#include "D3D12WindowRenderer.h"

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

using ::XCEngine::RHI::RHIDevice;
using ::XCEngine::RHI::RHISwapChain;
using ::XCEngine::RHI::D3D12Texture;

bool D3D12WindowRenderer::Initialize(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 (!m_hostDevice.Initialize()) {
        m_lastError = m_hostDevice.GetLastError();
        return false;
    }

    if (!m_presenter.Initialize(m_hostDevice, hwnd, width, height)) {
        m_lastError = m_presenter.GetLastError();
        Shutdown();
        return false;
    }

    auto* device = m_hostDevice.GetRHIDevice();
    if (device == nullptr ||
        !m_viewportTextureAllocator.Initialize(*device)) {
        m_lastError = "Failed to initialize the viewport texture allocator.";
        Shutdown();
        return false;
    }

    m_lastError.clear();
    return true;
}

void D3D12WindowRenderer::Shutdown() {
    m_viewportTextureCpuHandles.clear();
    m_viewportTextureAllocator.Shutdown();
    m_presenter.Shutdown();
    m_hostDevice.Shutdown();
    m_activeBackBufferIndex = 0u;
    m_lastError.clear();
}

bool D3D12WindowRenderer::Resize(int width, int height) {
    if (!m_presenter.Resize(width, height)) {
        m_lastError = m_presenter.GetLastError();
        return false;
    }

    m_activeBackBufferIndex = m_presenter.GetCurrentBackBufferIndex();
    m_lastError = m_presenter.GetLastError();
    if (!m_lastError.empty()) {
        return true;
    }
    m_lastError.clear();
    return true;
}

bool D3D12WindowRenderer::BeginFrame() {
    if (m_presenter.GetSwapChain() == nullptr) {
        m_lastError = "BeginFrame requires an initialized swap chain.";
        return false;
    }

    m_activeBackBufferIndex = m_presenter.GetCurrentBackBufferIndex();
    if (!m_hostDevice.BeginFrame(m_activeBackBufferIndex)) {
        m_lastError = m_hostDevice.GetLastError();
        return false;
    }

    m_lastError.clear();
    return true;
}

bool D3D12WindowRenderer::PreparePresentSurface() {
    ::XCEngine::Rendering::RenderContext renderContext = GetRenderContext();
    if (!renderContext.IsValid() || renderContext.commandList == nullptr) {
        m_lastError = "PreparePresentSurface requires a valid render context.";
        return false;
    }

    const bool prepared = m_presenter.PreparePresentSurface(renderContext);
    m_lastError = prepared ? std::string() : m_presenter.GetLastError();
    return prepared;
}

bool D3D12WindowRenderer::SubmitFrame(bool presentSwapChain) {
    if (presentSwapChain && m_presenter.GetSwapChain() == nullptr) {
        m_lastError = "SubmitFrame requested present without a swap chain.";
        return false;
    }

    if (!m_hostDevice.SubmitFrame(m_activeBackBufferIndex)) {
        m_lastError = m_hostDevice.GetLastError();
        return false;
    }

    if (presentSwapChain) {
        if (!m_presenter.PresentFrame()) {
            m_lastError = m_presenter.GetLastError();
            return false;
        }
    }
    m_lastError.clear();
    return true;
}

bool D3D12WindowRenderer::SignalFrameCompletion() {
    if (!m_hostDevice.SignalFrameCompletion(m_activeBackBufferIndex)) {
        m_lastError = m_hostDevice.GetLastError();
        return false;
    }

    m_lastError.clear();
    return true;
}

bool D3D12WindowRenderer::PresentFrame() {
    const bool presented = m_presenter.PresentFrame();
    m_lastError = presented ? std::string() : m_presenter.GetLastError();
    return presented;
}

ID3D12Device* D3D12WindowRenderer::GetDevice() const {
    return m_hostDevice.GetDevice();
}

ID3D12CommandQueue* D3D12WindowRenderer::GetCommandQueue() const {
    return m_hostDevice.GetCommandQueue();
}

const std::string& D3D12WindowRenderer::GetLastError() const {
    return m_lastError;
}

RHIDevice* D3D12WindowRenderer::GetRHIDevice() const {
    return m_hostDevice.GetRHIDevice();
}

bool D3D12WindowRenderer::CreateViewportTextureHandle(
    ::XCEngine::RHI::RHITexture& texture,
    std::uint32_t width,
    std::uint32_t height,
    ::XCEngine::UI::UITextureHandle& outTexture) {
    outTexture = {};
    if (width == 0u ||
        height == 0u ||
        !m_viewportTextureAllocator.IsInitialized()) {
        return false;
    }

    D3D12_CPU_DESCRIPTOR_HANDLE cpuHandle = {};
    D3D12_GPU_DESCRIPTOR_HANDLE gpuHandle = {};
    if (!m_viewportTextureAllocator.CreateTextureDescriptor(
            &texture,
            &cpuHandle,
            &gpuHandle) ||
        cpuHandle.ptr == 0u ||
        gpuHandle.ptr == 0u) {
        return false;
    }

    outTexture.nativeHandle = static_cast<std::uintptr_t>(gpuHandle.ptr);
    outTexture.width = width;
    outTexture.height = height;
    outTexture.kind = ::XCEngine::UI::UITextureHandleKind::ShaderResourceView;
    outTexture.resourceHandle = reinterpret_cast<std::uintptr_t>(&texture);
    m_viewportTextureCpuHandles[outTexture.nativeHandle] = cpuHandle;
    return true;
}

void D3D12WindowRenderer::ReleaseViewportTextureHandle(
    ::XCEngine::UI::UITextureHandle& texture) {
    if (!texture.IsValid()) {
        texture = {};
        return;
    }

    const auto found = m_viewportTextureCpuHandles.find(texture.nativeHandle);
    if (found != m_viewportTextureCpuHandles.end()) {
        D3D12_GPU_DESCRIPTOR_HANDLE gpuHandle = {};
        gpuHandle.ptr = static_cast<UINT64>(texture.nativeHandle);
        m_viewportTextureAllocator.Free(found->second, gpuHandle);
        m_viewportTextureCpuHandles.erase(found);
    }

    texture = {};
}

RHISwapChain* D3D12WindowRenderer::GetSwapChain() const {
    return m_presenter.GetSwapChain();
}

const ::XCEngine::Rendering::RenderSurface* D3D12WindowRenderer::GetCurrentRenderSurface() const {
    return m_presenter.GetCurrentRenderSurface();
}

const D3D12Texture* D3D12WindowRenderer::GetCurrentBackBufferTexture() const {
    return m_presenter.GetCurrentBackBufferTexture();
}

const D3D12Texture* D3D12WindowRenderer::GetBackBufferTexture(std::uint32_t index) const {
    return m_presenter.GetBackBufferTexture(index);
}

std::uint32_t D3D12WindowRenderer::GetBackBufferCount() const {
    return m_presenter.GetBackBufferCount();
}

::XCEngine::Rendering::RenderContext D3D12WindowRenderer::GetRenderContext() const {
    return m_hostDevice.GetRenderContext(m_activeBackBufferIndex);
}

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