/*
 * Copyright 2021 Google LLC
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#ifndef skgpu_graphite_Caps_DEFINED
#define skgpu_graphite_Caps_DEFINED

#include <optional>
#include <string>
#include <string_view>
#include <utility>

#include "include/core/SkImageInfo.h"
#include "include/core/SkRefCnt.h"
#include "include/private/base/SkAlign.h"
#include "src/base/SkEnumBitMask.h"
#include "src/gpu/ResourceKey.h"
#include "src/gpu/Swizzle.h"
#include "src/gpu/graphite/ResourceTypes.h"
#include "src/gpu/graphite/TextureProxy.h"
#include "src/text/gpu/SubRunControl.h"

#if defined(GPU_TEST_UTILS)
#include "src/gpu/graphite/ContextOptionsPriv.h"
#endif

enum class SkBlendMode;
enum class SkTextureCompressionType;
class SkCapabilities;

namespace SkSL { struct ShaderCaps; }

namespace skgpu { class ShaderErrorHandler; }

namespace skgpu::graphite {

enum class BufferType : int;
struct ContextOptions;
class ComputePipelineDesc;
class GraphicsPipelineDesc;
class GraphiteResourceKey;
class RendererProvider;
struct RenderPassDesc;
class TextureInfo;

struct ResourceBindingRequirements {
    // The required data layout rules for the contents of a uniform buffer.
    Layout fUniformBufferLayout = Layout::kInvalid;

    // The required data layout rules for the contents of a storage buffer.
    Layout fStorageBufferLayout = Layout::kInvalid;

    // Whether combined texture-sampler types are supported. Backends that do not support
    // combined image samplers (i.e. sampler2D) require a texture and sampler object to be bound
    // separately and their binding indices explicitly specified in the shader text.
    bool fSeparateTextureAndSamplerBinding = false;

    // Whether buffer, texture, and sampler resource bindings use distinct index ranges.
    bool fDistinctIndexRanges = false;

    int fIntrinsicBufferBinding = -1;
    int fRenderStepBufferBinding = -1;
    int fPaintParamsBufferBinding = -1;
    int fGradientBufferBinding = -1;
};

enum class DstReadRequirement {
    kNone,
    kTextureCopy,
    kTextureSample,
    kFramebufferFetch,
};

class Caps {
public:
    virtual ~Caps();

    const SkSL::ShaderCaps* shaderCaps() const { return fShaderCaps.get(); }

    sk_sp<SkCapabilities> capabilities() const;

#if defined(GPU_TEST_UTILS)
    std::string_view deviceName() const { return fDeviceName; }

    PathRendererStrategy requestedPathRendererStrategy() const {
        return fRequestedPathRendererStrategy;
    }
#endif

    virtual TextureInfo getDefaultSampledTextureInfo(SkColorType,
                                                     Mipmapped mipmapped,
                                                     Protected,
                                                     Renderable) const = 0;

    virtual TextureInfo getTextureInfoForSampledCopy(const TextureInfo& textureInfo,
                                                     Mipmapped mipmapped) const = 0;

    virtual TextureInfo getDefaultCompressedTextureInfo(SkTextureCompressionType,
                                                        Mipmapped mipmapped,
                                                        Protected) const = 0;

    virtual TextureInfo getDefaultMSAATextureInfo(const TextureInfo& singleSampledInfo,
                                                  Discardable discardable) const = 0;

    virtual TextureInfo getDefaultDepthStencilTextureInfo(SkEnumBitMask<DepthStencilFlags>,
                                                          uint32_t sampleCount,
                                                          Protected) const = 0;

    virtual TextureInfo getDefaultStorageTextureInfo(SkColorType) const = 0;

    // Get required depth attachment dimensions for a givin color attachment info and dimensions.
    virtual SkISize getDepthAttachmentDimensions(const TextureInfo&,
                                                 const SkISize colorAttachmentDimensions) const;

    virtual UniqueKey makeGraphicsPipelineKey(const GraphicsPipelineDesc&,
                                              const RenderPassDesc&) const = 0;
    virtual UniqueKey makeComputePipelineKey(const ComputePipelineDesc&) const = 0;

    // Returns a GraphiteResourceKey based upon a SamplerDesc with any additional information that
    // backends append within their implementation. By default, simply returns a key based upon
    // the SamplerDesc with no extra info.
    // TODO: Rather than going through a GraphiteResourceKey, migrate to having a cache of samplers
    // keyed off of SamplerDesc to minimize heap allocations.
    virtual GraphiteResourceKey makeSamplerKey(const SamplerDesc& samplerDesc) const;

    // Backends can optionally override this method to return meaningful sampler conversion info.
    // By default, simply return a default ImmutableSamplerInfo.
    virtual ImmutableSamplerInfo getImmutableSamplerInfo(const TextureProxy*) const {
        return {};
    }

    virtual bool extractGraphicsDescs(const UniqueKey&,
                                      GraphicsPipelineDesc*,
                                      RenderPassDesc*,
                                      const RendererProvider*) const { return false; }

    bool areColorTypeAndTextureInfoCompatible(SkColorType, const TextureInfo&) const;
    virtual uint32_t channelMask(const TextureInfo&) const = 0;

    bool isTexturable(const TextureInfo&) const;
    virtual bool isRenderable(const TextureInfo&) const = 0;
    virtual bool isStorage(const TextureInfo&) const = 0;

    virtual bool loadOpAffectsMSAAPipelines() const { return false; }

    int maxTextureSize() const { return fMaxTextureSize; }
    int defaultMSAASamplesCount() const { return fDefaultMSAASamples; }

    virtual void buildKeyForTexture(SkISize dimensions,
                                    const TextureInfo&,
                                    ResourceType,
                                    Shareable,
                                    GraphiteResourceKey*) const = 0;

    const ResourceBindingRequirements& resourceBindingRequirements() const {
        return fResourceBindingReqs;
    }

    // Returns the required alignment in bytes for the offset into a uniform buffer when binding it
    // to a draw.
    size_t requiredUniformBufferAlignment() const { return fRequiredUniformBufferAlignment; }

    // Returns the required alignment in bytes for the offset into a storage buffer when binding it
    // to a draw.
    size_t requiredStorageBufferAlignment() const { return fRequiredStorageBufferAlignment; }

    // Returns the required alignment in bytes for the offset and size of copies involving a buffer.
    size_t requiredTransferBufferAlignment() const { return fRequiredTransferBufferAlignment; }

    // Returns the aligned rowBytes when transfering to or from a Texture
    size_t getAlignedTextureDataRowBytes(size_t rowBytes) const {
        return SkAlignTo(rowBytes, fTextureDataRowBytesAlignment);
    }

    /**
     * Backends may have restrictions on what types of textures support Device::writePixels().
     * If this returns false then the caller should implement a fallback where a temporary texture
     * is created, pixels are written to it, and then that is copied or drawn into the the surface.
     */
    virtual bool supportsWritePixels(const TextureInfo& textureInfo) const = 0;

    /**
     * Backends may have restrictions on what types of textures support Device::readPixels().
     * If this returns false then the caller should implement a fallback where a temporary texture
     * is created, the original texture is copied or drawn into it, and then pixels read from
     * the temporary texture.
     */
    virtual bool supportsReadPixels(const TextureInfo& textureInfo) const = 0;

    /**
     * Given a dst pixel config and a src color type what color type must the caller coax the
     * the data into in order to use writePixels.
     *
     * We currently don't have an SkColorType for a 3 channel RGB format. Additionally the current
     * implementation of raster pipeline requires power of 2 channels, so it is not easy to add such
     * an SkColorType. Thus we need to check for data that is 3 channels using the isRGBFormat
     * return value and handle it manually
     */
    virtual std::pair<SkColorType, bool /*isRGB888Format*/> supportedWritePixelsColorType(
            SkColorType dstColorType,
            const TextureInfo& dstTextureInfo,
            SkColorType srcColorType) const = 0;

    /**
     * Given a src surface's color type and its texture info as well as a color type the caller
     * would like read into, this provides a legal color type that the caller can use for
     * readPixels. The returned color type may differ from the passed dstColorType, in
     * which case the caller must convert the read pixel data (see GrConvertPixels). When converting
     * to dstColorType the swizzle in the returned struct should be applied. The caller must check
     * the returned color type for kUnknown.
     *
     * We currently don't have an SkColorType for a 3 channel RGB format. Additionally the current
     * implementation of raster pipeline requires power of 2 channels, so it is not easy to add such
     * an SkColorType. Thus we need to check for data that is 3 channels using the isRGBFormat
     * return value and handle it manually
     */
    virtual std::pair<SkColorType, bool /*isRGBFormat*/> supportedReadPixelsColorType(
            SkColorType srcColorType,
            const TextureInfo& srcTextureInfo,
            SkColorType dstColorType) const = 0;

    /**
     * Checks whether the passed color type is renderable. If so, the same color type is passed
     * back. If not, provides an alternative (perhaps lower bit depth and/or unorm instead of float)
     * color type that is supported or kUnknown if there no renderable fallback format.
     */
    SkColorType getRenderableColorType(SkColorType) const;

    // Determines the orientation of the NDC coordinates emitted by the vertex stage relative to
    // both Skia's presumed top-left Y-down system and the viewport coordinates (which are also
    // always top-left, Y-down for all supported backends).)
    //
    // If true is returned, then (-1,-1) in normalized device coords maps to the top-left of the
    // configured viewport and positive Y points down. This aligns with Skia's conventions.
    // If false is returned, then (-1,-1) in NDC maps to the bottom-left of the viewport and
    // positive Y points up (so NDC is flipped relative to sk_Position and the viewport coords).
    //
    // There is no backend difference in handling the X axis so it's assumed -1 maps to the left
    // edge and +1 maps to the right edge.
    bool ndcYAxisPointsDown() const { return fNDCYAxisPointsDown; }

    bool clampToBorderSupport() const { return fClampToBorderSupport; }

    bool protectedSupport() const { return fProtectedSupport; }

    // Supports BackendSemaphores
    bool semaphoreSupport() const { return fSemaphoreSupport; }

    // If false then calling Context::submit with SyncToCpu::kYes is an error.
    bool allowCpuSync() const { return fAllowCpuSync; }

    // Returns whether storage buffers are supported and to be preferred over uniform buffers.
    bool storageBufferSupport() const { return fStorageBufferSupport; }

    // The gradient buffer is an unsized float array so it is only optimal memory-wise to use it if
    // the storage buffer memory layout is std430 or in metal, which is also the only supported
    // way the data is packed.
    bool gradientBufferSupport() const {
        return fStorageBufferSupport &&
               (fResourceBindingReqs.fStorageBufferLayout == Layout::kStd430 ||
                fResourceBindingReqs.fStorageBufferLayout == Layout::kMetal);
    }

    // Returns whether a draw buffer can be mapped.
    bool drawBufferCanBeMapped() const { return fDrawBufferCanBeMapped; }

#if defined(GPU_TEST_UTILS)
    bool drawBufferCanBeMappedForReadback() const { return fDrawBufferCanBeMappedForReadback; }
#endif

    // Returns whether using Buffer::asyncMap() must be used to map buffers. map() may only be
    // called after asyncMap() is called and will fail if the asynchronous map is not complete. This
    // excludes premapped buffers for which map() can be called freely until the first unmap() call.
    bool bufferMapsAreAsync() const { return fBufferMapsAreAsync; }

    // Returns whether multisampled render to single sampled is supported.
    bool msaaRenderToSingleSampledSupport() const { return fMSAARenderToSingleSampledSupport; }

    // Returns whether compute shaders are supported.
    bool computeSupport() const { return fComputeSupport; }

    /**
     * Returns true if the given backend supports importing AHardwareBuffers. This will only
     * ever be supported on Android devices with API level >= 26.
     */
    bool supportsAHardwareBufferImages() const { return fSupportsAHardwareBufferImages; }

    // Returns the skgpu::Swizzle to use when sampling or reading back from a texture with the
    // passed in SkColorType and TextureInfo.
    skgpu::Swizzle getReadSwizzle(SkColorType, const TextureInfo&) const;

    // Returns the skgpu::Swizzle to use when writing colors to a surface with the passed in
    // SkColorType and TextureInfo.
    skgpu::Swizzle getWriteSwizzle(SkColorType, const TextureInfo&) const;

    skgpu::ShaderErrorHandler* shaderErrorHandler() const { return fShaderErrorHandler; }

    // Returns what method of dst read is required for a draw using the dst color.
    DstReadRequirement getDstReadRequirement() const;

    float minDistanceFieldFontSize() const { return fMinDistanceFieldFontSize; }
    float glyphsAsPathsFontSize() const { return fGlyphsAsPathsFontSize; }

    size_t glyphCacheTextureMaximumBytes() const { return fGlyphCacheTextureMaximumBytes; }
    int maxPathAtlasTextureSize() const { return fMaxPathAtlasTextureSize; }

    bool allowMultipleAtlasTextures() const { return fAllowMultipleAtlasTextures; }
    bool supportBilerpFromGlyphAtlas() const { return fSupportBilerpFromGlyphAtlas; }

    bool requireOrderedRecordings() const { return fRequireOrderedRecordings; }

    // When uploading to a full compressed texture do we need to pad the size out to a multiple of
    // the block width and height.
    bool fullCompressedUploadSizeMustAlignToBlockDims() const {
        return fFullCompressedUploadSizeMustAlignToBlockDims;
    }

    sktext::gpu::SubRunControl getSubRunControl(bool useSDFTForSmallText) const;

    bool setBackendLabels() const { return fSetBackendLabels; }

    GpuStatsFlags supportedGpuStats() const { return fSupportedGpuStats; }

protected:
    Caps();

    // Subclasses must call this at the end of their init method in order to do final processing on
    // the caps.
    void finishInitialization(const ContextOptions&);

#if defined(GPU_TEST_UTILS)
    void setDeviceName(std::string n) {
        fDeviceName = std::move(n);
    }
#endif

    // There are only a few possible valid sample counts (1, 2, 4, 8, 16). So we can key on those 5
    // options instead of the actual sample value.
    static inline uint32_t SamplesToKey(uint32_t numSamples) {
        switch (numSamples) {
            case 1:
                return 0;
            case 2:
                return 1;
            case 4:
                return 2;
            case 8:
                return 3;
            case 16:
                return 4;
            default:
                SkUNREACHABLE;
        }
    }

    // ColorTypeInfo for a specific format. Used in format tables.
    struct ColorTypeInfo {
        ColorTypeInfo() = default;
        ColorTypeInfo(SkColorType ct, SkColorType transferCt, uint32_t flags,
                      skgpu::Swizzle readSwizzle, skgpu::Swizzle writeSwizzle)
                : fColorType(ct)
                , fTransferColorType(transferCt)
                , fFlags(flags)
                , fReadSwizzle(readSwizzle)
                , fWriteSwizzle(writeSwizzle) {}

        SkColorType fColorType = kUnknown_SkColorType;
        SkColorType fTransferColorType = kUnknown_SkColorType;
        enum {
            kUploadData_Flag = 0x1,
            // Does Graphite itself support rendering to this colorType & format pair. Renderability
            // still additionally depends on if the format itself is renderable.
            kRenderable_Flag = 0x2,
        };
        uint32_t fFlags = 0;

        skgpu::Swizzle fReadSwizzle;
        skgpu::Swizzle fWriteSwizzle;
    };

    int fMaxTextureSize = 0;
    int fDefaultMSAASamples = 4;
    size_t fRequiredUniformBufferAlignment = 0;
    size_t fRequiredStorageBufferAlignment = 0;
    size_t fRequiredTransferBufferAlignment = 0;
    size_t fTextureDataRowBytesAlignment = 1;

    std::unique_ptr<SkSL::ShaderCaps> fShaderCaps;

    bool fNDCYAxisPointsDown = false; // Most backends have NDC +Y pointing up
    bool fClampToBorderSupport = true;
    bool fProtectedSupport = false;
    bool fSemaphoreSupport = false;
    bool fAllowCpuSync = true;
    bool fStorageBufferSupport = false;
    bool fDrawBufferCanBeMapped = true;
    bool fBufferMapsAreAsync = false;
    bool fMSAARenderToSingleSampledSupport = false;

    bool fComputeSupport = false;
    bool fSupportsAHardwareBufferImages = false;
    bool fFullCompressedUploadSizeMustAlignToBlockDims = false;

#if defined(GPU_TEST_UTILS)
    bool fDrawBufferCanBeMappedForReadback = true;
#endif

    ResourceBindingRequirements fResourceBindingReqs;

    GpuStatsFlags fSupportedGpuStats = GpuStatsFlags::kNone;

    //////////////////////////////////////////////////////////////////////////////////////////
    // Client-provided Caps

    /**
     * If present, use this object to report shader compilation failures. If not, report failures
     * via SkDebugf and assert.
     */
    ShaderErrorHandler* fShaderErrorHandler = nullptr;

#if defined(GPU_TEST_UTILS)
    std::string fDeviceName;
    int fMaxTextureAtlasSize = 2048;
    PathRendererStrategy fRequestedPathRendererStrategy;
#endif
    size_t fGlyphCacheTextureMaximumBytes = 2048 * 1024 * 4;

    float fMinDistanceFieldFontSize = 18;
    float fGlyphsAsPathsFontSize = 324;

    int fMaxPathAtlasTextureSize = 8192;

    bool fAllowMultipleAtlasTextures = true;
    bool fSupportBilerpFromGlyphAtlas = false;

    // Set based on client options
    bool fRequireOrderedRecordings = false;

    bool fSetBackendLabels = false;

private:
    virtual bool onIsTexturable(const TextureInfo&) const = 0;
    virtual const ColorTypeInfo* getColorTypeInfo(SkColorType, const TextureInfo&) const = 0;

    sk_sp<SkCapabilities> fCapabilities;
};

} // namespace skgpu::graphite

#endif // skgpu_graphite_Caps_DEFINED