#include "pch.h"
#include "TextureLoader.h"
#include "DeviceResources.h"
#include "App.h"
#include "Logger.h"
#include "DDS.h"
#include "DDSLoderHelpers.h"
#include "Utils.h"


///////////////////////////////////////////////////////////////////
// 读取 DDS 文件的代码取自 https://github.com/microsoft/DirectXTK //
///////////////////////////////////////////////////////////////////


HRESULT CreateD3DResources(
        _In_ ID3D11Device* d3dDevice,
        _In_ uint32_t resDim,
        _In_ size_t width,
        _In_ size_t height,
        _In_ size_t depth,
        _In_ size_t mipCount,
        _In_ size_t arraySize,
        _In_ DXGI_FORMAT format,
        _In_ D3D11_USAGE usage,
        _In_ unsigned int bindFlags,
        _In_ unsigned int cpuAccessFlags,
        _In_ unsigned int miscFlags,
        _In_ bool forceSRGB,
        _In_ bool isCubeMap,
        _In_reads_opt_(mipCount* arraySize) const D3D11_SUBRESOURCE_DATA* initData,
        _Outptr_opt_ ID3D11Resource** texture,
        _Outptr_opt_ ID3D11ShaderResourceView** textureView) noexcept {
    if (!d3dDevice)
        return E_POINTER;

    HRESULT hr = E_FAIL;

    if (forceSRGB) {
        format = MakeSRGB(format);
    }

    switch (resDim) {
    case D3D11_RESOURCE_DIMENSION_TEXTURE1D:
    {
        D3D11_TEXTURE1D_DESC desc = {};
        desc.Width = static_cast<UINT>(width);
        desc.MipLevels = static_cast<UINT>(mipCount);
        desc.ArraySize = static_cast<UINT>(arraySize);
        desc.Format = format;
        desc.Usage = usage;
        desc.BindFlags = bindFlags;
        desc.CPUAccessFlags = cpuAccessFlags;
        desc.MiscFlags = miscFlags & ~static_cast<unsigned int>(D3D11_RESOURCE_MISC_TEXTURECUBE);

        ID3D11Texture1D* tex = nullptr;
        hr = d3dDevice->CreateTexture1D(&desc,
            initData,
            &tex
        );
        if (SUCCEEDED(hr) && tex) {
            if (textureView) {
                D3D11_SHADER_RESOURCE_VIEW_DESC SRVDesc = {};
                SRVDesc.Format = format;

                if (arraySize > 1) {
                    SRVDesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE1DARRAY;
                    SRVDesc.Texture1DArray.MipLevels = (!mipCount) ? UINT(-1) : desc.MipLevels;
                    SRVDesc.Texture1DArray.ArraySize = static_cast<UINT>(arraySize);
                } else {
                    SRVDesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE1D;
                    SRVDesc.Texture1D.MipLevels = (!mipCount) ? UINT(-1) : desc.MipLevels;
                }

                hr = d3dDevice->CreateShaderResourceView(tex,
                    &SRVDesc,
                    textureView
                );
                if (FAILED(hr)) {
                    tex->Release();
                    return hr;
                }
            }

            if (texture) {
                *texture = tex;
            } else {
                tex->Release();
            }
        }
    }
    break;

    case D3D11_RESOURCE_DIMENSION_TEXTURE2D:
    {
        D3D11_TEXTURE2D_DESC desc = {};
        desc.Width = static_cast<UINT>(width);
        desc.Height = static_cast<UINT>(height);
        desc.MipLevels = static_cast<UINT>(mipCount);
        desc.ArraySize = static_cast<UINT>(arraySize);
        desc.Format = format;
        desc.SampleDesc.Count = 1;
        desc.SampleDesc.Quality = 0;
        desc.Usage = usage;
        desc.BindFlags = bindFlags;
        desc.CPUAccessFlags = cpuAccessFlags;
        if (isCubeMap) {
            desc.MiscFlags = miscFlags | D3D11_RESOURCE_MISC_TEXTURECUBE;
        } else {
            desc.MiscFlags = miscFlags & ~static_cast<unsigned int>(D3D11_RESOURCE_MISC_TEXTURECUBE);
        }

        ID3D11Texture2D* tex = nullptr;
        hr = d3dDevice->CreateTexture2D(&desc,
            initData,
            &tex
        );
        if (SUCCEEDED(hr) && tex) {
            if (textureView) {
                D3D11_SHADER_RESOURCE_VIEW_DESC SRVDesc = {};
                SRVDesc.Format = format;

                if (isCubeMap) {
                    if (arraySize > 6) {
                        SRVDesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURECUBEARRAY;
                        SRVDesc.TextureCubeArray.MipLevels = (!mipCount) ? UINT(-1) : desc.MipLevels;

                        // Earlier we set arraySize to (NumCubes * 6)
                        SRVDesc.TextureCubeArray.NumCubes = static_cast<UINT>(arraySize / 6);
                    } else {
                        SRVDesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURECUBE;
                        SRVDesc.TextureCube.MipLevels = (!mipCount) ? UINT(-1) : desc.MipLevels;
                    }
                } else if (arraySize > 1) {
                    SRVDesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE2DARRAY;
                    SRVDesc.Texture2DArray.MipLevels = (!mipCount) ? UINT(-1) : desc.MipLevels;
                    SRVDesc.Texture2DArray.ArraySize = static_cast<UINT>(arraySize);
                } else {
                    SRVDesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE2D;
                    SRVDesc.Texture2D.MipLevels = (!mipCount) ? UINT(-1) : desc.MipLevels;
                }

                hr = d3dDevice->CreateShaderResourceView(tex,
                    &SRVDesc,
                    textureView
                );
                if (FAILED(hr)) {
                    tex->Release();
                    return hr;
                }
            }

            if (texture) {
                *texture = tex;
            } else {
                tex->Release();
            }
        }
    }
    break;

    case D3D11_RESOURCE_DIMENSION_TEXTURE3D:
    {
        D3D11_TEXTURE3D_DESC desc = {};
        desc.Width = static_cast<UINT>(width);
        desc.Height = static_cast<UINT>(height);
        desc.Depth = static_cast<UINT>(depth);
        desc.MipLevels = static_cast<UINT>(mipCount);
        desc.Format = format;
        desc.Usage = usage;
        desc.BindFlags = bindFlags;
        desc.CPUAccessFlags = cpuAccessFlags;
        desc.MiscFlags = miscFlags & ~UINT(D3D11_RESOURCE_MISC_TEXTURECUBE);

        ID3D11Texture3D* tex = nullptr;
        hr = d3dDevice->CreateTexture3D(&desc,
            initData,
            &tex
        );
        if (SUCCEEDED(hr) && tex) {
            if (textureView) {
                D3D11_SHADER_RESOURCE_VIEW_DESC SRVDesc = {};
                SRVDesc.Format = format;

                SRVDesc.ViewDimension = D3D11_SRV_DIMENSION_TEXTURE3D;
                SRVDesc.Texture3D.MipLevels = (!mipCount) ? UINT(-1) : desc.MipLevels;

                hr = d3dDevice->CreateShaderResourceView(tex,
                    &SRVDesc,
                    textureView
                );
                if (FAILED(hr)) {
                    tex->Release();
                    return hr;
                }
            }

            if (texture) {
                *texture = tex;
            } else {
                tex->Release();
            }
        }
    }
    break;
    }

    return hr;
}

HRESULT FillInitData(
        _In_ size_t width,
        _In_ size_t height,
        _In_ size_t depth,
        _In_ size_t mipCount,
        _In_ size_t arraySize,
        _In_ DXGI_FORMAT format,
        _In_ size_t maxsize,
        _In_ size_t bitSize,
        _In_reads_bytes_(bitSize) const uint8_t* bitData,
        _Out_ size_t& twidth,
        _Out_ size_t& theight,
        _Out_ size_t& tdepth,
        _Out_ size_t& skipMip,
        _Out_writes_(mipCount* arraySize) D3D11_SUBRESOURCE_DATA* initData) noexcept {
    if (!bitData || !initData) {
        return E_POINTER;
    }

    skipMip = 0;
    twidth = 0;
    theight = 0;
    tdepth = 0;

    size_t NumBytes = 0;
    size_t RowBytes = 0;
    const uint8_t* pSrcBits = bitData;
    const uint8_t* pEndBits = bitData + bitSize;

    size_t index = 0;
    for (size_t j = 0; j < arraySize; j++) {
        size_t w = width;
        size_t h = height;
        size_t d = depth;
        for (size_t i = 0; i < mipCount; i++) {
            HRESULT hr = GetSurfaceInfo(w, h, format, &NumBytes, &RowBytes, nullptr);
            if (FAILED(hr))
                return hr;

            if (NumBytes > UINT32_MAX || RowBytes > UINT32_MAX)
                return HRESULT_FROM_WIN32(ERROR_ARITHMETIC_OVERFLOW);

            if ((mipCount <= 1) || !maxsize || (w <= maxsize && h <= maxsize && d <= maxsize)) {
                if (!twidth) {
                    twidth = w;
                    theight = h;
                    tdepth = d;
                }

                assert(index < mipCount* arraySize);
                _Analysis_assume_(index < mipCount* arraySize);
                initData[index].pSysMem = pSrcBits;
                initData[index].SysMemPitch = static_cast<UINT>(RowBytes);
                initData[index].SysMemSlicePitch = static_cast<UINT>(NumBytes);
                ++index;
            } else if (!j) {
                // Count number of skipped mipmaps (first item only)
                ++skipMip;
            }

            if (pSrcBits + (NumBytes * d) > pEndBits) {
                return HRESULT_FROM_WIN32(ERROR_HANDLE_EOF);
            }

            pSrcBits += NumBytes * d;

            w = w >> 1;
            h = h >> 1;
            d = d >> 1;
            if (w == 0) {
                w = 1;
            }
            if (h == 0) {
                h = 1;
            }
            if (d == 0) {
                d = 1;
            }
        }
    }

    return (index > 0) ? S_OK : E_FAIL;
}

HRESULT CreateTextureFromDDS(
        _In_ ID3D11Device* d3dDevice,
        _In_opt_ ID3D11DeviceContext* d3dContext,
        _In_ const DDS_HEADER* header,
        _In_reads_bytes_(bitSize) const uint8_t* bitData,
        _In_ size_t bitSize,
        _In_ size_t maxsize,
        _In_ D3D11_USAGE usage,
        _In_ unsigned int bindFlags,
        _In_ unsigned int cpuAccessFlags,
        _In_ unsigned int miscFlags,
        _In_ bool forceSRGB,
        _Outptr_opt_ ID3D11Resource** texture,
        _Outptr_opt_ ID3D11ShaderResourceView** textureView) noexcept 
{
    HRESULT hr = S_OK;

    const UINT width = header->width;
    UINT height = header->height;
    UINT depth = header->depth;

    uint32_t resDim = D3D11_RESOURCE_DIMENSION_UNKNOWN;
    UINT arraySize = 1;
    DXGI_FORMAT format = DXGI_FORMAT_UNKNOWN;
    bool isCubeMap = false;

    size_t mipCount = header->mipMapCount;
    if (0 == mipCount) {
        mipCount = 1;
    }

    if ((header->ddspf.flags & DDS_FOURCC) &&
        (MAKEFOURCC('D', 'X', '1', '0') == header->ddspf.fourCC)) {
        auto d3d10ext = reinterpret_cast<const DDS_HEADER_DXT10*>(reinterpret_cast<const char*>(header) + sizeof(DDS_HEADER));

        arraySize = d3d10ext->arraySize;
        if (arraySize == 0) {
            return HRESULT_FROM_WIN32(ERROR_INVALID_DATA);
        }

        switch (d3d10ext->dxgiFormat) {
        case DXGI_FORMAT_AI44:
        case DXGI_FORMAT_IA44:
        case DXGI_FORMAT_P8:
        case DXGI_FORMAT_A8P8:
            Logger::Get().Error("ERROR: DDSTextureLoader does not support video textures. Consider using DirectXTex instead.\n");
            return HRESULT_FROM_WIN32(ERROR_NOT_SUPPORTED);

        default:
            if (BitsPerPixel(d3d10ext->dxgiFormat) == 0) {
                Logger::Get().Error(fmt::format("ERROR: Unknown DXGI format ({})\n", static_cast<uint32_t>(d3d10ext->dxgiFormat)));
                return HRESULT_FROM_WIN32(ERROR_NOT_SUPPORTED);
            }
        }

        format = d3d10ext->dxgiFormat;

        switch (d3d10ext->resourceDimension) {
        case D3D11_RESOURCE_DIMENSION_TEXTURE1D:
            // D3DX writes 1D textures with a fixed Height of 1
            if ((header->flags & DDS_HEIGHT) && height != 1) {
                return HRESULT_FROM_WIN32(ERROR_INVALID_DATA);
            }
            height = depth = 1;
            break;

        case D3D11_RESOURCE_DIMENSION_TEXTURE2D:
            if (d3d10ext->miscFlag & D3D11_RESOURCE_MISC_TEXTURECUBE) {
                arraySize *= 6;
                isCubeMap = true;
            }
            depth = 1;
            break;

        case D3D11_RESOURCE_DIMENSION_TEXTURE3D:
            if (!(header->flags & DDS_HEADER_FLAGS_VOLUME)) {
                return HRESULT_FROM_WIN32(ERROR_INVALID_DATA);
            }

            if (arraySize > 1) {
                Logger::Get().Error("ERROR: Volume textures are not texture arrays\n");
                return HRESULT_FROM_WIN32(ERROR_NOT_SUPPORTED);
            }
            break;

        case D3D11_RESOURCE_DIMENSION_BUFFER:
            Logger::Get().Error("ERROR: Resource dimension buffer type not supported for textures\n");
            return HRESULT_FROM_WIN32(ERROR_NOT_SUPPORTED);

        case D3D11_RESOURCE_DIMENSION_UNKNOWN:
        default:
            Logger::Get().Error(fmt::format("ERROR: Unknown resource dimension ({})\n", static_cast<uint32_t>(d3d10ext->resourceDimension)));
            return HRESULT_FROM_WIN32(ERROR_NOT_SUPPORTED);
        }

        resDim = d3d10ext->resourceDimension;
    } else {
        format = GetDXGIFormat(header->ddspf);

        if (format == DXGI_FORMAT_UNKNOWN) {
            Logger::Get().Error("ERROR: DDSTextureLoader does not support all legacy DDS formats. Consider using DirectXTex.\n");
            return HRESULT_FROM_WIN32(ERROR_NOT_SUPPORTED);
        }

        if (header->flags & DDS_HEADER_FLAGS_VOLUME) {
            resDim = D3D11_RESOURCE_DIMENSION_TEXTURE3D;
        } else {
            if (header->caps2 & DDS_CUBEMAP) {
                // We require all six faces to be defined
                if ((header->caps2 & DDS_CUBEMAP_ALLFACES) != DDS_CUBEMAP_ALLFACES) {
                    Logger::Get().Error("ERROR: DirectX 11 does not support partial cubemaps\n");
                    return HRESULT_FROM_WIN32(ERROR_NOT_SUPPORTED);
                }

                arraySize = 6;
                isCubeMap = true;
            }

            depth = 1;
            resDim = D3D11_RESOURCE_DIMENSION_TEXTURE2D;

            // Note there's no way for a legacy Direct3D 9 DDS to express a '1D' texture
        }

        assert(BitsPerPixel(format) != 0);
    }

    if ((miscFlags & D3D11_RESOURCE_MISC_TEXTURECUBE)
        && (resDim == D3D11_RESOURCE_DIMENSION_TEXTURE2D)
        && ((arraySize % 6) == 0)) {
        isCubeMap = true;
    }

    // Bound sizes (for security purposes we don't trust DDS file metadata larger than the Direct3D hardware requirements)
    if (mipCount > D3D11_REQ_MIP_LEVELS) {
        Logger::Get().Error(fmt::format("ERROR: Too many mipmap levels defined for DirectX 11 ({}).\n", mipCount));
        return HRESULT_FROM_WIN32(ERROR_NOT_SUPPORTED);
    }

    switch (resDim) {
    case D3D11_RESOURCE_DIMENSION_TEXTURE1D:
        if ((arraySize > D3D11_REQ_TEXTURE1D_ARRAY_AXIS_DIMENSION) ||
            (width > D3D11_REQ_TEXTURE1D_U_DIMENSION)) {
            Logger::Get().Error(fmt::format("ERROR: Resource dimensions too large for DirectX 11 (1D: array {}, size {})\n", arraySize, width));
            return HRESULT_FROM_WIN32(ERROR_NOT_SUPPORTED);
        }
        break;

    case D3D11_RESOURCE_DIMENSION_TEXTURE2D:
        if (isCubeMap) {
            // This is the right bound because we set arraySize to (NumCubes*6) above
            if ((arraySize > D3D11_REQ_TEXTURE2D_ARRAY_AXIS_DIMENSION) ||
                (width > D3D11_REQ_TEXTURECUBE_DIMENSION) ||
                (height > D3D11_REQ_TEXTURECUBE_DIMENSION)) {
                Logger::Get().Error(fmt::format("ERROR: Resource dimensions too large for DirectX 11 (2D cubemap: array {}, size {} by {})\n", arraySize, width, height));
                return HRESULT_FROM_WIN32(ERROR_NOT_SUPPORTED);
            }
        } else if ((arraySize > D3D11_REQ_TEXTURE2D_ARRAY_AXIS_DIMENSION) ||
            (width > D3D11_REQ_TEXTURE2D_U_OR_V_DIMENSION) ||
            (height > D3D11_REQ_TEXTURE2D_U_OR_V_DIMENSION)) {
            Logger::Get().Error(fmt::format("ERROR: Resource dimensions too large for DirectX 11 (2D: array {}, size {} by {})\n", arraySize, width, height));
            return HRESULT_FROM_WIN32(ERROR_NOT_SUPPORTED);
        }
        break;

    case D3D11_RESOURCE_DIMENSION_TEXTURE3D:
        if ((arraySize > 1) ||
            (width > D3D11_REQ_TEXTURE3D_U_V_OR_W_DIMENSION) ||
            (height > D3D11_REQ_TEXTURE3D_U_V_OR_W_DIMENSION) ||
            (depth > D3D11_REQ_TEXTURE3D_U_V_OR_W_DIMENSION)) {
            Logger::Get().Error(fmt::format("ERROR: Resource dimensions too large for DirectX 11 (3D: array {}, size {} by {} by {})\n", arraySize, width, height, depth));
            return HRESULT_FROM_WIN32(ERROR_NOT_SUPPORTED);
        }
        break;

    case D3D11_RESOURCE_DIMENSION_BUFFER:
        Logger::Get().Error("ERROR: Resource dimension buffer type not supported for textures\n");
        return HRESULT_FROM_WIN32(ERROR_NOT_SUPPORTED);

    case D3D11_RESOURCE_DIMENSION_UNKNOWN:
    default:
        Logger::Get().Error(fmt::format("ERROR: Unknown resource dimension ({})\n", static_cast<uint32_t>(resDim)));
        return HRESULT_FROM_WIN32(ERROR_NOT_SUPPORTED);
    }

    bool autogen = false;
    if (mipCount == 1 && d3dContext && textureView) // Must have context and shader-view to auto generate mipmaps
    {
        // See if format is supported for auto-gen mipmaps (varies by feature level)
        UINT fmtSupport = 0;
        hr = d3dDevice->CheckFormatSupport(format, &fmtSupport);
        if (SUCCEEDED(hr) && (fmtSupport & D3D11_FORMAT_SUPPORT_MIP_AUTOGEN)) {
            // 10level9 feature levels do not support auto-gen mipgen for volume textures
            if ((resDim != D3D11_RESOURCE_DIMENSION_TEXTURE3D)
                || (d3dDevice->GetFeatureLevel() >= D3D_FEATURE_LEVEL_10_0)) {
                autogen = true;
            }
        }
    }

    if (autogen) {
        // Create texture with auto-generated mipmaps
        ID3D11Resource* tex = nullptr;
        hr = CreateD3DResources(d3dDevice,
            resDim, width, height, depth, 0, arraySize,
            format,
            usage,
            bindFlags | D3D11_BIND_SHADER_RESOURCE | D3D11_BIND_RENDER_TARGET,
            cpuAccessFlags,
            miscFlags | D3D11_RESOURCE_MISC_GENERATE_MIPS, forceSRGB,
            isCubeMap,
            nullptr,
            &tex, textureView);
        if (SUCCEEDED(hr)) {
            size_t numBytes = 0;
            size_t rowBytes = 0;
            hr = GetSurfaceInfo(width, height, format, &numBytes, &rowBytes, nullptr);
            if (FAILED(hr))
                return hr;

            if (numBytes > bitSize) {
                (*textureView)->Release();
                *textureView = nullptr;
                tex->Release();
                return HRESULT_FROM_WIN32(ERROR_HANDLE_EOF);
            }

            if (numBytes > UINT32_MAX || rowBytes > UINT32_MAX)
                return HRESULT_FROM_WIN32(ERROR_ARITHMETIC_OVERFLOW);

            D3D11_SHADER_RESOURCE_VIEW_DESC desc = {};
            (*textureView)->GetDesc(&desc);

            UINT mipLevels = 1;

            switch (desc.ViewDimension) {
            case D3D_SRV_DIMENSION_TEXTURE1D:       mipLevels = desc.Texture1D.MipLevels; break;
            case D3D_SRV_DIMENSION_TEXTURE1DARRAY:  mipLevels = desc.Texture1DArray.MipLevels; break;
            case D3D_SRV_DIMENSION_TEXTURE2D:       mipLevels = desc.Texture2D.MipLevels; break;
            case D3D_SRV_DIMENSION_TEXTURE2DARRAY:  mipLevels = desc.Texture2DArray.MipLevels; break;
            case D3D_SRV_DIMENSION_TEXTURECUBE:     mipLevels = desc.TextureCube.MipLevels; break;
            case D3D_SRV_DIMENSION_TEXTURECUBEARRAY:mipLevels = desc.TextureCubeArray.MipLevels; break;
            case D3D_SRV_DIMENSION_TEXTURE3D:       mipLevels = desc.Texture3D.MipLevels; break;
            default:
                (*textureView)->Release();
                *textureView = nullptr;
                tex->Release();
                return E_UNEXPECTED;
            }

            if (arraySize > 1) {
                const uint8_t* pSrcBits = bitData;
                const uint8_t* pEndBits = bitData + bitSize;
                for (UINT item = 0; item < arraySize; ++item) {
                    if ((pSrcBits + numBytes) > pEndBits) {
                        (*textureView)->Release();
                        *textureView = nullptr;
                        tex->Release();
                        return HRESULT_FROM_WIN32(ERROR_HANDLE_EOF);
                    }

                    const UINT res = D3D11CalcSubresource(0, item, mipLevels);
                    d3dContext->UpdateSubresource(tex, res, nullptr, pSrcBits, static_cast<UINT>(rowBytes), static_cast<UINT>(numBytes));
                    pSrcBits += numBytes;
                }
            } else {
                d3dContext->UpdateSubresource(tex, 0, nullptr, bitData, static_cast<UINT>(rowBytes), static_cast<UINT>(numBytes));
            }

            d3dContext->GenerateMips(*textureView);

            if (texture) {
                *texture = tex;
            } else {
                tex->Release();
            }
        }
    } else {
        // Create the texture
        std::unique_ptr<D3D11_SUBRESOURCE_DATA[]> initData(new (std::nothrow) D3D11_SUBRESOURCE_DATA[mipCount * arraySize]);
        if (!initData) {
            return E_OUTOFMEMORY;
        }

        size_t skipMip = 0;
        size_t twidth = 0;
        size_t theight = 0;
        size_t tdepth = 0;
        hr = FillInitData(width, height, depth, mipCount, arraySize, format,
            maxsize, bitSize, bitData,
            twidth, theight, tdepth, skipMip, initData.get());

        if (SUCCEEDED(hr)) {
            hr = CreateD3DResources(d3dDevice,
                resDim, twidth, theight, tdepth, mipCount - skipMip, arraySize,
                format,
                usage, bindFlags, cpuAccessFlags, miscFlags,
                forceSRGB,
                isCubeMap,
                initData.get(),
                texture, textureView);

            if (FAILED(hr) && !maxsize && (mipCount > 1)) {
                // Retry with a maxsize determined by feature level
                switch (d3dDevice->GetFeatureLevel()) {
                case D3D_FEATURE_LEVEL_9_1:
                case D3D_FEATURE_LEVEL_9_2:
                    if (isCubeMap) {
                        maxsize = 512u /*D3D_FL9_1_REQ_TEXTURECUBE_DIMENSION*/;
                    } else {
                        maxsize = (resDim == D3D11_RESOURCE_DIMENSION_TEXTURE3D)
                            ? 256u /*D3D_FL9_1_REQ_TEXTURE3D_U_V_OR_W_DIMENSION*/
                            : 2048u /*D3D_FL9_1_REQ_TEXTURE2D_U_OR_V_DIMENSION*/;
                    }
                    break;

                case D3D_FEATURE_LEVEL_9_3:
                    maxsize = (resDim == D3D11_RESOURCE_DIMENSION_TEXTURE3D)
                        ? 256u /*D3D_FL9_1_REQ_TEXTURE3D_U_V_OR_W_DIMENSION*/
                        : 4096u /*D3D_FL9_3_REQ_TEXTURE2D_U_OR_V_DIMENSION*/;
                    break;

                default: // D3D_FEATURE_LEVEL_10_0 & D3D_FEATURE_LEVEL_10_1
                    maxsize = (resDim == D3D11_RESOURCE_DIMENSION_TEXTURE3D)
                        ? 2048u /*D3D10_REQ_TEXTURE3D_U_V_OR_W_DIMENSION*/
                        : 8192u /*D3D10_REQ_TEXTURE2D_U_OR_V_DIMENSION*/;
                    break;
                }

                hr = FillInitData(width, height, depth, mipCount, arraySize, format,
                    maxsize, bitSize, bitData,
                    twidth, theight, tdepth, skipMip, initData.get());
                if (SUCCEEDED(hr)) {
                    hr = CreateD3DResources(d3dDevice,
                        resDim, twidth, theight, tdepth, mipCount - skipMip, arraySize,
                        format,
                        usage, bindFlags, cpuAccessFlags, miscFlags,
                        forceSRGB,
                        isCubeMap,
                        initData.get(),
                        texture, textureView);
                }
            }
        }
    }

    return hr;
}

HRESULT CreateDDSTextureFromFileEx(
	ID3D11Device* d3dDevice,
	const wchar_t* fileName,
	size_t maxsize,
	D3D11_USAGE usage,
	unsigned int bindFlags,
	unsigned int cpuAccessFlags,
	unsigned int miscFlags,
	bool forceSRGB,
	ID3D11Resource** texture,
	ID3D11ShaderResourceView** textureView,
	DDS_ALPHA_MODE* alphaMode) noexcept {
	if (texture) {
		*texture = nullptr;
	}
	if (textureView) {
		*textureView = nullptr;
	}
	if (alphaMode) {
		*alphaMode = DDS_ALPHA_MODE_UNKNOWN;
	}

	if (!d3dDevice || !fileName || (!texture && !textureView)) {
		return E_INVALIDARG;
	}

	if (textureView && !(bindFlags & D3D11_BIND_SHADER_RESOURCE)) {
		return E_INVALIDARG;
	}

	const DDS_HEADER* header = nullptr;
	const uint8_t* bitData = nullptr;
	size_t bitSize = 0;

	std::unique_ptr<uint8_t[]> ddsData;
	HRESULT hr = LoadTextureDataFromFile(fileName,
		ddsData,
		&header,
		&bitData,
		&bitSize
	);
	if (FAILED(hr)) {
		return hr;
	}

	hr = CreateTextureFromDDS(d3dDevice, nullptr,
		header, bitData, bitSize,
		maxsize,
		usage, bindFlags, cpuAccessFlags, miscFlags,
		forceSRGB,
		texture, textureView);

	if (SUCCEEDED(hr)) {
		if (alphaMode)
			*alphaMode = GetAlphaMode(header);
	}

	return hr;
}

winrt::com_ptr<ID3D11Texture2D> LoadImg(const wchar_t* fileName) {
	winrt::com_ptr<IWICImagingFactory2> factory = App::Get().GetWICImageFactory();
	if (!factory) {
		Logger::Get().Error("GetWICImageFactory 失败");
		return nullptr;
	}

	// 读取图像文件
	winrt::com_ptr<IWICBitmapDecoder> decoder;
	HRESULT hr = factory->CreateDecoderFromFilename(fileName, nullptr, GENERIC_READ, WICDecodeMetadataCacheOnDemand, decoder.put());
	if (FAILED(hr)) {
		Logger::Get().ComError("CreateDecoderFromFilename 失败", hr);
		return nullptr;
	}

	winrt::com_ptr<IWICBitmapFrameDecode> frame;
	hr = decoder->GetFrame(0, frame.put());
	if (FAILED(hr)) {
		Logger::Get().ComError("IWICBitmapFrameDecode::GetFrame 失败", hr);
		return nullptr;
	}

	bool useFloatFormat = false;
	{
		WICPixelFormatGUID sourceFormat;
		hr = frame->GetPixelFormat(&sourceFormat);
		if (FAILED(hr)) {
			Logger::Get().ComError("GetPixelFormat 失败", hr);
			return nullptr;
		}

		winrt::com_ptr<IWICComponentInfo> cInfo;
		hr = factory->CreateComponentInfo(sourceFormat, cInfo.put());
		if (FAILED(hr)) {
			Logger::Get().ComError("CreateComponentInfo", hr);
			return nullptr;
		}
		winrt::com_ptr<IWICPixelFormatInfo2> formatInfo = cInfo.try_as<IWICPixelFormatInfo2>();
		if (!formatInfo) {
			Logger::Get().Error("IWICComponentInfo 转换为 IWICPixelFormatInfo2 时失败");
			return nullptr;
		}

		UINT bitsPerPixel;
		WICPixelFormatNumericRepresentation type;
		hr = formatInfo->GetBitsPerPixel(&bitsPerPixel);
		if (FAILED(hr)) {
			Logger::Get().ComError("GetBitsPerPixel", hr);
			return nullptr;
		}
		hr = formatInfo->GetNumericRepresentation(&type);
		if (FAILED(hr)) {
			Logger::Get().ComError("GetNumericRepresentation", hr);
			return nullptr;
		}

		useFloatFormat = bitsPerPixel > 32 || type == WICPixelFormatNumericRepresentationFixed || type == WICPixelFormatNumericRepresentationFloat;
	}

	// 转换格式
	winrt::com_ptr<IWICFormatConverter> formatConverter;
	hr = factory->CreateFormatConverter(formatConverter.put());
	if (FAILED(hr)) {
		Logger::Get().ComError("CreateFormatConverter 失败", hr);
		return nullptr;
	}

	WICPixelFormatGUID targetFormat = useFloatFormat ? GUID_WICPixelFormat64bppRGBAHalf : GUID_WICPixelFormat32bppBGRA;
	hr = formatConverter->Initialize(frame.get(), targetFormat, WICBitmapDitherTypeNone, nullptr, 0, WICBitmapPaletteTypeCustom);
	if (FAILED(hr)) {
		Logger::Get().ComError("IWICFormatConverter::Initialize 失败", hr);
		return nullptr;
	}

	// 检查 D3D 纹理尺寸限制
	UINT width, height;
	hr = formatConverter->GetSize(&width, &height);
	if (FAILED(hr)) {
		Logger::Get().ComError("GetSize 失败", hr);
		return nullptr;
	}

	if (width > D3D11_REQ_TEXTURE2D_U_OR_V_DIMENSION || height > D3D11_REQ_TEXTURE2D_U_OR_V_DIMENSION) {
		Logger::Get().Error("图像尺寸超出限制");
		return nullptr;
	}

	UINT stride = width * (useFloatFormat ? 8 : 4);
	UINT size = stride * height;
	std::unique_ptr<BYTE[]> buf(new BYTE[size]);

	hr = formatConverter->CopyPixels(nullptr, stride, size, buf.get());
	if (FAILED(hr)) {
		Logger::Get().ComError("CopyPixels 失败", hr);
		return nullptr;
	}

	D3D11_TEXTURE2D_DESC desc{};
	desc.Width = width;
	desc.Height = height;
	desc.MipLevels = 1;
	desc.ArraySize = 1;
	desc.Format = useFloatFormat ? DXGI_FORMAT_R16G16B16A16_FLOAT : DXGI_FORMAT_R8G8B8A8_UNORM;
	desc.SampleDesc.Count = 1;
	desc.SampleDesc.Quality = 0;
	desc.Usage = D3D11_USAGE_DEFAULT;
	desc.BindFlags = D3D11_BIND_SHADER_RESOURCE | D3D11_BIND_RENDER_TARGET;

	D3D11_SUBRESOURCE_DATA initData{};
	initData.pSysMem = buf.get();
	initData.SysMemPitch = stride;

	winrt::com_ptr<ID3D11Texture2D> result;
	hr = App::Get().GetDeviceResources().GetD3DDevice()->CreateTexture2D(&desc, &initData, result.put());
	if (FAILED(hr)) {
		Logger::Get().ComError("CreateTexture2D 失败", hr);
		return nullptr;
	}

	return result;
}

winrt::com_ptr<ID3D11Texture2D> LoadDDS(const wchar_t* fileName) {
	winrt::com_ptr<ID3D11Resource> result;

	DDS_ALPHA_MODE alphaMode = DDS_ALPHA_MODE_STRAIGHT;
	HRESULT hr = CreateDDSTextureFromFileEx(
		App::Get().GetDeviceResources().GetD3DDevice(),
		fileName,
		0,
		D3D11_USAGE_DEFAULT,
		D3D11_BIND_SHADER_RESOURCE | D3D11_BIND_UNORDERED_ACCESS,
		0,
		0,
		false,
		result.put(),
		nullptr,
		&alphaMode
	);
	if (FAILED(hr)) {
		Logger::Get().ComInfo("CreateDDSTextureFromFile 失败，将尝试不作为渲染目标", hr);

		// 第二次尝试，不作为渲染目标
		hr = CreateDDSTextureFromFileEx(
			App::Get().GetDeviceResources().GetD3DDevice(),
			fileName,
			0,
			D3D11_USAGE_DEFAULT,
			D3D11_BIND_SHADER_RESOURCE,
			0,
			0,
			false,
			result.put(),
			nullptr,
			&alphaMode
		);

		if (FAILED(hr)) {
			Logger::Get().ComError("CreateDDSTextureFromFile 失败", hr);
			return nullptr;
		}
	}

	winrt::com_ptr<ID3D11Texture2D> tex = result.try_as<ID3D11Texture2D>();
	if (!tex) {
		Logger::Get().Error("从 ID3D11Resource 获取 ID3D11Texture2D 失败");
		return nullptr;
	}

	return tex;
}

winrt::com_ptr<ID3D11Texture2D> TextureLoader::Load(const wchar_t* fileName) {
	std::wstring_view sv(fileName);
	size_t npos = sv.find_last_of(L'.');
	if (npos == std::wstring_view::npos) {
		Logger::Get().Error("文件名无后缀名");
		return nullptr;
	}

	std::wstring_view suffix = sv.substr(npos + 1);
	
	static std::unordered_map<std::wstring_view, winrt::com_ptr<ID3D11Texture2D>(*)(const wchar_t*)> funcs = {
		{L"bmp", LoadImg},
		{L"jpg", LoadImg},
		{L"jpeg", LoadImg},
		{L"png", LoadImg},
		{L"tif", LoadImg},
		{L"tiff", LoadImg},
		{L"dds", LoadDDS}
	};

	auto it = funcs.find(suffix);
	if (it == funcs.end()) {
		Logger::Get().Error("不支持读取该格式");
		return nullptr;
	}

	return it->second(fileName);
}