/*
 *
 *  * Copyright 2010-2014 Orient Technologies LTD (info(at)orientechnologies.com)
 *  *
 *  * 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.
 *
 */

package com.orientechnologies.orient.etl.transformer;

import com.orientechnologies.orient.core.command.OCommandContext;
import com.orientechnologies.orient.core.db.record.OIdentifiable;
import com.orientechnologies.orient.core.id.ORID;
import com.orientechnologies.orient.core.index.OIndex;
import com.orientechnologies.orient.core.metadata.schema.OType;
import com.orientechnologies.orient.core.record.impl.ODocument;
import com.orientechnologies.orient.core.sql.query.OSQLQuery;
import com.orientechnologies.orient.core.sql.query.OSQLSynchQuery;
import com.orientechnologies.orient.etl.OETLProcessor;

import java.util.ArrayList;
import java.util.Collection;
import java.util.List;

/**
 * Merges two records. Useful when a record needs to be updated rather than created.
 */
public abstract class OAbstractLookupTransformer extends OAbstractTransformer {
  protected String             joinFieldName;
  protected Object             joinValue;
  protected String             lookup;
  protected ACTION             unresolvedLinkAction = ACTION.NOTHING;
  private OSQLQuery<ODocument> sqlQuery;
  private OIndex<?>            index;

  protected enum ACTION {
    NOTHING, WARNING, ERROR, HALT, SKIP, CREATE
  }

  @Override
  public void configure(final OETLProcessor iProcessor, final ODocument iConfiguration, OCommandContext iContext) {
    super.configure(iProcessor, iConfiguration, iContext);

    joinFieldName = iConfiguration.field("joinFieldName");

    if (iConfiguration.containsField("joinValue"))
      joinValue = iConfiguration.field("joinValue");

    if (iConfiguration.containsField("lookup"))
      lookup = iConfiguration.field("lookup");

    if (iConfiguration.containsField("unresolvedLinkAction"))
      unresolvedLinkAction = ACTION.valueOf(iConfiguration.field("unresolvedLinkAction").toString().toUpperCase());
  }

  protected Object lookup(Object joinValue, final boolean iReturnRIDS) {
    Object result = null;

    if (joinValue != null) {
      if (sqlQuery == null && index == null) {
        // ONLY THE FIRST TIME
        if (lookup.toUpperCase().startsWith("SELECT"))
          sqlQuery = new OSQLSynchQuery<ODocument>(lookup);
        else {
          index = pipeline.getDocumentDatabase().getMetadata().getIndexManager().getIndex(lookup);
          if (index == null) {
            log(OETLProcessor.LOG_LEVELS.DEBUG, "WARNING: index %s not found. Lookups could be really slow", lookup);
            final String[] parts = lookup.split("\\.");
            sqlQuery = new OSQLSynchQuery<ODocument>("SELECT FROM " + parts[0] + " WHERE " + parts[1] + " = ?");
          }
        }
      }

      if (index != null) {
        final OType idxFieldType = index.getDefinition().getTypes()[0];
        joinValue = OType.convert(joinValue, idxFieldType.getDefaultJavaType());
        result = index.get(joinValue);
      } else {
        if (sqlQuery instanceof OSQLSynchQuery)
          ((OSQLSynchQuery) sqlQuery).resetPagination();

        result = pipeline.getDocumentDatabase().query(sqlQuery, joinValue);
      }

      if (result != null && result instanceof Collection) {
        final Collection coll = (Collection) result;

        if (!coll.isEmpty()) {
          if (iReturnRIDS) {
            // CONVERT COLLECTION OF RECORDS IN RIDS
            final List<ORID> resultRIDs = new ArrayList<ORID>(coll.size());
            for (Object o : coll) {
              if (o instanceof OIdentifiable)
                resultRIDs.add(((OIdentifiable) o).getIdentity());
            }
            result = resultRIDs;
          }
        } else
          result = null;
      } else if (result instanceof OIdentifiable) {
        if (iReturnRIDS)
          result = ((OIdentifiable) result).getIdentity();
        else
          result = ((OIdentifiable) result).getRecord();
      }
    }

    return result;
  }
}