/*
 * Copyright 2010-2012 Luca Garulli (l.garulli--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.core.sql.functions.math;

import com.orientechnologies.orient.core.command.OCommandContext;
import com.orientechnologies.orient.core.db.record.OIdentifiable;
import com.orientechnologies.orient.core.record.impl.ODocument;
import com.orientechnologies.orient.core.sql.filter.OSQLPredicate;

import java.util.List;

/**
 * Evaluates a complex expression.
 * 
 * @author Luca Garulli (l.garulli--at--orientechnologies.com)
 * 
 */
public class OSQLFunctionEval extends OSQLFunctionMathAbstract {
  public static final String NAME = "eval";

  private OSQLPredicate      predicate;

  public OSQLFunctionEval() {
    super(NAME, 1, 1);
  }

  public Object execute(Object iThis, final OIdentifiable iRecord, final Object iCurrentResult, final Object[] iParams,
      OCommandContext iContext) {
    if (predicate == null)
      predicate = new OSQLPredicate((String) iParams[0].toString());

    try {
      return predicate.evaluate(iRecord != null ? iRecord.getRecord() : null, (ODocument) iCurrentResult, iContext);
    } catch (ArithmeticException e) {
      // DIVISION BY 0
      return 0;
    } catch (Exception e) {
      return null;
    }
  }

  public boolean aggregateResults() {
    return false;
  }

  public String getSyntax() {
    return "eval(<expression>)";
  }

  @Override
  public Object getResult() {
    return null;
  }

  @Override
  public Object mergeDistributedResult(List<Object> resultsToMerge) {
    return null;
  }
}
