/*

 * Copyright 2021 Google LLC

 *

 * Use of this source code is governed by a BSD-style license that can be

 * found in the LICENSE file.

 */

#include "tools/MSKPPlayer.h"

#include "include/core/SkCanvas.h"

#include "include/core/SkCanvasVirtualEnforcer.h"

#include "include/core/SkPicture.h"

#include "include/core/SkPictureRecorder.h"

#include "include/core/SkSurface.h"

#include "include/docs/SkMultiPictureDocument.h"

#include "include/gpu/GrDirectContext.h"

#include "include/private/base/SkTArray.h"

#include "include/utils/SkNoDrawCanvas.h"

#include "src/base/SkTLazy.h"

#include "src/core/SkCanvasPriv.h"

#include "src/core/SkStringUtils.h"

#include "tools/SkSharingProc.h"

using namespace skia_private;

///////////////////////////////////////////////////////////////////////////////

// Base Cmd struct.

struct MSKPPlayer::Cmd {

    virtual ~Cmd() = default;

    virtual bool isFullRedraw(SkCanvas*) const = 0;

    virtual void draw(SkCanvas* canvas, const LayerMap&, LayerStateMap*) const = 0;

    // If this command draws another layer, return it's ID. Otherwise, -1.

    virtual int layerID() const { return -1; }

};

// Draws a SkPicture.

struct MSKPPlayer::PicCmd : Cmd {

    sk_sp<SkPicture> fContent;

    SkIRect fClipRect = SkIRect::MakeEmpty(); // clip for picture (no clip if empty).

    bool isFullRedraw(SkCanvas* canvas) const override {

        if (fClipRect.isEmpty()) {

            return false;

        }

        return fClipRect.contains(SkIRect::MakeSize(canvas->getBaseLayerSize()));

    }

    void draw(SkCanvas* canvas, const LayerMap&, LayerStateMap*) const override {

        if (!fClipRect.isEmpty()) {

            canvas->save();

            canvas->clipIRect(fClipRect);

        }

        canvas->drawPicture(fContent.get());

        if (!fClipRect.isEmpty()) {

            canvas->restore();

        }

    }

};

// Draws another layer. Stores the ID of the layer to draw and what command index on that

// layer should be current when the layer is drawn. The layer contents are updated to the

// stored command index before the layer is drawn.

struct MSKPPlayer::DrawLayerCmd : Cmd {

    int                         fLayerId;

    size_t                      fLayerCmdCnt;

    SkRect                      fSrcRect;

    SkRect                      fDstRect;

    SkSamplingOptions           fSampling;

    SkCanvas::SrcRectConstraint fConstraint;

    SkTLazy<SkPaint>            fPaint;

    bool isFullRedraw(SkCanvas* canvas) const override { return false; }

    void draw(SkCanvas* canvas, const LayerMap&, LayerStateMap*) const override;

    int layerID() const override { return fLayerId; }

};

void MSKPPlayer::DrawLayerCmd::draw(SkCanvas* canvas,

                                    const LayerMap& layerMap,

                                    LayerStateMap* layerStateMap) const {

    const LayerCmds& layer = layerMap.at(fLayerId);

    LayerState* layerState = &(*layerStateMap)[fLayerId];

    if (!layerState->fSurface) {

        layerState->fCurrCmd = 0;

        layerState->fSurface = MSKPPlayer::MakeSurfaceForLayer(layer, canvas);

        if (!layerState->fSurface) {

            SkDebugf("Couldn't create surface for layer");

            return;

        }

    }

    size_t cmd = layerState->fCurrCmd;

    if (cmd > fLayerCmdCnt) {

        // If the layer contains contents from later commands then replay from the beginning.

        cmd = 0;

    }

    SkCanvas* layerCanvas = layerState->fSurface->getCanvas();

    // Check if there is a full redraw between cmd and fLayerCmdCnt and if so jump to it and ensure

    // we clear the canvas if starting from a full redraw.

    for (size_t checkCmd = fLayerCmdCnt - 1; checkCmd > cmd; --checkCmd) {

        if (layer.fCmds[checkCmd]->isFullRedraw(layerCanvas)) {

            cmd = checkCmd;

            break;

        }

    }

    for (; cmd < fLayerCmdCnt; ++cmd) {

        if (cmd == 0 || layer.fCmds[cmd]->isFullRedraw(layerCanvas)) {

            layerState->fSurface->getCanvas()->clear(SK_ColorTRANSPARENT);

        }

        layer.fCmds[cmd]->draw(layerCanvas, layerMap, layerStateMap);

    }

    layerState->fCurrCmd = fLayerCmdCnt;

    const SkPaint* paint = fPaint.isValid() ? fPaint.get() : nullptr;

    canvas->drawImageRect(layerState->fSurface->makeImageSnapshot(),

                          fSrcRect,

                          fDstRect,

                          fSampling,

                          paint,

                          fConstraint);

}

///////////////////////////////////////////////////////////////////////////////

class MSKPPlayer::CmdRecordCanvas : public SkCanvasVirtualEnforcer<SkCanvas> {

public:

    CmdRecordCanvas(LayerCmds* dst, LayerMap* offscreenLayers, const SkIRect* clipRect = nullptr)

            : fDst(dst), fOffscreenLayers(offscreenLayers) {

        if (clipRect) {

            fClipRect = *clipRect;

        }

        fRecorder.beginRecording(SkRect::Make(dst->fDimensions));

    }

    ~CmdRecordCanvas() override { this->recordPicCmd(); }

protected:

    void onDrawPaint(const SkPaint& paint) override {

        fRecorder.getRecordingCanvas()->drawPaint(paint);

    }

    void onDrawBehind(const SkPaint& paint) override {

        SkCanvasPriv::DrawBehind(fRecorder.getRecordingCanvas(), paint);

    }

    void onDrawRect(const SkRect& rect, const SkPaint& paint) override {

        fRecorder.getRecordingCanvas()->drawRect(rect, paint);

    }

    void onDrawRRect(const SkRRect& rrect, const SkPaint& paint) override {

        fRecorder.getRecordingCanvas()->drawRRect(rrect, paint);

    }

    void onDrawDRRect(const SkRRect& outer, const SkRRect& inner, const SkPaint& paint) override {

        fRecorder.getRecordingCanvas()->drawDRRect(outer, inner, paint);

    }

    void onDrawOval(const SkRect& rect, const SkPaint& paint) override {

        fRecorder.getRecordingCanvas()->drawOval(rect, paint);

    }

    void onDrawArc(const SkRect& rect,

                   SkScalar startAngle,

                   SkScalar sweepAngle,

                   bool useCenter,

                   const SkPaint& paint) override {

        fRecorder.getRecordingCanvas()->drawArc(rect, startAngle, sweepAngle, useCenter, paint);

    }

    void onDrawPath(const SkPath& path, const SkPaint& paint) override {

        fRecorder.getRecordingCanvas()->drawPath(path, paint);

    }

    void onDrawRegion(const SkRegion& region, const SkPaint& paint) override {

        fRecorder.getRecordingCanvas()->drawRegion(region, paint);

    }

    void onDrawTextBlob(const SkTextBlob* blob,

                        SkScalar x,

                        SkScalar y,

                        const SkPaint& paint) override {

        fRecorder.getRecordingCanvas()->drawTextBlob(blob, x, y, paint);

    }

    void onDrawPatch(const SkPoint cubics[12],

                     const SkColor colors[4],

                     const SkPoint texCoords[4],

                     SkBlendMode mode,

                     const SkPaint& paint) override {

        fRecorder.getRecordingCanvas()->drawPatch(cubics, colors, texCoords, mode, paint);

    }

    void onDrawPoints(SkCanvas::PointMode mode,

                      size_t count,

                      const SkPoint pts[],

                      const SkPaint& paint) override {

        fRecorder.getRecordingCanvas()->drawPoints(mode, count, pts, paint);

    }

    void onDrawImage2(const SkImage* image,

                      SkScalar dx,

                      SkScalar dy,

                      const SkSamplingOptions& sampling,

                      const SkPaint* paint) override {

        fRecorder.getRecordingCanvas()->drawImage(image, dx, dy, sampling, paint);

    }

    void onDrawImageRect2(const SkImage* image,

                          const SkRect& src,

                          const SkRect& dst,

                          const SkSamplingOptions& sampling,

                          const SkPaint* paint,

                          SrcRectConstraint constraint) override {

        if (fNextDrawImageFromLayerID != -1) {

            this->recordPicCmd();

            auto drawLayer = std::make_unique<DrawLayerCmd>();

            drawLayer->fLayerId = fNextDrawImageFromLayerID;

            drawLayer->fLayerCmdCnt = fOffscreenLayers->at(fNextDrawImageFromLayerID).fCmds.size();

            drawLayer->fSrcRect = src;

            drawLayer->fDstRect = dst;

            drawLayer->fSampling = sampling;

            drawLayer->fConstraint = constraint;

            if (paint) {

                drawLayer->fPaint.init(*paint);

            }

            fDst->fCmds.push_back(std::move(drawLayer));

            fNextDrawImageFromLayerID = -1;

            return;

        }

        fRecorder.getRecordingCanvas()->drawImageRect(image, src, dst, sampling, paint, constraint);

    }

    void onDrawImageLattice2(const SkImage* image,

                             const Lattice& lattice,

                             const SkRect& dst,

                             SkFilterMode mode,

                             const SkPaint* paint) override {

        fRecorder.getRecordingCanvas()->drawImageLattice(image, lattice, dst, mode, paint);

    }

    void onDrawAtlas2(const SkImage* image,

                      const SkRSXform rsxForms[],

                      const SkRect src[],

                      const SkColor colors[],

                      int count,

                      SkBlendMode mode,

                      const SkSamplingOptions& sampling,

                      const SkRect* cull,

                      const SkPaint* paint) override {

        fRecorder.getRecordingCanvas()->drawAtlas(image,

                                                  rsxForms,

                                                  src,

                                                  colors,

                                                  count,

                                                  mode,

                                                  sampling,

                                                  cull,

                                                  paint);

    }

    void onDrawEdgeAAImageSet2(const ImageSetEntry imageSet[],

                               int count,

                               const SkPoint dstClips[],

                               const SkMatrix preViewMatrices[],

                               const SkSamplingOptions& sampling,

                               const SkPaint* paint,

                               SrcRectConstraint constraint) override {

        fRecorder.getRecordingCanvas()->experimental_DrawEdgeAAImageSet(imageSet,

                                                                        count,

                                                                        dstClips,

                                                                        preViewMatrices,

                                                                        sampling,

                                                                        paint,

                                                                        constraint);

    }

#ifdef SK_BUILD_FOR_ANDROID_FRAMEWORK

    void onDrawEdgeAAQuad(const SkRect& rect,

                          const SkPoint clip[4],

                          SkCanvas::QuadAAFlags aaFlags,

                          const SkColor4f& color,

                          SkBlendMode mode) override {}

#else

    void onDrawEdgeAAQuad(const SkRect& rect,

                          const SkPoint clip[4],

                          SkCanvas::QuadAAFlags aaFlags,

                          const SkColor4f& color,

                          SkBlendMode mode) override {

        fRecorder.getRecordingCanvas()->experimental_DrawEdgeAAQuad(rect,

                                                                    clip,

                                                                    aaFlags,

                                                                    color,

                                                                    mode);

    }

#endif

    void onDrawAnnotation(const SkRect& rect, const char key[], SkData* value) override {

        static constexpr char kOffscreenLayerDraw[] = "OffscreenLayerDraw";

        static constexpr char kSurfaceID[] = "SurfaceID";

        TArray<SkString> tokens;

        SkStrSplit(key, "|", kStrict_SkStrSplitMode, &tokens);

        if (tokens.size() == 2) {

            if (tokens[0].equals(kOffscreenLayerDraw)) {

                // Indicates that the next drawPicture command contains the SkPicture to render

                // to the layer identified by the ID. 'rect' indicates the dirty area to update

                // (and indicates the layer size if this command is introducing a new layer id).

                fNextDrawPictureToLayerID = std::stoi(tokens[1].c_str());

                fNextDrawPictureToLayerClipRect = rect.roundOut();

                if (fOffscreenLayers->find(fNextDrawPictureToLayerID) == fOffscreenLayers->end()) {

                    SkASSERT(fNextDrawPictureToLayerClipRect.left() == 0 &&

                             fNextDrawPictureToLayerClipRect.top()  == 0);

                    (*fOffscreenLayers)[fNextDrawPictureToLayerID].fDimensions =

                            fNextDrawPictureToLayerClipRect.size();

                }

                // The next draw picture will notice that fNextDrawPictureToLayerID is set and

                // redirect the picture to the offscreen layer.

                return;

            } else if (tokens[0].equals(kSurfaceID)) {

                // Indicates that the following drawImageRect should draw an offscreen layer

                // to this layer.

                fNextDrawImageFromLayerID = std::stoi(tokens[1].c_str());

                return;

            }

        }

    }

Unexecuted instantiation: MSKPPlayer::CmdRecordCanvas::onDrawAnnotation(SkRect const&, char const*, SkData*)

Unexecuted instantiation: MSKPPlayer::CmdRecordCanvas::onDrawAnnotation(SkRect const&, char const*, SkData*)

    void onDrawShadowRec(const SkPath& path, const SkDrawShadowRec& rec) override {

        fRecorder.getRecordingCanvas()->private_draw_shadow_rec(path, rec);

    }

    void onDrawDrawable(SkDrawable* drawable, const SkMatrix* matrix) override {

        fRecorder.getRecordingCanvas()->drawDrawable(drawable, matrix);

    }

    void onDrawPicture(const SkPicture* picture,

                       const SkMatrix* matrix,

                       const SkPaint* paint) override {

        if (fNextDrawPictureToLayerID != -1) {

            SkASSERT(!matrix);

            SkASSERT(!paint);

            LayerCmds* layer = &fOffscreenLayers->at(fNextDrawPictureToLayerID);

            CmdRecordCanvas sc(layer, fOffscreenLayers, &fNextDrawPictureToLayerClipRect);

            picture->playback(&sc);

            fNextDrawPictureToLayerID = -1;

            fNextDrawPictureToLayerClipRect = SkIRect::MakeEmpty();

            return;

        }

        if (paint) {

            this->saveLayer(nullptr, paint);

        }

        if (matrix) {

            this->save();

            this->concat(*matrix);

        }

        picture->playback(this);

        if (matrix) {

            this->restore();

        }

        if (paint) {

            this->restore();

        }

    }

Unexecuted instantiation: MSKPPlayer::CmdRecordCanvas::onDrawPicture(SkPicture const*, SkMatrix const*, SkPaint const*)

Unexecuted instantiation: MSKPPlayer::CmdRecordCanvas::onDrawPicture(SkPicture const*, SkMatrix const*, SkPaint const*)

private:

    void recordPicCmd() {

        auto cmd = std::make_unique<PicCmd>();

        cmd->fContent = fRecorder.finishRecordingAsPicture();

        cmd->fClipRect = fClipRect;

        if (cmd->fContent) {

            fDst->fCmds.push_back(std::move(cmd));

        }

        // Set up to accumulate again.

        fRecorder.beginRecording(SkRect::Make(fDst->fDimensions));

    }

    SkPictureRecorder fRecorder; // accumulates draws until we draw an offscreen into this layer.

    LayerCmds*        fDst                            = nullptr;

    SkIRect           fClipRect                       = SkIRect::MakeEmpty();

    int               fNextDrawPictureToLayerID       = -1;

    SkIRect           fNextDrawPictureToLayerClipRect = SkIRect::MakeEmpty();

    int               fNextDrawImageFromLayerID       = -1;

    LayerMap*         fOffscreenLayers                = nullptr;

};

///////////////////////////////////////////////////////////////////////////////

std::unique_ptr<MSKPPlayer> MSKPPlayer::Make(SkStreamSeekable* stream) {

    auto deserialContext = std::make_unique<SkSharingDeserialContext>();

    SkDeserialProcs procs;

    procs.fImageProc = SkSharingDeserialContext::deserializeImage;

    procs.fImageCtx = deserialContext.get();

    int pageCount = SkMultiPictureDocument::ReadPageCount(stream);

    if (!pageCount) {

        return nullptr;

    }

    std::vector<SkDocumentPage> pages(pageCount);

    if (!SkMultiPictureDocument::Read(stream, pages.data(), pageCount, &procs)) {

        return nullptr;

    }

    std::unique_ptr<MSKPPlayer> result(new MSKPPlayer);

    result->fRootLayers.reserve(pages.size());

    for (const auto& page : pages) {

        SkISize dims = {SkScalarCeilToInt(page.fSize.width()),

                        SkScalarCeilToInt(page.fSize.height())};

        result->fRootLayers.emplace_back();

        result->fRootLayers.back().fDimensions = dims;

        result->fMaxDimensions.fWidth  = std::max(dims.width() , result->fMaxDimensions.width() );

        result->fMaxDimensions.fHeight = std::max(dims.height(), result->fMaxDimensions.height());

        CmdRecordCanvas sc(&result->fRootLayers.back(), &result->fOffscreenLayers);

        page.fPicture->playback(&sc);

    }

    return result;

}

MSKPPlayer::~MSKPPlayer() = default;

SkISize MSKPPlayer::frameDimensions(int i) const {

    if (i < 0 || i >= this->numFrames()) {

        return {-1, -1};

    }

    return fRootLayers[i].fDimensions;

}

bool MSKPPlayer::playFrame(SkCanvas* canvas, int i) {

    if (i < 0 || i >= this->numFrames()) {

        return false;

    }

    // Find the first offscreen layer that has a valid surface. If it's recording context

    // differs from the passed canvas's then reset all the layers. Playback will

    // automatically allocate new surfaces for offscreen layers as they're encountered.

    for (const auto& ols : fOffscreenLayerStates) {

        const LayerState& state = ols.second;

        if (state.fSurface) {

            if (state.fSurface->recordingContext() != canvas->recordingContext()) {

                this->resetLayers();

            }

            break;

        }

    }

    // Replay all the commands for this frame to the caller's canvas.

    const LayerCmds& layer = fRootLayers[i];

    for (const auto& cmd : layer.fCmds) {

        cmd->draw(canvas, fOffscreenLayers, &fOffscreenLayerStates);

    }

    return true;

}

sk_sp<SkSurface> MSKPPlayer::MakeSurfaceForLayer(const LayerCmds& layer, SkCanvas* rootCanvas) {

    // Assume layer has same surface props and info as this (mskp doesn't currently record this

    // data).

    SkSurfaceProps props;

    rootCanvas->getProps(&props);

    return rootCanvas->makeSurface(rootCanvas->imageInfo().makeDimensions(layer.fDimensions),

                                   &props);

}

void MSKPPlayer::resetLayers() { fOffscreenLayerStates.clear(); }

void MSKPPlayer::rewindLayers() {

    for (auto& [id, state] : fOffscreenLayerStates) {

        state.fCurrCmd = -1;

    }

}

void MSKPPlayer::allocateLayers(SkCanvas* canvas) {

    // Iterate over layers not states as states are lazily created in playback but here we want to

    // create any that don't already exist.

    for (auto& [id, layer] : fOffscreenLayers) {

        LayerState& state = fOffscreenLayerStates[id];

        if (!state.fSurface || state.fSurface->recordingContext() != canvas->recordingContext()) {

            state.fCurrCmd = -1;

            state.fSurface = MakeSurfaceForLayer(fOffscreenLayers[id], canvas);

        }

    }

}

std::vector<int> MSKPPlayer::layerIDs(int frame) const {

    std::vector<int> result;

    if (frame < 0) {

        result.reserve(fOffscreenLayers.size());

        for (auto& [id, _] : fOffscreenLayers) {

            result.push_back(id);

        }

        return result;

    }

    if (frame < static_cast<int>(fRootLayers.size())) {

        this->collectReferencedLayers(fRootLayers[frame], &result);

    }

    return result;

}

sk_sp<SkImage> MSKPPlayer::layerSnapshot(int layerID) const {

    auto iter = fOffscreenLayerStates.find(layerID);

    if (iter == fOffscreenLayerStates.end() || !iter->second.fSurface) {

        return nullptr;

    }

    return iter->second.fSurface->makeImageSnapshot();

}

void MSKPPlayer::collectReferencedLayers(const LayerCmds& layer, std::vector<int>* out) const {

    for (const auto& cmd : layer.fCmds) {

        if (int id = cmd->layerID(); id >= 0) {

            // Linear, but we'd need to have a lot of layers to actually care.

            if (std::find(out->begin(), out->end(), id) == out->end()) {

                out->push_back(id);

                auto iter = fOffscreenLayers.find(id);

                SkASSERT(iter != fOffscreenLayers.end());

                this->collectReferencedLayers(iter->second, out);

            }

        }

    }

}

Unexecuted instantiation: MSKPPlayer::collectReferencedLayers(MSKPPlayer::LayerCmds const&, std::__1::vector<int, std::__1::allocator<int> >*) const

Unexecuted instantiation: MSKPPlayer::collectReferencedLayers(MSKPPlayer::LayerCmds const&, std::__1::vector<int, std::__1::allocator<int> >*) const