#include "Rendering/D3D12/D3D12WindowSwapChainPresenter.h"

namespace XCEngine::UI::Editor::Host {

using ::XCEngine::RHI::D3D12SwapChain;
using ::XCEngine::RHI::D3D12Texture;
using ::XCEngine::RHI::RHISwapChain;
using ::XCEngine::RHI::SwapChainDesc;

bool D3D12WindowSwapChainPresenter::Initialize(
    D3D12HostDevice& hostDevice,
    HWND hwnd,
    int width,
    int height) {
    Shutdown();

    if (hwnd == nullptr || width <= 0 || height <= 0) {
        m_lastError = "Initialize rejected an invalid hwnd or size.";
        return false;
    }

    if (hostDevice.GetRHIDevice() == nullptr || hostDevice.GetRHICommandQueue() == nullptr) {
        m_lastError = "Initialize requires an initialized host D3D12 device.";
        return false;
    }

    m_hwnd = hwnd;
    m_width = width;
    m_height = height;
    m_hostDevice = &hostDevice;

    if (!CreateSwapChain(width, height)) {
        Shutdown();
        return false;
    }

    m_lastError.clear();
    return true;
}

bool D3D12WindowSwapChainPresenter::CreateSwapChain(int width, int height) {
    if (m_hostDevice == nullptr ||
        m_hostDevice->GetRHIDevice() == nullptr ||
        m_hostDevice->GetRHICommandQueue() == nullptr) {
        m_lastError = "CreateSwapChain requires an initialized host D3D12 device.";
        return false;
    }

    SwapChainDesc swapChainDesc = {};
    swapChainDesc.windowHandle = m_hwnd;
    swapChainDesc.width = static_cast<std::uint32_t>(width);
    swapChainDesc.height = static_cast<std::uint32_t>(height);
    swapChainDesc.bufferCount = kSwapChainBufferCount;
    m_swapChain = m_hostDevice->GetRHIDevice()->CreateSwapChain(
        swapChainDesc,
        m_hostDevice->GetRHICommandQueue());
    if (m_swapChain == nullptr || GetD3D12SwapChain() == nullptr) {
        m_lastError = "Failed to create the D3D12 swap chain.";
        return false;
    }

    ConfigureFrameLatency();

    if (!RecreateBackBufferViews()) {
        m_lastError = "Failed to create swap chain back buffer views.";
        return false;
    }

    m_width = width;
    m_height = height;
    return true;
}

void D3D12WindowSwapChainPresenter::ConfigureFrameLatency() {
    D3D12SwapChain* d3d12SwapChain = GetD3D12SwapChain();
    if (d3d12SwapChain == nullptr) {
        return;
    }

    auto* nativeSwapChain =
        static_cast<IDXGISwapChain3*>(d3d12SwapChain->GetNativeHandle());
    if (nativeSwapChain == nullptr) {
        return;
    }

    nativeSwapChain->SetMaximumFrameLatency(1u);
}

void D3D12WindowSwapChainPresenter::DestroySwapChain() {
    ReleaseBackBufferViews();

    if (m_swapChain != nullptr) {
        m_swapChain->Shutdown();
        delete m_swapChain;
        m_swapChain = nullptr;
    }
}

bool D3D12WindowSwapChainPresenter::RecreateSwapChain(int width, int height) {
    DestroySwapChain();
    m_hostDevice->ResetFrameTracking();
    return CreateSwapChain(width, height);
}

void D3D12WindowSwapChainPresenter::Shutdown() {
    if (m_hostDevice != nullptr) {
        m_hostDevice->WaitForGpuIdle();
    }

    DestroySwapChain();

    m_hwnd = nullptr;
    m_width = 0;
    m_height = 0;
    m_hostDevice = nullptr;
    m_lastError.clear();
}

const std::string& D3D12WindowSwapChainPresenter::GetLastError() const {
    return m_lastError;
}

RHISwapChain* D3D12WindowSwapChainPresenter::GetSwapChain() const {
    return m_swapChain;
}

const ::XCEngine::Rendering::RenderSurface*
D3D12WindowSwapChainPresenter::GetCurrentRenderSurface() const {
    if (m_swapChain == nullptr) {
        return nullptr;
    }

    const std::uint32_t backBufferIndex = m_swapChain->GetCurrentBackBufferIndex();
    if (backBufferIndex >= m_backBufferSurfaces.size()) {
        return nullptr;
    }

    return &m_backBufferSurfaces[backBufferIndex];
}

const D3D12Texture* D3D12WindowSwapChainPresenter::GetCurrentBackBufferTexture() const {
    if (m_swapChain == nullptr) {
        return nullptr;
    }

    return GetBackBufferTexture(m_swapChain->GetCurrentBackBufferIndex());
}

const D3D12Texture* D3D12WindowSwapChainPresenter::GetBackBufferTexture(std::uint32_t index) const {
    const D3D12SwapChain* d3d12SwapChain = GetD3D12SwapChain();
    if (d3d12SwapChain == nullptr) {
        return nullptr;
    }

    return d3d12SwapChain->TryGetBackBuffer(index);
}

std::uint32_t D3D12WindowSwapChainPresenter::GetBackBufferCount() const {
    return kSwapChainBufferCount;
}

std::uint32_t D3D12WindowSwapChainPresenter::GetCurrentBackBufferIndex() const {
    return m_swapChain != nullptr ? m_swapChain->GetCurrentBackBufferIndex() : 0u;
}

D3D12SwapChain* D3D12WindowSwapChainPresenter::GetD3D12SwapChain() const {
    return m_swapChain != nullptr ? static_cast<D3D12SwapChain*>(m_swapChain) : nullptr;
}

} // namespace XCEngine::UI::Editor::Host