/*
 * Copyright 2015 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "SkPath.h"
#include "SkRect.h"
#include "SkRemote.h"

namespace SkRemote {

    Misc Misc::CreateFrom(const SkPaint& paint) {
        Misc misc = {
            paint.getColor(),
            paint.getFilterQuality(),
            paint.isAntiAlias(),
            paint.isDither(),
        };
        return misc;
    }

    void Misc::applyTo(SkPaint* paint) const {
        paint->setColor        (fColor);
        paint->setFilterQuality(fFilterQuality);
        paint->setAntiAlias    (fAntiAlias);
        paint->setDither       (fDither);
    }

    static bool operator==(const Misc& a, const Misc& b) {
        return a.fColor         == b.fColor
            && a.fFilterQuality == b.fFilterQuality
            && a.fAntiAlias     == b.fAntiAlias
            && a.fDither        == b.fDither;
    }

    // Misc carries 10 bytes of data in a 12 byte struct, so we need a custom hash.
    static_assert(sizeof(Misc) > offsetof(Misc, fDither) + sizeof(Misc().fDither), "");
    struct MiscHash {
        uint32_t operator()(const Misc& misc) {
            return SkChecksum::Murmur3(&misc, offsetof(Misc, fDither) + sizeof(Misc().fDither));
        }
    };

    Stroke Stroke::CreateFrom(const SkPaint& paint) {
        Stroke stroke = {
            paint.getStrokeWidth(),
            paint.getStrokeMiter(),
            paint.getStrokeCap(),
            paint.getStrokeJoin(),
        };
        return stroke;
    }

    void Stroke::applyTo(SkPaint* paint) const {
        paint->setStrokeWidth(fWidth);
        paint->setStrokeMiter(fMiter);
        paint->setStrokeCap  (fCap);
        paint->setStrokeJoin (fJoin);
    }

    static bool operator==(const Stroke& a, const Stroke& b) {
        return a.fWidth == b.fWidth
            && a.fMiter == b.fMiter
            && a.fCap   == b.fCap
            && a.fJoin  == b.fJoin;
    }

    // The default SkGoodHash works fine for Stroke, as it's dense.
    static_assert(sizeof(Stroke) == offsetof(Stroke, fJoin) + sizeof(Stroke().fJoin), "");

    // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ //

    class LookupScope {
    public:
        LookupScope(Cache* cache, Encoder* encoder) : fCache(cache), fEncoder(encoder) {}
        ~LookupScope() { for (ID id : fToUndefine) { fEncoder->undefine(id); } }
        void undefineWhenDone(ID id) { fToUndefine.push_back(id); }

        template <typename T>
        ID lookup(const T& val) {
            ID id;
            if (!fCache->lookup(val, &id, this)) {
                fEncoder->define(id, val);
            }
            return id;
        }

    private:
        Cache*   fCache;
        Encoder* fEncoder;
        SkSTArray<4, ID> fToUndefine;
    };


    Cache* Cache::CreateNeverCache() {
        struct NeverCache final : public Cache {
            NeverCache()
                : fNextMatrix(Type::kMatrix)
                , fNextMisc  (Type::kMisc)
                , fNextPath  (Type::kPath)
                , fNextStroke(Type::kStroke)
            {}
            void cleanup(Encoder*) override {}

            static bool Helper(ID* next, ID* id, LookupScope* ls) {
                *id = (*next)++;
                ls->undefineWhenDone(*id);
                return false;
            }

            bool lookup(const SkMatrix&, ID* id, LookupScope* ls) override {
                return Helper(&fNextMatrix, id, ls);
            }
            bool lookup(const Misc&, ID* id, LookupScope* ls) override {
                return Helper(&fNextMisc, id, ls);
            }
            bool lookup(const SkPath&, ID* id, LookupScope* ls) override {
                return Helper(&fNextPath, id, ls);
            }
            bool lookup(const Stroke&, ID* id, LookupScope* ls) override {
                return Helper(&fNextStroke, id, ls);
            }

            ID fNextMatrix,
               fNextMisc,
               fNextPath,
               fNextStroke;
        };
        return new NeverCache;
    }

    // Can't be declared locally inside AlwaysCache because of the templating.  :(
    template <typename T, typename Map>
    static bool always_cache_helper(const T& val, Map* map, ID* next, ID* id) {
        if (ID* found = map->find(val)) {
            *id = *found;
            return true;
        }
        *id = (*next)++;
        map->set(val, *id);
        return false;
    }

    Cache* Cache::CreateAlwaysCache() {
        struct AlwaysCache final : public Cache {
            AlwaysCache()
                : fNextMatrix(Type::kMatrix)
                , fNextMisc  (Type::kMisc)
                , fNextPath  (Type::kPath)
                , fNextStroke(Type::kStroke)
            {}

            void cleanup(Encoder* encoder) override {
                fMatrix.foreach([=](const SkMatrix&, ID* id) { encoder->undefine(*id); });
                fMisc  .foreach([=](const Misc&,     ID* id) { encoder->undefine(*id); });
                fPath  .foreach([=](const SkPath&,   ID* id) { encoder->undefine(*id); });
                fStroke.foreach([=](const Stroke&,   ID* id) { encoder->undefine(*id); });
            }


            bool lookup(const SkMatrix& matrix, ID* id, LookupScope*) override {
                return always_cache_helper(matrix, &fMatrix, &fNextMatrix, id);
            }
            bool lookup(const Misc& misc, ID* id, LookupScope*) override {
                return always_cache_helper(misc, &fMisc, &fNextMisc, id);
            }
            bool lookup(const SkPath& path, ID* id, LookupScope*) override {
                return always_cache_helper(path, &fPath, &fNextPath, id);
            }
            bool lookup(const Stroke& stroke, ID* id, LookupScope*) override {
                return always_cache_helper(stroke, &fStroke, &fNextStroke, id);
            }

            SkTHashMap<SkMatrix, ID>           fMatrix;
            SkTHashMap<Misc,     ID, MiscHash> fMisc;
            SkTHashMap<SkPath,   ID>           fPath;
            SkTHashMap<Stroke,   ID>           fStroke;
            ID fNextMatrix,
               fNextMisc,
               fNextPath,
               fNextStroke;
        };
        return new AlwaysCache;
    }

    // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ //

    Client::Client(Cache* cache, Encoder* encoder)
        : SkCanvas(1,1)
        , fCache(cache)
        , fEncoder(encoder)
    {}

    Client::~Client() {
        fCache->cleanup(fEncoder);
    }

    void Client::willSave()   { fEncoder->save(); }
    void Client::didRestore() { fEncoder->restore(); }

    void Client::didConcat   (const SkMatrix&) { this->didSetMatrix(this->getTotalMatrix()); }
    void Client::didSetMatrix(const SkMatrix& matrix) {
        LookupScope ls(fCache, fEncoder);
        fEncoder->setMatrix(ls.lookup(matrix));
    }

    void Client::onDrawOval(const SkRect& oval, const SkPaint& paint) {
        SkPath path;
        path.addOval(oval);
        this->onDrawPath(path, paint);
    }

    void Client::onDrawRect(const SkRect& rect, const SkPaint& paint) {
        SkPath path;
        path.addRect(rect);
        this->onDrawPath(path, paint);
    }

    void Client::onDrawRRect(const SkRRect& rrect, const SkPaint& paint) {
        SkPath path;
        path.addRRect(rrect);
        this->onDrawPath(path, paint);
    }

    void Client::onDrawDRRect(const SkRRect& outside,
                              const SkRRect& inside,
                              const SkPaint& paint) {
        SkPath path;
        path.addRRect(outside);
        path.addRRect(inside, SkPath::kCCW_Direction);
        this->onDrawPath(path, paint);
    }

    void Client::onDrawPath(const SkPath& path, const SkPaint& paint) {
        LookupScope ls(fCache, fEncoder);
        ID p = ls.lookup(path),
           m = ls.lookup(Misc::CreateFrom(paint));

        if (paint.getStyle() == SkPaint::kFill_Style) {
            fEncoder->fillPath(p, m);
        } else {
            // TODO: handle kStrokeAndFill_Style
            fEncoder->strokePath(p, m, ls.lookup(Stroke::CreateFrom(paint)));
        }
    }

    void Client::onDrawPaint(const SkPaint& paint) {
        SkPath path;
        path.setFillType(SkPath::kInverseWinding_FillType);  // Either inverse FillType works fine.
        this->onDrawPath(path, paint);
    }

    void Client::onDrawText(const void* text, size_t byteLength, SkScalar x,
                            SkScalar y, const SkPaint& paint) {
        // Text-as-paths is a temporary hack.
        // TODO: send SkTextBlobs and SkTypefaces
        SkPath path;
        paint.getTextPath(text, byteLength, x, y, &path);
        this->onDrawPath(path, paint);
    }

    void Client::onDrawPosText(const void* text, size_t byteLength,
                               const SkPoint pos[], const SkPaint& paint) {
        // Text-as-paths is a temporary hack.
        // TODO: send SkTextBlobs and SkTypefaces
        SkPath path;
        paint.getPosTextPath(text, byteLength, pos, &path);
        this->onDrawPath(path, paint);
    }

    void Client::onDrawPosTextH(const void* text, size_t byteLength,
                                const SkScalar xpos[], SkScalar constY,
                                const SkPaint& paint) {
        size_t length = paint.countText(text, byteLength);
        SkAutoTArray<SkPoint> pos(length);
        for(size_t i = 0; i < length; ++i) {
            pos[i].set(xpos[i], constY);
        }
        this->onDrawPosText(text, byteLength, &pos[0], paint);
    }

    void Client::onClipRect(const SkRect& rect, SkRegion::Op op, ClipEdgeStyle edgeStyle) {
        SkPath path;
        path.addRect(rect);
        this->onClipPath(path, op, edgeStyle);
    }

    void Client::onClipRRect(const SkRRect& rrect, SkRegion::Op op, ClipEdgeStyle edgeStyle) {
        SkPath path;
        path.addRRect(rrect);
        this->onClipPath(path, op, edgeStyle);
    }

    void Client::onClipPath(const SkPath& path, SkRegion::Op op, ClipEdgeStyle edgeStyle) {
        LookupScope ls(fCache, fEncoder);
        fEncoder->clipPath(ls.lookup(path), op, edgeStyle == kSoft_ClipEdgeStyle);
    }

    // ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ //

    Server::Server(SkCanvas* canvas) : fCanvas(canvas) {}

    void Server::define(ID id, const SkMatrix& v) { fMatrix.set(id, v); }
    void Server::define(ID id, const Misc&     v) { fMisc  .set(id, v); }
    void Server::define(ID id, const SkPath&   v) { fPath  .set(id, v); }
    void Server::define(ID id, const Stroke&   v) { fStroke.set(id, v); }

    void Server::undefine(ID id) {
        switch(id.type()) {
            case Type::kMatrix: return fMatrix.remove(id);
            case Type::kMisc:   return fMisc  .remove(id);
            case Type::kPath:   return fPath  .remove(id);
            case Type::kStroke: return fStroke.remove(id);

            case Type::kNone: SkASSERT(false);
        };
    }

    void Server::   save() { fCanvas->save(); }
    void Server::restore() { fCanvas->restore(); }

    void Server::setMatrix(ID matrix) { fCanvas->setMatrix(fMatrix.find(matrix)); }

    void Server::clipPath(ID path, SkRegion::Op op, bool aa) {
        fCanvas->clipPath(fPath.find(path), op, aa);
    }
    void Server::fillPath(ID path, ID misc) {
        SkPaint paint;
        paint.setStyle(SkPaint::kFill_Style);
        fMisc.find(misc).applyTo(&paint);
        fCanvas->drawPath(fPath.find(path), paint);
    }
    void Server::strokePath(ID path, ID misc, ID stroke) {
        SkPaint paint;
        paint.setStyle(SkPaint::kStroke_Style);
        fMisc  .find(misc  ).applyTo(&paint);
        fStroke.find(stroke).applyTo(&paint);
        fCanvas->drawPath(fPath.find(path), paint);
    }

} // namespace SkRemote