/*******************************************************************************
 * Copyright (c) 2007, 2010 Association for Decentralized Information Management
 * in Industry THTH ry.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     VTT Technical Research Centre of Finland - initial API and implementation
 *******************************************************************************/
package org.simantics.scenegraph.utils;

import java.awt.Color;
import java.awt.Graphics2D;
import java.awt.Point;
import java.awt.RenderingHints;
import java.awt.geom.AffineTransform;
import java.awt.geom.Rectangle2D;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import com.kitfox.svg.SVGDiagram;

/**
 * Video-ram cache suitable for rasterized PaintableSymbols scalable vector graphics.
 * <p>
 * This implementation rasterizes the same symbol from different mip map levels.
 * 
 * @see VRamImage
 * @author Toni Kalajainen
 */
public class MipMapBufferedImage extends BufferedImage {

    /** Extra margin to the bounds reported by batik */
    public static final double MARGIN_PERCENT = 3;

    // Was 800 in VRam.. ?
    public static final double MAX_DIMENSION  = 600;
    public static final double MIN_DIMENSION  = 4;

    //Shape outline;

    Map<Double, IRaster>       rasters        = new HashMap<Double, IRaster>();
    double[]                   resolutions;
    double                     minResolution, maxResolution;

    /**
     * @param original
     * @param imageBounds
     * @param referenceSize
     * 
     * FIXME: shouldn't be SVG dependent
     */
    public MipMapBufferedImage(SVGDiagram original, Rectangle2D imageBounds, Point referenceSize) {
        super(original, imageBounds, referenceSize);
        initializeRasters();
    }

    private void initializeRasters() {
        List<Double> resolutions = new ArrayList<Double>();

        if (referenceSize != null && !imageBounds.isEmpty()) {
            // Init rasters - they are built on-demand
            double maxResolution = maxResolution();
            double minResolution = minResolution();
            double fitResolution = fitResolution(referenceSize);
            double resolution = fitResolution;
            while (true) {
                double next = resolution * 2;
                if (next > maxResolution)
                    break;
                resolution = next;
            }
            while (resolution > minResolution) {
                IRaster r = createRaster(resolution);
                rasters.put(resolution, r);
                resolutions.add(resolution);
                resolution /= 2;
            }
        } else {
            // Init rasters - they are built on-demand
            double maxResolution = maxResolution();
            double minResolution = minResolution();
            double resolution = maxResolution;
            while (resolution > minResolution) {
                IRaster r = createRaster(resolution);
                rasters.put(resolution, r);
                resolutions.add(resolution);
                resolution /= 2;
            }
        }

        // arraylist -> array
        this.resolutions = new double[resolutions.size()];
        for (int i=0; i<resolutions.size(); i++)
            this.resolutions[i] = resolutions.get(resolutions.size()-1-i);
        this.minResolution = this.resolutions[0];
        this.maxResolution = this.resolutions[this.resolutions.length-1];
        //System.out.println("RESOLUTIONS: " + Arrays.toString(this.resolutions));
    }

    protected IRaster createRaster(double resolution) {
        return new BufferedRaster(resolution);
    }

    private double fitResolution(Point p)
    {
        double wid = imageBounds.getWidth();
        double hei = imageBounds.getHeight();
        double rx = p.x / wid;
        double ry = p.y / hei;
        return Math.min(rx, ry);
    }

    private double maxResolution()
    {
        double wid = imageBounds.getWidth();
        double hei = imageBounds.getHeight();
        return MAX_DIMENSION/Math.sqrt(wid*hei);
    }

    private double minResolution()
    {
        double wid = imageBounds.getWidth();
        double hei = imageBounds.getHeight();
        return MIN_DIMENSION/Math.sqrt(wid*hei);
    }

    protected double requiredResolution(AffineTransform at)
    {
        double m00 = at.getScaleX();
        double m11 = at.getScaleY();
        double m10 = at.getShearY();
        double m01 = at.getShearX();
        // Project unit vector to canvas
        double sx = Math.sqrt( m00*m00 + m10*m10 );
        double sy = Math.sqrt( m01*m01 + m11*m11 );
        return Math.max(sx, sy);
        //return Math.sqrt(sx*sx+sy*sy);
    }

    protected double findClosestResolution(double resolution)
    {
        int index = Arrays.binarySearch(resolutions, resolution);
        if (index>=0) return resolutions[index];
        index  = -(index+1);

        if (index>=resolutions.length) index = resolutions.length-1;
        if (index<0) index = 0;
        return resolutions[index];
    }

    @Override
    public void paint(Graphics2D g) {
        // Quality rendering requested, do not render from cache
        //QualityHints.HIGH_QUALITY_HINTS.setQuality(g);
        if (g.getRenderingHint(RenderingHints.KEY_RENDERING) == RenderingHints.VALUE_RENDER_QUALITY)
        {
            try {
                source.render(g);
            } catch (Exception e) {
                // NOTE: Catching Exception instead of SVGException due to an
                // NPE when encountering invalid color SVG definitions (e.g.
                // rgb(256,-1,0))
                e.printStackTrace();
            }
            return;
        }

        double requiredResolution = requiredResolution(g.getTransform());
        // This scale makes the mipmapped painting use a mipmap that is smaller
        // than the requested image pixel size in cases where the required
        // resolution only slightly exceeds the size of an available mipmap.
        requiredResolution *= 0.95;
        //System.out.println("required resolution: " + requiredResolution);

        if (requiredResolution > getRasterRenderingThresholdResolution()) {
            Graphics2D g2d = (Graphics2D) g.create();
            setupSourceRender(g2d);
            try {
                source.render(g2d);
            } catch (Exception e) {
                // NOTE: Catching Exception instead of SVGException due to an
                // NPE when encountering invalid color SVG definitions (e.g.
                // rgb(256,-1,0))
                e.printStackTrace();
            } finally {
                g2d.dispose();
            }
        } else {
            Object origInterpolationHint = g.getRenderingHint(RenderingHints.KEY_INTERPOLATION);
            if (origInterpolationHint==null)
                origInterpolationHint = RenderingHints.VALUE_INTERPOLATION_NEAREST_NEIGHBOR;

            g.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BICUBIC);

            double closestResolution = findClosestResolution(requiredResolution);
            //System.out.println("  resolutions: " + Arrays.toString(resolutions));
            //System.out.println("  closest resolution: " + closestResolution);
            IRaster raster = rasters.get(closestResolution);
            try {
                raster.paint( g );
            } finally {
                g.setRenderingHint(RenderingHints.KEY_INTERPOLATION, origInterpolationHint);
            }
        }
    }

    protected void setupSourceRender(Graphics2D g2d) {
        g2d.setRenderingHint(RenderingHints.KEY_ALPHA_INTERPOLATION, RenderingHints.VALUE_ALPHA_INTERPOLATION_SPEED);
        g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_OFF);
        g2d.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR);
        g2d.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_OFF);
        g2d.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_SPEED);
        g2d.setRenderingHint(RenderingHints.KEY_DITHERING, RenderingHints.VALUE_DITHER_DISABLE);
    }

    protected double getRasterRenderingThresholdResolution() {
        return maxResolution;
    }

    @Override
    public synchronized void releaseRaster() {
        for (IRaster r : rasters.values())
            r.release();
    }

    static interface IRaster extends Comparable<IRaster> {
        double getResolution();
        void paint(Graphics2D g);
        void release();
    }

    static abstract class Raster implements IRaster {
        protected final double resolution;

        public Raster(double resolution) {
            this.resolution = resolution;
        }

        public double getResolution() {
            return resolution;
        }

        public int compareTo(IRaster o) {
            double r = getResolution();
            double or = o.getResolution();
            if (or < r)
                return -1;
            if (or > r)
                return 1;
            return 0;
        }
    }

    class BufferedRaster extends Raster {
        java.awt.image.BufferedImage image;
        //int widMargin, heiMargin;
        int wid, hei;

        BufferedRaster(double resolution) {
            super(resolution);
            double wid = imageBounds.getWidth();
            double hei = imageBounds.getHeight();
            this.wid = (int) (wid * resolution);
            this.hei = (int) (hei * resolution);
//            widMargin = (int) (wid * resolution * (MARGIN_PERCENT/100)) +1;
//            heiMargin = (int) (hei * resolution * (MARGIN_PERCENT/100)) +1;
        }

        synchronized java.awt.image.BufferedImage getOrCreate()
        {
            if (image!=null) return image;
            image = new java.awt.image.BufferedImage(
                    (wid+0*2+1),
                    (hei+0*2+1),
                    java.awt.image.BufferedImage.TYPE_INT_ARGB);

            Graphics2D target = image.createGraphics();
            target.setBackground(new Color(255,255,255,0));
            target.clearRect(0, 0, image.getWidth(), image.getHeight());

            target.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
            target.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
            target.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING, RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
            target.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BICUBIC);

//            target.translate(widMargin, heiMargin);
            target.scale(resolution, resolution);
            target.translate(-imageBounds.getMinX(), -imageBounds.getMinY());
            try {
                source.render(target);
            } catch (Exception e) {
                // TODO Auto-generated catch block
                // NOTE: Catching Exception instead of SVGException due to an
                // NPE when encountering invalid color SVG definitions (e.g.
                // rgb(256,-1,0))
                e.printStackTrace();
            }
//            source.paint(
//                    new GraphicsContextImpl(target, new Rectangle2D.Double(0,0, image.getWidth(), image.getHeight()), null)
//            );
            target.dispose();

            return image;
        }

        public void paint(Graphics2D g) {
            java.awt.image.BufferedImage image = getOrCreate();
            if (image==null)
            {
                try {
                    source.render(g);
                } catch (Exception e) {
                    // TODO Auto-generated catch block
                    // NOTE: Catching Exception instead of SVGException due to an
                    // NPE when encountering invalid color SVG definitions (e.g.
                    // rgb(256,-1,0))
                    e.printStackTrace();
                }
                return;
            }
            AffineTransform af = g.getTransform();
            Object rh = g.getRenderingHint(RenderingHints.KEY_INTERPOLATION);
            try {
                /// Bicubic interpolation is very slow with opengl pipeline
                if (rh == RenderingHints.VALUE_INTERPOLATION_BICUBIC)
                    g.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
                            RenderingHints.VALUE_INTERPOLATION_BILINEAR);
                g.translate(imageBounds.getMinX(), imageBounds.getMinY());
                g.scale(1/resolution, 1/resolution);
//                g.translate(-widMargin, -heiMargin);
                g.drawImage(image, 0, 0, null);
            } finally {
                g.setTransform(af);
                g.setRenderingHint(RenderingHints.KEY_INTERPOLATION, rh);
            }
        }

        public void release() {
            image = null;
        }
    }

}