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 Copyright (c) 2021-2023 Xiamen Yaji Software Co., Ltd.

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 of this software and associated documentation files (the "Software"), to deal
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 of the Software, and to permit persons to whom the Software is furnished to do so,
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 The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.

 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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#include "renderer/core/TextureBufferPool.h"
#include <cmath>
#include "core/ArrayBuffer.h"
#include "core/TypedArray.h"
#include "renderer/gfx-base/GFXDevice.h"

namespace {

uint32_t roundUp(uint32_t n, uint32_t alignment) {
    return static_cast<uint32_t>(std::ceil(n / alignment)) * alignment;
}
} // namespace

namespace cc {

TextureBufferPool::TextureBufferPool() = default;

TextureBufferPool::TextureBufferPool(gfx::Device *device) {
    _device = device;
}

TextureBufferPool::~TextureBufferPool() = default;

void TextureBufferPool::initialize(const ITextureBufferPoolInfo &info) {
    const auto &formatInfo = gfx::GFX_FORMAT_INFOS[static_cast<uint32_t>(info.format)];
    _format = info.format;
    _formatSize = formatInfo.size;
    _channels = formatInfo.count;
    _roundUpFn = info.roundUpFn.has_value() ? info.roundUpFn.value() : nullptr;
    _alignment = info.alignment.has_value() ? info.alignment.value() : 1;
    _useMcDonaldAlloc = info.alignment.has_value() && info.alignment.value();
}

void TextureBufferPool::destroy() {
    for (auto &chunk : _chunks) {
        CC_SAFE_DESTROY_AND_DELETE(chunk.texture);
    }
    _chunks.clear();
    _handles.clear();
}

ITextureBufferHandle TextureBufferPool::alloc(uint32_t size) {
    if (_useMcDonaldAlloc) {
        return mcDonaldAlloc(size);
    }

    size = roundUp(size, _alignment);
    index_t index = CC_INVALID_INDEX;
    index_t start = CC_INVALID_INDEX;
    if (start < 0) {
        for (index_t i = 0; i < _chunkCount; ++i) {
            index = i;
            start = findAvailableSpace(size, index);
            if (start >= 0) break;
        }
    }

    if (start >= 0) {
        auto chunk = _chunks[index];
        chunk.start += static_cast<index_t>(size);
        ITextureBufferHandle handle;
        handle.chunkIdx = index;
        handle.start = start;
        handle.end = static_cast<index_t>(start + size);
        handle.texture = chunk.texture;

        _handles.emplace_back(handle);
        return handle;
    }
    // create a new one
    auto targetSize = static_cast<int32_t>(std::sqrt(size / _formatSize));
    uint32_t texLength = _roundUpFn ? _roundUpFn(targetSize, _formatSize) : std::max(1024, static_cast<int>(utils::nextPOT(targetSize)));
    auto newChunk = _chunks[createChunk(texLength)];

    newChunk.start += static_cast<index_t>(size);
    ITextureBufferHandle texHandle;
    texHandle.chunkIdx = static_cast<index_t>(_chunkCount - 1);
    texHandle.start = 0;
    texHandle.end = static_cast<index_t>(size);
    texHandle.texture = newChunk.texture;
    _handles.emplace_back(texHandle);
    return texHandle;
}

ITextureBufferHandle TextureBufferPool::alloc(uint32_t size, index_t chunkIdx) {
    size = roundUp(size, _alignment);
    index_t index = chunkIdx;
    index_t start = findAvailableSpace(size, index);

    if (start < 0) {
        for (index_t i = 0; i < _chunkCount; ++i) {
            index = i;
            start = findAvailableSpace(size, index);
            if (start >= 0) break;
        }
    }

    if (start >= 0) {
        auto chunk = _chunks[index];
        chunk.start += static_cast<index_t>(size);
        ITextureBufferHandle handle;
        handle.chunkIdx = index;
        handle.start = start;
        handle.end = static_cast<index_t>(start + size);
        handle.texture = chunk.texture;

        _handles.emplace_back(handle);
        return handle;
    }
    // create a new one
    auto targetSize = static_cast<int32_t>(std::sqrt(size / _formatSize));
    uint32_t texLength = _roundUpFn ? _roundUpFn(targetSize, _formatSize) : std::max(1024, static_cast<int>(utils::nextPOT(targetSize)));
    auto newChunk = _chunks[createChunk(texLength)];

    newChunk.start += static_cast<index_t>(size);
    ITextureBufferHandle texHandle;
    texHandle.chunkIdx = static_cast<index_t>(_chunkCount - 1);
    texHandle.start = 0;
    texHandle.end = static_cast<index_t>(size);
    texHandle.texture = newChunk.texture;
    _handles.emplace_back(texHandle);
    return texHandle;
}

void TextureBufferPool::free(const ITextureBufferHandle &handle) {
    auto iter = std::find(_handles.begin(), _handles.end(), handle);
    if (iter != _handles.end()) {
        _chunks[handle.chunkIdx].end = handle.end;
        _handles.erase(iter);
    }
}

uint32_t TextureBufferPool::createChunk(uint32_t length) {
    uint32_t texSize = length * length * _formatSize;
    // debug(`TextureBufferPool: Allocate chunk $device->createTexture({gfx::TextureType::TEX2D,
    auto *texture = _device->createTexture({gfx::TextureType::TEX2D,
                                            gfx::TextureUsageBit::SAMPLED | gfx::TextureUsageBit::TRANSFER_DST,
                                            _format,
                                            length,
                                            length});

    ITextureBuffer chunk;
    chunk.texture = texture;
    chunk.size = texSize;
    chunk.start = 0;
    chunk.end = static_cast<index_t>(texSize);
    _chunks[_chunkCount] = chunk;
    return _chunkCount++;
}

void TextureBufferPool::update(const ITextureBufferHandle &handle, ArrayBuffer *buffer) {
    gfx::BufferDataList buffers;
    uint8_t *bufferData = buffer->getData();
    gfx::BufferTextureCopyList regions;
    auto start = static_cast<int32_t>(handle.start / _formatSize);

    uint32_t remainSize = buffer->byteLength() / _formatSize;
    int32_t offsetX = start % static_cast<int32_t>(handle.texture->getWidth());
    int32_t offsetY = std::floor(start / handle.texture->getWidth());
    uint32_t copySize = std::min(handle.texture->getWidth() - offsetX, remainSize);
    uint32_t begin = 0;

    if (offsetX > 0) {
        _region0.texOffset.x = offsetX;
        _region0.texOffset.y = offsetY;
        _region0.texExtent.width = copySize;
        _region0.texExtent.height = 1;
        buffers.emplace_back(bufferData + begin * _formatSize);
        regions.emplace_back(_region0);
        offsetX = 0;
        offsetY += 1;
        remainSize -= copySize;
        begin += copySize;
    }

    if (remainSize > 0) {
        _region1.texOffset.x = offsetX;
        _region1.texOffset.y = offsetY;

        if (remainSize > handle.texture->getWidth()) {
            _region1.texExtent.width = handle.texture->getWidth();
            _region1.texExtent.height = std::floor(remainSize / handle.texture->getWidth());
            copySize = _region1.texExtent.width * _region1.texExtent.height;
        } else {
            copySize = remainSize;
            _region1.texExtent.width = copySize;
            _region1.texExtent.height = 1;
        }

        buffers.emplace_back(bufferData + begin * _formatSize);
        regions.emplace_back(_region1);

        offsetX = 0;
        offsetY += static_cast<int32_t>(_region1.texExtent.height);
        remainSize -= copySize;
        begin += copySize;
    }

    if (remainSize > 0) {
        _region2.texOffset.x = offsetX;
        _region2.texOffset.y = offsetY;
        _region2.texExtent.width = remainSize;
        _region2.texExtent.height = 1;

        buffers.emplace_back(bufferData + begin * _formatSize);
        regions.emplace_back(_region2);
    }
    _device->copyBuffersToTexture(buffers, handle.texture, regions);
}

index_t TextureBufferPool::findAvailableSpace(uint32_t size, index_t chunkIdx) const {
    auto chunk = _chunks[chunkIdx];
    bool isFound = false;
    index_t start = chunk.start;
    if ((start + size) <= chunk.size) {
        isFound = true;
    } else {
        start = 0; // try to find from head again
        ccstd::vector<ITextureBufferHandle> handles;
        for (auto h : _handles) {
            if (h.chunkIdx == chunkIdx) {
                handles.emplace_back(h);
            }
        }
        std::sort(handles.begin(), handles.end(), [](const ITextureBufferHandle &a, const ITextureBufferHandle &b) { return a.start - b.start; });
        for (auto handle : handles) {
            if ((start + size) <= handle.start) {
                isFound = true;
                break;
            }
            start = handle.end;
        }
        if (!isFound && (start + size) <= chunk.size) {
            isFound = true;
        }
    }
    return isFound ? start : CC_INVALID_INDEX;
}

ITextureBufferHandle TextureBufferPool::mcDonaldAlloc(uint32_t size) {
    size = roundUp(size, _alignment);
    for (index_t i = 0; i < _chunkCount; ++i) {
        auto chunk = _chunks[i];
        bool isFound = false;
        index_t start = chunk.start;
        if ((start + size) <= chunk.end) {
            isFound = true;
        } else if (start > chunk.end) {
            if ((start + size) <= chunk.size) {
                isFound = true;
            } else if (size <= chunk.end) {
                // Try to find from head again.
                start = 0;
                chunk.start = 0;
                isFound = true;
            }
        } else if (start == chunk.end) {
            start = 0;
            chunk.start = 0;
            chunk.end = static_cast<index_t>(chunk.size);
            if (size <= chunk.end) {
                isFound = true;
            }
        }
        if (isFound) {
            chunk.start += static_cast<index_t>(size);

            ITextureBufferHandle handle;
            handle.chunkIdx = i;
            handle.start = start;
            handle.end = static_cast<index_t>(size);
            handle.texture = chunk.texture;
            _handles.emplace_back(handle);
            return handle;
        }
    }
    // create a new one
    auto targetSize = static_cast<int32_t>(std::sqrt(size / _formatSize));
    uint32_t texLength = _roundUpFn ? _roundUpFn(targetSize, _formatSize) : std::max(1024, static_cast<int>(utils::nextPOT(targetSize)));
    auto newChunk = _chunks[createChunk(texLength)];

    newChunk.start += static_cast<index_t>(size);
    ITextureBufferHandle texHandle;
    texHandle.chunkIdx = static_cast<index_t>(_chunkCount);
    texHandle.start = 0;
    texHandle.end = static_cast<index_t>(size),
    texHandle.texture = newChunk.texture;
    _handles.emplace_back(texHandle);
    return texHandle;
}

} // namespace cc