/*
    * 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.ifs2;
  
  import java.io.IOException;
  import java.nio.file.Files;
  import java.nio.file.Path;
  import java.util.Optional;
  
  import org.apache.logging.log4j.LogManager;
  import org.apache.logging.log4j.Logger;
  import org.jdom2.JDOMException;
  import org.mycore.common.MCRException;
  import org.mycore.common.config.MCRConfiguration2;
  import org.mycore.common.content.MCRContent;
  
  /**
   * Stores XML metadata documents (or optionally any other BLOB data) in a
   * persistent filesystem structure
   * 
   * For each object type, a store must be defined as follows:
   * 
   * MCR.IFS2.Store.DocPortal_document.Class=org.mycore.datamodel.ifs2.MCRMetadataStore 
   * MCR.IFS2.Store.DocPortal_document.BaseDir=/foo/bar
   * MCR.IFS2.Store.DocPortal_document.SlotLayout=4-2-2 
   * MCR.IFS2.Store.DocPortal_document.ForceXML=true (which is default)
   * 
   * @author Frank Lützenkirchen
   */
  public class MCRMetadataStore extends MCRStore {
  
      public static final Logger LOGGER = LogManager.getLogger();
  
      /**
       * If true (which is default), store will enforce it gets
       * XML to store, otherwise any binary content can be stored here.
       * 
       * Override with MCR.IFS2.Store.&lt;ObjectType&gt;.ForceXML=true|false
       */
      protected boolean forceXML = true;
  
      protected String forceDocType;
  
      /**
       * Initializes a new metadata store instance.
       * 
       * @param type
       *            the document type that is stored in this store
       */
      @Override
      protected void init(String type) {
          super.init(type);
          prefix = MCRConfiguration2.getString("MCR.IFS2.Store." + type + ".Prefix").orElse(type + "_");
          suffix = ".xml";
          forceXML = MCRConfiguration2.getBoolean("MCR.IFS2.Store." + type + ".ForceXML").orElse(true);
          if (forceXML) {
              forceDocType = MCRConfiguration2.getString("MCR.IFS2.Store." + type + ".ForceDocType").orElse(null);
              LOGGER.debug("Set doctype for {} to {}", type, forceDocType);
          }
      }
  
      /**
       * Initializes a new metadata store instance.
       * 
       * @param config
       *            the configuration for the store
       */
      @Override
      protected void init(MCRStoreConfig config) {
          super.init(config);
          prefix = Optional.ofNullable(config.getPrefix()).orElseGet(() -> config.getID() + "_");
          suffix = ".xml";
          forceXML = MCRConfiguration2.getBoolean("MCR.IFS2.Store." + config.getID() + ".ForceXML").orElse(true);
          if (forceXML) {
              forceDocType = MCRConfiguration2.getString("MCR.IFS2.Store." + config.getID() + ".ForceDocType")
                  .orElse(null);
              LOGGER.debug("Set doctype for {} to {}", config.getID(), forceDocType);
          }
      }
  
      protected boolean shouldForceXML() {
          return forceXML;
      }
 
     /**
      * Stores a newly created document, using the next free ID.
      * 
      * @param xml
      *            the XML document to be stored
      * @return the stored metadata object
      */
     public MCRStoredMetadata create(MCRContent xml) throws IOException, JDOMException {
         int id = getNextFreeID();
         return create(xml, id);
     }
 
     /**
      * Stores a newly created document under the given ID.
      * 
      * @param xml
      *            the XML document to be stored
      * @param id
      *            the ID under which the document should be stored
      * @return the stored metadata object
      */
     public MCRStoredMetadata create(MCRContent xml, int id) throws IOException, JDOMException {
         if (id <= 0) {
             throw new MCRException("ID of metadata object must be a positive integer");
         }
         Path path = getSlot(id);
         if (Files.exists(path)) {
             String msg = "Metadata object with ID " + id + " already exists in store";
             throw new MCRException(msg);
         }
         if (!Files.exists(path.getParent())) {
             Files.createDirectories(path.getParent());
         }
         MCRStoredMetadata meta = buildMetadataObject(path, id);
         meta.create(xml);
         return meta;
     }
 
     /**
      * Returns the metadata stored under the given ID, or null
      * 
      * @param id
      *            the ID of the XML document
      * @return the metadata stored under that ID, or null when there is no such
      *         metadata object
      */
     public MCRStoredMetadata retrieve(int id) throws IOException {
         Path path = getSlot(id);
         if (!Files.exists(path)) {
             return null;
         } else {
             return buildMetadataObject(path, id);
         }
     }
 
     /**
      * Builds a new stored metadata object in this store
      * 
      * @param fo
      *            the FileObject that stores the data
      * @param id
      *            the ID of the metadata object
      */
     protected MCRStoredMetadata buildMetadataObject(Path fo, int id) {
         return new MCRStoredMetadata(this, fo, id, forceDocType);
     }
 }