/*
    * 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.io;
  
  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.assertTrue;
  import static org.junit.jupiter.api.Assumptions.assumeFalse;
  
  import java.nio.charset.Charset;
  import java.nio.charset.StandardCharsets;
  import java.util.Collection;
  import java.util.Set;
  import java.util.SortedMap;
  import java.util.stream.Stream;
  
  import org.apache.commons.lang3.StringUtils;
  import org.junit.jupiter.api.Test;
  import org.junit.jupiter.params.ParameterizedTest;
  import org.junit.jupiter.params.provider.Arguments;
  import org.junit.jupiter.params.provider.MethodSource;
  
  /**
   * Tests {@link Charsets}.
   */
  @SuppressWarnings("deprecation") // testing deprecated code
  public class CharsetsTest {
  
      /**
       * For parameterized tests.
       */
      public static final String AVAIL_CHARSETS = "org.apache.commons.io.CharsetsTest#availableCharsetsKeySet";
  
      /**
       * For parameterized tests.
       */
      public static final String REQUIRED_CHARSETS = "org.apache.commons.io.CharsetsTest#getRequiredCharsetNames";
  
      /**
       * For parameterized tests.
       *
       * @return {@code Charset.availableCharsets().keySet()}.
       */
      public static Set<String> availableCharsetsKeySet() {
          return Charset.availableCharsets().keySet();
      }
  
      /**
       * For parameterized tests.
       *
       * @return {@code Charset.availableCharsets().values()}.
       */
      public static Collection<Charset> availableCharsetsValues() {
          return Charset.availableCharsets().values();
      }
  
      static Stream<Arguments> charsetAliasProvider() {
          return Charset.availableCharsets().entrySet().stream()
                  .flatMap(entry -> entry.getValue().aliases().stream().map(a -> Arguments.of(entry.getValue(), a)));
      }
  
      /**
       * For parameterized tests.
       *
       * @return {@code Charset.requiredCharsets().keySet()}.
       */
      public static Set<String> getRequiredCharsetNames() {
          return Charsets.requiredCharsets().keySet();
      }
  
      @ParameterizedTest
      @MethodSource("charsetAliasProvider")
      void testIsAlias(final Charset charset, final String charsetAlias) {
          assertTrue(Charsets.isAlias(charset, charsetAlias));
          assertTrue(Charsets.isAlias(charset, charsetAlias.toLowerCase()));
          assertTrue(Charsets.isAlias(charset, charsetAlias.toUpperCase()));
          assertTrue(Charsets.isAlias(charset, charset.name()));
          assertFalse(Charsets.isAlias(charset, null));
      }
  
      @Test
      void testIso8859_1() {
          assertEquals("ISO-8859-1", Charsets.ISO_8859_1.name());
     }
 
     @ParameterizedTest
     @MethodSource("availableCharsetsValues")
     void testIsUTF8Charset(final Charset charset) {
         assumeFalse(StandardCharsets.UTF_8.equals(charset));
         charset.aliases().forEach(n -> assertFalse(Charsets.isUTF8(Charset.forName(n))));
     }
 
     void testIsUTF8CharsetUTF8() {
         assertTrue(Charsets.isUTF8(StandardCharsets.UTF_8));
         StandardCharsets.UTF_8.aliases().forEach(n -> assertTrue(Charsets.isUTF8(Charset.forName(n))));
     }
 
     @Test
     void testRequiredCharsets() {
         final SortedMap<String, Charset> requiredCharsets = Charsets.requiredCharsets();
         // test for what we expect to be there as of Java 6
         // Make sure the object at the given key is the right one
         assertEquals(requiredCharsets.get("US-ASCII").name(), "US-ASCII");
         assertEquals(requiredCharsets.get("ISO-8859-1").name(), "ISO-8859-1");
         assertEquals(requiredCharsets.get("UTF-8").name(), "UTF-8");
         assertEquals(requiredCharsets.get("UTF-16").name(), "UTF-16");
         assertEquals(requiredCharsets.get("UTF-16BE").name(), "UTF-16BE");
         assertEquals(requiredCharsets.get("UTF-16LE").name(), "UTF-16LE");
     }
 
     @Test
     void testToCharset_String() {
         assertEquals(Charset.defaultCharset(), Charsets.toCharset((String) null));
         assertEquals(Charset.defaultCharset(), Charsets.toCharset((Charset) null));
         assertEquals(Charset.defaultCharset(), Charsets.toCharset(Charset.defaultCharset()));
         assertEquals(StandardCharsets.UTF_8, Charsets.toCharset(StandardCharsets.UTF_8));
     }
 
     @Test
     void testToCharsetDefault() {
         assertEquals(Charset.defaultCharset(), Charsets.toCharsetDefault((String) null, null));
         assertEquals(Charset.defaultCharset(), Charsets.toCharsetDefault(StringUtils.EMPTY, null));
         assertEquals(Charset.defaultCharset(), Charsets.toCharsetDefault(".", null));
         assertEquals(Charset.defaultCharset(), Charsets.toCharsetDefault(null, Charset.defaultCharset()));
         assertEquals(Charset.defaultCharset(), Charsets.toCharsetDefault(Charset.defaultCharset().name(), Charset.defaultCharset()));
         assertEquals(StandardCharsets.UTF_8, Charsets.toCharsetDefault(StandardCharsets.UTF_8.name(), Charset.defaultCharset()));
         assertEquals(StandardCharsets.UTF_8, Charsets.toCharsetDefault(StandardCharsets.UTF_8.name(), null));
     }
 
     @Test
     void testToCharsetWithStringCharset() {
         assertNull(Charsets.toCharset((String) null, null));
         assertEquals(Charset.defaultCharset(), Charsets.toCharset((String) null, Charset.defaultCharset()));
         assertEquals(Charset.defaultCharset(), Charsets.toCharset((Charset) null, Charset.defaultCharset()));
         assertNull(Charsets.toCharset((Charset) null, null));
         assertEquals(Charset.defaultCharset(), Charsets.toCharset(Charset.defaultCharset(), Charset.defaultCharset()));
         assertEquals(StandardCharsets.UTF_8, Charsets.toCharset(StandardCharsets.UTF_8, Charset.defaultCharset()));
         assertEquals(StandardCharsets.UTF_8, Charsets.toCharset(StandardCharsets.UTF_8, null));
     }
 
     @Test
     void testUsAscii() {
         assertEquals(StandardCharsets.US_ASCII.name(), Charsets.US_ASCII.name());
     }
 
     @Test
     void testUtf16() {
         assertEquals(StandardCharsets.UTF_16.name(), Charsets.UTF_16.name());
     }
 
     @Test
     void testUtf16Be() {
         assertEquals(StandardCharsets.UTF_16BE.name(), Charsets.UTF_16BE.name());
     }
 
     @Test
     void testUtf16Le() {
         assertEquals(StandardCharsets.UTF_16LE.name(), Charsets.UTF_16LE.name());
     }
 
     @Test
     void testUtf8() {
         assertEquals(StandardCharsets.UTF_8.name(), Charsets.UTF_8.name());
     }
 
 }