters.
      */
     @Test
     void testConvertToHierarchicalDelimiters() {
         final BaseConfiguration conf = new BaseConfiguration();
         conf.setListDelimiterHandler(new DefaultListDelimiterHandler(','));
         conf.addProperty("test.key", "1\\,2\\,3");
         assertEquals("1,2,3", conf.getString("test.key"));
         final HierarchicalConfiguration<?> hc = ConfigurationUtils.convertToHierarchical(conf);
         assertEquals("1,2,3", hc.getString("test.key"));
     }
 
     /**
      * Tests converting a configuration to a hierarchical one using a specific expression engine.
      */
     @Test
     void testConvertToHierarchicalEngine() {
         final Configuration conf = new BaseConfiguration();
         conf.addProperty("test(a)", Boolean.TRUE);
         conf.addProperty("test(b)", Boolean.FALSE);
         final DefaultExpressionEngine engine = new DefaultExpressionEngine(
             new DefaultExpressionEngineSymbols.Builder(DefaultExpressionEngineSymbols.DEFAULT_SYMBOLS).setIndexStart("[").setIndexEnd("]").create());
         final HierarchicalConfiguration<?> hc = ConfigurationUtils.convertToHierarchical(conf, engine);
         assertTrue(hc.getBoolean("test(a)"));
         assertFalse(hc.getBoolean("test(b)"));
     }
 
     /**
      * Tests converting a configuration to a hierarchical one that contains a property with multiple values. This test is
      * related to CONFIGURATION-346.
      */
     @Test
     void testConvertToHierarchicalMultiValues() {
         final BaseConfiguration config = new BaseConfiguration();
         config.setListDelimiterHandler(new DefaultListDelimiterHandler(','));
         config.addProperty("test", "1,2,3");
         final HierarchicalConfiguration<?> hc = ConfigurationUtils.convertToHierarchical(config);
         assertEquals(1, hc.getInt("test(0)"));
         assertEquals(2, hc.getInt("test(1)"));
         assertEquals(3, hc.getInt("test(2)"));
     }
 
     /**
      * Tests that the structure of the resulting hierarchical configuration does not depend on the order of properties in
      * the source configuration. This test is related to CONFIGURATION-604.
      */
     @Test
     void testConvertToHierarchicalOrderOfProperties() {
         final PropertiesConfiguration config = new PropertiesConfiguration();
         config.addProperty("x.y.z", true);
         config.addProperty("x.y", true);
         @SuppressWarnings("unchecked")
         final HierarchicalConfiguration<ImmutableNode> hc = (HierarchicalConfiguration<ImmutableNode>) ConfigurationUtils.convertToHierarchical(config);
         final ImmutableNode rootNode = hc.getNodeModel().getNodeHandler().getRootNode();
         final ImmutableNode nodeX = rootNode.getChildren().get(0);
         assertEquals(1, nodeX.getChildren().size());
     }
 
     @Test
     void testCopy() {
         // create the source configuration
         final Configuration conf1 = new BaseConfiguration();
         conf1.addProperty("key1", "value1");
         conf1.addProperty("key2", "value2");
         // create the target configuration
         final Configuration conf2 = new BaseConfiguration();
         conf2.addProperty("key1", "value3");
         conf2.addProperty("key2", "value4");
         // copy the source configuration into the target configuration
         ConfigurationUtils.copy(conf1, conf2);
         assertEquals("value1", conf2.getProperty("key1"));
         assertEquals("value2", conf2.getProperty("key2"));
     }
 
     /**
      * Tests whether runtime exceptions can be enabled.
      */
     @Test
     void testEnableRuntimeExceptions() {
         final PropertiesConfiguration config = new PropertiesConfiguration() {
             @Override
             protected void addPropertyDirect(final String key, final Object value) {
                 // always simulate an exception
                 fireError(ConfigurationErrorEvent.WRITE, ConfigurationEvent.ADD_PROPERTY, key, value, new RuntimeException("A faked exception!"));
             }
         };
         config.clearErrorListeners();
         ConfigurationUtils.enableRuntimeExceptions(config);
         assertThrows(ConfigurationRuntimeException.class, () -> config.addProperty("test", "testValue"));
     }
 
     /**
      * Tries to enable runtime exceptions for a configuration that does not inherit from EventSource. This should cause an
      * exception.
      */
     @Test
     void testEnableRuntimeExceptionsInvalid() {
         final Configuration c = mock(Configuration.class);
         assertThrows(IllegalArgumentException.class, () -> ConfigurationUtils.enableRuntimeExceptions(c));
     }
 
     /**
      * Tries to enable runtime exceptions for a null configuration. This should cause an exception.
      */
     @Test
     void testEnableRuntimeExceptionsNull() {
         assertThrows(IllegalArgumentException.class, () -> ConfigurationUtils.enableRuntimeExceptions(null));
     }
 
     /**
      * Tests whether a class can be loaded if it is not found by the CCL.
      */
     @Test
     void testLoadClassCCLNotFound() throws ClassNotFoundException {
         Thread.currentThread().setContextClassLoader(new ClassLoader() {
             @Override
             public Class<?> loadClass(final String name) throws ClassNotFoundException {
                 throw new ClassNotFoundException(name);
             }
         });
         assertEquals(CLS_NAME, ConfigurationUtils.loadClass(CLS_NAME).getName());
     }
 
     /**
      * Tests whether a class can be loaded if there is no CCL.
      */
     @Test
     void testLoadClassCCLNull() throws ClassNotFoundException {
         Thread.currentThread().setContextClassLoader(null);
         assertEquals(CLS_NAME, ConfigurationUtils.loadClass(CLS_NAME).getName());
     }
 
     /**
      * Tests whether a class can be loaded from CCL.
      */
     @Test
     void testLoadClassFromCCL() throws ClassNotFoundException {
         Thread.currentThread().setContextClassLoader(getClass().getClassLoader());
         assertEquals(CLS_NAME, ConfigurationUtils.loadClass(CLS_NAME).getName());
     }
 
     /**
      * Tests loadClassNoEx() if the class can be resolved.
      */
     @Test
     void testLoadClassNoExFound() {
         assertEquals(CLS_NAME, ConfigurationUtils.loadClassNoEx(CLS_NAME).getName());
     }
 
     /**
      * Tests loadClassNoEx() if the class cannot be resolved.
      */
     @Test
     void testLoadClassNoExNotFound() {
         assertThrows(ConfigurationRuntimeException.class, () -> ConfigurationUtils.loadClassNoEx("a non existing class!"));
     }
 
     /**
      * Tests the behavior of loadClass() for a non-existing class.
      */
     @Test
     void testLoadClassNotFound() {
         assertThrows(ClassNotFoundException.class, () -> ConfigurationUtils.loadClass("a non existing class!"));
     }
 
     @Test
     void testToString() {
         final Configuration config = new BaseConfiguration();
         final String lineSeparator = System.lineSeparator();
 
         assertEquals("", ConfigurationUtils.toString(config));
 
         config.setProperty("one", "1");
         assertEquals("one=1", ConfigurationUtils.toString(config));
 
         config.setProperty("two", "2");
         assertEquals("one=1" + lineSeparator + "two=2", ConfigurationUtils.toString(config));
 
         config.clearProperty("one");
         assertEquals("two=2", ConfigurationUtils.toString(config));
 
         config.setProperty("one", "1");
         assertEquals("two=2" + lineSeparator + "one=1", ConfigurationUtils.toString(config));
     }
 }