// 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.

#include "dawn_native/d3d12/TextureD3D12.h"

#include "dawn_native/d3d12/DeviceD3D12.h"
#include "dawn_native/d3d12/ResourceAllocator.h"

namespace dawn_native { namespace d3d12 {

    namespace {
        D3D12_RESOURCE_STATES D3D12TextureUsage(dawn::TextureUsageBit usage,
                                                dawn::TextureFormat format) {
            D3D12_RESOURCE_STATES resourceState = D3D12_RESOURCE_STATE_COMMON;

            // Present is an exclusive flag.
            if (usage & dawn::TextureUsageBit::Present) {
                return D3D12_RESOURCE_STATE_PRESENT;
            }

            if (usage & dawn::TextureUsageBit::TransferSrc) {
                resourceState |= D3D12_RESOURCE_STATE_COPY_SOURCE;
            }
            if (usage & dawn::TextureUsageBit::TransferDst) {
                resourceState |= D3D12_RESOURCE_STATE_COPY_DEST;
            }
            if (usage & dawn::TextureUsageBit::Sampled) {
                resourceState |= (D3D12_RESOURCE_STATE_PIXEL_SHADER_RESOURCE |
                                  D3D12_RESOURCE_STATE_NON_PIXEL_SHADER_RESOURCE);
            }
            if (usage & dawn::TextureUsageBit::Storage) {
                resourceState |= D3D12_RESOURCE_STATE_UNORDERED_ACCESS;
            }
            if (usage & dawn::TextureUsageBit::OutputAttachment) {
                if (TextureFormatHasDepth(format) || TextureFormatHasStencil(format)) {
                    resourceState |= D3D12_RESOURCE_STATE_DEPTH_WRITE;
                } else {
                    resourceState |= D3D12_RESOURCE_STATE_RENDER_TARGET;
                }
            }

            return resourceState;
        }

        D3D12_RESOURCE_FLAGS D3D12ResourceFlags(dawn::TextureUsageBit usage,
                                                dawn::TextureFormat format) {
            D3D12_RESOURCE_FLAGS flags = D3D12_RESOURCE_FLAG_NONE;

            if (usage & dawn::TextureUsageBit::Storage) {
                flags |= D3D12_RESOURCE_FLAG_ALLOW_UNORDERED_ACCESS;
            }
            if (usage & dawn::TextureUsageBit::OutputAttachment) {
                if (TextureFormatHasDepth(format) || TextureFormatHasStencil(format)) {
                    flags |= D3D12_RESOURCE_FLAG_ALLOW_DEPTH_STENCIL;
                } else {
                    flags |= D3D12_RESOURCE_FLAG_ALLOW_RENDER_TARGET;
                }
            }

            ASSERT(!(flags & D3D12_RESOURCE_FLAG_ALLOW_DEPTH_STENCIL) ||
                   flags == D3D12_RESOURCE_FLAG_ALLOW_DEPTH_STENCIL);
            return flags;
        }

        D3D12_RESOURCE_DIMENSION D3D12TextureDimension(dawn::TextureDimension dimension) {
            switch (dimension) {
                case dawn::TextureDimension::e2D:
                    return D3D12_RESOURCE_DIMENSION_TEXTURE2D;
                default:
                    UNREACHABLE();
            }
        }

    }  // namespace

    DXGI_FORMAT D3D12TextureFormat(dawn::TextureFormat format) {
        switch (format) {
            case dawn::TextureFormat::R8G8B8A8Unorm:
                return DXGI_FORMAT_R8G8B8A8_UNORM;
            case dawn::TextureFormat::R8G8Unorm:
                return DXGI_FORMAT_R8G8_UNORM;
            case dawn::TextureFormat::R8Unorm:
                return DXGI_FORMAT_R8_UNORM;
            case dawn::TextureFormat::R8G8B8A8Uint:
                return DXGI_FORMAT_R8G8B8A8_UINT;
            case dawn::TextureFormat::R8G8Uint:
                return DXGI_FORMAT_R8G8_UINT;
            case dawn::TextureFormat::R8Uint:
                return DXGI_FORMAT_R8_UINT;
            case dawn::TextureFormat::B8G8R8A8Unorm:
                return DXGI_FORMAT_B8G8R8A8_UNORM;
            case dawn::TextureFormat::D32FloatS8Uint:
                return DXGI_FORMAT_D32_FLOAT_S8X24_UINT;
            default:
                UNREACHABLE();
        }
    }

    Texture::Texture(Device* device, const TextureDescriptor* descriptor)
        : TextureBase(device, descriptor) {
        D3D12_RESOURCE_DESC resourceDescriptor;
        resourceDescriptor.Dimension = D3D12TextureDimension(GetDimension());
        resourceDescriptor.Alignment = 0;
        resourceDescriptor.Width = GetWidth();
        resourceDescriptor.Height = GetHeight();
        resourceDescriptor.DepthOrArraySize = static_cast<UINT16>(GetDepth());
        resourceDescriptor.MipLevels = static_cast<UINT16>(GetNumMipLevels());
        resourceDescriptor.Format = D3D12TextureFormat(GetFormat());
        resourceDescriptor.SampleDesc.Count = 1;
        resourceDescriptor.SampleDesc.Quality = 0;
        resourceDescriptor.Layout = D3D12_TEXTURE_LAYOUT_UNKNOWN;
        resourceDescriptor.Flags = D3D12ResourceFlags(GetUsage(), GetFormat());

        mResource = ToBackend(GetDevice())
                        ->GetResourceAllocator()
                        ->Allocate(D3D12_HEAP_TYPE_DEFAULT, resourceDescriptor,
                                   D3D12_RESOURCE_STATE_COMMON);
        mResourcePtr = mResource.Get();
    }

    // With this constructor, the lifetime of the ID3D12Resource is externally managed.
    Texture::Texture(Device* device,
                     const TextureDescriptor* descriptor,
                     ID3D12Resource* nativeTexture)
        : TextureBase(device, descriptor), mResourcePtr(nativeTexture) {
    }

    Texture::~Texture() {
        if (mResource) {
            // If we own the resource, release it.
            ToBackend(GetDevice())->GetResourceAllocator()->Release(mResource);
        }
    }

    DXGI_FORMAT Texture::GetD3D12Format() const {
        return D3D12TextureFormat(GetFormat());
    }

    ID3D12Resource* Texture::GetD3D12Resource() {
        return mResourcePtr;
    }

    void Texture::TransitionUsageNow(ComPtr<ID3D12GraphicsCommandList> commandList,
                                     dawn::TextureUsageBit usage) {
        // Avoid transitioning the texture when it isn't needed.
        // TODO(cwallez@chromium.org): Need some form of UAV barriers at some point.
        if (usage == mLastUsage) {
            return;
        }

        D3D12_RESOURCE_STATES lastState = D3D12TextureUsage(mLastUsage, GetFormat());
        D3D12_RESOURCE_STATES newState = D3D12TextureUsage(usage, GetFormat());

        D3D12_RESOURCE_BARRIER barrier;
        barrier.Type = D3D12_RESOURCE_BARRIER_TYPE_TRANSITION;
        barrier.Flags = D3D12_RESOURCE_BARRIER_FLAG_NONE;
        barrier.Transition.pResource = mResourcePtr;
        barrier.Transition.StateBefore = lastState;
        barrier.Transition.StateAfter = newState;
        barrier.Transition.Subresource = D3D12_RESOURCE_BARRIER_ALL_SUBRESOURCES;

        commandList->ResourceBarrier(1, &barrier);

        mLastUsage = usage;
    }

    TextureView::TextureView(TextureViewBuilder* builder) : TextureViewBase(builder) {
        mSrvDesc.Format = D3D12TextureFormat(GetTexture()->GetFormat());
        mSrvDesc.Shader4ComponentMapping = D3D12_DEFAULT_SHADER_4_COMPONENT_MAPPING;
        switch (GetTexture()->GetDimension()) {
            case dawn::TextureDimension::e2D:
                mSrvDesc.ViewDimension = D3D12_SRV_DIMENSION_TEXTURE2D;
                mSrvDesc.Texture2D.MostDetailedMip = 0;
                mSrvDesc.Texture2D.MipLevels = GetTexture()->GetNumMipLevels();
                mSrvDesc.Texture2D.PlaneSlice = 0;
                mSrvDesc.Texture2D.ResourceMinLODClamp = 0;
                break;
        }
    }

    const D3D12_SHADER_RESOURCE_VIEW_DESC& TextureView::GetSRVDescriptor() const {
        return mSrvDesc;
    }

    D3D12_RENDER_TARGET_VIEW_DESC TextureView::GetRTVDescriptor() {
        D3D12_RENDER_TARGET_VIEW_DESC rtvDesc;
        rtvDesc.Format = ToBackend(GetTexture())->GetD3D12Format();
        rtvDesc.ViewDimension = D3D12_RTV_DIMENSION_TEXTURE2D;
        rtvDesc.Texture2D.MipSlice = 0;
        rtvDesc.Texture2D.PlaneSlice = 0;
        return rtvDesc;
    }

    D3D12_DEPTH_STENCIL_VIEW_DESC TextureView::GetDSVDescriptor() {
        D3D12_DEPTH_STENCIL_VIEW_DESC dsvDesc;
        dsvDesc.Format = ToBackend(GetTexture())->GetD3D12Format();
        dsvDesc.ViewDimension = D3D12_DSV_DIMENSION_TEXTURE2D;
        dsvDesc.Texture2D.MipSlice = 0;
        dsvDesc.Flags = D3D12_DSV_FLAG_NONE;
        return dsvDesc;
    }

}}  // namespace dawn_native::d3d12