/*!
 * 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.engine.classic.core.function.formula;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.pentaho.reporting.engine.classic.core.DataFactory;
import org.pentaho.reporting.engine.classic.core.function.ReportFormulaContext;
import org.pentaho.reporting.engine.classic.core.states.QueryDataRowWrapper;
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.coretypes.AnyType;

import javax.swing.table.TableModel;

public class SingleValueQueryFunction implements Function {
  private static final Log logger = LogFactory.getLog( SingleValueQueryFunction.class );

  public SingleValueQueryFunction() {
  }

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

  public TypeValuePair evaluate( final FormulaContext context, final ParameterCallback parameters )
    throws EvaluationException {
    if ( context instanceof ReportFormulaContext == false ) {
      throw EvaluationException.getInstance( LibFormulaErrorValue.ERROR_INVALID_FUNCTION_VALUE );
    }

    final ReportFormulaContext rfc = (ReportFormulaContext) context;

    final int parameterCount = parameters.getParameterCount();
    if ( parameterCount < 1 ) {
      throw EvaluationException.getInstance( LibFormulaErrorValue.ERROR_ARGUMENTS_VALUE );
    }

    final Type textType = parameters.getType( 0 );
    final Object textValue = parameters.getValue( 0 );
    final String query = context.getTypeRegistry().convertToText( textType, textValue );

    if ( query == null ) {
      throw EvaluationException.getInstance( LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE );
    }

    final String resultColumn;
    if ( parameterCount > 1 ) {
      final Type encodingType = parameters.getType( 1 );
      final Object encodingValue = parameters.getValue( 1 );
      resultColumn = context.getTypeRegistry().convertToText( encodingType, encodingValue );
      if ( resultColumn == null ) {
        throw EvaluationException.getInstance( LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE );
      }
    } else {
      resultColumn = null;
    }

    final int queryTimeOut;
    if ( parameterCount > 2 ) {
      final Type encodingType = parameters.getType( 2 );
      final Object encodingValue = parameters.getValue( 2 );
      final Number number = context.getTypeRegistry().convertToNumber( encodingType, encodingValue );
      if ( number == null ) {
        throw EvaluationException.getInstance( LibFormulaErrorValue.ERROR_INVALID_ARGUMENT_VALUE );
      }
      queryTimeOut = number.intValue();
    } else {
      queryTimeOut = 0;
    }

    final Object result = performQuery( rfc, query, resultColumn, queryTimeOut );
    return new TypeValuePair( AnyType.TYPE, result );
  }

  private Object performQuery( final ReportFormulaContext context, final String query, final String column,
      final int queryTimeout ) throws EvaluationException {

    try {
      final DataFactory dataFactory = context.getRuntime().getDataFactory();
      final TableModel tableModel =
          dataFactory.queryData( query, new QueryDataRowWrapper( context.getDataRow(), 1, queryTimeout ) );
      if ( tableModel == null ) {
        return null;
      }

      final int columnCount = tableModel.getColumnCount();
      if ( tableModel.getRowCount() == 0 || columnCount == 0 ) {
        return null;
      }
      if ( column == null ) {
        return tableModel.getValueAt( 0, 0 );
      }
      for ( int i = 0; i < columnCount; i++ ) {
        if ( column.equals( tableModel.getColumnName( i ) ) ) {
          return tableModel.getValueAt( 0, i );
        }
      }
      throw EvaluationException.getInstance( LibFormulaErrorValue.ERROR_UNEXPECTED_VALUE );
    } catch ( EvaluationException e ) {
      throw e;
    } catch ( Exception e ) {
      SingleValueQueryFunction.logger.warn( "SingleValueQueryFunction: Failed to perform query", e );
      throw EvaluationException.getInstance( LibFormulaErrorValue.ERROR_UNEXPECTED_VALUE );
    }
  }
}