/**

 * 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

 *

 * 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;

		}

	}

}