#include "Application.h"
#include <imgui_impl_win32.h>
#include <imgui_impl_dx12.h>
#include <imgui_internal.h>
#include <stdio.h>

extern IMGUI_IMPL_API LRESULT ImGui_ImplWin32_WndProcHandler(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam);

namespace UI {

Application& Application::Get() {
    static Application instance;
    return instance;
}

bool Application::Initialize(HWND hwnd) {
    m_hwnd = hwnd;
    
    if (!CreateDevice()) {
        MessageBoxW(hwnd, L"Failed to create D3D12 device", L"Error", MB_OK | MB_ICONERROR);
        return false;
    }
    if (!CreateRenderTarget()) {
        MessageBoxW(hwnd, L"Failed to create render target", L"Error", MB_OK | MB_ICONERROR);
        return false;
    }
    
    IMGUI_CHECKVERSION();
    ImGui::CreateContext();
    ImGuiIO& io = ImGui::GetIO();
    io.ConfigFlags |= ImGuiConfigFlags_DockingEnable;
    
    io.Fonts->AddFontFromFileTTF("C:/Windows/Fonts/msyh.ttc", 16.0f);
    io.Fonts->AddFontDefault();
    
    unsigned char* pixels;
    int width, height;
    io.Fonts->GetTexDataAsRGBA32(&pixels, &width, &height);
    
    ApplyUnityDarkTheme();
    
    ImGui_ImplWin32_Init(hwnd);
    ImGui_ImplDX12_Init(m_device, 3, DXGI_FORMAT_R8G8B8A8_UNORM, m_srvHeap,
        m_srvHeap->GetCPUDescriptorHandleForHeapStart(),
        m_srvHeap->GetGPUDescriptorHandleForHeapStart());
    
    m_menuBar = std::make_unique<MenuBar>();
    m_hierarchyPanel = std::make_unique<HierarchyPanel>();
    m_sceneViewPanel = std::make_unique<SceneViewPanel>();
    m_gameViewPanel = std::make_unique<GameViewPanel>();
    m_inspectorPanel = std::make_unique<InspectorPanel>();
    m_consolePanel = std::make_unique<ConsolePanel>();
    m_projectPanel = std::make_unique<ProjectPanel>();
    
    wchar_t exePath[MAX_PATH];
    GetModuleFileNameW(nullptr, exePath, MAX_PATH);
    std::wstring exeDirW(exePath);
    size_t pos = exeDirW.find_last_of(L"\\/");
    if (pos != std::wstring::npos) {
        exeDirW = exeDirW.substr(0, pos);
    }
    std::string exeDir;
    int len = WideCharToMultiByte(CP_UTF8, 0, exeDirW.c_str(), -1, nullptr, 0, nullptr, nullptr);
    if (len > 0) {
        exeDir.resize(len - 1);
        WideCharToMultiByte(CP_UTF8, 0, exeDirW.c_str(), -1, &exeDir[0], len, nullptr, nullptr);
    }
    m_projectPanel->Initialize(exeDir);
    
    return true;
}

void Application::Shutdown() {
    ImGui_ImplDX12_Shutdown();
    ImGui_ImplWin32_Shutdown();
    ImGui::DestroyContext();
    
    CleanupRenderTarget();
    
    if (m_fence) m_fence->Release();
    if (m_commandList) m_commandList->Release();
    if (m_commandAllocator) m_commandAllocator->Release();
    if (m_commandQueue) m_commandQueue->Release();
    if (m_rtvHeap) m_rtvHeap->Release();
    if (m_srvHeap) m_srvHeap->Release();
    if (m_swapChain) m_swapChain->Release();
    if (m_device) m_device->Release();
}

void Application::Render() {
    ImGui_ImplDX12_NewFrame();
    ImGui_ImplWin32_NewFrame();
    ImGui::NewFrame();
    
    SetupDockspace();
    RenderUI();
    
    ImGui::Render();
    
    m_frameIndex = m_swapChain->GetCurrentBackBufferIndex();
    m_commandAllocator->Reset();
    m_commandList->Reset(m_commandAllocator, nullptr);
    
    D3D12_RESOURCE_BARRIER barrier = {};
    barrier.Type = D3D12_RESOURCE_BARRIER_TYPE_TRANSITION;
    barrier.Flags = D3D12_RESOURCE_BARRIER_FLAG_NONE;
    barrier.Transition.pResource = m_renderTargets[m_frameIndex];
    barrier.Transition.StateBefore = D3D12_RESOURCE_STATE_PRESENT;
    barrier.Transition.StateAfter = D3D12_RESOURCE_STATE_RENDER_TARGET;
    barrier.Transition.Subresource = D3D12_RESOURCE_BARRIER_ALL_SUBRESOURCES;
    m_commandList->ResourceBarrier(1, &barrier);
    
    float clearColor[4] = { 0.12f, 0.12f, 0.12f, 1.0f };
    D3D12_CPU_DESCRIPTOR_HANDLE rtvHandle = m_rtvHeap->GetCPUDescriptorHandleForHeapStart();
    rtvHandle.ptr += m_frameIndex * m_rtvDescriptorSize;
    m_commandList->ClearRenderTargetView(rtvHandle, clearColor, 0, nullptr);
    m_commandList->OMSetRenderTargets(1, &rtvHandle, FALSE, nullptr);
    
    ID3D12DescriptorHeap* heaps[] = { m_srvHeap };
    m_commandList->SetDescriptorHeaps(1, heaps);
    
    ImGui_ImplDX12_RenderDrawData(ImGui::GetDrawData(), m_commandList);
    
    barrier.Transition.StateBefore = D3D12_RESOURCE_STATE_RENDER_TARGET;
    barrier.Transition.StateAfter = D3D12_RESOURCE_STATE_PRESENT;
    m_commandList->ResourceBarrier(1, &barrier);
    
    m_commandList->Close();
    ID3D12CommandList* cmdLists[] = { m_commandList };
    m_commandQueue->ExecuteCommandLists(1, cmdLists);
    
    m_swapChain->Present(1, 0);
    
    m_fenceValue++;
    m_commandQueue->Signal(m_fence, m_fenceValue);
    if (m_fence->GetCompletedValue() < m_fenceValue) {
        m_fence->SetEventOnCompletion(m_fenceValue, nullptr);
    }
}

void Application::OnResize(int width, int height) {
    if (width <= 0 || height <= 0) return;
    
    m_width = width;
    m_height = height;
    
    CleanupRenderTarget();
    
    if (m_swapChain) {
        DXGI_SWAP_CHAIN_DESC desc;
        m_swapChain->GetDesc(&desc);
        m_swapChain->ResizeBuffers(3, width, height, desc.BufferDesc.Format, desc.Flags);
    }
    
    CreateRenderTarget();
}

bool Application::CreateDevice() {
    HRESULT hr = D3D12CreateDevice(nullptr, D3D_FEATURE_LEVEL_11_0, IID_PPV_ARGS(&m_device));
    if (FAILED(hr)) {
        return false;
    }
    
    D3D12_COMMAND_QUEUE_DESC queueDesc = {};
    queueDesc.Type = D3D12_COMMAND_LIST_TYPE_DIRECT;
    queueDesc.Priority = 0;
    queueDesc.Flags = D3D12_COMMAND_QUEUE_FLAG_NONE;
    queueDesc.NodeMask = 0;
    hr = m_device->CreateCommandQueue(&queueDesc, IID_PPV_ARGS(&m_commandQueue));
    if (FAILED(hr)) return false;
    
    hr = m_device->CreateCommandAllocator(D3D12_COMMAND_LIST_TYPE_DIRECT, IID_PPV_ARGS(&m_commandAllocator));
    if (FAILED(hr)) return false;
    
    hr = m_device->CreateCommandList(0, D3D12_COMMAND_LIST_TYPE_DIRECT, m_commandAllocator, nullptr, IID_PPV_ARGS(&m_commandList));
    if (FAILED(hr)) return false;
    m_commandList->Close();
    
    hr = m_device->CreateFence(0, D3D12_FENCE_FLAG_NONE, IID_PPV_ARGS(&m_fence));
    if (FAILED(hr)) return false;
    
    IDXGIFactory4* factory = nullptr;
    hr = CreateDXGIFactory1(IID_PPV_ARGS(&factory));
    if (FAILED(hr)) return false;
    
    DXGI_SWAP_CHAIN_DESC1 swapChainDesc = {};
    swapChainDesc.BufferCount = 3;
    swapChainDesc.Width = m_width;
    swapChainDesc.Height = m_height;
    swapChainDesc.Format = DXGI_FORMAT_R8G8B8A8_UNORM;
    swapChainDesc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
    swapChainDesc.SwapEffect = DXGI_SWAP_EFFECT_FLIP_DISCARD;
    swapChainDesc.SampleDesc.Count = 1;
    
    IDXGISwapChain1* swapChain1 = nullptr;
    hr = factory->CreateSwapChainForHwnd(m_commandQueue, m_hwnd, &swapChainDesc, nullptr, nullptr, &swapChain1);
    factory->Release();
    if (FAILED(hr)) return false;
    
    hr = swapChain1->QueryInterface(IID_PPV_ARGS(&m_swapChain));
    swapChain1->Release();
    if (FAILED(hr)) return false;
    
    D3D12_DESCRIPTOR_HEAP_DESC rtvDesc = {};
    rtvDesc.Type = D3D12_DESCRIPTOR_HEAP_TYPE_RTV;
    rtvDesc.NumDescriptors = 3;
    rtvDesc.Flags = D3D12_DESCRIPTOR_HEAP_FLAG_NONE;
    hr = m_device->CreateDescriptorHeap(&rtvDesc, IID_PPV_ARGS(&m_rtvHeap));
    if (FAILED(hr)) return false;
    m_rtvDescriptorSize = m_device->GetDescriptorHandleIncrementSize(D3D12_DESCRIPTOR_HEAP_TYPE_RTV);
    
    D3D12_DESCRIPTOR_HEAP_DESC srvDesc = {};
    srvDesc.Type = D3D12_DESCRIPTOR_HEAP_TYPE_CBV_SRV_UAV;
    srvDesc.NumDescriptors = 1;
    srvDesc.Flags = D3D12_DESCRIPTOR_HEAP_FLAG_SHADER_VISIBLE;
    hr = m_device->CreateDescriptorHeap(&srvDesc, IID_PPV_ARGS(&m_srvHeap));
    if (FAILED(hr)) return false;
    
    return true;
}

bool Application::CreateRenderTarget() {
    if (!m_swapChain || !m_device || !m_rtvHeap) return false;
    
    for (UINT i = 0; i < 3; i++) {
        HRESULT hr = m_swapChain->GetBuffer(i, IID_PPV_ARGS(&m_renderTargets[i]));
        if (FAILED(hr)) return false;
        
        D3D12_CPU_DESCRIPTOR_HANDLE rtvHandle = m_rtvHeap->GetCPUDescriptorHandleForHeapStart();
        rtvHandle.ptr += i * m_rtvDescriptorSize;
        m_device->CreateRenderTargetView(m_renderTargets[i], nullptr, rtvHandle);
    }
    return true;
}

void Application::CleanupRenderTarget() {
    for (UINT i = 0; i < 3; i++) {
        if (m_renderTargets[i]) {
            m_renderTargets[i]->Release();
            m_renderTargets[i] = nullptr;
        }
    }
}

void Application::SetupDockspace() {
    static ImGuiDockNodeFlags dockspaceFlags = ImGuiDockNodeFlags_NoWindowMenuButton;
    
    ImGuiWindowFlags windowFlags = ImGuiWindowFlags_MenuBar | ImGuiWindowFlags_NoDocking;
    
    ImGuiViewport* viewport = ImGui::GetMainViewport();
    ImGui::SetNextWindowPos(viewport->Pos);
    ImGui::SetNextWindowSize(viewport->Size);
    ImGui::SetNextWindowViewport(viewport->ID);
    ImGui::PushStyleVar(ImGuiStyleVar_WindowRounding, 0.0f);
    ImGui::PushStyleVar(ImGuiStyleVar_WindowBorderSize, 0.0f);
    windowFlags |= ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoCollapse | ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoMove;
    windowFlags |= ImGuiWindowFlags_NoBringToFrontOnFocus | ImGuiWindowFlags_NoNavFocus;
    
    ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, ImVec2(0.0f, 0.0f));
    ImGui::Begin("MainDockspace", nullptr, windowFlags);
    ImGui::PopStyleVar();
    ImGui::PopStyleVar(2);
    
    ImGuiID dockspaceId = ImGui::GetID("MyDockspace");
    ImGui::DockSpace(dockspaceId, ImVec2(0.0f, 0.0f), dockspaceFlags);
    
    static bool firstTime = true;
    if (firstTime) {
        firstTime = false;
        ImGui::DockBuilderRemoveNode(dockspaceId);
        ImGui::DockBuilderAddNode(dockspaceId, dockspaceFlags | ImGuiDockNodeFlags_DockSpace);
        ImGui::DockBuilderSetNodeSize(dockspaceId, viewport->Size);
        
        ImGuiID dockMain = dockspaceId;
        ImGuiID dockBottom = ImGui::DockBuilderSplitNode(dockMain, ImGuiDir_Down, 0.25f, nullptr, &dockMain);
        ImGuiID dockLeft = ImGui::DockBuilderSplitNode(dockMain, ImGuiDir_Left, 0.15f, nullptr, &dockMain);
        ImGuiID dockRight = ImGui::DockBuilderSplitNode(dockMain, ImGuiDir_Right, 0.25f, nullptr, &dockMain);
        
        ImGui::DockBuilderDockWindow("Hierarchy", dockLeft);
        ImGui::DockBuilderDockWindow("Scene", dockMain);
        ImGui::DockBuilderDockWindow("Game", dockMain);
        ImGui::DockBuilderDockWindow("Inspector", dockRight);
        ImGui::DockBuilderDockWindow("Console", dockBottom);
        ImGui::DockBuilderDockWindow("Project", dockBottom);
        
        ImGui::DockBuilderFinish(dockspaceId);
    }
    
    ImGui::End();
}

void Application::RenderUI() {
    m_menuBar->Render();
    
    m_hierarchyPanel->Render();
    m_sceneViewPanel->Render();
    m_gameViewPanel->Render();
    m_inspectorPanel->Render();
    m_consolePanel->Render();
    m_projectPanel->Render();
}

}