/*
 * RDFmanager.java
 *
 * Version: $Revision: 0.1 $
 *
 * Date: $Date: 2008/02/13 11:29:28 $
 *
 */

package nl.leidenuniv.dspace.rdf;

import java.sql.SQLException;

//import org.dspace.authorize.AuthorizeException;
//import org.dspace.authorize.AuthorizeManager;
//import org.dspace.content.DSpaceObject;
import org.dspace.content.DCValue;
import org.dspace.core.Context;
//import org.dspace.core.LogManager;
import org.dspace.storage.rdbms.DatabaseManager;
import org.dspace.storage.rdbms.TableRow;
import org.dspace.storage.rdbms.TableRowIterator;

//import org.dspace.core.Constants;
import nl.leidenuniv.dspace.rdf.RDFpredicate;
import nl.leidenuniv.dspace.rdf.RDFvalue;
import nl.leidenuniv.dspace.rdf.RDFresource;
//import org.dspace.content.Bitstream;
//import org.dspace.content.Bundle;
//import org.dspace.content.Collection;
//import org.dspace.content.Community;
import org.dspace.content.Item;
//import org.dspace.eperson.EPerson;
//import org.dspace.eperson.Group;

//import java.util.ArrayList;
//import java.util.List;

/**
 * Manager for Resource Description Framework triples
 *
 * @author Lucas van Schaik
 * @version $Revision: 0.1 $
 */
public class RDFmanager
{

  public static boolean addTriple(Context context, Item item, 
                                  String subject_type, String subject_value, 
                                  String predicateString, 
                                  String object_type, String object_value)
                              throws SQLException {
    if (subject_value == null || object_value == null) {
      return false;
    }
    Object subject = findResource(context, item, subject_type, subject_value);
    Object object = findResource(context, item, object_type, object_value);
    if (object == null || subject == null) {
      return false;
    }
    RDFpredicate predicate = RDFpredicate.find(context,predicateString);
    if (predicate == null) {
      predicate = new RDFpredicate(context,predicateString);
    }
    RDFtriple triple = RDFtriple.find(context,subject,predicate,null);
    if (triple != null) {
      if (object != null) {
        Object obj = triple.getObject();
        if ( ! object.equals(obj)) {
          triple.setObject(object);
          triple.update();
        }
      }
      else {
        // komt hier nooit
        triple.delete();
        return false;
      }
    }
    else {
      if (object!= null) {
        triple = new RDFtriple(context,subject,predicate,object);
      }
    }
    return true;
  }

  private static Object findResource(Context context, Item item, String type, String value) {
    Object object = null;
    if (type.startsWith("dc:")) {
      String[] parts = type.split("[:.]");
      String element = parts[1];
      String qualifier = null;
      if (parts.length > 2) {
        qualifier = parts[2];
      }
      DCValue[] dcs = item.getDC(element,qualifier,Item.ANY);
      for (int i=0; i<dcs.length; i++) {
        if (value.equals(dcs[i].value)) {
          object = dcs[i];
          break;
        }
      }
    }
    else if (type.equals("string")) {
      if (value != null && ((String)value).length() > 0) {
        object = value;
      }
    }
    else if (type.equals("item")) {
      object = item;
    }
    return object;
  }

  public static void main(String[] argv) {

   if (argv.length != 5) {
     System.err.println("usage: RDFmanager subject_type subject_value predicate_string object_type object_value\n       example: RDFmanager dc:contributor.author \"Piet, J.E.\" hasDAI string \"123459657\"\n"); 
     return;
   }
   String subject_type = argv[0];
   String subject_value = argv[1];
   String predicateString = argv[2];
   String object_type = argv[3];
   String object_value = argv[4];

   try {
    Context context = new Context();
    boolean done = false;
    if (subject_type.startsWith("dc:")) {
      String[] parts = subject_type.split("[:.]");
      String element = parts[1];
      String sql = "SELECT v.item_id as itemid FROM dcvalue v, dctyperegistry t WHERE " 
                 + "v.dc_type_id = t.dc_type_id and "
                 + "v.text_value = '"+subject_value+"' and "
                 + "t.element = '"+element+"'";
      if (parts.length > 2) {
        if (!parts[2].equals("*")) {
          sql += " and t.qualifier = '"+parts[2]+"'";
        }
      }
      else {
        sql += " and t.qualifier is null";
      }
      TableRowIterator tri = null;
      try {
        tri = DatabaseManager.query(context,sql);
        while (tri.hasNext()) {
          TableRow r = (TableRow) tri.next();
          int itemid = r.getIntColumn("itemid"); 
          Item item = Item.find(context,itemid); 
          if (item.isArchived()) {
            System.out.println("Adding triple to item "+item.getHandle()+" with subject "+subject_type+" "+subject_value+" "+predicateString+" "+object_type+" "+object_value);
            done = RDFmanager.addTriple(context, item, subject_type, subject_value, predicateString,
                        object_type, object_value);
            if (!done) {
              System.err.println("FAILED to add triple to item "+item.getHandle()+" with subject "+subject_type+" "+subject_value+" "+predicateString+" "+object_type+" "+object_value);
            }
          }
        }
      }
      finally {
        if (tri != null) {
          tri.close();
        }
      }
    }
    else {
      System.err.println("Only subject_type dc:... implemented... bailing....\n");
    }
    context.complete();
   }
   catch (Exception e) {
     System.out.print("EXCEPTION: "+e);
     e.printStackTrace();
   }
  }


}