/*
* 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) 2006 - 2013 Pentaho Corporation and Contributors.  All rights reserved.
*/

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

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.LValue;
import org.pentaho.reporting.libraries.formula.lvalues.TypeValuePair;
import org.pentaho.reporting.libraries.formula.typing.Sequence;
import org.pentaho.reporting.libraries.formula.typing.Type;
import org.pentaho.reporting.libraries.formula.typing.TypeRegistry;
import org.pentaho.reporting.libraries.formula.typing.coretypes.TextType;

/**
 * This function returns the given value as text.
 *
 * @author Cedric Pronzato
 */
public class ConcatenateFunction implements Function {
  private static final long serialVersionUID = 3505313019941429911L;

  public ConcatenateFunction() {
  }

  public TypeValuePair evaluate( final FormulaContext context,
                                 final ParameterCallback parameters ) throws EvaluationException {
    final StringBuffer computedResult = new StringBuffer( 512 );
    final int parameterCount = parameters.getParameterCount();

    if ( parameterCount == 0 ) {
      throw EvaluationException.getInstance( LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE );
    }

    final TypeRegistry typeRegistry = context.getTypeRegistry();
    for ( int paramIdx = 0; paramIdx < parameterCount; paramIdx++ ) {
      final Type type = parameters.getType( paramIdx );
      final Object value = parameters.getValue( paramIdx );
      final Sequence sequence = typeRegistry.convertToSequence( type, value );

      while ( sequence.hasNext() ) {
        final LValue lValue = sequence.nextRawValue();
        final TypeValuePair pair = lValue.evaluate();
        final Type type1 = pair.getType();
        final Object o = pair.getValue();
        final String str = typeRegistry.convertToText( type1, o );
        computedResult.append( str );
      }
    }

    return new TypeValuePair( TextType.TYPE, computedResult.toString() );
  }

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

}