/*!
* This program is free software; you can redistribute it and/or modify it under the
* terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software
* Foundation.
*
* You should have received a copy of the GNU Lesser General Public License along with this
* program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html
* or from the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* This program 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 Lesser General Public License for more details.
*
* Copyright (c) 2002-2013 Pentaho Corporation..  All rights reserved.
*/

package org.pentaho.reporting.libraries.formula.function.database;

import org.pentaho.reporting.libraries.formula.EvaluationException;
import org.pentaho.reporting.libraries.formula.FormulaContext;
import org.pentaho.reporting.libraries.formula.LibFormulaErrorValue;
import org.pentaho.reporting.libraries.formula.function.Function;
import org.pentaho.reporting.libraries.formula.function.ParameterCallback;
import org.pentaho.reporting.libraries.formula.lvalues.TypeValuePair;
import org.pentaho.reporting.libraries.formula.typing.Type;
import org.pentaho.reporting.libraries.formula.typing.TypeRegistry;
import org.pentaho.reporting.libraries.formula.typing.coretypes.LogicalType;

import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * This function is similar to the LIKE function in SQL, and is needed for the inline ETL implementation of Pentaho
 * Metadata.
 *
 * @author Will Gorman (wgorman@pentaho.com)
 */
public class LikeFunction implements Function {
  private static final long serialVersionUID = 5834421661720115093L;

  private static final TypeValuePair RETURN_FALSE = new TypeValuePair( LogicalType.TYPE, Boolean.FALSE );
  private static final TypeValuePair RETURN_TRUE = new TypeValuePair( LogicalType.TYPE, Boolean.TRUE );

  public LikeFunction() {
  }

  public TypeValuePair evaluate( final FormulaContext context,
                                 final ParameterCallback parameters ) throws EvaluationException {
    final int parameterCount = parameters.getParameterCount();
    if ( parameterCount != 2 ) {
      throw EvaluationException.getInstance( LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE );
    }
    final TypeRegistry typeRegistry = context.getTypeRegistry();

    final Type textType1 = parameters.getType( 0 );
    final Object textValue1 = parameters.getValue( 0 );
    final Type patternType = parameters.getType( 1 );
    final Object patternValue = parameters.getValue( 1 );

    final String text = typeRegistry.convertToText( textType1, textValue1 );

    String regex = typeRegistry.convertToText( patternType, patternValue );

    // replace any * or % with .*
    regex = regex.replaceAll( "\\*", ".*" ).replaceAll( "%", ".*" );

    final Pattern p = Pattern.compile( regex );
    final Matcher m = p.matcher( text );

    return m.find() ? RETURN_TRUE : RETURN_FALSE;
  }

  public String getCanonicalName() {
    return "LIKE";
  }

}