/*
    * Licensed to The Apereo Foundation under one or more contributor license
    * agreements. See the NOTICE file distributed with this work for additional
    * information regarding copyright ownership.
    *
    *
    * The Apereo Foundation licenses this file to you under the Educational
    * Community 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://opensource.org/licenses/ecl2.txt
   *
   * 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.opencastproject.metadata.dublincore;
  
  import static java.lang.String.format;
  import static org.opencastproject.util.EqualsUtil.eq;
  
  import org.opencastproject.mediapackage.EName;
  import org.opencastproject.util.EqualsUtil;
  import org.opencastproject.util.RequireUtil;
  
  import java.io.Serializable;
  import java.util.Optional;
  
  import javax.annotation.ParametersAreNonnullByDefault;
  import javax.annotation.concurrent.Immutable;
  
  /**
   * Representation of a DublinCore conforming property value.
   * <p>
   * See <a
   * href="http://dublincore.org/documents/dc-xml-guidelines/">http://dublincore.org/documents/dc-xml-guidelines/</a> for
   * further details.
   */
  @Immutable
  @ParametersAreNonnullByDefault
  public final class DublinCoreValue implements Serializable {
    private static final long serialVersionUID = 7660583858714438266L;
  
    private final String value;
    private final String language;
    private final Optional<EName> encodingScheme;
  
    /**
     * Create a new Dublin Core value.
     *
     * @param value
     *          the value
     * @param language
     *          the language (two letter ISO 639)
     * @param encodingScheme
     *          the encoding scheme used to encode the value
     */
    public DublinCoreValue(String value, String language, Optional<EName> encodingScheme) {
      this.value = RequireUtil.notNull(value, "value");
      this.language = RequireUtil.notNull(language, "language");
      this.encodingScheme = RequireUtil.notNull(encodingScheme, "encodingScheme");
    }
  
    /**
     * Create a new Dublin Core value.
     *
     * @param value
     *         the value
     * @param language
     *         the language (two letter ISO 639)
     * @param encodingScheme
     *         the encoding scheme used to encode the value
     */
    public static DublinCoreValue mk(String value, String language, Optional<EName> encodingScheme) {
      return new DublinCoreValue(value, language, encodingScheme);
    }
  
    /**
     * Create a new Dublin Core value.
     *
     * @param value
     *         the value
     * @param language
     *         the language (two letter ISO 639)
     * @param encodingScheme
     *         the encoding scheme used to encode the value
     */
    public static DublinCoreValue mk(String value, String language, EName encodingScheme) {
      return new DublinCoreValue(value, language, Optional.of(encodingScheme));
    }
  
    /**
     * Creates a new Dublin Core value without an encoding scheme.
     *
    * @param value
    *          the value
    * @param language
    *          the language (two letter ISO 639)
    */
   public static DublinCoreValue mk(String value, String language) {
     return new DublinCoreValue(value, language, Optional.empty());
   }
 
   /**
    * Create a new Dublin Core value with the language set to undefined and no particular encoding scheme.
    *
    * @param value
    *          the value
    * @see org.opencastproject.metadata.dublincore.DublinCore#LANGUAGE_UNDEFINED
    */
   public static DublinCoreValue mk(String value) {
     return new DublinCoreValue(value, DublinCore.LANGUAGE_UNDEFINED, Optional.empty());
   }
 
   /**
    * Return the value of the property.
    */
   public String getValue() {
     return value;
   }
 
   /**
    * Return the language.
    */
   public String getLanguage() {
     return language;
   }
 
   /**
    * Return the encoding scheme.
    */
   public Optional<EName> getEncodingScheme() {
     return encodingScheme;
   }
 
   public boolean hasEncodingScheme() {
     return encodingScheme.isPresent();
   }
 
   @Override
   public boolean equals(Object that) {
     return (this == that) || (that instanceof DublinCoreValue && eqFields((DublinCoreValue) that));
   }
 
   private boolean eqFields(DublinCoreValue that) {
     return eq(value, that.value) && eq(language, that.language) && eq(encodingScheme, that.encodingScheme);
   }
 
   @Override
   public int hashCode() {
     return EqualsUtil.hash(value, language, encodingScheme);
   }
 
   @Override public String toString() {
     return format("DublinCoreValue(%s,%s,%s)", value, language, encodingScheme);
   }
 }