/*
 * Copyright (c) 2009, 2017, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

package com.sun.prism.impl.ps;

import com.sun.javafx.geom.BaseBounds;
import com.sun.javafx.geom.RectBounds;
import com.sun.javafx.geom.Shape;
import com.sun.javafx.geom.transform.BaseTransform;
import com.sun.prism.BasicStroke;
import com.sun.prism.Graphics;
import com.sun.prism.Texture;
import com.sun.prism.Texture.WrapMode;
import com.sun.prism.paint.Paint;
import com.sun.prism.shape.ShapeRep;
import com.sun.prism.impl.Disposer;
import com.sun.prism.impl.PrismSettings;
import com.sun.prism.impl.VertexBuffer;
import com.sun.prism.impl.ps.BaseShaderContext.MaskType;
import com.sun.prism.impl.shape.ShapeUtil;
import com.sun.prism.impl.shape.MaskData;
import com.sun.prism.ps.Shader;
import java.util.Arrays;
import java.util.Comparator;

An implementation of ShapeRep that attempts to cache and reuse the
mask texture that is used to render the filled/stroked geometry.
There is an artificial cap on the size of shapes that are considered
for caching, so that we do not fill up VRAM with lots of large shape
masks.  The shape is considered for caching only when it is rendered
a certain number of times with unchanging transform (ignoring the
translation components) and geometry.  This means that this class is
good for caching static shapes that are either completely stationary
or being translated.  This class will also attempt to reuse a mask
that corresponds to a completely different shape instance as long as
the two shapes are equal and the transforms only differ by their
translation components.  This means that if you have 1000 Path nodes
all with exactly the same geometry but with different translation factors,
then we will only rasterize and cache a single mask texture and reuse
it among all the Path nodes.
(Of course, the fact that we reuse the same mask texture for different
sub-pixel translation factors means we're knowingly being a bit sloppy,
so when caching is enabled you may see some dancing at the shape edges
for slowly animating translations, but otherwise will hopefully not be
too noticeable.)
The current implementation limits the size of the cache (512 pixels in
each dimension, and 4 MB in total) so that it doesn't grow without bound.
Space is granted on a first come first served basis.
/**
 * An implementation of ShapeRep that attempts to cache and reuse the
 * mask texture that is used to render the filled/stroked geometry.
 * There is an artificial cap on the size of shapes that are considered
 * for caching, so that we do not fill up VRAM with lots of large shape
 * masks.  The shape is considered for caching only when it is rendered
 * a certain number of times with unchanging transform (ignoring the
 * translation components) and geometry.  This means that this class is
 * good for caching static shapes that are either completely stationary
 * or being translated.  This class will also attempt to reuse a mask
 * that corresponds to a completely different shape instance as long as
 * the two shapes are equal and the transforms only differ by their
 * translation components.  This means that if you have 1000 Path nodes
 * all with exactly the same geometry but with different translation factors,
 * then we will only rasterize and cache a single mask texture and reuse
 * it among all the Path nodes.
 *
 * (Of course, the fact that we reuse the same mask texture for different
 * sub-pixel translation factors means we're knowingly being a bit sloppy,
 * so when caching is enabled you may see some dancing at the shape edges
 * for slowly animating translations, but otherwise will hopefully not be
 * too noticeable.)
 *
 * The current implementation limits the size of the cache (512 pixels in
 * each dimension, and 4 MB in total) so that it doesn't grow without bound.
 * Space is granted on a first come first served basis.
 */
public class CachingShapeRep implements ShapeRep {

    private CachingShapeRepState fillState;
    private CachingShapeRepState drawState;

    public CachingShapeRep() {
    }

    CachingShapeRepState createState() {
        return new CachingShapeRepState();
    }

    public boolean is3DCapable() {
        return false;
    }

    public void invalidate(InvalidationType type) {
        // NOTE: for now we invalidate for any location or geometry change;
        // should consider allowing certain location changes...
        if (fillState != null) {
            fillState.invalidate();
        }
        if (drawState != null) {
            drawState.invalidate();
        }
    }

    public void fill(Graphics g, Shape shape, BaseBounds bounds) {
        if (fillState == null) {
            fillState = createState();
        }
        fillState.render(g, shape, (RectBounds) bounds, null);
    }

    public void draw(Graphics g, Shape shape, BaseBounds bounds) {
        if (drawState == null) {
            drawState = createState();
        }
        drawState.render(g, shape,(RectBounds) bounds, g.getStroke());
    }

    public void dispose() {
        if (fillState != null) {
            fillState.dispose();
            fillState = null;
        }
        if (drawState != null) {
            drawState.dispose();
            drawState = null;
        }
    }
}

class CachingShapeRepState {

    private static class MaskTexData {
        private CacheEntry cacheEntry;
        private Texture maskTex;
        private float maskX;
        private float maskY;
        private int maskW;
        private int maskH;

        void adjustOrigin(BaseTransform xform) {
            float dx = (float)(xform.getMxt()-cacheEntry.xform.getMxt());
            float dy = (float)(xform.getMyt()-cacheEntry.xform.getMyt());
            this.maskX = cacheEntry.texData.maskX + dx;
            this.maskY = cacheEntry.texData.maskY + dy;
        }

        MaskTexData copy() {
            MaskTexData data = new MaskTexData();
            data.cacheEntry = this.cacheEntry;
            data.maskTex = this.maskTex;
            data.maskX = this.maskX;
            data.maskY = this.maskY;
            data.maskW = this.maskW;
            data.maskH = this.maskH;
            return data;
        }

        void copyInto(MaskTexData other) {
            if (other == null) {
                throw new InternalError("MaskTexData must be non-null");
            }
            other.cacheEntry = this.cacheEntry;
            other.maskTex = this.maskTex;
            other.maskX = this.maskX;
            other.maskY = this.maskY;
            other.maskW = this.maskW;
            other.maskH = this.maskH;
        }
    }

    private static class CacheEntry {
        Shape shape;
        BasicStroke stroke;
        BaseTransform xform;
        RectBounds xformBounds;
        MaskTexData texData;
        boolean antialiasedShape;
        int refCount;
    }

    private static class MaskCache {
        private static final int MAX_MASK_DIM = 512;
        private static final int MAX_SIZE_IN_PIXELS = 4194304; // 4 MB
        private static Comparator<CacheEntry> comparator = (o1, o2) -> {
            int widthCompare = Float.compare(o1.xformBounds.getWidth(), o2.xformBounds.getWidth());
            if (widthCompare != 0) {
                return widthCompare;
            }
            return Float.compare(o1.xformBounds.getHeight(), o2.xformBounds.getHeight());
        };

        private CacheEntry[] entries = new CacheEntry[8];
        private int entriesSize = 0;
        private int totalPixels;

        private CacheEntry tmpKey = new CacheEntry();
        {
            tmpKey.xformBounds = new RectBounds();
        }

        private void ensureSize(int size) {
            if (entries.length < size) {
                CacheEntry[] newEntries = new CacheEntry[size * 3 / 2];
                System.arraycopy(entries, 0, newEntries, 0, entries.length);
                entries = newEntries;
            }
        }

        private void addEntry(CacheEntry entry) {
            ensureSize(entriesSize + 1);
            int pos = Arrays.binarySearch(entries, 0, entriesSize, entry, comparator);
            if (pos < 0) {
                pos = ~pos;
            }
            System.arraycopy(entries, pos, entries, pos + 1, entriesSize - pos);
            entries[pos] = entry;
            ++entriesSize;
        }

        private void removeEntry(CacheEntry entry) {
            int pos = Arrays.binarySearch(entries, 0, entriesSize, entry, comparator);
            if (pos < 0) {
                throw new IllegalStateException("Trying to remove a cached item that's not in the cache");
            }
            if (entries[pos] != entry) {
                tmpKey.xformBounds.deriveWithNewBounds(0, 0, 0, entry.xformBounds.getWidth(), Math.nextAfter(entry.xformBounds.getHeight(), Float.NEGATIVE_INFINITY), 0);
                pos = Arrays.binarySearch(entries, 0, entriesSize, tmpKey, comparator);
                if (pos < 0) {
                    pos = ~pos;
                }
                tmpKey.xformBounds.deriveWithNewBounds(0, 0, 0, entry.xformBounds.getWidth(), Math.nextAfter(entry.xformBounds.getHeight(), Float.POSITIVE_INFINITY), 0);
                int toPos = Arrays.binarySearch(entries, 0, entriesSize, tmpKey, comparator);
                if (toPos < 0) {
                    toPos = ~toPos;
                }
                while (entries[pos] != entry && pos < toPos) { ++pos; };
                if (pos >= toPos) {
                    throw new IllegalStateException("Trying to remove a cached item that's not in the cache");
                }
            }
            System.arraycopy(entries, pos + 1, entries, pos, entriesSize - pos - 1);
            --entriesSize;
        }

        boolean hasRoom(RectBounds xformBounds) {
            int w = (int)(xformBounds.getWidth() + 0.5f);
            int h = (int)(xformBounds.getHeight() + 0.5f);
            int size = w*h;
            return
                w <= MAX_MASK_DIM &&
                h <= MAX_MASK_DIM &&
                totalPixels + size <= MAX_SIZE_IN_PIXELS;
        }

        boolean entryMatches(CacheEntry entry, Shape shape, BasicStroke stroke, BaseTransform xform, boolean antialiasedShape) {
            return (entry.antialiasedShape == antialiasedShape) && equalsIgnoreTranslation(xform, entry.xform) && entry.shape.equals(shape) &&
                   (stroke == null ? entry.stroke == null : stroke.equals(entry.stroke));

        }

        void get(BaseShaderContext context,
                 MaskTexData texData,
                 Shape shape, BasicStroke stroke, BaseTransform xform,
                 RectBounds xformBounds,
                 boolean xformBoundsIsACopy, boolean antialiasedShape)
        {
            if (texData == null) {
                throw new InternalError("MaskTexData must be non-null");
            }
            if (texData.cacheEntry != null) {
                throw new InternalError("CacheEntry should already be null");
            }

            tmpKey.xformBounds.deriveWithNewBounds(0, 0, 0, xformBounds.getWidth(), Math.nextAfter(xformBounds.getHeight(), Float.NEGATIVE_INFINITY), 0);
            int i = Arrays.binarySearch(entries, 0, entriesSize, tmpKey, comparator);
            if (i < 0) {
                i = ~i;
            }

            tmpKey.xformBounds.deriveWithNewBounds(0, 0, 0, xformBounds.getWidth(), Math.nextAfter(xformBounds.getHeight(), Float.POSITIVE_INFINITY), 0);
            int toPos = Arrays.binarySearch(entries, 0, entriesSize, tmpKey, comparator);
            if (toPos < 0) {
                toPos = ~toPos;
            }
            for (;i < toPos; i++) {
                CacheEntry entry = entries[i];

                if (entryMatches(entry, shape, stroke, xform, antialiasedShape))
                {
                    entry.texData.maskTex.lock();
                    if (entry.texData.maskTex.isSurfaceLost()) {
                        // Eventually refcount will go to zero and entry will be freed
                        entry.texData.maskTex.unlock();
                        continue;
                    }
                    // increment ref count for the chosen entry and
                    // link the given texData to it
                    entry.refCount++;
                    entry.texData.copyInto(texData);
                    texData.cacheEntry = entry;
                    // adjust the maskX/maskY by the delta between the
                    // cached transform and the current transform
                    texData.adjustOrigin(xform);
                    return;
                }
            }

            // did not find an existing mask; create a new one here
            MaskData maskData =
                ShapeUtil.rasterizeShape(shape, stroke, xformBounds, xform, true, antialiasedShape);
            int mw = maskData.getWidth();
            int mh = maskData.getHeight();
            texData.maskX = maskData.getOriginX();
            texData.maskY = maskData.getOriginY();
            texData.maskW = mw;
            texData.maskH = mh;
            texData.maskTex =
                context.getResourceFactory().createMaskTexture(mw, mh, WrapMode.CLAMP_TO_ZERO);
            maskData.uploadToTexture(texData.maskTex, 0, 0, false);
            texData.maskTex.contentsUseful();

            // add the new mask texture to the cache; note that we copy the
            // shape and transform so that dependents are not affected
            // if the original geometry is mutated (since NGPath will reuse
            // and mutate a single Path2D instance, for example)
            CacheEntry entry = new CacheEntry();
            entry.shape = shape.copy();
            if (stroke != null) entry.stroke = stroke.copy();
            entry.xform = xform.copy();
            entry.xformBounds = xformBoundsIsACopy ? xformBounds : (RectBounds)xformBounds.copy();
            entry.texData = texData.copy();
            entry.antialiasedShape = antialiasedShape;
            entry.refCount = 1;
            texData.cacheEntry = entry;
            addEntry(entry);
            totalPixels += mw*mh;
        }

        void unref(MaskTexData texData) {
            if (texData == null) {
                throw new InternalError("MaskTexData must be non-null");
            }
            CacheEntry entry = texData.cacheEntry;
            if (entry == null) {
                return;
            }
            texData.cacheEntry = null;
            texData.maskTex = null;
            entry.refCount--;
            if (entry.refCount <= 0) {
                removeEntry(entry);
                entry.shape = null;
                entry.stroke = null;
                entry.xform = null;
                entry.xformBounds = null;
                entry.texData.maskTex.dispose();
                entry.antialiasedShape = false;
                entry.texData = null;
                totalPixels -= (texData.maskW * texData.maskH);
            }
        }
    }

    
Returns true if the two transforms are equal or if they differ only
in their translation components; otherwise returns false.
/**
     * Returns true if the two transforms are equal or if they differ only
     * in their translation components; otherwise returns false.
     */
    private static boolean equalsIgnoreTranslation(BaseTransform a,
                                                   BaseTransform b)
    {
        if (a == b) {
            return true;
        }

        return
            a.getMxx() == b.getMxx() &&
            a.getMxy() == b.getMxy() &&
            a.getMyx() == b.getMyx() &&
            a.getMyy() == b.getMyy();
    }

    private static final BaseTransform IDENT = BaseTransform.IDENTITY_TRANSFORM;
    // NOTE: need separate MaskCache per context?
    private static final MaskCache maskCache = new MaskCache();
    // Number of back to back similar renderings before we cache the mask
    private static final int CACHE_THRESHOLD = 2;

    private int renderCount;
    private Boolean tryCache;
    private BaseTransform lastXform;
    private final MaskTexData texData;
    private float[] bbox;

    private final Object disposerReferent = new Object();
    private final Disposer.Record disposerRecord;

    CachingShapeRepState() {
        this.texData = new MaskTexData();
        this.disposerRecord = new CSRDisposerRecord(texData);
        Disposer.addRecord(disposerReferent, disposerRecord);
    }

    // Note: Subclasses may override this method to use a more direct op.
    void fillNoCache(Graphics g, Shape shape) {
        g.fill(shape);
    }

    // Note: Subclasses may override this method to use a more direct op.
    void drawNoCache(Graphics g, Shape shape) {
        g.draw(shape);
    }

    void invalidate() {
        // Note: this method will be called from the FX thread, so just mark
        // the state as invalid and then the next render() call will take
        // care of unref'ing the cache entry (on the render thread).
        renderCount = 0;
        tryCache = null;
        lastXform = null;
        bbox = null;
    }

    private void invalidateMaskTexData() {
        // Note: this method should only be called from the render thread
        // (since calling unref() may cause textures to be disposed).
        tryCache = null;
        lastXform = null;
        maskCache.unref(texData);
    }

    void render(Graphics g, Shape shape, RectBounds shapeBounds, BasicStroke stroke) {
        // The following is safe; this method does not mutate xform
        BaseTransform xform = g.getTransformNoClone();

        boolean doResetMask;
        boolean doUpdateMask;

        if (lastXform == null) {
            doResetMask = doUpdateMask = true;
        } else if (equalsIgnoreTranslation(xform, lastXform)) {
            doResetMask = false;
            doUpdateMask = (xform.getMxt() != lastXform.getMxt() ||
                            xform.getMyt() != lastXform.getMyt());
        } else {
            doResetMask = doUpdateMask = true;
        }

        // we need to invalidate our cached MaskTexData if:
        //   - lastXform is null, indicating that we were marked invalid
        //     (due to a geometry or location change), or
        //   - the current transform is significantly different than the last
        if (doResetMask) {
            invalidateMaskTexData();

            renderCount = 0;
        }
        if (doResetMask || doUpdateMask) {
            if (lastXform == null) {
                lastXform = xform.copy();
            } else {
                lastXform.setTransform(xform);
            }
        }

        if (texData.cacheEntry != null) {
            texData.maskTex.lock();
            if (texData.maskTex.isSurfaceLost()) {
                texData.maskTex.unlock();
                invalidateMaskTexData();
            }
        }

        RectBounds xformBounds = null;
        boolean boundsCopy = false;

        if (tryCache == null) {
            // determine whether the shape size is within the limits
            if (xform.isIdentity()) {
                xformBounds = shapeBounds;
            } else {
                xformBounds = new RectBounds();
                boundsCopy = true;
                //this is a safe cast as this ShapeRep is not 3d capable.
                // all 3d transformed shapes are thus rendered by different ShapeRep
                xformBounds = (RectBounds) xform.transform(shapeBounds, xformBounds);
            }
            tryCache = !xformBounds.isEmpty() && maskCache.hasRoom(xformBounds);
        }

        renderCount++;
        if (tryCache == Boolean.FALSE ||
            renderCount < CACHE_THRESHOLD ||
            (!(g instanceof BaseShaderGraphics)) ||
            ((BaseShaderGraphics)g).isComplexPaint())
        {
            // render the slow way if:
            //   - the shape size exceeds the threshold, or
            //   - we haven't rendered enough times to get an idea of
            //     whether it is worth caching the mask, or
            //   - there is a complex paint set (note that we could
            //     potentially use the cached mask in this case, but the
            //     complex paint case is not common enough to warrant
            //     further optimization at this time)
            if (stroke == null) {
                fillNoCache(g, shape);
            } else {
                drawNoCache(g, shape);
            }
            return;
        }

        BaseShaderGraphics bsg = (BaseShaderGraphics)g;
        BaseShaderContext context = bsg.getContext();
        if (doUpdateMask || texData.cacheEntry == null) {
            // need to create a new mask texture, or reuse an existing one
            if (xformBounds == null) {
                if (xform.isIdentity()) {
                    xformBounds = shapeBounds;
                } else {
                    xformBounds = new RectBounds();
                    boundsCopy = true;
                    xformBounds = (RectBounds) xform.transform(shapeBounds, xformBounds);
                }
            }

            if (texData.cacheEntry != null) {
                // in this case, we already have a valid mask texture, but
                // the transform (translation) has changed since we last used
                // it, so we just need to update the maskX/maskY variables
                texData.adjustOrigin(xform);
            } else {
                // the following will locate an existing cached mask that
                // matches the given parameters, or failing that, will create
                // a new mask and put it in the cache
                maskCache.get(context, texData, shape, stroke, xform, xformBounds, boundsCopy, g.isAntialiasedShape());
            }
        }

        Paint paint = bsg.getPaint();
        float bx = 0f, by = 0f, bw = 0f, bh = 0f;
        if (paint.isProportional()) {
            if (bbox == null) {
                bbox = new float[] {
                    Float.POSITIVE_INFINITY, Float.POSITIVE_INFINITY,
                    Float.NEGATIVE_INFINITY, Float.NEGATIVE_INFINITY,
                };
                Shape.accumulate(bbox, shape, BaseTransform.IDENTITY_TRANSFORM);
            }
            bx = bbox[0];
            by = bbox[1];
            bw = bbox[2] - bx;
            bh = bbox[3] - by;
        }

        int mw = texData.maskW;
        int mh = texData.maskH;
        Texture maskTex = texData.maskTex;
        float tw = maskTex.getPhysicalWidth();
        float th = maskTex.getPhysicalHeight();
        float dx1 = texData.maskX;
        float dy1 = texData.maskY;
        float dx2 = dx1 + mw;
        float dy2 = dy1 + mh;
        float tx1 = maskTex.getContentX() / tw;
        float ty1 = maskTex.getContentY() / th;
        float tx2 = tx1 + mw / tw;
        float ty2 = ty1 + mh / th;

        if (PrismSettings.primTextureSize != 0) {
            // the mask has been generated in device space, so we use
            // identity transform here
            Shader shader =
                context.validatePaintOp(bsg, IDENT,
                                        MaskType.ALPHA_TEXTURE, texData.maskTex,
                                        bx, by, bw, bh);

            VertexBuffer vb = context.getVertexBuffer();
            vb.addQuad(dx1, dy1, dx2, dy2, tx1, ty1, tx2, ty2,
                       bsg.getPaintTextureTx(xform, shader, bx, by, bw, bh));
        } else {
            // the mask has been generated in device space, so we use
            // identity transform here
            context.validatePaintOp(bsg, IDENT, texData.maskTex, bx, by, bw, bh);

            VertexBuffer vb = context.getVertexBuffer();
            vb.addQuad(dx1, dy1, dx2, dy2, tx1, ty1, tx2, ty2);
        }
        maskTex.unlock();
    }

    void dispose() {
        // Note: this method will be called from the FX thread; just
        // invalidate and let the DisposerRecord take care of cutting
        // the ties with the mask cache and disposing textures if necessary
        // (on the render thread).
        invalidate();
    }

    private static class CSRDisposerRecord implements Disposer.Record {
        private MaskTexData texData;

        private CSRDisposerRecord(MaskTexData texData) {
            this.texData = texData;
        }

        public void dispose() {
            // Note: this method should only be called from the rendering thread
            if (texData != null) {
                maskCache.unref(texData);
                texData = null;
            }
        }
    }
}