/*
 *  Copyright 2019-2021 Diligent Graphics LLC
 *  Copyright 2015-2019 Egor Yusov
 *  
 *  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.
 *
 *  In no event and under no legal theory, whether in tort (including negligence), 
 *  contract, or otherwise, unless required by applicable law (such as deliberate 
 *  and grossly negligent acts) or agreed to in writing, shall any Contributor be
 *  liable for any damages, including any direct, indirect, special, incidental, 
 *  or consequential damages of any character arising as a result of this License or 
 *  out of the use or inability to use the software (including but not limited to damages 
 *  for loss of goodwill, work stoppage, computer failure or malfunction, or any and 
 *  all other commercial damages or losses), even if such Contributor has been advised 
 *  of the possibility of such damages.
 */

#include "pch.h"
#include "D3D12DynamicHeap.hpp"
#include "RenderDeviceD3D12Impl.hpp"

namespace Diligent
{

D3D12DynamicPage::D3D12DynamicPage(ID3D12Device* pd3d12Device, Uint64 Size)
{
    D3D12_HEAP_PROPERTIES HeapProps;
    HeapProps.CPUPageProperty      = D3D12_CPU_PAGE_PROPERTY_UNKNOWN;
    HeapProps.MemoryPoolPreference = D3D12_MEMORY_POOL_UNKNOWN;
    HeapProps.CreationNodeMask     = 1;
    HeapProps.VisibleNodeMask      = 1;

    D3D12_RESOURCE_DESC ResourceDesc;
    ResourceDesc.Dimension          = D3D12_RESOURCE_DIMENSION_BUFFER;
    ResourceDesc.Alignment          = 0;
    ResourceDesc.Height             = 1;
    ResourceDesc.DepthOrArraySize   = 1;
    ResourceDesc.MipLevels          = 1;
    ResourceDesc.Format             = DXGI_FORMAT_UNKNOWN;
    ResourceDesc.SampleDesc.Count   = 1;
    ResourceDesc.SampleDesc.Quality = 0;
    ResourceDesc.Layout             = D3D12_TEXTURE_LAYOUT_ROW_MAJOR;

    D3D12_RESOURCE_STATES DefaultUsage = D3D12_RESOURCE_STATE_GENERIC_READ;
    HeapProps.Type                     = D3D12_HEAP_TYPE_UPLOAD;
    ResourceDesc.Flags                 = D3D12_RESOURCE_FLAG_NONE;
    DefaultUsage                       = D3D12_RESOURCE_STATE_GENERIC_READ;
    ResourceDesc.Width                 = Size;

    auto hr = pd3d12Device->CreateCommittedResource(&HeapProps, D3D12_HEAP_FLAG_NONE, &ResourceDesc,
                                                    DefaultUsage, nullptr, __uuidof(m_pd3d12Buffer),
                                                    reinterpret_cast<void**>(static_cast<ID3D12Resource**>(&m_pd3d12Buffer)));
    if (FAILED(hr))
    {
        LOG_D3D_ERROR(hr, "Failed to create dynamic page");
        return;
    }

    m_pd3d12Buffer->SetName(L"Dynamic memory page");

    m_GPUVirtualAddress = m_pd3d12Buffer->GetGPUVirtualAddress();

    m_pd3d12Buffer->Map(0, nullptr, &m_CPUVirtualAddress);

    LOG_INFO_MESSAGE("Created dynamic memory page. Size: ", FormatMemorySize(Size, 2), "; GPU virtual address 0x", std::hex, m_GPUVirtualAddress);
}

D3D12DynamicMemoryManager::D3D12DynamicMemoryManager(IMemoryAllocator&      Allocator,
                                                     RenderDeviceD3D12Impl& DeviceD3D12Impl,
                                                     Uint32                 NumPagesToReserve,
                                                     Uint64                 PageSize) :
    m_DeviceD3D12Impl{DeviceD3D12Impl},
    m_AvailablePages(STD_ALLOCATOR_RAW_MEM(AvailablePagesMapElemType, Allocator, "Allocator for multimap<AvailablePagesMapElemType>"))
{
    for (Uint32 i = 0; i < NumPagesToReserve; ++i)
    {
        D3D12DynamicPage Page(m_DeviceD3D12Impl.GetD3D12Device(), PageSize);
        auto             Size = Page.GetSize();
        m_AvailablePages.emplace(Size, std::move(Page));
    }
}

D3D12DynamicPage D3D12DynamicMemoryManager::AllocatePage(Uint64 SizeInBytes)
{
    std::lock_guard<std::mutex> AvailablePagesLock(m_AvailablePagesMtx);
#ifdef DILIGENT_DEVELOPMENT
    ++m_AllocatedPageCounter;
#endif
    auto PageIt = m_AvailablePages.lower_bound(SizeInBytes); // Returns an iterator pointing to the first element that is not less than key
    if (PageIt != m_AvailablePages.end())
    {
        VERIFY_EXPR(PageIt->first >= SizeInBytes);
        D3D12DynamicPage Page(std::move(PageIt->second));
        m_AvailablePages.erase(PageIt);
        return Page;
    }
    else
    {
        return D3D12DynamicPage{m_DeviceD3D12Impl.GetD3D12Device(), SizeInBytes};
    }
}

void D3D12DynamicMemoryManager::ReleasePages(std::vector<D3D12DynamicPage>& Pages, Uint64 QueueMask)
{
    struct StalePage
    {
        D3D12DynamicPage           Page;
        D3D12DynamicMemoryManager* Mgr;

        // clang-format off
        StalePage(D3D12DynamicPage&& _Page, D3D12DynamicMemoryManager& _Mgr)noexcept :
            Page {std::move(_Page)},
            Mgr  {&_Mgr}
        {
        }

        StalePage            (const StalePage&)  = delete;
        StalePage& operator= (const StalePage&)  = delete;
        StalePage& operator= (      StalePage&&) = delete;
            
        StalePage(StalePage&& rhs)noexcept : 
            Page {std::move(rhs.Page)},
            Mgr  {rhs.Mgr}
        {
            rhs.Mgr  = nullptr;
        }
        // clang-format on

        ~StalePage()
        {
            if (Mgr != nullptr)
            {
                std::lock_guard<std::mutex> Lock{Mgr->m_AvailablePagesMtx};
#ifdef DILIGENT_DEVELOPMENT
                --Mgr->m_AllocatedPageCounter;
#endif
                auto PageSize = Page.GetSize();
                Mgr->m_AvailablePages.emplace(PageSize, std::move(Page));
            }
        }
    };
    for (auto& Page : Pages)
    {
        m_DeviceD3D12Impl.SafeReleaseDeviceObject(StalePage{std::move(Page), *this}, QueueMask);
    }
}

void D3D12DynamicMemoryManager::Destroy()
{
    DEV_CHECK_ERR(m_AllocatedPageCounter == 0, m_AllocatedPageCounter, " page(s) have not been returned to the manager.");
    Uint64 TotalAllocatedSize = 0;
    for (const auto& Page : m_AvailablePages)
        TotalAllocatedSize += Page.second.GetSize();

    LOG_INFO_MESSAGE("Dynamic memory manager usage stats:\n"
                     "                       Total allocated memory: ",
                     FormatMemorySize(TotalAllocatedSize, 2));

    m_AvailablePages.clear();
}

D3D12DynamicMemoryManager::~D3D12DynamicMemoryManager()
{
    DEV_CHECK_ERR(m_AllocatedPageCounter == 0, m_AllocatedPageCounter, " page(s) have not been released. If there are outstanding references to the pages in release queues, the app will crash when the page is returned to the manager.");
    VERIFY(m_AvailablePages.empty(), "Not all pages are destroyed. Dynamic memory manager must be explicitly destroyed with Destroy() method");
}


D3D12DynamicHeap::~D3D12DynamicHeap()
{
    VERIFY(m_AllocatedPages.empty(), "Allocated pages have not been released which indicates FinishFrame() has not been called");

    auto PeakAllocatedPages = m_PeakAllocatedSize / m_PageSize;
    LOG_INFO_MESSAGE(m_HeapName,
                     " usage stats:\n"
                     "                       Peak used/aligned/allocated size: ",
                     FormatMemorySize(m_PeakUsedSize, 2, m_PeakAlignedSize), " / ",
                     FormatMemorySize(m_PeakAlignedSize, 2, m_PeakAlignedSize), " / ",
                     FormatMemorySize(m_PeakAllocatedSize, 2, m_PeakAllocatedSize),
                     " (", PeakAllocatedPages, (PeakAllocatedPages == 1 ? " page)" : " pages)"),
                     ". Peak efficiency (used/aligned): ", std::fixed, std::setprecision(1), static_cast<double>(m_PeakUsedSize) / static_cast<double>(std::max(m_PeakAlignedSize, Uint64{1})) * 100.0, '%',
                     ". Peak utilization (used/allocated): ", std::fixed, std::setprecision(1), static_cast<double>(m_PeakUsedSize) / static_cast<double>(std::max(m_PeakAllocatedSize, Uint64{1})) * 100.0, '%');
}

D3D12DynamicAllocation D3D12DynamicHeap::Allocate(Uint64 SizeInBytes, Uint64 Alignment, Uint64 DvpCtxFrameNumber)
{
    VERIFY_EXPR(Alignment > 0);
    VERIFY(IsPowerOfTwo(Alignment), "Alignment (", Alignment, ") must be power of 2");

    if (m_CurrOffset == InvalidOffset || SizeInBytes + (AlignUp(m_CurrOffset, Alignment) - m_CurrOffset) > m_AvailableSize)
    {
        auto NewPageSize = m_PageSize;
        while (NewPageSize < SizeInBytes)
            NewPageSize *= 2;

        auto NewPage = m_GlobalDynamicMemMgr.AllocatePage(NewPageSize);
        if (NewPage.IsValid())
        {
            m_CurrOffset    = 0;
            m_AvailableSize = NewPage.GetSize();

            m_CurrAllocatedSize += m_AvailableSize;
            m_PeakAllocatedSize = std::max(m_PeakAllocatedSize, m_CurrAllocatedSize);

            m_AllocatedPages.emplace_back(std::move(NewPage));
        }
    }

    if (m_CurrOffset != InvalidOffset && SizeInBytes + (AlignUp(m_CurrOffset, Alignment) - m_CurrOffset) <= m_AvailableSize)
    {
        auto AlignedOffset = AlignUp(m_CurrOffset, Alignment);
        auto AdjustedSize  = SizeInBytes + (AlignedOffset - m_CurrOffset);
        VERIFY_EXPR(AdjustedSize <= m_AvailableSize);
        m_AvailableSize -= AdjustedSize;
        m_CurrOffset += AdjustedSize;

        m_CurrUsedSize += SizeInBytes;
        m_PeakUsedSize = std::max(m_PeakUsedSize, m_CurrUsedSize);

        m_CurrAlignedSize += AdjustedSize;
        m_PeakAlignedSize = std::max(m_PeakAlignedSize, m_CurrAlignedSize);

        auto& CurrPage = m_AllocatedPages.back();
        // clang-format off
        return D3D12DynamicAllocation
        {
            CurrPage.GetD3D12Buffer(),
            AlignedOffset,
            SizeInBytes,
            CurrPage.GetCPUAddress(AlignedOffset),
            CurrPage.GetGPUAddress(AlignedOffset)
#ifdef DILIGENT_DEVELOPMENT
            , DvpCtxFrameNumber
#endif
        };
        // clang-format on
    }
    else
        return D3D12DynamicAllocation{};
}

void D3D12DynamicHeap::ReleaseAllocatedPages(Uint64 QueueMask)
{
    m_GlobalDynamicMemMgr.ReleasePages(m_AllocatedPages, QueueMask);
    m_AllocatedPages.clear();

    m_CurrOffset        = InvalidOffset;
    m_AvailableSize     = 0;
    m_CurrAllocatedSize = 0;
    m_CurrUsedSize      = 0;
    m_CurrAlignedSize   = 0;
}

} // namespace Diligent