/* ===========================================================
 * JFreeChart : a free chart library for the Java(tm) platform
 * ===========================================================
 *
 * (C) Copyright 2000-2007, 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.  
 *
 * [Java is a trademark or registered trademark of Sun Microsystems, Inc. 
 * in the United States and other countries.]
 *
 * ---------------------------
 * ClusteredXYBarRenderer.java
 * ---------------------------
 * (C) Copyright 2003-2007, by Paolo Cova and Contributors.
 *
 * Original Author:  Paolo Cova;
 * Contributor(s):   David Gilbert (for Object Refinery Limited);
 *                   Christian W. Zuckschwerdt;
 *                   Matthias Rose;
 *
 * Changes
 * -------
 * 24-Jan-2003 : Version 1, contributed by Paolo Cova (DG);
 * 25-Mar-2003 : Implemented Serializable (DG);
 * 01-May-2003 : Modified drawItem() method signature (DG);
 * 30-Jul-2003 : Modified entity constructor (CZ);
 * 20-Aug-2003 : Implemented Cloneable and PublicCloneable (DG);
 * 16-Sep-2003 : Changed ChartRenderingInfo --> PlotRenderingInfo (DG);
 * 07-Oct-2003 : Added renderer state (DG);
 * 03-Nov-2003 : In draw method added state parameter and y==null value 
 *               handling (MR);
 * 25-Feb-2004 : Replaced CrosshairInfo with CrosshairState (DG);
 * 15-Jul-2004 : Switched getX() with getXValue() and getY() with 
 *               getYValue() (DG);
 * 01-Oct-2004 : Fixed bug where 'drawBarOutline' flag is ignored (DG);
 * 16-May-2005 : Fixed to used outline stroke for bar outlines.  Removed some 
 *               redundant code with the result that the renderer now respects 
 *               the 'base' setting from the super-class. Added an equals() 
 *               method (DG);
 * 19-May-2005 : Added minimal item label implementation - needs improving (DG);
 * ------------- JFREECHART 1.0.x ---------------------------------------------
 * 11-Dec-2006 : Added support for GradientPaint (DG);
 * 12-Jun-2007 : Added override to findDomainBounds() to handle cluster offset,
 *               fixed rendering to handle inverted axes, and simplified 
 *               entity generation code (DG);
 * 
 */

package org.jfree.chart.renderer.xy;

import java.awt.GradientPaint;
import java.awt.Graphics2D;
import java.awt.Paint;
import java.awt.geom.Rectangle2D;
import java.io.Serializable;

import org.jfree.chart.axis.ValueAxis;
import org.jfree.chart.entity.EntityCollection;
import org.jfree.chart.labels.XYItemLabelGenerator;
import org.jfree.chart.plot.CrosshairState;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.plot.PlotRenderingInfo;
import org.jfree.chart.plot.XYPlot;
import org.jfree.data.Range;
import org.jfree.data.xy.IntervalXYDataset;
import org.jfree.data.xy.XYDataset;
import org.jfree.ui.RectangleEdge;
import org.jfree.util.PublicCloneable;

/**
 * An extension of {@link XYBarRenderer} that displays bars for different
 * series values at the same x next to each other. The assumption here is
 * that for each x (time or else) there is a y value for each series. If
 * this is not the case, there will be spaces between bars for a given x.
 * <P>
 * This renderer does not include code to calculate the crosshair point for the
 * plot.
 */
public class ClusteredXYBarRenderer extends XYBarRenderer 
        implements Cloneable, PublicCloneable, Serializable {

    /** For serialization. */
    private static final long serialVersionUID = 5864462149177133147L;
    
    /** Determines whether bar center should be interval start. */
    private boolean centerBarAtStartValue;

    /**
     * Default constructor. Bar margin is set to 0.0.
     */
    public ClusteredXYBarRenderer() {
        this(0.0, false);
    }

    /**
     * Constructs a new XY clustered bar renderer.
     *
     * @param margin  the percentage amount to trim from the width of each bar.
     * @param centerBarAtStartValue  if true, bars will be centered on the 
     *         start of the time period.
     */
    public ClusteredXYBarRenderer(double margin, 
                                  boolean centerBarAtStartValue) {
        super(margin);
        this.centerBarAtStartValue = centerBarAtStartValue;
    }

    /**
     * Returns the x-value bounds for the specified dataset.
     * 
     * @param dataset  the dataset (<code>null</code> permitted).
     * 
     * @return The bounds (possibly <code>null</code>).
     */
    public Range findDomainBounds(XYDataset dataset) {
        if (dataset == null) {
            return null;
        }
        // need to handle cluster centering as a special case
        if (this.centerBarAtStartValue) {
            return findDomainBoundsWithOffset((IntervalXYDataset) dataset);
        }
        else {
            return super.findDomainBounds(dataset);
        }
    }
    
    /**
     * Iterates over the items in an {@link IntervalXYDataset} to find
     * the range of x-values including the interval OFFSET so that it centers
     * the interval around the start value. 
     *  
     * @param dataset  the dataset (<code>null</code> not permitted).
     *   
     * @return The range (possibly <code>null</code>).
     */
    protected Range findDomainBoundsWithOffset(IntervalXYDataset dataset) {
        if (dataset == null) {
            throw new IllegalArgumentException("Null 'dataset' argument.");   
        }
        double minimum = Double.POSITIVE_INFINITY;
        double maximum = Double.NEGATIVE_INFINITY;
        int seriesCount = dataset.getSeriesCount();
        double lvalue;
        double uvalue;
        for (int series = 0; series < seriesCount; series++) {
            int itemCount = dataset.getItemCount(series);
            for (int item = 0; item < itemCount; item++) {
                lvalue = dataset.getStartXValue(series, item);
                uvalue = dataset.getEndXValue(series, item);
                double offset = (uvalue - lvalue) / 2.0;
                lvalue = lvalue - offset;
                uvalue = uvalue - offset;
                minimum = Math.min(minimum, lvalue);
                maximum = Math.max(maximum, uvalue);
            }
        }

        if (minimum > maximum) {
            return null;
        }
        else {
            return new Range(minimum, maximum);
        }
    }

    /**
     * Draws the visual representation of a single data item. This method
     * is mostly copied from the superclass, the change is that in the
     * calculated space for a singe bar we draw bars for each series next to
     * each other. The width of each bar is the available width divided by
     * the number of series. Bars for each series are drawn in order left to
     * right.
     *
     * @param g2  the graphics device.
     * @param state  the renderer state.
     * @param dataArea  the area within which the plot is being drawn.
     * @param info  collects information about the drawing.
     * @param plot  the plot (can be used to obtain standard color 
     *              information etc).
     * @param domainAxis  the domain axis.
     * @param rangeAxis  the range axis.
     * @param dataset  the dataset.
     * @param series  the series index.
     * @param item  the item index.
     * @param crosshairState  crosshair information for the plot 
     *                        (<code>null</code> permitted).
     * @param pass  the pass index.
     */
    public void drawItem(Graphics2D g2,
                         XYItemRendererState state,
                         Rectangle2D dataArea,
                         PlotRenderingInfo info,
                         XYPlot plot, 
                         ValueAxis domainAxis, 
                         ValueAxis rangeAxis,
                         XYDataset dataset, int series, int item,
                         CrosshairState crosshairState,
                         int pass) {

        IntervalXYDataset intervalDataset = (IntervalXYDataset) dataset;

        double y0;
        double y1;
        if (getUseYInterval()) {
            y0 = intervalDataset.getStartYValue(series, item);
            y1 = intervalDataset.getEndYValue(series, item);
        }
        else {
            y0 = getBase();
            y1 = intervalDataset.getYValue(series, item);
        }
        if (Double.isNaN(y0) || Double.isNaN(y1)) {
            return;
        }

        double yy0 = rangeAxis.valueToJava2D(y0, dataArea, 
                plot.getRangeAxisEdge());
        double yy1 = rangeAxis.valueToJava2D(y1, dataArea, 
                plot.getRangeAxisEdge());

        RectangleEdge xAxisLocation = plot.getDomainAxisEdge();
        double x0 = intervalDataset.getStartXValue(series, item);
        double xx0 = domainAxis.valueToJava2D(x0, dataArea, xAxisLocation);
        
        double x1 = intervalDataset.getEndXValue(series, item);
        double xx1 = domainAxis.valueToJava2D(x1, dataArea, xAxisLocation);
        
        double intervalW = xx1 - xx0;  // this may be negative
        double baseX = xx0;
        if (this.centerBarAtStartValue) {
            baseX = baseX - intervalW / 2.0;
        }
        double m = getMargin();
        if (m > 0.0) {
            double cut = intervalW * getMargin();
            intervalW = intervalW - cut;
            baseX = baseX + (cut / 2);
        }
        
        double intervalH = Math.abs(yy0 - yy1);  // we don't need the sign

        PlotOrientation orientation = plot.getOrientation();        

        int numSeries = dataset.getSeriesCount();
        double seriesBarWidth = intervalW / numSeries;  // may be negative

        Rectangle2D bar = null;
        if (orientation == PlotOrientation.HORIZONTAL) {
            double barY0 = baseX + (seriesBarWidth * series);
            double barY1 = barY0 + seriesBarWidth;
            double rx = Math.min(yy0, yy1);
            double rw = intervalH;
            double ry = Math.min(barY0, barY1);
            double rh = Math.abs(barY1 - barY0);
            bar = new Rectangle2D.Double(rx, ry, rw, rh);
        }
        else if (orientation == PlotOrientation.VERTICAL) {
            double barX0 = baseX + (seriesBarWidth * series);
            double barX1 = barX0 + seriesBarWidth;
            double rx = Math.min(barX0, barX1);
            double rw = Math.abs(barX1 - barX0);
            double ry = Math.min(yy0, yy1);;
            double rh = intervalH;
            bar = new Rectangle2D.Double(rx, ry, rw, rh);
        }
        Paint itemPaint = getItemPaint(series, item);
        if (getGradientPaintTransformer() 
                != null && itemPaint instanceof GradientPaint) {
            GradientPaint gp = (GradientPaint) itemPaint;
            itemPaint = getGradientPaintTransformer().transform(gp, bar);
        }
        g2.setPaint(itemPaint);

        g2.fill(bar);
        if (isDrawBarOutline() && Math.abs(seriesBarWidth) > 3) {
            g2.setStroke(getItemOutlineStroke(series, item));
            g2.setPaint(getItemOutlinePaint(series, item));
            g2.draw(bar);
        }

        if (isItemLabelVisible(series, item)) {
            XYItemLabelGenerator generator = getItemLabelGenerator(series, 
                    item);
            drawItemLabel(g2, dataset, series, item, plot, generator, bar, 
                    y1 < 0.0);
        }

        // add an entity for the item...
        if (info != null) {
            EntityCollection entities = info.getOwner().getEntityCollection();
            if (entities != null) {
                addEntity(entities, bar, dataset, series, item, 
                        bar.getCenterX(), bar.getCenterY());
            }
        }

    }

    /**
     * Tests this renderer for equality with an arbitrary object, returning
     * <code>true</code> if <code>obj</code> is a 
     * <code>ClusteredXYBarRenderer</code> with the same settings as this
     * renderer, and <code>false</code> otherwise.
     * 
     * @param obj  the object (<code>null</code> permitted).
     * 
     * @return A boolean.
     */
    public boolean equals(Object obj) {
        if (obj == this) {
            return true;
        }
        if (!(obj instanceof ClusteredXYBarRenderer)) {
            return false;
        }
        ClusteredXYBarRenderer that = (ClusteredXYBarRenderer) obj;
        if (this.centerBarAtStartValue != that.centerBarAtStartValue) {
            return false;
        }
        return super.equals(obj);
    }
    
    /**
     * Returns a clone of the renderer.
     * 
     * @return A clone.
     * 
     * @throws CloneNotSupportedException  if the renderer cannot be cloned.
     */
    public Object clone() throws CloneNotSupportedException {
        return super.clone();
    }
    
}