// 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/SwapChainD3D12.h"

#include <windows.ui.xaml.media.dxinterop.h>

#include <utility>

#include "dawn/dawn_wsi.h"
#include "dawn/native/Surface.h"
#include "dawn/native/d3d12/D3D12Error.h"
#include "dawn/native/d3d12/DeviceD3D12.h"
#include "dawn/native/d3d12/TextureD3D12.h"

namespace dawn::native::d3d12 {
namespace {

uint32_t PresentModeToBufferCount(wgpu::PresentMode mode) {
    switch (mode) {
        case wgpu::PresentMode::Immediate:
        case wgpu::PresentMode::Fifo:
            return 2;
        case wgpu::PresentMode::Mailbox:
            return 3;
    }
}

uint32_t PresentModeToSwapInterval(wgpu::PresentMode mode) {
    switch (mode) {
        case wgpu::PresentMode::Immediate:
        case wgpu::PresentMode::Mailbox:
            return 0;
        case wgpu::PresentMode::Fifo:
            return 1;
    }
}

UINT PresentModeToSwapChainFlags(wgpu::PresentMode mode) {
    UINT flags = DXGI_SWAP_CHAIN_FLAG_ALLOW_MODE_SWITCH;

    if (mode == wgpu::PresentMode::Immediate) {
        flags |= DXGI_SWAP_CHAIN_FLAG_ALLOW_TEARING;
    }

    return flags;
}

DXGI_USAGE ToDXGIUsage(wgpu::TextureUsage usage) {
    DXGI_USAGE dxgiUsage = DXGI_CPU_ACCESS_NONE;
    if (usage & wgpu::TextureUsage::TextureBinding) {
        dxgiUsage |= DXGI_USAGE_SHADER_INPUT;
    }
    if (usage & wgpu::TextureUsage::StorageBinding) {
        dxgiUsage |= DXGI_USAGE_UNORDERED_ACCESS;
    }
    if (usage & wgpu::TextureUsage::RenderAttachment) {
        dxgiUsage |= DXGI_USAGE_RENDER_TARGET_OUTPUT;
    }
    return dxgiUsage;
}

}  // namespace

// OldSwapChain

// static
Ref<OldSwapChain> OldSwapChain::Create(Device* device, const SwapChainDescriptor* descriptor) {
    return AcquireRef(new OldSwapChain(device, descriptor));
}

OldSwapChain::OldSwapChain(Device* device, const SwapChainDescriptor* descriptor)
    : OldSwapChainBase(device, descriptor) {
    const auto& im = GetImplementation();
    DawnWSIContextD3D12 wsiContext = {};
    wsiContext.device = ToAPI(GetDevice());
    im.Init(im.userData, &wsiContext);

    ASSERT(im.textureUsage != WGPUTextureUsage_None);
    mTextureUsage = static_cast<wgpu::TextureUsage>(im.textureUsage);
}

OldSwapChain::~OldSwapChain() = default;

TextureBase* OldSwapChain::GetNextTextureImpl(const TextureDescriptor* descriptor) {
    DeviceBase* device = GetDevice();
    const auto& im = GetImplementation();
    DawnSwapChainNextTexture next = {};
    DawnSwapChainError error = im.GetNextTexture(im.userData, &next);
    if (error) {
        device->HandleError(InternalErrorType::Internal, error);
        return nullptr;
    }

    ComPtr<ID3D12Resource> d3d12Texture = static_cast<ID3D12Resource*>(next.texture.ptr);
    Ref<Texture> dawnTexture;
    if (device->ConsumedError(
            Texture::Create(ToBackend(GetDevice()), descriptor, std::move(d3d12Texture)),
            &dawnTexture)) {
        return nullptr;
    }

    return dawnTexture.Detach();
}

MaybeError OldSwapChain::OnBeforePresent(TextureViewBase* view) {
    Device* device = ToBackend(GetDevice());

    CommandRecordingContext* commandContext;
    DAWN_TRY_ASSIGN(commandContext, device->GetPendingCommandContext());

    // Perform the necessary transition for the texture to be presented.
    ToBackend(view->GetTexture())
        ->TrackUsageAndTransitionNow(commandContext, mTextureUsage, view->GetSubresourceRange());

    DAWN_TRY(device->ExecutePendingCommandContext());

    return {};
}

// SwapChain

// static
ResultOrError<Ref<SwapChain>> SwapChain::Create(Device* device,
                                                Surface* surface,
                                                NewSwapChainBase* previousSwapChain,
                                                const SwapChainDescriptor* descriptor) {
    Ref<SwapChain> swapchain = AcquireRef(new SwapChain(device, surface, descriptor));
    DAWN_TRY(swapchain->Initialize(previousSwapChain));
    return swapchain;
}

SwapChain::~SwapChain() = default;

void SwapChain::DestroyImpl() {
    SwapChainBase::DestroyImpl();
    DetachFromSurface();
}

// Initializes the swapchain on the surface. Note that `previousSwapChain` may or may not be
// nullptr. If it is not nullptr it means that it is the swapchain previously in use on the
// surface and that we have a chance to reuse it's underlying IDXGISwapChain and "buffers".
MaybeError SwapChain::Initialize(NewSwapChainBase* previousSwapChain) {
    ASSERT(GetSurface()->GetType() == Surface::Type::WindowsHWND);

    // Precompute the configuration parameters we want for the DXGI swapchain.
    mConfig.bufferCount = PresentModeToBufferCount(GetPresentMode());
    mConfig.format = D3D12TextureFormat(GetFormat());
    mConfig.swapChainFlags = PresentModeToSwapChainFlags(GetPresentMode());
    mConfig.usage = ToDXGIUsage(GetUsage());

    // There is no previous swapchain so we can create one directly and don't have anything else
    // to do.
    if (previousSwapChain == nullptr) {
        return InitializeSwapChainFromScratch();
    }

    // TODO(crbug.com/dawn/269): figure out what should happen when surfaces are used by
    // multiple backends one after the other. It probably needs to block until the backend
    // and GPU are completely finished with the previous swapchain.
    DAWN_INVALID_IF(previousSwapChain->GetBackendType() != wgpu::BackendType::D3D12,
                    "D3D12 SwapChain cannot switch backend types from %s to %s.",
                    previousSwapChain->GetBackendType(), wgpu::BackendType::D3D12);

    // TODO(crbug.com/dawn/269): use ToBackend once OldSwapChainBase is removed.
    SwapChain* previousD3D12SwapChain = static_cast<SwapChain*>(previousSwapChain);

    // TODO(crbug.com/dawn/269): Figure out switching an HWND between devices, it might
    // require just losing the reference to the swapchain, but might also need to wait for
    // all previous operations to complete.
    DAWN_INVALID_IF(GetDevice() != previousSwapChain->GetDevice(),
                    "D3D12 SwapChain cannot switch between D3D Devices");

    // The previous swapchain is on the same device so we want to reuse it but it is still not
    // always possible. Because DXGI requires that a new swapchain be created if the
    // DXGI_SWAP_CHAIN_FLAG_ALLOW_TEARING flag is changed.
    bool canReuseSwapChain =
        ((mConfig.swapChainFlags ^ previousD3D12SwapChain->mConfig.swapChainFlags) &
         DXGI_SWAP_CHAIN_FLAG_ALLOW_TEARING) == 0;

    // We can't reuse the previous swapchain, so we destroy it and wait for all of its reference
    // to be forgotten (otherwise DXGI complains that there are outstanding references).
    if (!canReuseSwapChain) {
        DAWN_TRY(previousD3D12SwapChain->DetachAndWaitForDeallocation());
        return InitializeSwapChainFromScratch();
    }

    // After all this we know we can reuse the swapchain, see if it is possible to also reuse
    // the buffers.
    mDXGISwapChain = std::move(previousD3D12SwapChain->mDXGISwapChain);

    bool canReuseBuffers = GetWidth() == previousSwapChain->GetWidth() &&
                           GetHeight() == previousSwapChain->GetHeight() &&
                           GetFormat() == previousSwapChain->GetFormat() &&
                           GetPresentMode() == previousSwapChain->GetPresentMode();
    if (canReuseBuffers) {
        mBuffers = std::move(previousD3D12SwapChain->mBuffers);
        mBufferLastUsedSerials = std::move(previousD3D12SwapChain->mBufferLastUsedSerials);
        mCurrentBuffer = previousD3D12SwapChain->mCurrentBuffer;
        return {};
    }

    // We can't reuse the buffers so we need to resize, IDXGSwapChain->ResizeBuffers requires
    // that all references to buffers are lost before it is called. Contrary to D3D11, the
    // application is responsible for keeping references to the buffers until the GPU is done
    // using them so we have no choice but to synchrounously wait for all operations to complete
    // on the previous swapchain and then lose references to its buffers.
    DAWN_TRY(previousD3D12SwapChain->DetachAndWaitForDeallocation());
    DAWN_TRY(
        CheckHRESULT(mDXGISwapChain->ResizeBuffers(mConfig.bufferCount, GetWidth(), GetHeight(),
                                                   mConfig.format, mConfig.swapChainFlags),
                     "IDXGISwapChain::ResizeBuffer"));
    return CollectSwapChainBuffers();
}

MaybeError SwapChain::InitializeSwapChainFromScratch() {
    ASSERT(mDXGISwapChain == nullptr);

    Device* device = ToBackend(GetDevice());

    DXGI_SWAP_CHAIN_DESC1 swapChainDesc = {};
    swapChainDesc.Width = GetWidth();
    swapChainDesc.Height = GetHeight();
    swapChainDesc.Format = mConfig.format;
    swapChainDesc.Stereo = false;
    swapChainDesc.SampleDesc.Count = 1;
    swapChainDesc.SampleDesc.Quality = 0;
    swapChainDesc.BufferUsage = mConfig.usage;
    swapChainDesc.BufferCount = mConfig.bufferCount;
    swapChainDesc.Scaling = DXGI_SCALING_STRETCH;
    swapChainDesc.SwapEffect = DXGI_SWAP_EFFECT_FLIP_DISCARD;
    swapChainDesc.AlphaMode = DXGI_ALPHA_MODE_IGNORE;
    swapChainDesc.Flags = mConfig.swapChainFlags;

    ComPtr<IDXGIFactory2> factory2 = nullptr;
    DAWN_TRY(CheckHRESULT(device->GetFactory()->QueryInterface(IID_PPV_ARGS(&factory2)),
                          "Getting IDXGIFactory2"));

    ComPtr<IDXGISwapChain1> swapChain1;
    switch (GetSurface()->GetType()) {
        case Surface::Type::WindowsHWND: {
            DAWN_TRY(CheckHRESULT(
                factory2->CreateSwapChainForHwnd(device->GetCommandQueue().Get(),
                                                 static_cast<HWND>(GetSurface()->GetHWND()),
                                                 &swapChainDesc, nullptr, nullptr, &swapChain1),
                "Creating the IDXGISwapChain1"));
            break;
        }
        case Surface::Type::WindowsCoreWindow: {
            DAWN_TRY(CheckHRESULT(
                factory2->CreateSwapChainForCoreWindow(device->GetCommandQueue().Get(),
                                                       GetSurface()->GetCoreWindow(),
                                                       &swapChainDesc, nullptr, &swapChain1),
                "Creating the IDXGISwapChain1"));
            break;
        }
        case Surface::Type::WindowsSwapChainPanel: {
            DAWN_TRY(CheckHRESULT(
                factory2->CreateSwapChainForComposition(device->GetCommandQueue().Get(),
                                                        &swapChainDesc, nullptr, &swapChain1),
                "Creating the IDXGISwapChain1"));
            ComPtr<ISwapChainPanelNative> swapChainPanelNative;
            DAWN_TRY(CheckHRESULT(GetSurface()->GetSwapChainPanel()->QueryInterface(
                                      IID_PPV_ARGS(&swapChainPanelNative)),
                                  "Getting ISwapChainPanelNative"));
            DAWN_TRY(CheckHRESULT(swapChainPanelNative->SetSwapChain(swapChain1.Get()),
                                  "Setting SwapChain"));
            break;
        }
        default:
            UNREACHABLE();
    }

    DAWN_TRY(CheckHRESULT(swapChain1.As(&mDXGISwapChain), "Gettting IDXGISwapChain1"));

    return CollectSwapChainBuffers();
}

MaybeError SwapChain::CollectSwapChainBuffers() {
    ASSERT(mDXGISwapChain != nullptr);
    ASSERT(mBuffers.empty());

    mBuffers.resize(mConfig.bufferCount);
    for (uint32_t i = 0; i < mConfig.bufferCount; i++) {
        DAWN_TRY(CheckHRESULT(mDXGISwapChain->GetBuffer(i, IID_PPV_ARGS(&mBuffers[i])),
                              "Getting IDXGISwapChain buffer"));
    }

    // Pretend all the buffers were last used at the beginning of time.
    mBufferLastUsedSerials.resize(mConfig.bufferCount, ExecutionSerial(0));
    return {};
}

MaybeError SwapChain::PresentImpl() {
    Device* device = ToBackend(GetDevice());

    // Transition the texture to the present state as required by IDXGISwapChain1::Present()
    // TODO(crbug.com/dawn/269): Remove the need for this by eagerly transitioning the
    // presentable texture to present at the end of submits that use them.
    CommandRecordingContext* commandContext;
    DAWN_TRY_ASSIGN(commandContext, device->GetPendingCommandContext());
    mApiTexture->TrackUsageAndTransitionNow(commandContext, kPresentTextureUsage,
                                            mApiTexture->GetAllSubresources());
    DAWN_TRY(device->ExecutePendingCommandContext());

    // Do the actual present. DXGI_STATUS_OCCLUDED is a valid return value that's just a
    // message to the application that it could stop rendering.
    HRESULT presentResult = mDXGISwapChain->Present(PresentModeToSwapInterval(GetPresentMode()), 0);
    if (presentResult != DXGI_STATUS_OCCLUDED) {
        DAWN_TRY(CheckHRESULT(presentResult, "IDXGISwapChain::Present"));
    }

    // Record that "new" is the last time the buffer has been used.
    DAWN_TRY(device->NextSerial());
    mBufferLastUsedSerials[mCurrentBuffer] = device->GetPendingCommandSerial();

    mApiTexture->APIDestroy();
    mApiTexture = nullptr;

    return {};
}

ResultOrError<Ref<TextureViewBase>> SwapChain::GetCurrentTextureViewImpl() {
    Device* device = ToBackend(GetDevice());

    // Synchronously wait until previous operations on the next swapchain buffer are finished.
    // This is the logic that performs frame pacing.
    // TODO(crbug.com/dawn/269): Consider whether this should  be lifted for Mailbox so that
    // there is not frame pacing.
    mCurrentBuffer = mDXGISwapChain->GetCurrentBackBufferIndex();
    DAWN_TRY(device->WaitForSerial(mBufferLastUsedSerials[mCurrentBuffer]));

    // Create the API side objects for this use of the swapchain's buffer.
    TextureDescriptor descriptor = GetSwapChainBaseTextureDescriptor(this);
    DAWN_TRY_ASSIGN(mApiTexture,
                    Texture::Create(ToBackend(GetDevice()), &descriptor, mBuffers[mCurrentBuffer]));
    return mApiTexture->CreateView();
}

MaybeError SwapChain::DetachAndWaitForDeallocation() {
    DetachFromSurface();

    // DetachFromSurface calls Texture->Destroy that enqueues the D3D12 resource in a
    // SerialQueue with the current "pending serial" so that we don't destroy the texture
    // before it is finished being used. Flush the commands and wait for that serial to be
    // passed, then Tick the device to make sure the reference to the D3D12 texture is removed.
    Device* device = ToBackend(GetDevice());
    DAWN_TRY(device->NextSerial());
    DAWN_TRY(device->WaitForSerial(device->GetLastSubmittedCommandSerial()));
    return device->TickImpl();
}

void SwapChain::DetachFromSurfaceImpl() {
    if (mApiTexture != nullptr) {
        mApiTexture->APIDestroy();
        mApiTexture = nullptr;
    }

    mDXGISwapChain = nullptr;
    mBuffers.clear();
}

}  // namespace dawn::native::d3d12