/*!
* 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.plugin.jfreereport.reportcharts;

import org.jfree.chart.labels.CategoryToolTipGenerator;
import org.jfree.data.category.CategoryDataset;
import org.pentaho.reporting.engine.classic.core.StaticDataRow;
import org.pentaho.reporting.engine.classic.core.function.ExpressionRuntime;
import org.pentaho.reporting.engine.classic.core.function.FormulaExpression;
import org.pentaho.reporting.engine.classic.core.function.GenericExpressionRuntime;
import org.pentaho.reporting.engine.classic.core.function.WrapperExpressionRuntime;
import org.pentaho.reporting.engine.classic.core.util.IntegerCache;

public class FormulaCategoryTooltipGenerator implements CategoryToolTipGenerator {
  private FormulaExpression formulaExpression;
  private GenericExpressionRuntime runtime;
  private static final String[] ADDITIONAL_COLUMN_KEYS = new String[] {
    "chart::series-key", "chart::category-key",
    "chart::series-index", "chart::category-index",
    "chart::series-keys", "chart::category-keys",
    "chart::value"
  };

  public FormulaCategoryTooltipGenerator( final ExpressionRuntime runtime,
                                          final String formula ) {
    this.runtime = new GenericExpressionRuntime( runtime );
    this.formulaExpression = new FormulaExpression();
    this.formulaExpression.setFormula( formula );
  }

  /**
   * Generates the tool tip text for an item in a dataset.  Note: in the current dataset implementation, each row is a
   * series, and each column contains values for a particular category.
   *
   * @param dataset  the dataset (<code>null</code> not permitted).
   * @param series   the series (zero-based index).
   * @param category the category.
   * @return The tooltip text (possibly <code>null</code>).
   */
  public String generateToolTip( final CategoryDataset dataset, final int series, final int category ) {
    try {
      final Comparable seriesKey = dataset.getRowKey( series );
      final Comparable categoryKey = dataset.getColumnKey( category );
      final Object[] categoryKeys = dataset.getColumnKeys().toArray();
      final Object[] seriesKeys = dataset.getRowKeys().toArray();
      final Object value = dataset.getValue( series, category );

      final Object[] values = new Object[] {
        seriesKey, categoryKey,
        IntegerCache.getInteger( series ), IntegerCache.getInteger( category ),
        seriesKeys, categoryKeys,
        value
      };
      final StaticDataRow datarow = new StaticDataRow( ADDITIONAL_COLUMN_KEYS, values );
      final WrapperExpressionRuntime wrapper = new WrapperExpressionRuntime( datarow, runtime );
      formulaExpression.setRuntime( wrapper );
      final Object o = formulaExpression.getValue();
      if ( o == null ) {
        return null;
      }
      return String.valueOf( o );
    } finally {
      formulaExpression.setRuntime( null );
    }
  }
}