/**
    * 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.rdf.rdf4j.impl;
  
  import java.util.Locale;
  import java.util.Objects;
  import java.util.Optional;
  
  import org.apache.commons.rdf.rdf4j.RDF4JLiteral;
  import org.eclipse.rdf4j.model.vocabulary.XMLSchema;
  import org.eclipse.rdf4j.rio.turtle.TurtleUtil;
  
  final class LiteralImpl extends AbstractRDFTerm<org.eclipse.rdf4j.model.Literal> implements RDF4JLiteral {
  
      private static final String QUOTE = "\"";
  
      LiteralImpl(final org.eclipse.rdf4j.model.Literal literal) {
          super(literal);
      }
  
      private static String lowerCase(final String langTag) {
          return langTag.toLowerCase(Locale.ROOT);
      }
  
      @Override
      public boolean equals(final Object obj) {
          if (obj == this) {
              return true;
          }
          if (obj instanceof org.apache.commons.rdf.api.Literal) {
              final org.apache.commons.rdf.api.Literal other = (org.apache.commons.rdf.api.Literal) obj;
              return getLexicalForm().equals(other.getLexicalForm()) &&
                      getDatatype().equals(other.getDatatype()) &&
                      getLanguageTag().map(LiteralImpl::lowerCase).equals(
                              other.getLanguageTag().map(LiteralImpl::lowerCase));
          }
          return false;
      }
  
      @Override
      public org.apache.commons.rdf.api.IRI getDatatype() {
          return new IRIImpl(value.getDatatype());
      }
  
      @Override
      public Optional<String> getLanguageTag() {
          return value.getLanguage();
      }
  
      @Override
      public String getLexicalForm() {
          return value.getLabel();
      }
  
      @Override
      public int hashCode() {
          return Objects.hash(value.getLabel(), value.getDatatype(),
                  getLanguageTag().map(LiteralImpl::lowerCase));
      }
  
      @Override
      public String ntriplesString() {
          // TODO: Use a more efficient StringBuffer
          final String escaped = QUOTE + TurtleUtil.encodeString(value.getLabel()) + QUOTE;
          if (value.getLanguage().isPresent()) {
              return escaped + "@" + value.getLanguage().get();
          }
          if (value.getDatatype().equals(XMLSchema.STRING)) {
              return escaped;
          }
          return escaped + "^^<" + TurtleUtil.encodeURIString(value.getDatatype().toString()) + ">";
      }
  
      @Override
      public String toString() {
          return ntriplesString();
      }
  }