package de.intevation.flys.exports;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Stroke;

import java.io.IOException;

import java.text.NumberFormat;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.TreeMap;
import java.util.List;
import java.util.Map;
import java.util.SortedMap;

import org.w3c.dom.Document;

import org.apache.log4j.Logger;

import org.jfree.chart.ChartFactory;
import org.jfree.chart.JFreeChart;
import org.jfree.chart.LegendItem;
import org.jfree.chart.LegendItemCollection;
import org.jfree.chart.annotations.XYTextAnnotation;
import org.jfree.chart.axis.AxisLocation;
import org.jfree.chart.axis.NumberAxis;
import org.jfree.chart.axis.ValueAxis;
import org.jfree.chart.plot.PlotOrientation;
import org.jfree.chart.plot.XYPlot;
import org.jfree.chart.renderer.xy.XYItemRenderer;
import org.jfree.chart.renderer.xy.XYLineAndShapeRenderer;
import org.jfree.data.Range;
import org.jfree.data.xy.XYSeries;
import org.jfree.data.xy.XYSeriesCollection;
import org.jfree.data.xy.XYDataset;

import org.jfree.ui.RectangleInsets;

import de.intevation.artifactdatabase.state.Facet;

import de.intevation.flys.exports.ChartExportHelper;
import de.intevation.flys.jfree.FLYSAnnotation;
import de.intevation.flys.jfree.StickyAxisAnnotation;

import de.intevation.flys.utils.ThemeAccess;

/**
 * An abstract base class for creating XY charts.
 *
 * With respect to datasets, ranges and axis, there are following requirements:
 * <ul>
 *   <li> First in, first drawn: "Early" datasets should be of lower Z-Oder
 *        than later ones (only works per-axis). </li>
 *   <li> Visible axis should initially show the range of all datasets that
 *        show data for this axis (even invisible ones). Motivation: Once
 *        a dataset (theme) has been activated, it should be on screen. </li>
 *   <li> There should always be a Y-Axis on the "left". </li>
 * </ul>
 *
 * @author <a href="mailto:ingo.weinzierl@intevation.de">Ingo Weinzierl</a>
 */
public abstract class XYChartGenerator extends ChartGenerator {

    private class AxisDataset {
        /** Symbolic integer, but also coding the priority (0 goes first). */
        protected int axisSymbol;
        /** List of assigned datasets (in order). */
        protected List<XYDataset> datasets;
        /** Range to use to include all given datasets. */
        protected Range range;

        /** Create AxisDataset. */
        public AxisDataset(int symb) {
            this.axisSymbol = symb;
            datasets        = new ArrayList<XYDataset>();
        }

        /** Merge (or create given range with range so far (if any). */
        private void mergeRanges(Range subRange) {
            if (range == null) {
                range = subRange;
                return;
            }
            range = Range.combine(range, subRange);
        }

        /** Add a dataset, include its range. */
        public void addDataset(XYSeries dataset) {
            this.datasets.add(new XYSeriesCollection(dataset));
            includeRange(dataset);
        }

        /** Adjust range to include given dataset. */
        public void includeRange(XYSeries dataset) {
            mergeRanges(new Range(dataset.getMinY(), dataset.getMaxY()));
        }

        /** True if no datasets given. */
        public boolean isEmpty() {
            return this.datasets.isEmpty();
        }

    }


    /** The logger that is used in this generator. */
    private static Logger logger = Logger.getLogger(XYChartGenerator.class);

    /** Map of datasets ("index"). */
    protected SortedMap<Integer, AxisDataset> datasets;

    /** List of annotations to insert in plot. */
    protected List<FLYSAnnotation> annotations;

    /** The max X range to include all X values of all series for each axis. */
    protected Map<Integer, Range> xRanges;

    /** The max Y range to include all Y values of all series for each axis. */
    protected Map<Integer, Range> yRanges;

    public static final Color DEFAULT_GRID_COLOR      = Color.GRAY;
    public static final float DEFAULT_GRID_LINE_WIDTH = 0.3f;


    public XYChartGenerator() {
        xRanges  = new HashMap<Integer, Range>();
        yRanges  = new HashMap<Integer, Range>();
        datasets = new TreeMap<Integer, AxisDataset>();
    }


    /**
     * Returns the title of a chart.
     *
     * @return the title of a chart.
     */
    protected abstract String getChartTitle();


    /**
     * Returns the X-Axis label of a chart.
     *
     * @return the X-Axis label of a chart.
     */
    protected abstract String getXAxisLabel();


    /**
     * Returns the Y-Axis label of a chart.
     *
     * @return the Y-Axis label of a chart.
     */
    protected abstract String getYAxisLabel();

    /**
     * Generate chart.
     */
    public void generate()
    throws IOException
    {
        logger.debug("XYChartGenerator.generate");

        JFreeChart chart = generateChart();

        String format = getFormat();
        int[]  size   = getSize();

        context.putContextValue("chart.width",  size[0]);
        context.putContextValue("chart.height", size[1]);

        if (format.equals(ChartExportHelper.FORMAT_PNG)) {
            context.putContextValue("chart.image.format", "png");

            ChartExportHelper.exportImage(
                out,
                chart,
                context);
        }
        else if (format.equals(ChartExportHelper.FORMAT_PDF)) {
            context.putContextValue("chart.marginLeft",   5f);
            context.putContextValue("chart.marginRight",  5f);
            context.putContextValue("chart.marginTop",    5f);
            context.putContextValue("chart.marginBottom", 5f);
            context.putContextValue(
                "chart.page.format",
                ChartExportHelper.DEFAULT_PAGE_SIZE);

            ChartExportHelper.exportPDF(
                out,
                chart,
                context);
        }
        else if (format.equals(ChartExportHelper.FORMAT_SVG)) {
            context.putContextValue(
                "chart.encoding",
                ChartExportHelper.DEFAULT_ENCODING);

            ChartExportHelper.exportSVG(
                out,
                chart,
                context);
        }
    }


    /**
     * Generate the chart anew (including localized axis and all).
     */
    public JFreeChart generateChart() {
        logger.debug("XYChartGenerator.generateChart");

        JFreeChart chart = ChartFactory.createXYLineChart(
            getChartTitle(),
            getXAxisLabel(),
            getYAxisLabel(),
            null,
            PlotOrientation.VERTICAL,
            true,
            false,
            false);

        XYPlot plot = (XYPlot) chart.getPlot();
        chart.setBackgroundPaint(Color.WHITE);
        plot.setBackgroundPaint(Color.WHITE);
        addSubtitles(chart);
        adjustPlot(plot);

        //debugAxis(plot);

        addDatasets(plot);

        //debugDatasets(plot);

        recoverEmptyPlot(plot);
        preparePointRanges(plot);

        addAnnotationsToRenderer(plot);

        //debugAxis(plot);

        localizeAxes(plot);
        adjustAxes(plot);
        autoZoom(plot);

        return chart;
    }


    /**
     * Put debug output about datasets.
     */
    public void debugDatasets(XYPlot plot) {
        logger.debug("Number of datasets: " + plot.getDatasetCount());
        for (int i = 0; i < plot.getDatasetCount(); i++) {
            if (plot.getDataset(i) == null) {
                logger.debug("Dataset #" + i + " is null");
                continue;
            }
            logger.debug("Dataset #" + i + ":" + plot.getDataset(i));
        }
    }


    /**
     * Put debug output about axes.
     */
    public void debugAxis(XYPlot plot) {
        logger.debug("...............");
        for (int i = 0; i < plot.getRangeAxisCount(); i++) {
            if (plot.getRangeAxis(i) == null)
                logger.debug("Axis #" + i + " == null");
            else {
                logger.debug("Axis " + i + " != null [" +
                    plot.getRangeAxis(i).getRange().getLowerBound() +
                    "  " + plot.getRangeAxis(i).getRange().getUpperBound() +
                    "]");
            }

        }
        logger.debug("...............");
    }


    /**
     * Add datasets to plot.
     * @param plot plot to add datasets to.
     */
    protected void addDatasets(XYPlot plot) {
        // AxisDatasets are sorted, but some might be empty.
        // Thus, generate numbering on the fly.
        int axisIndex    = 0;
        int datasetIndex = 0;
        for (Map.Entry<Integer, AxisDataset> entry: datasets.entrySet()) {
            if (!entry.getValue().isEmpty()) {
                // Add axis and range information.
                AxisDataset axisDataset = entry.getValue();
                NumberAxis axis = createYAxis(entry.getKey());

                plot.setRangeAxis(axisIndex, axis);
                if (axis.getAutoRangeIncludesZero()) {
                    axisDataset.range = Range.expandToInclude(axisDataset.range, 0d);
                }
                yRanges.put(axisIndex, expandPointRange(axisDataset.range));

                // Add contained datasets, mapping to axis.
                for (XYDataset dataset: axisDataset.datasets) {
                    plot.setDataset(datasetIndex, dataset);
                    plot.mapDatasetToRangeAxis(datasetIndex, axisIndex);
                    applyThemes(plot, (XYSeriesCollection) dataset, datasetIndex);
                    datasetIndex++;
                }
                axisIndex++;
            }
        }
    }


    /**
     * Add given series if visible, if not visible adjust ranges (such that
     * all points in data would be plotted once visible).
     * @param series the dataseries to include in plot.
     * @param index  index of the series and of its axis.
     * @param visible whether or not the data should be plotted.
     */
    public void addAxisSeries(XYSeries series, int index, boolean visible) {
        if (series == null) {
            return;
        }

        AxisDataset axisDataset = datasets.get(index);

        if (axisDataset == null) {
            axisDataset = new AxisDataset(index);
            datasets.put(index, axisDataset);
        }

        if (visible) {
            axisDataset.addDataset(series);
        }
        else {
            // Do this also when not visible to have axis scaled by default such
            // that every data-point could be seen (except for annotations).
            axisDataset.includeRange(series);
        }

        combineXRanges(new Range(series.getMinX(), series.getMaxX()), 0);
    }


    /**
     * Effect: extend range of x axis to include given limits.
     * @param range the given ("minimal") range.
     * @param index index of axis to be merged.
     */
    private void combineXRanges(Range range, int index) {

        Range old = xRanges.get(index);

        if (old != null) {
            range = Range.combine(old, range);
        }

        xRanges.put(index, range);
    }


    /**
     * Adds annotations to list (if visible is true).
     */
    public void addAnnotations(FLYSAnnotation annotation, boolean visible) {
        if (!visible) {
            return;
        }

        if (annotations == null) {
            annotations = new ArrayList<FLYSAnnotation>();
        }

        annotations.add(annotation);
    }


    /**
     * Create Y (range) axis for given index.
     * Shall be overriden by subclasses.
     */
    protected NumberAxis createYAxis(int index) {
        NumberAxis axis = new NumberAxis(getYAxisLabel());
        axis.setAutoRangeIncludesZero(false);
        return axis;
    }


    /**
     * If no data is visible, draw at least empty axis.
     */
    private void recoverEmptyPlot(XYPlot plot) {
        if (plot.getRangeAxis() == null) {
            logger.debug("debug: No range axis");
            plot.setRangeAxis(createYAxis(0));
        }
    }


    /**
     * Expands a given range if it collapses into one point.
     */
    private Range expandPointRange(Range range) {
        if (range.getLowerBound() == range.getUpperBound()) {
            return expandRange(range, 5);
        }
        return range;
    }


    /**
     * Expands X axes if only a point is shown.
     */
    private void preparePointRanges(XYPlot plot) {
        for (int i = 0, num = plot.getDomainAxisCount(); i < num; i++) {
            logger.debug("Check whether to expand a x axis.");
            Integer key = Integer.valueOf(i);

            Range r = xRanges.get(key);
            if (r != null && r.getLowerBound() == r.getUpperBound()) {
                xRanges.put(key, expandRange(r, 5));
            }
        }
    }


    /**
     * Expand range by percent.
     */
    public static Range expandRange(Range range, double percent) {
        if (range == null) {
            return null;
        }

        double value  = range.getLowerBound();
        double expand = value / 100 * percent;

        return expand != 0
            ? new Range(value-expand, value+expand)
            : new Range(-0.01 * percent, 0.01 * percent);
    }


    /**
     * This method zooms the plot to the specified ranges in the attribute
     * document or to the ranges specified by the min/max values in the
     * datasets. <b>Note:</b> We determine the range manually if no zoom ranges
     * are given, because JFreeCharts auto-zoom adds a margin to the left and
     * right of the data area.
     *
     * @param plot The XYPlot.
     */
    protected void autoZoom(XYPlot plot) {
        logger.debug("Zoom to specified ranges.");

        Range xrange = getDomainAxisRange();
        Range yrange = getValueAxisRange();

        zoomX(plot, plot.getDomainAxis(), xRanges.get(0), xrange);

        for (int i = 0, num = plot.getRangeAxisCount(); i < num; i++) {
            ValueAxis yaxis = plot.getRangeAxis(i);

            if (yaxis == null) {
                logger.debug("Zoom problem: no Y Axis for index: " + i);
                continue;
            }

            logger.debug("Prepare zoom settings for y axis at index: " + i);
            zoomY(plot, yaxis, yRanges.get(Integer.valueOf(i)), yrange);
        }
    }


    protected boolean zoomX(XYPlot plot, ValueAxis axis, Range range, Range x) {
        return zoom(plot, axis, range, x);
    }


    protected boolean zoomY(XYPlot plot, ValueAxis axis, Range range, Range x) {
        return zoom(plot, axis, range, x);
    }


    /**
     * Zooms the x axis to the range specified in the attribute document.
     *
     * @param plot The XYPlot.
     * @param axis The axis the shoud be modified.
     * @param range The whole range specified by a dataset.
     * @param x A user defined range (null permitted).
     *
     * @return true, if a zoom range was specified, otherwise false.
     */
    protected boolean zoom(XYPlot plot, ValueAxis axis, Range range, Range x) {

        if (range == null) {
            return false;
        }

        if (x != null) {
            double min  = range.getLowerBound();
            double max  = range.getUpperBound();
            double diff = max > min ? max - min : min - max;

            Range computed = new Range(
                min + x.getLowerBound() * diff,
                min + x.getUpperBound() * diff);

            axis.setRangeWithMargins(computed);

            logger.debug("Zoom axis to: " + computed);

            return true;
        }

        axis.setRangeWithMargins(range);
        return false;
    }


    /**
     * This method extracts the minimum and maximum values for x and y axes
     * which are stored in <i>xRanges</i> and <i>yRanges</i>.
     *
     * @param index The index of the y-Axis.
     *
     * @return a Range[] as follows: [x-Range, y-Range].
     */
    public Range[] getRangesForAxis(int index) {
        logger.debug("getRangesForAxis " + index);
        return new Range[] {
            xRanges.get(Integer.valueOf(0)),
            yRanges.get(Integer.valueOf(index))
        };
    }


    /**
     * Add annotations to Renderer.
     */
    protected void addAnnotationsToRenderer(XYPlot plot) {
        plot.clearAnnotations();

        if (annotations == null) {
            logger.debug("No Annotations given.");
            return;
        }

        LegendItemCollection lic = new LegendItemCollection();
        LegendItemCollection old = plot.getFixedLegendItems();

        XYItemRenderer renderer = plot.getRenderer(0);

        for (FLYSAnnotation fa: annotations) {
            Document theme = fa.getTheme();

            ThemeAccess themeAccess = new ThemeAccess(theme);

            Color color   = themeAccess.parseLineColorField();
            int lineWidth = themeAccess.parseLineWidth();
            lic.add(new LegendItem(fa.getLabel(), color));

            for (XYTextAnnotation ta: fa.getAnnotations()) {
                if(ta instanceof StickyAxisAnnotation) {
                    StickyAxisAnnotation sta = (StickyAxisAnnotation)ta;
                    sta.applyTheme(themeAccess);
                    renderer.addAnnotation(sta);
                }
                else {
                    ta.setPaint(color);
                    ta.setOutlineStroke(new BasicStroke((float) lineWidth));
                    renderer.addAnnotation(ta);
                }
            }

        }

        // (Re-)Add prior legend entries.
        if (old != null) {
            old.addAll(lic);
        }
        else {
            old = lic;
        }

        plot.setFixedLegendItems(old);
    }


    /**
     * Adjusts the axes of a plot (the first axis does not include zero).
     * To be overridden by children.
     * @param plot The XYPlot of the chart.
     */
    protected void adjustAxes(XYPlot plot) {
        /*
        NumberAxis yAxis = (NumberAxis) plot.getRangeAxis();
        if (yAxis == null) {
            logger.warn("No Axis to setAutoRangeIncludeZero.");
        }
        else {
            yAxis.setAutoRangeIncludesZero(false);
        }
        */
    }


    /**
     * Set some Stroke/Grid defaults.
     */
    protected void adjustPlot(XYPlot plot) {
        Stroke gridStroke = new BasicStroke(
            DEFAULT_GRID_LINE_WIDTH,
            BasicStroke.CAP_BUTT,
            BasicStroke.JOIN_MITER,
            3.0f,
            new float[] { 3.0f },
            0.0f);

        plot.setDomainGridlineStroke(gridStroke);
        plot.setDomainGridlinePaint(DEFAULT_GRID_COLOR);
        plot.setDomainGridlinesVisible(true);

        plot.setRangeGridlineStroke(gridStroke);
        plot.setRangeGridlinePaint(DEFAULT_GRID_COLOR);
        plot.setRangeGridlinesVisible(true);

        plot.setAxisOffset(new RectangleInsets(0d, 0d, 0d, 0d));
    }


    protected void addSubtitles(JFreeChart chart) {
        // override this method in subclasses that need subtitles
    }


    /**
     * This method walks over all axes (domain and range) of <i>plot</i> and
     * calls localizeDomainAxis() for domain axes or localizeRangeAxis() for
     * range axes.
     *
     * @param plot The XYPlot.
     */
    private void localizeAxes(XYPlot plot) {
        for (int i = 0, num = plot.getDomainAxisCount(); i < num; i++) {
            ValueAxis axis = plot.getDomainAxis(i);

            if (axis != null) {
                localizeDomainAxis(axis);
            }
            else {
                logger.warn("Domain axis at " + i + " is null.");
            }
        }

        for (int i = 0, num = plot.getRangeAxisCount(); i < num; i++) {
            ValueAxis axis = plot.getRangeAxis(i);

            if (axis != null) {
                localizeRangeAxis(axis);
            }
            else {
                logger.warn("Range axis at " + i + " is null.");
            }
        }
    }


    /**
     * Overrides the NumberFormat with the NumberFormat for the current locale
     * that is provided by getLocale().
     *
     * @param domainAxis The domain axis that needs localization.
     */
    protected void localizeDomainAxis(ValueAxis domainAxis) {
        NumberFormat nf = NumberFormat.getInstance(getLocale());
        ((NumberAxis) domainAxis).setNumberFormatOverride(nf);
    }


    /**
     * Overrides the NumberFormat with the NumberFormat for the current locale
     * that is provided by getLocale().
     *
     * @param domainAxis The domain axis that needs localization.
     */
    protected void localizeRangeAxis(ValueAxis rangeAxis) {
        NumberFormat nf = NumberFormat.getInstance(getLocale());
        ((NumberAxis) rangeAxis).setNumberFormatOverride(nf);
    }


    /**
     * @param idx "index" of dataset/series (first dataset to be drawn has
     *            index 0), correlates with renderer index.
     * @return idx increased by number of items addded.
     */
    protected int applyThemes(XYPlot plot, XYSeriesCollection series, int idx) {
        LegendItemCollection lic  = new LegendItemCollection();
        LegendItemCollection anno = plot.getFixedLegendItems();

        XYLineAndShapeRenderer renderer = getRenderer(plot, idx);
        int retidx = idx;

        for (int s = 0, num = series.getSeriesCount(); s < num; s++) {
            XYSeries serie = series.getSeries(s);

            if (serie instanceof StyledXYSeries) {
                ((StyledXYSeries) serie).applyTheme(renderer, s);
            }

            // special case: if there is just one single item, we need to enable
            // points for this series, otherwise we would not see anything in
            // the chart area.
            if (serie.getItemCount() == 1) {
                renderer.setSeriesShapesVisible(s, true);
            }

            LegendItem li = renderer.getLegendItem(idx, s);
            if (li != null) {
                lic.add(li);
            }
            else {
                logger.warn("Could not get LegentItem for renderer: "
                     + idx + ", series-idx " + s);
            }
            retidx++;
        }

        if (anno != null) {
            lic.addAll(anno);
        }

        plot.setFixedLegendItems(lic);

        plot.setRenderer(idx, renderer);

        return retidx;
    }


    /**
     * Get renderer, from plot or cloned default renderer otherwise.
     */
    protected XYLineAndShapeRenderer getRenderer(XYPlot plot, int idx) {
        XYLineAndShapeRenderer r =
            (XYLineAndShapeRenderer) plot.getRenderer(idx);

        if (r != null) {
            return r;
        }

        if (idx == 0) {
            logger.warn("No default renderer set!");
            return new XYLineAndShapeRenderer();
        }

        r = (XYLineAndShapeRenderer) plot.getRenderer(0);

        try {
            return (XYLineAndShapeRenderer) r.clone();
        }
        catch (CloneNotSupportedException cnse) {
            logger.warn(cnse, cnse);
        }

        logger.warn("No applicalable renderer found!");

        return new XYLineAndShapeRenderer();
    }


    /**
     * Register annotations like MainValues for later plotting
     *
     * @param o     list of annotations (data of facet).
     * @param facet The facet. This facet does NOT support any data objects. Use
     * FLYSArtifact.getNativeFacet() instead to retrieve a Facet which supports
     * data.
     * @param theme   Theme document for given annotations.
     * @param visible The visibility of the annotations.
     */
    protected void doAnnotations(
        FLYSAnnotation annotations,
        Facet facet,
        Document theme,
        boolean visible
    ){
        logger.debug("doAnnotations");

        // Add all annotations to our annotation pool.
        annotations.setTheme(theme);
        annotations.setLabel(facet.getDescription());
        addAnnotations(annotations, visible);
    }
}
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