// based off https://github.com/kevinmoran/BeginnerDirect3D11/tree/master/02.%20Drawing%20a%20Triangle
//
// This example should not be taken as "good" code, it is just an example of how to use librashader in Direct3D11.
// 
// Namely, you should not recreate the input texture every frame. It is much cheaper to have one long lived copy texture.
#define WIN32_LEAN_AND_MEAN
#define NOMINMAX
#define UNICODE
#include <d3d11_1.h>
#include <windows.h>
#pragma comment(lib, "d3d11.lib")
#include <d3dcompiler.h>
#pragma comment(lib, "d3dcompiler.lib")

#include <assert.h>
#define LIBRA_RUNTIME_D3D11
#define LIBRA_RUNTIME_D3D12

#include "../../../../include/librashader.h"
#include "../../../../include/librashader_ld.h"


static bool global_windowDidResize = false;

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam) {
    LRESULT result = 0;
    switch (msg) {
        case WM_KEYDOWN: {
            if (wparam == VK_ESCAPE) DestroyWindow(hwnd);
            break;
        }
        case WM_DESTROY: {
            PostQuitMessage(0);
            break;
        }
        case WM_SIZE: {
            global_windowDidResize = true;
            break;
        }
        default:
            result = DefWindowProcW(hwnd, msg, wparam, lparam);
    }
    return result;
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE /*hPrevInstance*/,
                   LPSTR /*lpCmdLine*/, int /*nShowCmd*/) {
    // Open a window
    HWND hwnd;
    {
        WNDCLASSEXW winClass = {};
        winClass.cbSize = sizeof(WNDCLASSEXW);
        winClass.style = CS_HREDRAW | CS_VREDRAW;
        winClass.lpfnWndProc = &WndProc;
        winClass.hInstance = hInstance;
        winClass.hIcon = LoadIconW(0, IDI_APPLICATION);
        winClass.hCursor = LoadCursorW(0, IDC_ARROW);
        winClass.lpszClassName = L"MyWindowClass";
        winClass.hIconSm = LoadIconW(0, IDI_APPLICATION);

        if (!RegisterClassExW(&winClass)) {
            MessageBoxA(0, "RegisterClassEx failed", "Fatal Error", MB_OK);
            return GetLastError();
        }

        RECT initialRect = {0, 0, 1024, 768};
        AdjustWindowRectEx(&initialRect, WS_OVERLAPPEDWINDOW, FALSE,
                           WS_EX_OVERLAPPEDWINDOW);
        LONG initialWidth = initialRect.right - initialRect.left;
        LONG initialHeight = initialRect.bottom - initialRect.top;

        hwnd = CreateWindowExW(WS_EX_OVERLAPPEDWINDOW, winClass.lpszClassName,
                               L"librashader-capi DirectX 11",
                               WS_OVERLAPPEDWINDOW | WS_VISIBLE, CW_USEDEFAULT,
                               CW_USEDEFAULT, initialWidth, initialHeight, 0, 0,
                               hInstance, 0);

        if (!hwnd) {
            MessageBoxA(0, "CreateWindowEx failed", "Fatal Error", MB_OK);
            return GetLastError();
        }
    }

    // Create D3D11 Device and Context
    ID3D11Device1* d3d11Device;
    ID3D11DeviceContext1* d3d11DeviceContext;
    {
        ID3D11Device* baseDevice;
        ID3D11DeviceContext* baseDeviceContext;
        D3D_FEATURE_LEVEL featureLevels[] = {D3D_FEATURE_LEVEL_11_0};
        UINT creationFlags = D3D11_CREATE_DEVICE_BGRA_SUPPORT;
#if defined(DEBUG_BUILD)
        creationFlags |= D3D11_CREATE_DEVICE_DEBUG;
#endif

        HRESULT hResult = D3D11CreateDevice(
            0, D3D_DRIVER_TYPE_HARDWARE, 0, creationFlags, featureLevels,
            ARRAYSIZE(featureLevels), D3D11_SDK_VERSION, &baseDevice, 0,
            &baseDeviceContext);
        if (FAILED(hResult)) {
            MessageBoxA(0, "D3D11CreateDevice() failed", "Fatal Error", MB_OK);
            return GetLastError();
        }

        // Get 1.1 interface of D3D11 Device and Context
        hResult = baseDevice->QueryInterface(__uuidof(ID3D11Device1),
                                             (void**)&d3d11Device);
        assert(SUCCEEDED(hResult));
        baseDevice->Release();

        hResult = baseDeviceContext->QueryInterface(
            __uuidof(ID3D11DeviceContext1), (void**)&d3d11DeviceContext);
        assert(SUCCEEDED(hResult));
        baseDeviceContext->Release();
    }

#ifdef DEBUG_BUILD
    // Set up debug layer to break on D3D11 errors
    ID3D11Debug* d3dDebug = nullptr;
    d3d11Device->QueryInterface(__uuidof(ID3D11Debug), (void**)&d3dDebug);
    if (d3dDebug) {
        ID3D11InfoQueue* d3dInfoQueue = nullptr;
        if (SUCCEEDED(d3dDebug->QueryInterface(__uuidof(ID3D11InfoQueue),
                                               (void**)&d3dInfoQueue))) {
            d3dInfoQueue->SetBreakOnSeverity(D3D11_MESSAGE_SEVERITY_CORRUPTION,
                                             true);
            d3dInfoQueue->SetBreakOnSeverity(D3D11_MESSAGE_SEVERITY_ERROR,
                                             true);
            d3dInfoQueue->Release();
        }
        d3dDebug->Release();
    }
#endif

    auto libra = librashader_load_instance();
    libra_shader_preset_t preset;
        auto error = libra.preset_create(
        "../../../slang-shaders/border/gameboy-player/"
        "gameboy-player-crt-royale.slangp",
        &preset);

    libra_d3d11_filter_chain_t filter_chain;

    libra.d3d11_filter_chain_create(&preset, NULL, d3d11Device,
                                    &filter_chain);

    // Create Swap Chain
    IDXGISwapChain1* d3d11SwapChain;
    {
        // Get DXGI Factory (needed to create Swap Chain)
        IDXGIFactory2* dxgiFactory;
        {
            IDXGIDevice1* dxgiDevice;
            HRESULT hResult = d3d11Device->QueryInterface(
                __uuidof(IDXGIDevice1), (void**)&dxgiDevice);
            assert(SUCCEEDED(hResult));

            IDXGIAdapter* dxgiAdapter;
            hResult = dxgiDevice->GetAdapter(&dxgiAdapter);
            assert(SUCCEEDED(hResult));
            dxgiDevice->Release();

            DXGI_ADAPTER_DESC adapterDesc;
            dxgiAdapter->GetDesc(&adapterDesc);

            OutputDebugStringA("Graphics Device: ");
            OutputDebugStringW(adapterDesc.Description);

            hResult = dxgiAdapter->GetParent(__uuidof(IDXGIFactory2),
                                             (void**)&dxgiFactory);
            assert(SUCCEEDED(hResult));
            dxgiAdapter->Release();
        }

        DXGI_SWAP_CHAIN_DESC1 d3d11SwapChainDesc = {};
        d3d11SwapChainDesc.Width = 0;     // use window width
        d3d11SwapChainDesc.Height = 0;    // use window height
        d3d11SwapChainDesc.Format = DXGI_FORMAT_B8G8R8A8_UNORM_SRGB;
        d3d11SwapChainDesc.SampleDesc.Count = 1;
        d3d11SwapChainDesc.SampleDesc.Quality = 0;
        d3d11SwapChainDesc.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
        d3d11SwapChainDesc.BufferCount = 2;
        d3d11SwapChainDesc.Scaling = DXGI_SCALING_STRETCH;
        d3d11SwapChainDesc.SwapEffect = DXGI_SWAP_EFFECT_DISCARD;
        d3d11SwapChainDesc.AlphaMode = DXGI_ALPHA_MODE_UNSPECIFIED;
        d3d11SwapChainDesc.Flags = 0;

        HRESULT hResult = dxgiFactory->CreateSwapChainForHwnd(
            d3d11Device, hwnd, &d3d11SwapChainDesc, 0, 0, &d3d11SwapChain);
        assert(SUCCEEDED(hResult));

        dxgiFactory->Release();
    }

    // Create Framebuffer Render Target
    ID3D11RenderTargetView* d3d11FrameBufferView;
    {
        ID3D11Texture2D* d3d11FrameBuffer;
        HRESULT hResult = d3d11SwapChain->GetBuffer(
            0, __uuidof(ID3D11Texture2D), (void**)&d3d11FrameBuffer);
        assert(SUCCEEDED(hResult));

        hResult = d3d11Device->CreateRenderTargetView(d3d11FrameBuffer, 0,
                                                      &d3d11FrameBufferView);
        assert(SUCCEEDED(hResult));
        d3d11FrameBuffer->Release();
    }

    // Create Vertex Shader
    ID3DBlob* vsBlob;
    ID3D11VertexShader* vertexShader;
    {
        ID3DBlob* shaderCompileErrorsBlob;
        HRESULT hResult = D3DCompileFromFile(L"shaders.hlsl", nullptr, nullptr,
                                             "vs_main", "vs_5_0", 0, 0, &vsBlob,
                                             &shaderCompileErrorsBlob);
        if (FAILED(hResult)) {
            const char* errorString = NULL;
            if (hResult == HRESULT_FROM_WIN32(ERROR_FILE_NOT_FOUND))
                errorString = "Could not compile shader; file not found";
            else if (shaderCompileErrorsBlob) {
                errorString =
                    (const char*)shaderCompileErrorsBlob->GetBufferPointer();
                shaderCompileErrorsBlob->Release();
            }
            MessageBoxA(0, errorString, "Shader Compiler Error",
                        MB_ICONERROR | MB_OK);
            return 1;
        }

        hResult = d3d11Device->CreateVertexShader(vsBlob->GetBufferPointer(),
                                                  vsBlob->GetBufferSize(),
                                                  nullptr, &vertexShader);
        assert(SUCCEEDED(hResult));
    }

    // Create Pixel Shader
    ID3D11PixelShader* pixelShader;
    {
        ID3DBlob* psBlob;
        ID3DBlob* shaderCompileErrorsBlob;
        HRESULT hResult = D3DCompileFromFile(L"shaders.hlsl", nullptr, nullptr,
                                             "ps_main", "ps_5_0", 0, 0, &psBlob,
                                             &shaderCompileErrorsBlob);
        if (FAILED(hResult)) {
            const char* errorString = NULL;
            if (hResult == HRESULT_FROM_WIN32(ERROR_FILE_NOT_FOUND))
                errorString = "Could not compile shader; file not found";
            else if (shaderCompileErrorsBlob) {
                errorString =
                    (const char*)shaderCompileErrorsBlob->GetBufferPointer();
                shaderCompileErrorsBlob->Release();
            }
            MessageBoxA(0, errorString, "Shader Compiler Error",
                        MB_ICONERROR | MB_OK);
            return 1;
        }

        hResult = d3d11Device->CreatePixelShader(psBlob->GetBufferPointer(),
                                                 psBlob->GetBufferSize(),
                                                 nullptr, &pixelShader);
        assert(SUCCEEDED(hResult));
        psBlob->Release();
    }

    // Create Input Layout
    ID3D11InputLayout* inputLayout;
    {
        D3D11_INPUT_ELEMENT_DESC inputElementDesc[] = {
            {"POS", 0, DXGI_FORMAT_R32G32_FLOAT, 0, 0,
             D3D11_INPUT_PER_VERTEX_DATA, 0},
            {"COL", 0, DXGI_FORMAT_R32G32B32A32_FLOAT, 0,
             D3D11_APPEND_ALIGNED_ELEMENT, D3D11_INPUT_PER_VERTEX_DATA, 0}};

        HRESULT hResult = d3d11Device->CreateInputLayout(
            inputElementDesc, ARRAYSIZE(inputElementDesc),
            vsBlob->GetBufferPointer(), vsBlob->GetBufferSize(), &inputLayout);
        assert(SUCCEEDED(hResult));
        vsBlob->Release();
    }

    // Create Vertex Buffer
    ID3D11Buffer* vertexBuffer;
    UINT numVerts;
    UINT stride;
    UINT offset;
    {
        float vertexData[] = {// x, y, r, g, b, a
                              0.0f,  0.5f,  0.f, 1.f, 0.f, 1.f,
                              0.5f,  -0.5f, 1.f, 0.f, 0.f, 1.f,
                              -0.5f, -0.5f, 0.f, 0.f, 1.f, 1.f};
        stride = 6 * sizeof(float);
        numVerts = sizeof(vertexData) / stride;
        offset = 0;

        D3D11_BUFFER_DESC vertexBufferDesc = {};
        vertexBufferDesc.ByteWidth = sizeof(vertexData);
        vertexBufferDesc.Usage = D3D11_USAGE_IMMUTABLE;
        vertexBufferDesc.BindFlags = D3D11_BIND_VERTEX_BUFFER;

        D3D11_SUBRESOURCE_DATA vertexSubresourceData = {vertexData};

        HRESULT hResult = d3d11Device->CreateBuffer(
            &vertexBufferDesc, &vertexSubresourceData, &vertexBuffer);
        assert(SUCCEEDED(hResult));
    }

    // Main Loop
    bool isRunning = true;
    size_t frameCount = 0;

    while (isRunning) {
        MSG msg = {};
        while (PeekMessageW(&msg, 0, 0, 0, PM_REMOVE)) {
            if (msg.message == WM_QUIT) isRunning = false;
            TranslateMessage(&msg);
            DispatchMessageW(&msg);
        }

        if (global_windowDidResize) {
            d3d11DeviceContext->OMSetRenderTargets(0, 0, 0);
            d3d11FrameBufferView->Release();

            HRESULT res =
                d3d11SwapChain->ResizeBuffers(0, 0, 0, DXGI_FORMAT_UNKNOWN, 0);
            assert(SUCCEEDED(res));

            ID3D11Texture2D* d3d11FrameBuffer;
            res = d3d11SwapChain->GetBuffer(0, __uuidof(ID3D11Texture2D),
                                            (void**)&d3d11FrameBuffer);
            assert(SUCCEEDED(res));

            res = d3d11Device->CreateRenderTargetView(d3d11FrameBuffer, NULL,
                                                      &d3d11FrameBufferView);
            assert(SUCCEEDED(res));
            d3d11FrameBuffer->Release();

            global_windowDidResize = false;
        }

        FLOAT backgroundColor[4] = {0.1f, 0.2f, 0.6f, 1.0f};
        d3d11DeviceContext->ClearRenderTargetView(d3d11FrameBufferView,
                                                  backgroundColor);

        RECT winRect;
        GetClientRect(hwnd, &winRect);
        D3D11_VIEWPORT viewport = {0.0f,
                                   0.0f,
                                   (FLOAT)(winRect.right - winRect.left),
                                   (FLOAT)(winRect.bottom - winRect.top),
                                   0.0f,
                                   1.0f};
        d3d11DeviceContext->RSSetViewports(1, &viewport);

        d3d11DeviceContext->OMSetRenderTargets(1, &d3d11FrameBufferView,
                                               nullptr);

        d3d11DeviceContext->IASetPrimitiveTopology(
            D3D11_PRIMITIVE_TOPOLOGY_TRIANGLELIST);
        d3d11DeviceContext->IASetInputLayout(inputLayout);

        d3d11DeviceContext->VSSetShader(vertexShader, nullptr, 0);
        d3d11DeviceContext->PSSetShader(pixelShader, nullptr, 0);

        d3d11DeviceContext->IASetVertexBuffers(0, 1, &vertexBuffer, &stride,
                                               &offset);

        d3d11DeviceContext->Draw(numVerts, 0);

        ID3D11Texture2D* framebufferCopy;
        ID3D11ShaderResourceView* copySrv;
        {
            ID3D11Texture2D* d3d11FrameBuffer;
            HRESULT hResult = d3d11SwapChain->GetBuffer(
                0, __uuidof(ID3D11Texture2D), (void**)&d3d11FrameBuffer);
            assert(SUCCEEDED(hResult));

            D3D11_TEXTURE2D_DESC framebufferDesc;
            d3d11FrameBuffer->GetDesc(&framebufferDesc);

            framebufferDesc.BindFlags =
                D3D11_BIND_SHADER_RESOURCE | D3D11_BIND_RENDER_TARGET;
            framebufferDesc.CPUAccessFlags =
                D3D11_CPU_ACCESS_READ | D3D11_CPU_ACCESS_READ;

            hResult = d3d11Device->CreateTexture2D(&framebufferDesc, nullptr,
                                                   &framebufferCopy);
            assert(SUCCEEDED(hResult));

            d3d11DeviceContext->CopyResource(framebufferCopy, d3d11FrameBuffer);

            hResult = d3d11Device->CreateShaderResourceView(framebufferCopy, 0,
                                                            &copySrv);
            assert(SUCCEEDED(hResult));

            d3d11FrameBuffer->Release();
        }

        assert(copySrv != nullptr);

        libra_source_image_d3d11_t input = {copySrv,
                                            viewport.Width,
                                            viewport.Height,};

        libra_viewport_t vp = {0, 0, viewport.Width, viewport.Height, };

        libra.d3d11_filter_chain_frame(&filter_chain, frameCount, input, vp,
                                       d3d11FrameBufferView, NULL, NULL);

        copySrv->Release();
        framebufferCopy->Release();
        d3d11SwapChain->Present(1, 0);
        frameCount += 1;
    }

    return 0;
}