/*
 * 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 "src/gpu/graphite/mtl/MtlResourceProvider.h"

#include "include/gpu/graphite/BackendTexture.h"
#include "src/gpu/graphite/GlobalCache.h"
#include "src/gpu/graphite/GraphicsPipelineDesc.h"
#include "src/gpu/graphite/mtl/MtlBuffer.h"
#include "src/gpu/graphite/mtl/MtlCommandBuffer.h"
#include "src/gpu/graphite/mtl/MtlComputePipeline.h"
#include "src/gpu/graphite/mtl/MtlGpu.h"
#include "src/gpu/graphite/mtl/MtlGraphicsPipeline.h"
#include "src/gpu/graphite/mtl/MtlSampler.h"
#include "src/gpu/graphite/mtl/MtlTexture.h"

#import <Metal/Metal.h>

namespace skgpu::graphite {

MtlResourceProvider::MtlResourceProvider(const Gpu* gpu,
                                         sk_sp<GlobalCache> globalCache,
                                         SingleOwner* singleOwner)
    : ResourceProvider(gpu, std::move(globalCache), singleOwner) {
}

const MtlGpu* MtlResourceProvider::mtlGpu() {
    return static_cast<const MtlGpu*>(fGpu);
}

sk_sp<CommandBuffer> MtlResourceProvider::createCommandBuffer() {
    return MtlCommandBuffer::Make(this->mtlGpu());
}

sk_sp<GraphicsPipeline> MtlResourceProvider::onCreateGraphicsPipeline(
        const GraphicsPipelineDesc& pipelineDesc,
        const RenderPassDesc& renderPassDesc) {
    return MtlGraphicsPipeline::Make(this,
                                     this->mtlGpu(),
                                     pipelineDesc,
                                     renderPassDesc);
}

sk_sp<ComputePipeline> MtlResourceProvider::onCreateComputePipeline(
        const ComputePipelineDesc& pipelineDesc) {
    return MtlComputePipeline::Make(this, this->mtlGpu(), pipelineDesc);
}

sk_sp<Texture> MtlResourceProvider::createTexture(SkISize dimensions,
                                                  const TextureInfo& info,
                                                  SkBudgeted budgeted) {
    return MtlTexture::Make(this->mtlGpu(), dimensions, info, budgeted);
}

sk_sp<Texture> MtlResourceProvider::createWrappedTexture(const BackendTexture& texture) {
    MtlHandle mtlHandleTexture = texture.getMtlTexture();
    if (!mtlHandleTexture) {
        return nullptr;
    }
    sk_cfp<id<MTLTexture>> mtlTexture = sk_ret_cfp((id<MTLTexture>)mtlHandleTexture);
    return MtlTexture::MakeWrapped(this->mtlGpu(),
                                   texture.dimensions(),
                                   texture.info(),
                                   std::move(mtlTexture));
}

sk_sp<Buffer> MtlResourceProvider::createBuffer(size_t size,
                                                BufferType type,
                                                PrioritizeGpuReads prioritizeGpuReads) {
    return MtlBuffer::Make(this->mtlGpu(), size, type, prioritizeGpuReads);
}

sk_sp<Sampler> MtlResourceProvider::createSampler(const SkSamplingOptions& samplingOptions,
                                                         SkTileMode xTileMode,
                                                         SkTileMode yTileMode) {
    return MtlSampler::Make(this->mtlGpu(), samplingOptions, xTileMode, yTileMode);
}

namespace {
MTLCompareFunction compare_op_to_mtl(CompareOp op) {
    switch (op) {
        case CompareOp::kAlways:
            return MTLCompareFunctionAlways;
        case CompareOp::kNever:
            return MTLCompareFunctionNever;
        case CompareOp::kGreater:
            return MTLCompareFunctionGreater;
        case CompareOp::kGEqual:
            return MTLCompareFunctionGreaterEqual;
        case CompareOp::kLess:
            return MTLCompareFunctionLess;
        case CompareOp::kLEqual:
            return MTLCompareFunctionLessEqual;
        case CompareOp::kEqual:
            return MTLCompareFunctionEqual;
        case CompareOp::kNotEqual:
            return MTLCompareFunctionNotEqual;
    }
}

MTLStencilOperation stencil_op_to_mtl(StencilOp op) {
    switch (op) {
        case StencilOp::kKeep:
            return MTLStencilOperationKeep;
        case StencilOp::kZero:
            return MTLStencilOperationZero;
        case StencilOp::kReplace:
            return MTLStencilOperationReplace;
        case StencilOp::kInvert:
            return MTLStencilOperationInvert;
        case StencilOp::kIncWrap:
            return MTLStencilOperationIncrementWrap;
        case StencilOp::kDecWrap:
            return MTLStencilOperationDecrementWrap;
        case StencilOp::kIncClamp:
            return MTLStencilOperationIncrementClamp;
        case StencilOp::kDecClamp:
            return MTLStencilOperationDecrementClamp;
    }
}

MTLStencilDescriptor* stencil_face_to_mtl(DepthStencilSettings::Face face) {
    MTLStencilDescriptor* result = [[MTLStencilDescriptor alloc] init];
    result.stencilCompareFunction = compare_op_to_mtl(face.fCompareOp);
    result.readMask = face.fReadMask;
    result.writeMask = face.fWriteMask;
    result.depthStencilPassOperation = stencil_op_to_mtl(face.fDepthStencilPassOp);
    result.stencilFailureOperation = stencil_op_to_mtl(face.fStencilFailOp);
    return result;
}
}  // anonymous namespace

sk_cfp<id<MTLDepthStencilState>> MtlResourceProvider::findOrCreateCompatibleDepthStencilState(
            const DepthStencilSettings& depthStencilSettings) {
    sk_cfp<id<MTLDepthStencilState>>* depthStencilState;
    depthStencilState = fDepthStencilStates.find(depthStencilSettings);
    if (!depthStencilState) {
        MTLDepthStencilDescriptor* desc = [[MTLDepthStencilDescriptor alloc] init];
        SkASSERT(depthStencilSettings.fDepthTestEnabled ||
                 depthStencilSettings.fDepthCompareOp == CompareOp::kAlways);
        desc.depthCompareFunction = compare_op_to_mtl(depthStencilSettings.fDepthCompareOp);
        if (depthStencilSettings.fDepthTestEnabled) {
            desc.depthWriteEnabled = depthStencilSettings.fDepthWriteEnabled;
        }
        if (depthStencilSettings.fStencilTestEnabled) {
            desc.frontFaceStencil = stencil_face_to_mtl(depthStencilSettings.fFrontStencil);
            desc.backFaceStencil = stencil_face_to_mtl(depthStencilSettings.fBackStencil);
        }

        sk_cfp<id<MTLDepthStencilState>> dss(
                [this->mtlGpu()->device() newDepthStencilStateWithDescriptor: desc]);
        depthStencilState = fDepthStencilStates.set(depthStencilSettings, std::move(dss));
    }

    SkASSERT(depthStencilState);
    return *depthStencilState;
}

} // namespace skgpu::graphite