/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2020, by Object Refinery Limited and Contributors.
 *
 * Project Info:  http://www.jfree.org/jfreechart/index.html
 *
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 *
 * This library 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.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
 * USA.
 *
 * [Oracle and Java are registered trademarks of Oracle and/or its affiliates. 
 * Other names may be trademarks of their respective owners.]
 *
 * ------------------------
 * StackedAreaRenderer.java
 * ------------------------
 * (C) Copyright 2002-2016, by Dan Rivett (d.rivett@ukonline.co.uk) and
 *                          Contributors.
 *
 * Original Author:  Dan Rivett (adapted from AreaRenderer);
 * Contributor(s):   Jon Iles;
 *                   David Gilbert (for Object Refinery Limited);
 *                   Christian W. Zuckschwerdt;
 *                   Peter Kolb (patch 2511330);
 */

package org.jfree.chart.renderer.category;

import java.awt.Graphics2D;
import java.awt.Paint;
import java.awt.Shape;
import java.awt.geom.GeneralPath;
import java.awt.geom.Rectangle2D;
import java.io.Serializable;

import org.jfree.chart.axis.CategoryAxis;
import org.jfree.chart.axis.ValueAxis;
import org.jfree.chart.entity.EntityCollection;
import org.jfree.chart.event.RendererChangeEvent;
import org.jfree.chart.plot.CategoryPlot;
import org.jfree.chart.ui.RectangleEdge;
import org.jfree.chart.util.PublicCloneable;
import org.jfree.data.DataUtils;
import org.jfree.data.Range;
import org.jfree.data.category.CategoryDataset;
import org.jfree.data.general.DatasetUtils;

/**
 * A renderer that draws stacked area charts for a {@link CategoryPlot}.
 * The example shown here is generated by the
 * {@code StackedAreaChartDemo1.java} program included in the
 * JFreeChart Demo Collection:
 * <br><br>
 * <img src="doc-files/StackedAreaRendererSample.png"
 * alt="StackedAreaRendererSample.png">
 */
public class StackedAreaRenderer extends AreaRenderer
        implements Cloneable, PublicCloneable, Serializable {

    /** For serialization. */
    private static final long serialVersionUID = -3595635038460823663L;

    /** A flag that controls whether the areas display values or percentages. */
    private boolean renderAsPercentages;

    /**
     * Creates a new renderer.
     */
    public StackedAreaRenderer() {
        this(false);
    }

    /**
     * Creates a new renderer.
     *
     * @param renderAsPercentages  a flag that controls whether the data values
     *                             are rendered as percentages.
     */
    public StackedAreaRenderer(boolean renderAsPercentages) {
        super();
        this.renderAsPercentages = renderAsPercentages;
    }

    /**
     * Returns {@code true} if the renderer displays each item value as
     * a percentage (so that the stacked areas add to 100%), and
     * {@code false} otherwise.
     *
     * @return A boolean.
     *
     * @since 1.0.3
     */
    public boolean getRenderAsPercentages() {
        return this.renderAsPercentages;
    }

    /**
     * Sets the flag that controls whether the renderer displays each item
     * value as a percentage (so that the stacked areas add to 100%), and sends
     * a {@link RendererChangeEvent} to all registered listeners.
     *
     * @param asPercentages  the flag.
     *
     * @since 1.0.3
     */
    public void setRenderAsPercentages(boolean asPercentages) {
        this.renderAsPercentages = asPercentages;
        fireChangeEvent();
    }

    /**
     * Returns the number of passes ({@code 2}) required by this renderer.
     * The first pass is used to draw the areas, the second pass is used to
     * draw the item labels (if visible).
     *
     * @return The number of passes required by the renderer.
     */
    @Override
    public int getPassCount() {
        return 2;
    }

    /**
     * Returns the range of values the renderer requires to display all the
     * items from the specified dataset.
     *
     * @param dataset  the dataset ({@code null} not permitted).
     *
     * @return The range (or {@code null} if the dataset is empty).
     */
    @Override
    public Range findRangeBounds(CategoryDataset dataset) {
        if (dataset == null) {
            return null;
        }
        if (this.renderAsPercentages) {
            return new Range(0.0, 1.0);
        }
        else {
            return DatasetUtils.findStackedRangeBounds(dataset);
        }
    }

    /**
     * Draw a single data item.
     *
     * @param g2  the graphics device.
     * @param state  the renderer state.
     * @param dataArea  the data plot area.
     * @param plot  the plot.
     * @param domainAxis  the domain axis.
     * @param rangeAxis  the range axis.
     * @param dataset  the data.
     * @param row  the row index (zero-based).
     * @param column  the column index (zero-based).
     * @param pass  the pass index.
     */
    @Override
    public void drawItem(Graphics2D g2, CategoryItemRendererState state,
            Rectangle2D dataArea, CategoryPlot plot, CategoryAxis domainAxis,
            ValueAxis rangeAxis, CategoryDataset dataset, int row, int column,
            int pass) {

        if (!isSeriesVisible(row)) {
            return;
        }
        
        // setup for collecting optional entity info...
        Shape entityArea;
        EntityCollection entities = state.getEntityCollection();

        double y1 = 0.0;
        Number n = dataset.getValue(row, column);
        if (n != null) {
            y1 = n.doubleValue();
            if (this.renderAsPercentages) {
                double total = DataUtils.calculateColumnTotal(dataset,
                        column, state.getVisibleSeriesArray());
                y1 = y1 / total;
            }
        }
        double[] stack1 = getStackValues(dataset, row, column,
                state.getVisibleSeriesArray());


        // leave the y values (y1, y0) untranslated as it is going to be be
        // stacked up later by previous series values, after this it will be
        // translated.
        double xx1 = domainAxis.getCategoryMiddle(column, getColumnCount(),
                dataArea, plot.getDomainAxisEdge());


        // get the previous point and the next point so we can calculate a
        // "hot spot" for the area (used by the chart entity)...
        double y0 = 0.0;
        n = dataset.getValue(row, Math.max(column - 1, 0));
        if (n != null) {
            y0 = n.doubleValue();
            if (this.renderAsPercentages) {
                double total = DataUtils.calculateColumnTotal(dataset,
                        Math.max(column - 1, 0), state.getVisibleSeriesArray());
                y0 = y0 / total;
            }
        }
        double[] stack0 = getStackValues(dataset, row, Math.max(column - 1, 0),
                state.getVisibleSeriesArray());

        // FIXME: calculate xx0
        double xx0 = domainAxis.getCategoryStart(column, getColumnCount(),
                dataArea, plot.getDomainAxisEdge());

        int itemCount = dataset.getColumnCount();
        double y2 = 0.0;
        n = dataset.getValue(row, Math.min(column + 1, itemCount - 1));
        if (n != null) {
            y2 = n.doubleValue();
            if (this.renderAsPercentages) {
                double total = DataUtils.calculateColumnTotal(dataset,
                        Math.min(column + 1, itemCount - 1),
                        state.getVisibleSeriesArray());
                y2 = y2 / total;
            }
        }
        double[] stack2 = getStackValues(dataset, row, Math.min(column + 1,
                itemCount - 1), state.getVisibleSeriesArray());

        double xx2 = domainAxis.getCategoryEnd(column, getColumnCount(),
                dataArea, plot.getDomainAxisEdge());

        // FIXME: calculate xxLeft and xxRight
        double xxLeft = xx0;
        double xxRight = xx2;

        double[] stackLeft = averageStackValues(stack0, stack1);
        double[] stackRight = averageStackValues(stack1, stack2);
        double[] adjStackLeft = adjustedStackValues(stack0, stack1);
        double[] adjStackRight = adjustedStackValues(stack1, stack2);

        float transY1;

        RectangleEdge edge1 = plot.getRangeAxisEdge();

        GeneralPath left = new GeneralPath();
        GeneralPath right = new GeneralPath();
        if (y1 >= 0.0) {  // handle positive value
            transY1 = (float) rangeAxis.valueToJava2D(y1 + stack1[1], dataArea,
                    edge1);
            float transStack1 = (float) rangeAxis.valueToJava2D(stack1[1],
                    dataArea, edge1);
            float transStackLeft = (float) rangeAxis.valueToJava2D(
                    adjStackLeft[1], dataArea, edge1);

            // LEFT POLYGON
            if (y0 >= 0.0) {
                double yleft = (y0 + y1) / 2.0 + stackLeft[1];
                float transYLeft
                    = (float) rangeAxis.valueToJava2D(yleft, dataArea, edge1);
                left.moveTo((float) xx1, transY1);
                left.lineTo((float) xx1, transStack1);
                left.lineTo((float) xxLeft, transStackLeft);
                left.lineTo((float) xxLeft, transYLeft);
                left.closePath();
            }
            else {
                left.moveTo((float) xx1, transStack1);
                left.lineTo((float) xx1, transY1);
                left.lineTo((float) xxLeft, transStackLeft);
                left.closePath();
            }

            float transStackRight = (float) rangeAxis.valueToJava2D(
                    adjStackRight[1], dataArea, edge1);
            // RIGHT POLYGON
            if (y2 >= 0.0) {
                double yright = (y1 + y2) / 2.0 + stackRight[1];
                float transYRight
                    = (float) rangeAxis.valueToJava2D(yright, dataArea, edge1);
                right.moveTo((float) xx1, transStack1);
                right.lineTo((float) xx1, transY1);
                right.lineTo((float) xxRight, transYRight);
                right.lineTo((float) xxRight, transStackRight);
                right.closePath();
            }
            else {
                right.moveTo((float) xx1, transStack1);
                right.lineTo((float) xx1, transY1);
                right.lineTo((float) xxRight, transStackRight);
                right.closePath();
            }
        }
        else {  // handle negative value
            transY1 = (float) rangeAxis.valueToJava2D(y1 + stack1[0], dataArea,
                    edge1);
            float transStack1 = (float) rangeAxis.valueToJava2D(stack1[0],
                    dataArea, edge1);
            float transStackLeft = (float) rangeAxis.valueToJava2D(
                    adjStackLeft[0], dataArea, edge1);

            // LEFT POLYGON
            if (y0 >= 0.0) {
                left.moveTo((float) xx1, transStack1);
                left.lineTo((float) xx1, transY1);
                left.lineTo((float) xxLeft, transStackLeft);
                left.clone();
            }
            else {
                double yleft = (y0 + y1) / 2.0 + stackLeft[0];
                float transYLeft = (float) rangeAxis.valueToJava2D(yleft,
                        dataArea, edge1);
                left.moveTo((float) xx1, transY1);
                left.lineTo((float) xx1, transStack1);
                left.lineTo((float) xxLeft, transStackLeft);
                left.lineTo((float) xxLeft, transYLeft);
                left.closePath();
            }
            float transStackRight = (float) rangeAxis.valueToJava2D(
                    adjStackRight[0], dataArea, edge1);

            // RIGHT POLYGON
            if (y2 >= 0.0) {
                right.moveTo((float) xx1, transStack1);
                right.lineTo((float) xx1, transY1);
                right.lineTo((float) xxRight, transStackRight);
                right.closePath();
            }
            else {
                double yright = (y1 + y2) / 2.0 + stackRight[0];
                float transYRight = (float) rangeAxis.valueToJava2D(yright,
                        dataArea, edge1);
                right.moveTo((float) xx1, transStack1);
                right.lineTo((float) xx1, transY1);
                right.lineTo((float) xxRight, transYRight);
                right.lineTo((float) xxRight, transStackRight);
                right.closePath();
            }
        }

        if (pass == 0) {
            Paint itemPaint = getItemPaint(row, column);
            g2.setPaint(itemPaint);
            g2.fill(left);
            g2.fill(right);

            // add an entity for the item...
            if (entities != null) {
                GeneralPath gp = new GeneralPath(left);
                gp.append(right, false);
                entityArea = gp;
                addItemEntity(entities, dataset, row, column, entityArea);
            }
        }
        else if (pass == 1) {
            drawItemLabel(g2, plot.getOrientation(), dataset, row, column,
                    xx1, transY1, y1 < 0.0);
        }

    }

    /**
     * Calculates the stacked values (one positive and one negative) of all
     * series up to, but not including, {@code series} for the specified
     * item. It returns [0.0, 0.0] if {@code series} is the first series.
     *
     * @param dataset  the dataset ({@code null} not permitted).
     * @param series  the series index.
     * @param index  the item index.
     * @param validRows  the valid rows.
     *
     * @return An array containing the cumulative negative and positive values
     *     for all series values up to but excluding {@code series}
     *     for {@code index}.
     */
    protected double[] getStackValues(CategoryDataset dataset,
            int series, int index, int[] validRows) {
        double[] result = new double[2];
        double total = 0.0;
        if (this.renderAsPercentages) {
            total = DataUtils.calculateColumnTotal(dataset, index, 
                    validRows);
        }
        for (int i = 0; i < series; i++) {
            if (isSeriesVisible(i)) {
                double v = 0.0;
                Number n = dataset.getValue(i, index);
                if (n != null) {
                    v = n.doubleValue();
                    if (this.renderAsPercentages) {
                        v = v / total;
                    }
                }
                if (!Double.isNaN(v)) {
                    if (v >= 0.0) {
                        result[1] += v;
                    }
                    else {
                        result[0] += v;
                    }
                }
            }
        }
        return result;
    }

    /**
     * Returns a pair of "stack" values calculated as the mean of the two
     * specified stack value pairs.
     *
     * @param stack1  the first stack pair.
     * @param stack2  the second stack pair.
     *
     * @return A pair of average stack values.
     */
    private double[] averageStackValues(double[] stack1, double[] stack2) {
        double[] result = new double[2];
        result[0] = (stack1[0] + stack2[0]) / 2.0;
        result[1] = (stack1[1] + stack2[1]) / 2.0;
        return result;
    }

    /**
     * Calculates adjusted stack values from the supplied values.  The value is
     * the mean of the supplied values, unless either of the supplied values
     * is zero, in which case the adjusted value is zero also.
     *
     * @param stack1  the first stack pair.
     * @param stack2  the second stack pair.
     *
     * @return A pair of average stack values.
     */
    private double[] adjustedStackValues(double[] stack1, double[] stack2) {
        double[] result = new double[2];
        if (stack1[0] == 0.0 || stack2[0] == 0.0) {
            result[0] = 0.0;
        }
        else {
            result[0] = (stack1[0] + stack2[0]) / 2.0;
        }
        if (stack1[1] == 0.0 || stack2[1] == 0.0) {
            result[1] = 0.0;
        }
        else {
            result[1] = (stack1[1] + stack2[1]) / 2.0;
        }
        return result;
    }

    /**
     * Checks this instance for equality with an arbitrary object.
     *
     * @param obj  the object ({@code null} not permitted).
     *
     * @return A boolean.
     */
    @Override
    public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        }
        if (!(obj instanceof StackedAreaRenderer)) {
            return false;
        }
        StackedAreaRenderer that = (StackedAreaRenderer) obj;
        if (this.renderAsPercentages != that.renderAsPercentages) {
            return false;
        }
        return super.equals(obj);
    }

}