/*
    * This file is part of ***  M y C o R e  ***
    * See http://www.mycore.de/ for details.
    *
    * MyCoRe is free software: you can redistribute it and/or modify
    * it under the terms of the GNU General Public License as published by
    * the Free Software Foundation, either version 3 of the License, or
    * (at your option) any later version.
    *
   * MyCoRe is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with MyCoRe.  If not, see <http://www.gnu.org/licenses/>.
   */
  
  package org.mycore.datamodel.metadata;
  
  import java.util.Objects;
  
  import org.jdom2.Element;
  import org.mycore.common.MCRException;
  
  import com.fasterxml.jackson.annotation.JsonClassDescription;
  import com.fasterxml.jackson.annotation.JsonIgnore;
  
  /**
   * This class implements all method for special handling with the MCRMetaLink
   * part of a metadata object. The MCRMetaLinkID class present two types. At once
   * a reference only of a other MCRObject. At second a bidirectional link between
   * two MCRObject's. Optional you can append the reference with the label
   * attribute. See to W3C XLink Standard for more informations.
   * <p>
   * &lt;tag class="MCRMetaLinkID"&gt;
   * <br>
   * &lt;subtag xlink:type="locator" xlink:href=" <em>MCRObjectID</em>"
   * xlink:label="..." xlink:title="..."/&gt; <br>
   * &lt;subtag xlink:type="arc" xlink:from=" <em>MCRObjectID</em>"
   * xlink:to="MCRObjectID"/&gt; <br>
   * &lt;/tag&gt; <br>
   *
   * @author Jens Kupferschmidt
   * @version $Revision$ $Date$
   */
  @JsonClassDescription("Links to other objects or derivates")
  public class MCRMetaLinkID extends MCRMetaLink {
      /**
       * initializes with empty values.
       */
      public MCRMetaLinkID() {
          super();
      }
  
      /**
       * initializes with given values.
       * @see MCRMetaLink#MCRMetaLink(String, int)
       */
      public MCRMetaLinkID(String subtag, int inherted) {
          super(subtag, inherted);
      }
  
      /**
       * initializes with all values needed to link to an MCRObject.
       *
       *  This is the same as running {@link #MCRMetaLinkID(String, int)} and
       *  {@link #setReference(MCRObjectID, String, String)}.
       */
      public MCRMetaLinkID(String subtag, MCRObjectID id, String label, String title) {
          this(subtag, id, label, title, null);
      }
  
      /**
       * initializes with all values needed to link to an MCRObject.
       *
       */
      public MCRMetaLinkID(String subtag, MCRObjectID id, String label, String title, String role) {
          this(subtag, 0);
          setReference(id, label, title);
          setXLinkRole(role);
      }
  
      /**
       * This method set a reference with xlink:href, xlink:label and xlink:title.
       *
       * @param href
       *            the reference as MCRObjectID string
       * @param label
       *            the new label string
       * @param title
       *            the new title string
       * @exception MCRException
       *                if the set_href value is null, empty or not a MCRObjectID
       */
      @Override
      public final void setReference(String href, String label, String title) throws MCRException {
          try {
              MCRObjectID hrefid = MCRObjectID.getInstance(href);
             super.setReference(hrefid.toString(), label, title);
         } catch (Exception e) {
             throw new MCRException("The href value is not a MCRObjectID: " + href, e);
         }
     }
 
     /**
      * This method set a reference with xlink:href, xlink:label and xlink:title.
      *
      * @param href
      *            the reference as MCRObjectID
      * @param label
      *            the new label string
      * @param title
      *            the new title string
      * @exception MCRException
      *                if the href value is null, empty or not a MCRObjectID
      */
     public final void setReference(MCRObjectID href, String label, String title) throws MCRException {
         if (href == null) {
             throw new MCRException("The href value is null.");
         }
 
         super.setReference(href.toString(), label, title);
     }
 
     /**
      * This method set a bidirectional link with xlink:from, xlink:to and
      * xlink:title.
      *
      * @param from
      *            the source MCRObjectID string
      * @param to
      *            the target MCRObjectID string
      * @param title
      *            the new title string
      * @exception MCRException
      *                if the from or to element is not a MCRObjectId
      */
     @Override
     public final void setBiLink(String from, String to, String title) throws MCRException {
         try {
             MCRObjectID fromid = MCRObjectID.getInstance(from);
             MCRObjectID toid = MCRObjectID.getInstance(to);
             super.setBiLink(fromid.toString(), toid.toString(), title);
         } catch (Exception e) {
             linktype = null;
             throw new MCRException("The from/to value is not a MCRObjectID.");
         }
     }
 
     /**
      * This method set a bidirectional link with xlink:from, xlink:to and
      * xlink:title.
      *
      * @param from
      *            the source MCRObjectID
      * @param to
      *            the target MCRObjectID
      * @param title
      *            the new title string
      * @exception MCRException
      *                if the from or to element is not a MCRObjectId
      */
     public final void setBiLink(MCRObjectID from, MCRObjectID to, String title) throws MCRException {
         if (from == null || to == null) {
             throw new MCRException("The from/to value is null.");
         }
 
         super.setBiLink(from.toString(), to.toString(), title);
     }
 
     /**
      * This method get the xlink:href element as MCRObjectID.
      *
      * @return the xlink:href element as MCRObjectID
      */
     @JsonIgnore
     public final MCRObjectID getXLinkHrefID() {
         return MCRObjectID.getInstance(href);
     }
 
     /**
      * This method get the xlink:from element as MCRObjectID.
      *
      * @return the xlink:from element as MCRObjectID
      */
     @JsonIgnore
     public final MCRObjectID getXLinkFromID() {
         return MCRObjectID.getInstance(from);
     }
 
     /**
      * This method get the xlink:to element as MCRObjectID.
      *
      * @return the xlink:to element as MCRObjectID
      */
     @JsonIgnore
     public final MCRObjectID getXLinkToID() {
         return MCRObjectID.getInstance(to);
     }
 
     /**
      * This method read the XML input stream part from a DOM part for the
      * metadata of the document.
      *
      * @param element
      *            a relevant DOM element for the metadata
      * @exception MCRException
      *                if the xlink:type is not locator or arc or if href or from
      *                and to are not a MCRObjectID
      */
     @Override
     public void setFromDOM(Element element) {
         super.setFromDOM(element);
 
         if (linktype.equals("locator")) {
             try {
                 MCRObjectID hrefid = MCRObjectID.getInstance(href);
                 href = hrefid.toString();
             } catch (Exception e) {
                 throw new MCRException("The xlink:href is not a MCRObjectID.");
             }
         } else {
             try {
                 MCRObjectID fromid = MCRObjectID.getInstance(from);
                 from = fromid.toString();
             } catch (Exception e) {
                 throw new MCRException("The xlink:from is not a MCRObjectID.");
             }
 
             try {
                 MCRObjectID toid = MCRObjectID.getInstance(to);
                 to = toid.toString();
             } catch (Exception e) {
                 throw new MCRException("The xlink:to is not a MCRObjectID.");
             }
         }
     }
 
     @Override
     public boolean equals(Object obj) {
         if (!super.equals(obj)) {
             return false;
         }
         MCRMetaLinkID other = (MCRMetaLinkID) obj;
         if (!Objects.equals(from, other.from)) {
             return false;
         } else if (!Objects.equals(href, other.href)) {
             return false;
         } else if (!Objects.equals(label, other.label)) {
             return false;
         } else if (!Objects.equals(linktype, other.linktype)) {
             return false;
         } else if (!Objects.equals(role, other.role)) {
             return false;
         } else if (!Objects.equals(title, other.title)) {
             return false;
         } else {
             return Objects.equals(to, other.to);
         }
     }
 
     @Override
     public MCRMetaLinkID clone() {
         return (MCRMetaLinkID) super.clone();
     }
 
     @Override
     public final String toString() {
         return getXLinkHref();
     }
 }