/*
    * 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;
  
  import static org.junit.jupiter.api.Assertions.assertEquals;
  import static org.junit.jupiter.api.Assertions.assertFalse;
  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.lang.reflect.Constructor;
  import java.util.ArrayList;
  import java.util.HashSet;
  import java.util.Iterator;
  import java.util.List;
  import java.util.NoSuchElementException;
  import java.util.Set;
  
  import org.apache.commons.configuration2.builder.FileBasedBuilderParametersImpl;
  import org.apache.commons.configuration2.builder.combined.CombinedConfigurationBuilder;
  import org.apache.commons.configuration2.convert.DefaultListDelimiterHandler;
  import org.apache.commons.configuration2.convert.ListDelimiterHandler;
  import org.apache.commons.configuration2.interpol.ConfigurationInterpolator;
  import org.junit.jupiter.api.Test;
  
  /**
   * Test case for the {@link SubsetConfiguration} class.
   */
  public class TestSubsetConfiguration {
      static final String TEST_DIR = ConfigurationAssert.TEST_DIR_NAME;
      static final String TEST_FILE = "testDigesterConfiguration2.xml";
  
      @Test
      public void testClear() {
          final Configuration config = new BaseConfiguration();
          config.setProperty("test.key1", "value1");
          config.setProperty("testing.key2", "value1");
  
          final Configuration subset = config.subset("test");
          subset.clear();
  
          assertTrue(subset.isEmpty());
          assertFalse(config.isEmpty());
      }
  
      /**
       * Tries to create an instance without a parent configuration.
       */
      @Test
      public void testConstructNullParent() {
          assertThrows(NullPointerException.class, () -> new SubsetConfiguration(null, ""));
      }
  
      @Test
      public void testGetChildKey() {
          final Configuration conf = new BaseConfiguration();
          // subset with delimiter
          SubsetConfiguration subset = new SubsetConfiguration(conf, "prefix", ".");
          assertEquals("key", subset.getChildKey("prefix.key"));
          assertEquals("", subset.getChildKey("prefix"));
  
          // subset without delimiter
          subset = new SubsetConfiguration(conf, "prefix", null);
          assertEquals("key", subset.getChildKey("prefixkey"));
          assertEquals("", subset.getChildKey("prefix"));
      }
  
      @Test
      public void testGetKeys() {
          final Configuration conf = new BaseConfiguration();
          conf.setProperty("test", "value0");
          conf.setProperty("test.key1", "value1");
          conf.setProperty("testing.key2", "value1");
  
          final Configuration subset = new SubsetConfiguration(conf, "test", ".");
  
          final Iterator<String> it = subset.getKeys();
          assertEquals("", it.next());
          assertEquals("key1", it.next());
          assertFalse(it.hasNext());
      }
  
     @Test
     public void testGetKeysWithPrefix() {
         final Configuration conf = new BaseConfiguration();
         conf.setProperty("test.abc", "value0");
         conf.setProperty("test.abc.key1", "value1");
         conf.setProperty("test.abcdef.key2", "value1");
 
         final Configuration subset = new SubsetConfiguration(conf, "test", ".");
 
         final Iterator<String> it = subset.getKeys("abc");
         assertEquals("abc", it.next());
         assertEquals("abc.key1", it.next());
         assertFalse(it.hasNext());
     }
 
     @Test
     public void testGetList() {
         final BaseConfiguration conf = new BaseConfiguration();
         conf.setListDelimiterHandler(new DefaultListDelimiterHandler(','));
         conf.setProperty("test.abc", "value0,value1");
         conf.addProperty("test.abc", "value3");
 
         final Configuration subset = new SubsetConfiguration(conf, "test", ".");
         final List<Object> list = subset.getList("abc", new ArrayList<>());
         assertEquals(3, list.size());
     }
 
     /**
      * Tests whether the list delimiter handler from the parent configuration is used.
      */
     @Test
     public void testGetListDelimiterHandlerFromParent() {
         final BaseConfiguration config = new BaseConfiguration();
         final AbstractConfiguration subset = (AbstractConfiguration) config.subset("prefix");
         final ListDelimiterHandler listHandler = new DefaultListDelimiterHandler(',');
         config.setListDelimiterHandler(listHandler);
         assertSame(listHandler, subset.getListDelimiterHandler());
     }
 
     @Test
     public void testGetParent() {
         final Configuration conf = new BaseConfiguration();
         final SubsetConfiguration subset = new SubsetConfiguration(conf, "prefix", ".");
 
         assertEquals(conf, subset.getParent());
     }
 
     @Test
     public void testGetParentKey() {
         final Configuration conf = new BaseConfiguration();
         // subset with delimiter
         SubsetConfiguration subset = new SubsetConfiguration(conf, "prefix", ".");
         assertEquals("prefix.key", subset.getParentKey("key"));
         assertEquals("prefix", subset.getParentKey(""));
 
         // subset without delimiter
         subset = new SubsetConfiguration(conf, "prefix", null);
         assertEquals("prefixkey", subset.getParentKey("key"));
         assertEquals("prefix", subset.getParentKey(""));
     }
 
     @Test
     public void testGetPrefix() {
         final Configuration conf = new BaseConfiguration();
         final SubsetConfiguration subset = new SubsetConfiguration(conf, "prefix", ".");
 
         assertEquals("prefix", subset.getPrefix());
     }
 
     @Test
     public void testGetProperty() {
         final Configuration conf = new BaseConfiguration();
         conf.setProperty("test.key1", "value1");
         conf.setProperty("testing.key2", "value1");
 
         final Configuration subset = new SubsetConfiguration(conf, "test", ".");
         assertFalse(subset.isEmpty());
         assertTrue(subset.containsKey("key1"));
         assertFalse(subset.containsKey("ng.key2"));
     }
 
     @Test
     public void testInterpolationForKeysOfTheParent() {
         final BaseConfiguration config = new BaseConfiguration();
         config.setProperty("test", "junit");
         config.setProperty("prefix.key", "${test}");
         final AbstractConfiguration subset = (AbstractConfiguration) config.subset("prefix");
         assertEquals("junit", subset.getString("key", ""));
     }
 
     /**
      * Tests manipulating the interpolator.
      */
     @Test
     public void testInterpolator() {
         final BaseConfiguration config = new BaseConfiguration();
         final AbstractConfiguration subset = (AbstractConfiguration) config.subset("prefix");
         InterpolationTestHelper.testGetInterpolator(subset);
     }
 
     /**
      * Tests whether a list delimiter handler is used correctly.
      */
     @Test
     public void testListDelimiterHandling() {
         final BaseConfiguration config = new BaseConfiguration();
         final Configuration subset = config.subset("prefix");
         config.setListDelimiterHandler(new DefaultListDelimiterHandler('/'));
         subset.addProperty("list", "a/b/c");
         assertEquals(3, config.getList("prefix.list").size());
 
         ((AbstractConfiguration) subset).setListDelimiterHandler(new DefaultListDelimiterHandler(';'));
         subset.addProperty("list2", "a;b;c");
         assertEquals(3, config.getList("prefix.list2").size());
     }
 
     @Test
     public void testLocalLookupsInInterpolatorAreInherited() {
         final BaseConfiguration config = new BaseConfiguration();
         final ConfigurationInterpolator interpolator = config.getInterpolator();
         interpolator.registerLookup("brackets", key -> "(" + key + ")");
         config.setProperty("prefix.var", "${brackets:x}");
         final AbstractConfiguration subset = (AbstractConfiguration) config.subset("prefix");
         assertEquals("(x)", subset.getString("var", ""));
     }
 
     @Test
     public void testNested() throws Exception {
         final CombinedConfigurationBuilder builder = new CombinedConfigurationBuilder();
         builder.configure(new FileBasedBuilderParametersImpl().setFile(ConfigurationAssert.getTestFile(TEST_FILE)));
         final Configuration config = builder.getConfiguration();
         final Configuration subConf = config.subset("tables.table(0)");
         assertTrue(subConf.getKeys().hasNext());
         final Configuration subSubConf = subConf.subset("fields.field(1)");
         final Iterator<String> itKeys = subSubConf.getKeys();
         final Set<String> keys = new HashSet<>();
         keys.add("name");
         keys.add("type");
         while (itKeys.hasNext()) {
             final String k = itKeys.next();
             assertTrue(keys.contains(k));
             keys.remove(k);
         }
         assertTrue(keys.isEmpty());
     }
 
     @Test
     public void testPrefixDelimiter(){
         final BaseConfiguration config = new BaseConfiguration();
         config.setProperty("part1.part2@test.key1", "value1");
         config.setProperty("part1.part2", "value2");
         config.setProperty("part3.part4@testing.key2", "value3");
 
         final SubsetConfiguration subset = new SubsetConfiguration(config, "part1.part2", "@");
         // Check subset properties
         assertEquals("value1", subset.getString("test.key1"));
         assertEquals("value2", subset.getString(""));
         assertNull(subset.getString("testing.key2"));
 
         // Check for empty subset configuration and iterator
         assertEquals(2, subset.size());
         assertFalse(subset.isEmpty());
         assertTrue(subset.getKeys().hasNext());
     }
 
     @Test
     public void testPrefixDelimiterNegativeTest(){
         final BaseConfiguration config = new BaseConfiguration();
         config.setProperty("part1.part2@test.key1", "value1");
         config.setProperty("part3.part4@testing.key2", "value2");
 
         final SubsetConfiguration subset = new SubsetConfiguration(config, "part1.part2", "@") {
             // Anonymous inner class declaration to override SubsetConfiguration.getKeysInternal() - Call
             // ImutableConfiguration.getKeys(String) on the parent configuration of the SubsetConfiguration in order to
             // not consequently pass the prefix delimiter
             @Override
             protected Iterator<String> getKeysInternal() {
                 Class<?> subsetIteratorClass;
                 try {
                     subsetIteratorClass = Class
                             .forName("org.apache.commons.configuration2.SubsetConfiguration$SubsetIterator");
                     final Constructor<?> ctor = subsetIteratorClass.getDeclaredConstructor(SubsetConfiguration.class,
                             Iterator.class);
                     ctor.setAccessible(true);
 
                     return (Iterator<String>) ctor.newInstance(this, parent.getKeys("part1.part2"));
                 } catch (final Exception ex) {
                     throw new IllegalArgumentException(ex);
                 }
             }
         };
 
         // Check subset properties - contains one property
         assertEquals("value1", subset.getString("test.key1"));
         assertNull(subset.getString("testing.key2"));
 
         // Check for empty subset configuration and iterator - even if the SubsetConfiguration contains properties, like
         // checked previously its states that it is empty
         assertEquals(0, subset.size());
         assertTrue(subset.isEmpty());
         assertFalse(subset.getKeys().hasNext());
     }
 
     /**
      * Tests whether the list delimiter handler is also set for the parent configuration.
      */
     @Test
     public void testSetListDelimiterHandlerInParent() {
         final BaseConfiguration config = new BaseConfiguration();
         final AbstractConfiguration subset = (AbstractConfiguration) config.subset("prefix");
         final ListDelimiterHandler listHandler = new DefaultListDelimiterHandler(',');
         subset.setListDelimiterHandler(listHandler);
         assertSame(listHandler, config.getListDelimiterHandler());
     }
 
     /**
      * Tests the case that the parent configuration is not derived from AbstractConfiguration and thus does not support a
      * list delimiter handler.
      */
     @Test
     public void testSetListDelimiterHandlerParentNotSupported() {
         final Configuration config = mock(Configuration.class);
         final SubsetConfiguration subset = new SubsetConfiguration(config, "prefix");
         final ListDelimiterHandler listHandler = new DefaultListDelimiterHandler(',');
         subset.setListDelimiterHandler(listHandler);
         assertSame(listHandler, subset.getListDelimiterHandler());
     }
 
     @Test
     public void testSetPrefix() {
         final Configuration conf = new BaseConfiguration();
         final SubsetConfiguration subset = new SubsetConfiguration(conf, null, ".");
         subset.setPrefix("prefix");
 
         assertEquals("prefix", subset.getPrefix());
     }
 
     @Test
     public void testSetProperty() {
         final Configuration conf = new BaseConfiguration();
         final Configuration subset = new SubsetConfiguration(conf, "test", ".");
 
         // set a property in the subset and check the parent
         subset.setProperty("key1", "value1");
         assertEquals("value1", subset.getProperty("key1"));
         assertEquals("value1", conf.getProperty("test.key1"));
 
         // set a property in the parent and check in the subset
         conf.setProperty("test.key2", "value2");
         assertEquals("value2", conf.getProperty("test.key2"));
         assertEquals("value2", subset.getProperty("key2"));
     }
 
     @Test
     public void testThrowExceptionOnMissing() {
         final BaseConfiguration config = new BaseConfiguration();
         config.setThrowExceptionOnMissing(true);
 
         final SubsetConfiguration subset = new SubsetConfiguration(config, "prefix");
 
         assertThrows(NoSuchElementException.class, () -> subset.getString("foo"));
 
         config.setThrowExceptionOnMissing(false);
         assertNull(subset.getString("foo"));
 
         subset.setThrowExceptionOnMissing(true);
         assertThrows(NoSuchElementException.class, () -> config.getString("foo"));
     }
 }