/**

  * SQL-DK

  * Copyright © 2015 František Kučera (frantovo.cz)

  *

  * This program is free software: you can redistribute it and/or modify

  * it under the terms of the GNU General Public License as published by

  * the Free Software Foundation, version 3 of the License.

  *

  * 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 General Public License for more details.

  *

  * You should have received a copy of the GNU General Public License

  * along with this program. If not, see <http://www.gnu.org/licenses/>.

  */

 package info.globalcode.sql.dk.formatting;

 import info.globalcode.sql.dk.Functions;

 import info.globalcode.sql.dk.configuration.PropertyDeclaration;

 import info.globalcode.sql.dk.logging.LoggerProducer;

 import java.math.BigDecimal;

 import java.math.MathContext;

 import java.math.RoundingMode;

 import java.util.List;

 import java.util.logging.Level;

 import java.util.logging.Logger;

 /**

  * TODO: min/max values – range for case that no value is 100 %

  *

  * TODO: multiple barcharts in same table (last column is still default) + multiple resultsets

  *

  * TODO: negative values - bar starting from the middle, not always from the left

  *

  * @author Ing. František Kučera (frantovo.cz)

  */

 @PropertyDeclaration(name = BarChartFormatter.PROPERTY_PRECISION, type = Integer.class, defaultValue = BarChartFormatter.PROPERTY_PRECISION_DEFAULT, description = "number of characters representing 100 % in the bar chart")

 public class BarChartFormatter extends TabularPrefetchingFormatter {

 	public static final String NAME = "barchart"; // bash-completion:formatter

 	public static final String PROPERTY_PRECISION = "precision";

 	protected static final String PROPERTY_PRECISION_DEFAULT = "100";

 	private static final MathContext mathContext = MathContext.DECIMAL128;

 	public static final Logger log = LoggerProducer.getLogger();

 	private final BigDecimal chartPrecision;

 	private final char chartFull;

 	private final char chartEmpty;

 	public BarChartFormatter(FormatterContext formatterContext) {

 		super(formatterContext);

 		chartPrecision = BigDecimal.valueOf(formatterContext.getProperties().getInteger(PROPERTY_PRECISION, Integer.parseInt(PROPERTY_PRECISION_DEFAULT)));

 		chartFull = isAsciiNostalgia() ? '#' : '█';

 		chartEmpty = isAsciiNostalgia() ? '~' : '░';

 		// TODO: consider using partial blocks for more precision: https://en.wikipedia.org/wiki/Block_Elements

 	}

 	@Override

 	protected void postprocessPrefetchedResultSet(ColumnsHeader currentHeader, List<Object[]> currentResultSet) {

 		super.postprocessPrefetchedResultSet(currentHeader, currentResultSet);

 		updateColumnWidth(currentHeader.getColumnCount(), chartPrecision.intValue());

 		BigDecimal maximum = BigDecimal.ZERO;

 		BigDecimal minimum = BigDecimal.ZERO;

 		int lastIndex = currentHeader.getColumnCount() - 1;

 		Object valueObject = null;

 		try {

 			for (Object[] row : currentResultSet) {

 				valueObject = row[lastIndex];

 				if (valueObject != null) {

 					BigDecimal value = new BigDecimal(valueObject.toString());

 					maximum = maximum.max(value);

 					minimum = minimum.min(value);

 				}

 			}

 			BigDecimal range = maximum.subtract(minimum);

 			for (Object[] row : currentResultSet) {

 				valueObject = row[lastIndex];

 				if (valueObject == null) {

 					row[lastIndex] = "";

 				} else {

 					BigDecimal value = new BigDecimal(valueObject.toString());

 					BigDecimal valueFromMinimum = value.subtract(minimum);

 					BigDecimal points = chartPrecision.divide(range, mathContext).multiply(valueFromMinimum, mathContext);

 					int pointsRounded = points.setScale(0, RoundingMode.HALF_UP).intValue();

 					row[lastIndex] = Functions.repeat(chartFull, pointsRounded) + Functions.repeat(chartEmpty, chartPrecision.intValue() - pointsRounded);

 				}

 			}

 		} catch (NumberFormatException e) {

 			// https://en.wiktionary.org/wiki/parsable

 			log.log(Level.SEVERE, "Last column must be number or an object with toString() value parsable to a number. But was „{0}“", valueObject);

 			// FIXME: throw FormatterException

 			throw e;

 		}

 	}

 }