#include "D3D12HostDevice.h"

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

using ::XCEngine::RHI::D3D12CommandList;
using ::XCEngine::RHI::RHICommandList;

bool D3D12HostDevice::BeginFrame(std::uint32_t frameIndex) {
    WaitForFrame(frameIndex);

    RHICommandList* commandList = GetCommandList(frameIndex);
    D3D12CommandList* d3d12CommandList = GetD3D12CommandList(frameIndex);
    if (commandList == nullptr || d3d12CommandList == nullptr) {
        m_lastError = "BeginFrame could not resolve the active command list.";
        return false;
    }

    commandList->Reset();
    m_lastError.clear();
    return true;
}

bool D3D12HostDevice::SubmitFrame(std::uint32_t frameIndex) {
    RHICommandList* commandList = GetCommandList(frameIndex);
    if (commandList == nullptr || m_commandQueue == nullptr) {
        m_lastError = "SubmitFrame requires an initialized command list and queue.";
        return false;
    }

    commandList->Close();
    void* commandLists[] = { commandList };
    m_commandQueue->ExecuteCommandLists(1, commandLists);
    m_lastError.clear();
    return true;
}

bool D3D12HostDevice::SignalFrameCompletion(std::uint32_t frameIndex) {
    ID3D12CommandQueue* commandQueue = GetCommandQueue();
    if (commandQueue == nullptr ||
        m_frameCompletionFence == nullptr ||
        frameIndex >= m_frameFenceValues.size()) {
        return false;
    }

    ++m_lastSubmittedFrameValue;
    const HRESULT hr = commandQueue->Signal(
        m_frameCompletionFence.Get(),
        m_lastSubmittedFrameValue);
    if (SUCCEEDED(hr)) {
        m_frameFenceValues[frameIndex] = m_lastSubmittedFrameValue;
        m_lastError.clear();
    }
    return SUCCEEDED(hr);
}

void D3D12HostDevice::WaitForFrame(std::uint32_t frameIndex) {
    if (m_frameCompletionFence == nullptr ||
        m_frameCompletionEvent == nullptr ||
        frameIndex >= m_frameFenceValues.size()) {
        return;
    }

    const std::uint64_t fenceValue = m_frameFenceValues[frameIndex];
    if (fenceValue == 0u ||
        m_frameCompletionFence->GetCompletedValue() >= fenceValue) {
        return;
    }

    const HRESULT hr = m_frameCompletionFence->SetEventOnCompletion(
        fenceValue,
        m_frameCompletionEvent);
    if (SUCCEEDED(hr)) {
        WaitForSingleObject(m_frameCompletionEvent, INFINITE);
    }
}

void D3D12HostDevice::WaitForGpuIdle() {
    ID3D12CommandQueue* commandQueue = GetCommandQueue();
    if (commandQueue == nullptr ||
        m_frameCompletionFence == nullptr ||
        m_frameCompletionEvent == nullptr) {
        if (m_commandQueue != nullptr) {
            m_commandQueue->WaitForIdle();
        }
        return;
    }

    ++m_lastSubmittedFrameValue;
    const std::uint64_t fenceValue = m_lastSubmittedFrameValue;
    const HRESULT signalHr = commandQueue->Signal(
        m_frameCompletionFence.Get(),
        fenceValue);
    if (FAILED(signalHr)) {
        return;
    }

    if (m_frameCompletionFence->GetCompletedValue() >= fenceValue) {
        return;
    }

    const HRESULT waitHr = m_frameCompletionFence->SetEventOnCompletion(
        fenceValue,
        m_frameCompletionEvent);
    if (SUCCEEDED(waitHr)) {
        WaitForSingleObject(m_frameCompletionEvent, INFINITE);
    }
}

void D3D12HostDevice::ResetFrameTracking() {
    m_frameFenceValues.fill(0u);
}

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