/*
    * Copyright 2003 - 2014 The eFaps Team
    *
    * Licensed 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.
   *
   * Revision:        $Rev$
   * Last Changed:    $Date$
   * Last Changed By: $Author$
   */
  
  package org.efaps.db.print;
  
  import java.sql.SQLException;
  import java.util.ArrayList;
  import java.util.Iterator;
  import java.util.List;
  
  import org.efaps.admin.datamodel.Attribute;
  import org.efaps.admin.datamodel.Type;
  import org.efaps.db.Instance;
  import org.efaps.db.wrapper.SQLSelect;
  import org.efaps.util.EFapsException;
  import org.efaps.util.cache.CacheReloadException;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Select Part for <code>linkto[ATTRIBUTENAME]</code>.
   * After invoking <code>{@link #next()}</code> currentinstance contains
   * the instance it was linked to.
   *
   * @author The eFaps Team
   * @version $Id$
   */
  public class LinkToSelectPart
      extends AbstractSelectPart
  {
      /**
       * Logging instance used in this class.
       */
      private static final Logger LOG = LoggerFactory.getLogger(OneSelect.class);
  
      /**
       * Name of the Attribute the link to is based on.
       */
      private final String attrName;
  
      /**
       * Type the {@link #attrName} belongs to.
       */
      private final Type type;
  
      /**
       * index of the id Column.
       */
      private int idColumnIndex;
  
      /**
       * index of the id Column.
       */
      private int typeColumnIndex = -1;
  
      /**
       * List of ids retrieved from the ResultSet returned
       * from the eFaps database. It represent one row in a result set.
       */
      private final List<Long> idList = new ArrayList<Long>();
  
      /**
       * List of typeIds retrieved from the ResultSet returned
       * from the eFaps database. It represent one row in a result set.
       */
      private final List<Long> typeIdList = new ArrayList<Long>();
  
      /**
       * Iterator for the ids.
       */
      private Iterator<Long> idIterator;
  
      /**
       * Iterator for the ypeIds.
       */
      private Iterator<Long> typeIdIterator;
  
      /**
       * The instance this Select is linked to.
       */
      private Instance currentInstance;
  
     /**
      * @param _attrName attribute name
      * @param _type     type
      */
     public LinkToSelectPart(final String _attrName,
                             final Type _type)
     {
         this.attrName = _attrName;
         this.type = _type;
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public int join(final OneSelect _oneSelect,
                     final SQLSelect _select,
                     final int _relIndex)
         throws EFapsException
     {
         // it must be evaluated if the attribute that is used as the base for the linkto is inside a child table
         final Attribute attr = this.type.getAttribute(this.attrName);
         if (attr == null) {
             LinkToSelectPart.LOG.error("Could not find an Attribute with name '{}' for type:{}", this.attrName,
                             this.type);
             throw new EFapsException(LinkToSelectPart.class, "joinNoAttribute");
         }
         Integer relIndex = _relIndex;
         if (attr != null && !attr.getTable().equals(this.type.getMainTable())) {
             final String childTableName = attr.getTable().getSqlTable();
             relIndex = _oneSelect.getTableIndex(childTableName, "ID", _relIndex, null);
             if (relIndex == null) {
                 relIndex = _oneSelect.getNewTableIndex(childTableName, "ID", _relIndex, null);
                 _select.leftJoin(childTableName, relIndex, "ID", _relIndex, "ID");
             }
         }
         Integer ret;
         final String tableName = attr.getLink().getMainTable().getSqlTable();
         final String column = attr.getSqlColNames().get(0);
         ret = _oneSelect.getTableIndex(tableName, column, relIndex, null);
         if (ret == null) {
             ret = _oneSelect.getNewTableIndex(tableName, column, relIndex, null);
             _select.leftJoin(tableName, ret, "ID", relIndex, column);
         }
         _select.column(ret, "ID");
         this.idColumnIndex = _select.getColumns().size();
         // select the type column if it has one
         if (attr.getLink().getMainTable().getSqlColType() != null) {
             _select.column(ret, attr.getLink().getMainTable().getSqlColType());
             this.typeColumnIndex = _select.getColumns().size();
         }
         return ret;
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public Type getType()
     {
         final Attribute attr = this.type.getAttribute(this.attrName);
         if (attr == null) {
             LinkToSelectPart.LOG.error("Could not find an Attribute with name '{}' for type:{}", this.attrName,
                             this.type);
         }
         Type ret = null;
         try {
             ret = attr.getLink();
             if (ret == null) {
                 LinkToSelectPart.LOG.error("No link for Attribute '{}'", attr);
             }
         } catch (final CacheReloadException e) {
             LinkToSelectPart.LOG.error("Could not get Link for Attribute '{}'", attr);
         }
         return ret;
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public void addObject(final Object[] _row)
         throws SQLException
     {
         this.idList.add((Long) _row[this.idColumnIndex - 1]);
         if (this.typeColumnIndex > -1) {
             this.typeIdList.add((Long) _row[this.typeColumnIndex - 1]);
         }
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public Object getObject()
     {
         return this.idList;
     }
 
     /**
      * {@inheritDoc}
      */
     @Override
     public void next()
         throws EFapsException
     {
         if (this.typeIdIterator == null) {
             this.typeIdIterator = this.typeIdList.iterator();
         }
         if (this.idIterator == null) {
             this.idIterator = this.idList.iterator();
         }
         if (this.idIterator.hasNext()) {
             final Long idTmp = this.idIterator.next();
             if (idTmp == null) {
                 this.currentInstance = Instance.get("");
             } else {
                 if (this.typeIdList.isEmpty()) {
                     this.currentInstance = Instance.get(this.type.getAttribute(this.attrName).getLink(), idTmp);
                 } else {
                     final Long typeIdTmp = this.typeIdIterator.next();
                     if (typeIdTmp != null) {
                         this.currentInstance = Instance.get(Type.get(typeIdTmp), idTmp);
                     }
                 }
             }
         }
     }
 
     /**
      * Getter method for the instance variable {@link #currentInstance}.
      *
      * @return value of instance variable {@link #currentInstance}
      */
     public Instance getCurrentInstance()
     {
         return this.currentInstance;
     }
 }