// Copyright 2020 The Dawn Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include <algorithm>
#include <vector>

#include "dawn/common/Assert.h"
#include "dawn/common/Constants.h"
#include "dawn/common/Math.h"
#include "dawn/utils/TestUtils.h"
#include "dawn/utils/TextureUtils.h"
#include "dawn/utils/WGPUHelpers.h"

namespace utils {

uint32_t GetMinimumBytesPerRow(wgpu::TextureFormat format, uint32_t width) {
    const uint32_t bytesPerBlock = utils::GetTexelBlockSizeInBytes(format);
    const uint32_t blockWidth = utils::GetTextureFormatBlockWidth(format);
    ASSERT(width % blockWidth == 0);
    return Align(bytesPerBlock * (width / blockWidth), kTextureBytesPerRowAlignment);
}

TextureDataCopyLayout GetTextureDataCopyLayoutForTextureAtLevel(wgpu::TextureFormat format,
                                                                wgpu::Extent3D textureSizeAtLevel0,
                                                                uint32_t mipmapLevel,
                                                                wgpu::TextureDimension dimension,
                                                                uint32_t rowsPerImage) {
    // Compressed texture formats not supported in this function yet.
    ASSERT(utils::GetTextureFormatBlockWidth(format) == 1);

    TextureDataCopyLayout layout;

    layout.mipSize = {std::max(textureSizeAtLevel0.width >> mipmapLevel, 1u),
                      std::max(textureSizeAtLevel0.height >> mipmapLevel, 1u),
                      textureSizeAtLevel0.depthOrArrayLayers};

    if (dimension == wgpu::TextureDimension::e3D) {
        layout.mipSize.depthOrArrayLayers =
            std::max(textureSizeAtLevel0.depthOrArrayLayers >> mipmapLevel, 1u);
    }

    layout.bytesPerRow = GetMinimumBytesPerRow(format, layout.mipSize.width);

    if (rowsPerImage == wgpu::kCopyStrideUndefined) {
        rowsPerImage = layout.mipSize.height;
    }
    layout.rowsPerImage = rowsPerImage;

    uint32_t appliedRowsPerImage = rowsPerImage > 0 ? rowsPerImage : layout.mipSize.height;
    layout.bytesPerImage = layout.bytesPerRow * appliedRowsPerImage;

    layout.byteLength =
        RequiredBytesInCopy(layout.bytesPerRow, appliedRowsPerImage, layout.mipSize, format);

    const uint32_t bytesPerTexel = utils::GetTexelBlockSizeInBytes(format);
    layout.texelBlocksPerRow = layout.bytesPerRow / bytesPerTexel;
    layout.texelBlocksPerImage = layout.bytesPerImage / bytesPerTexel;
    layout.texelBlockCount = layout.byteLength / bytesPerTexel;

    return layout;
}

uint64_t RequiredBytesInCopy(uint64_t bytesPerRow,
                             uint64_t rowsPerImage,
                             wgpu::Extent3D copyExtent,
                             wgpu::TextureFormat textureFormat) {
    uint32_t blockSize = utils::GetTexelBlockSizeInBytes(textureFormat);
    uint32_t blockWidth = utils::GetTextureFormatBlockWidth(textureFormat);
    uint32_t blockHeight = utils::GetTextureFormatBlockHeight(textureFormat);
    ASSERT(copyExtent.width % blockWidth == 0);
    uint32_t widthInBlocks = copyExtent.width / blockWidth;
    ASSERT(copyExtent.height % blockHeight == 0);
    uint32_t heightInBlocks = copyExtent.height / blockHeight;
    return RequiredBytesInCopy(bytesPerRow, rowsPerImage, widthInBlocks, heightInBlocks,
                               copyExtent.depthOrArrayLayers, blockSize);
}

uint64_t RequiredBytesInCopy(uint64_t bytesPerRow,
                             uint64_t rowsPerImage,
                             uint64_t widthInBlocks,
                             uint64_t heightInBlocks,
                             uint64_t depth,
                             uint64_t bytesPerBlock) {
    if (depth == 0) {
        return 0;
    }

    uint64_t bytesPerImage = bytesPerRow * rowsPerImage;
    uint64_t requiredBytesInCopy = bytesPerImage * (depth - 1);
    if (heightInBlocks != 0) {
        uint64_t lastRowBytes = widthInBlocks * bytesPerBlock;
        uint64_t lastImageBytes = bytesPerRow * (heightInBlocks - 1) + lastRowBytes;
        requiredBytesInCopy += lastImageBytes;
    }
    return requiredBytesInCopy;
}

uint64_t GetTexelCountInCopyRegion(uint64_t bytesPerRow,
                                   uint64_t rowsPerImage,
                                   wgpu::Extent3D copyExtent,
                                   wgpu::TextureFormat textureFormat) {
    return RequiredBytesInCopy(bytesPerRow, rowsPerImage, copyExtent, textureFormat) /
           utils::GetTexelBlockSizeInBytes(textureFormat);
}

void UnalignDynamicUploader(wgpu::Device device) {
    std::vector<uint8_t> data = {1};

    wgpu::TextureDescriptor descriptor = {};
    descriptor.size = {1, 1, 1};
    descriptor.format = wgpu::TextureFormat::R8Unorm;
    descriptor.usage = wgpu::TextureUsage::CopyDst | wgpu::TextureUsage::CopySrc;
    wgpu::Texture texture = device.CreateTexture(&descriptor);

    wgpu::ImageCopyTexture imageCopyTexture = utils::CreateImageCopyTexture(texture, 0, {0, 0, 0});
    wgpu::TextureDataLayout textureDataLayout =
        utils::CreateTextureDataLayout(0, wgpu::kCopyStrideUndefined);
    wgpu::Extent3D copyExtent = {1, 1, 1};

    // WriteTexture with exactly 1 byte of data.
    device.GetQueue().WriteTexture(&imageCopyTexture, data.data(), 1, &textureDataLayout,
                                   &copyExtent);
}

uint32_t VertexFormatSize(wgpu::VertexFormat format) {
    switch (format) {
        case wgpu::VertexFormat::Uint8x2:
        case wgpu::VertexFormat::Sint8x2:
        case wgpu::VertexFormat::Unorm8x2:
        case wgpu::VertexFormat::Snorm8x2:
            return 2;
        case wgpu::VertexFormat::Uint8x4:
        case wgpu::VertexFormat::Sint8x4:
        case wgpu::VertexFormat::Unorm8x4:
        case wgpu::VertexFormat::Snorm8x4:
        case wgpu::VertexFormat::Uint16x2:
        case wgpu::VertexFormat::Sint16x2:
        case wgpu::VertexFormat::Unorm16x2:
        case wgpu::VertexFormat::Snorm16x2:
        case wgpu::VertexFormat::Float16x2:
        case wgpu::VertexFormat::Float32:
        case wgpu::VertexFormat::Uint32:
        case wgpu::VertexFormat::Sint32:
            return 4;
        case wgpu::VertexFormat::Uint16x4:
        case wgpu::VertexFormat::Sint16x4:
        case wgpu::VertexFormat::Unorm16x4:
        case wgpu::VertexFormat::Snorm16x4:
        case wgpu::VertexFormat::Float16x4:
        case wgpu::VertexFormat::Float32x2:
        case wgpu::VertexFormat::Uint32x2:
        case wgpu::VertexFormat::Sint32x2:
            return 8;
        case wgpu::VertexFormat::Float32x3:
        case wgpu::VertexFormat::Uint32x3:
        case wgpu::VertexFormat::Sint32x3:
            return 12;
        case wgpu::VertexFormat::Float32x4:
        case wgpu::VertexFormat::Uint32x4:
        case wgpu::VertexFormat::Sint32x4:
            return 16;
        case wgpu::VertexFormat::Undefined:
            break;
    }
    UNREACHABLE();
}

}  // namespace utils