/*

 * Copyright 2016 Google Inc.

 *

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

 * found in the LICENSE file.

 */

#ifndef SkSVGRenderContext_DEFINED

#define SkSVGRenderContext_DEFINED

#include "include/core/SkFontMgr.h"

#include "include/core/SkM44.h"

#include "include/core/SkPaint.h"

#include "include/core/SkPath.h"

#include "include/core/SkRect.h"

#include "include/core/SkSize.h"

#include "include/core/SkTypes.h"

#include "modules/skresources/include/SkResources.h"

#include "modules/svg/include/SkSVGAttribute.h"

#include "modules/svg/include/SkSVGIDMapper.h"

#include "src/core/SkTLazy.h"

class SkCanvas;

class SkSVGLength;

class SkSVGLengthContext {

public:

    SkSVGLengthContext(const SkSize& viewport, SkScalar dpi = 90)

        : fViewport(viewport), fDPI(dpi) {}

    enum class LengthType {

        kHorizontal,

        kVertical,

        kOther,

    };

    const SkSize& viewPort() const { return fViewport; }

    void setViewPort(const SkSize& viewport) { fViewport = viewport; }

    SkScalar resolve(const SkSVGLength&, LengthType) const;

    SkRect   resolveRect(const SkSVGLength& x, const SkSVGLength& y,

                         const SkSVGLength& w, const SkSVGLength& h) const;

private:

    SkSize   fViewport;

    SkScalar fDPI;

};

struct SkSVGPresentationContext {

    SkSVGPresentationContext();

    SkSVGPresentationContext(const SkSVGPresentationContext&)            = default;

    SkSVGPresentationContext& operator=(const SkSVGPresentationContext&) = default;

    // Inherited presentation attributes, computed for the current node.

    SkSVGPresentationAttributes fInherited;

};

class SkSVGRenderContext {

public:

    // Captures data required for object bounding box resolution.

    struct OBBScope {

        const SkSVGNode*          fNode;

        const SkSVGRenderContext* fCtx;

    };

    SkSVGRenderContext(SkCanvas*, const sk_sp<SkFontMgr>&,

                       const sk_sp<skresources::ResourceProvider>&, const SkSVGIDMapper&,

                       const SkSVGLengthContext&, const SkSVGPresentationContext&,

                       const OBBScope&);

    SkSVGRenderContext(const SkSVGRenderContext&);

    SkSVGRenderContext(const SkSVGRenderContext&, SkCanvas*);

    // Establish a new OBB scope.  Normally used when entering a node's render scope.

    SkSVGRenderContext(const SkSVGRenderContext&, const SkSVGNode*);

    ~SkSVGRenderContext();

    const SkSVGLengthContext& lengthContext() const { return *fLengthContext; }

    SkSVGLengthContext* writableLengthContext() { return fLengthContext.writable(); }

    const SkSVGPresentationContext& presentationContext() const { return *fPresentationContext; }

    SkCanvas* canvas() const { return fCanvas; }

    void saveOnce();

    enum ApplyFlags {

        kLeaf = 1 << 0, // the target node doesn't have descendants

    };

    void applyPresentationAttributes(const SkSVGPresentationAttributes&, uint32_t flags);

    // Scoped wrapper that temporarily clears the original node reference.

    class BorrowedNode {

    public:

        explicit BorrowedNode(sk_sp<SkSVGNode>* node)

            : fOwner(node) {

            if (fOwner) {

                fBorrowed = std::move(*fOwner);

                *fOwner = nullptr;

            }

        }

        ~BorrowedNode() {

            if (fOwner) {

                *fOwner = std::move(fBorrowed);

            }

        }

        const SkSVGNode* get() const { return fBorrowed.get(); }

        const SkSVGNode* operator->() const { return fBorrowed.get(); }

        const SkSVGNode& operator*() const { return *fBorrowed; }

        operator bool() const { return !!fBorrowed; }

    private:

        // noncopyable

        BorrowedNode(const BorrowedNode&)      = delete;

        BorrowedNode& operator=(BorrowedNode&) = delete;

        sk_sp<SkSVGNode>* fOwner;

        sk_sp<SkSVGNode>  fBorrowed;

    };

    // Note: the id->node association is cleared for the lifetime of the returned value

    // (effectively breaks reference cycles, assuming appropriate return value scoping).

    BorrowedNode findNodeById(const SkSVGIRI&) const;

    SkTLazy<SkPaint> fillPaint() const;

    SkTLazy<SkPaint> strokePaint() const;

    SkSVGColorType resolveSvgColor(const SkSVGColor&) const;

    // The local computed clip path (not inherited).

    const SkPath* clipPath() const { return fClipPath.getMaybeNull(); }

    const sk_sp<skresources::ResourceProvider>& resourceProvider() const {

        return fResourceProvider;

    }

    sk_sp<SkFontMgr> fontMgr() const {

        return fFontMgr ? fFontMgr : SkFontMgr::RefDefault();

    }

    // Returns the translate/scale transformation required to map into the current OBB scope,

    // with the specified units.

    struct OBBTransform {

        SkV2 offset, scale;

    };

    OBBTransform transformForCurrentOBB(SkSVGObjectBoundingBoxUnits) const;

    SkRect resolveOBBRect(const SkSVGLength& x, const SkSVGLength& y,

                          const SkSVGLength& w, const SkSVGLength& h,

                          SkSVGObjectBoundingBoxUnits) const;

private:

    // Stack-only

    void* operator new(size_t)                               = delete;

    void* operator new(size_t, void*)                        = delete;

    SkSVGRenderContext& operator=(const SkSVGRenderContext&) = delete;

    void applyOpacity(SkScalar opacity, uint32_t flags, bool hasFilter);

    void applyFilter(const SkSVGFuncIRI&);

    void applyClip(const SkSVGFuncIRI&);

    void applyMask(const SkSVGFuncIRI&);

    SkTLazy<SkPaint> commonPaint(const SkSVGPaint&, float opacity) const;

    const sk_sp<SkFontMgr>&                       fFontMgr;

    const sk_sp<skresources::ResourceProvider>&   fResourceProvider;

    const SkSVGIDMapper&                          fIDMapper;

    SkTCopyOnFirstWrite<SkSVGLengthContext>       fLengthContext;

    SkTCopyOnFirstWrite<SkSVGPresentationContext> fPresentationContext;

    SkCanvas*                                     fCanvas;

    // The save count on 'fCanvas' at construction time.

    // A restoreToCount() will be issued on destruction.

    int                                           fCanvasSaveCount;

    // clipPath, if present for the current context (not inherited).

    SkTLazy<SkPath>                               fClipPath;

    // Deferred opacity optimization for leaf nodes.

    float                                         fDeferredPaintOpacity = 1;

    // Current object bounding box scope.

    const OBBScope                                fOBBScope;

};

#endif // SkSVGRenderContext_DEFINED