// Copyright 2017 The Dawn Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#ifndef DAWNNATIVE_D3D12_BINDGROUPLAYOUTD3D12_H_
#define DAWNNATIVE_D3D12_BINDGROUPLAYOUTD3D12_H_

#include "dawn_native/BindGroupLayout.h"

#include "common/SlabAllocator.h"
#include "common/ityp_stack_vec.h"
#include "dawn_native/d3d12/d3d12_platform.h"

namespace dawn_native::d3d12 {

    class BindGroup;
    class CPUDescriptorHeapAllocation;
    class Device;
    class StagingDescriptorAllocator;

    // A purposefully invalid register space.
    //
    // We use the bind group index as the register space, but don't know the bind group index until
    // pipeline layout creation time. This value should be replaced in PipelineLayoutD3D12.
    static constexpr uint32_t kRegisterSpacePlaceholder =
        D3D12_DRIVER_RESERVED_REGISTER_SPACE_VALUES_START;

    class BindGroupLayout final : public BindGroupLayoutBase {
      public:
        static Ref<BindGroupLayout> Create(Device* device,
                                           const BindGroupLayoutDescriptor* descriptor,
                                           PipelineCompatibilityToken pipelineCompatibilityToken);

        ResultOrError<Ref<BindGroup>> AllocateBindGroup(Device* device,
                                                        const BindGroupDescriptor* descriptor);
        void DeallocateBindGroup(BindGroup* bindGroup, CPUDescriptorHeapAllocation* viewAllocation);

        // The offset (in descriptor count) into the corresponding descriptor heap. Not valid for
        // dynamic binding indexes.
        ityp::span<BindingIndex, const uint32_t> GetDescriptorHeapOffsets() const;

        // The D3D shader register that the Dawn binding index is mapped to by this bind group
        // layout.
        uint32_t GetShaderRegister(BindingIndex bindingIndex) const;

        // Counts of descriptors in the descriptor tables.
        uint32_t GetCbvUavSrvDescriptorCount() const;
        uint32_t GetSamplerDescriptorCount() const;

        const std::vector<D3D12_DESCRIPTOR_RANGE>& GetCbvUavSrvDescriptorRanges() const;
        const std::vector<D3D12_DESCRIPTOR_RANGE>& GetSamplerDescriptorRanges() const;

      private:
        BindGroupLayout(Device* device,
                        const BindGroupLayoutDescriptor* descriptor,
                        PipelineCompatibilityToken pipelineCompatibilityToken);
        ~BindGroupLayout() override = default;

        // Contains the offset into the descriptor heap for the given resource view. Samplers and
        // non-samplers are stored in separate descriptor heaps, so the offsets should be unique
        // within each group and tightly packed.
        //
        // Dynamic resources are not used here since their descriptors are placed directly in root
        // parameters.
        ityp::stack_vec<BindingIndex, uint32_t, kMaxOptimalBindingsPerGroup> mDescriptorHeapOffsets;

        // Contains the shader register this binding is mapped to.
        ityp::stack_vec<BindingIndex, uint32_t, kMaxOptimalBindingsPerGroup> mShaderRegisters;

        uint32_t mCbvUavSrvDescriptorCount;
        uint32_t mSamplerDescriptorCount;

        std::vector<D3D12_DESCRIPTOR_RANGE> mCbvUavSrvDescriptorRanges;
        std::vector<D3D12_DESCRIPTOR_RANGE> mSamplerDescriptorRanges;

        SlabAllocator<BindGroup> mBindGroupAllocator;

        StagingDescriptorAllocator* mSamplerAllocator = nullptr;
        StagingDescriptorAllocator* mViewAllocator = nullptr;
    };

}  // namespace dawn_native::d3d12

#endif  // DAWNNATIVE_D3D12_BINDGROUPLAYOUTD3D12_H_