/***
    Copyright (C) 2021 J Reece Wilson (a/k/a "Reece"). All rights reserved.

    File: FileStream.NT.cpp
    Date: 2021-6-12
    Author: Reece
***/
#include <Source/RuntimeInternal.hpp>
#include "FS.hpp"
#include "FileStream.NT.hpp"
#include "FileAdvisory.NT.hpp"

#if !defined(_AURUNTIME_GENERICFILESTREAM)

namespace Aurora::IO::FS
{
    static const AuUInt64 kFileCopyBlock = 0xFFFF * 128;

    WinFileStream::~WinFileStream()
    {
        Close();
    }

    void WinFileStream::Init(AuSPtr<IIOHandle> pHandle)
    {
        this->pHandle_ = pHandle;
    }
    
    AuUInt64 WinFileStream::GetOffset()
    {
        LARGE_INTEGER distance {};
        LARGE_INTEGER pos {};
        HANDLE hHandle {};

        if (auto pHandle = this->pHandle_)
        {
            if (!pHandle->IsFile())
            {
                SysPushErrorIOResourceRejected();
                return 0;
            }

             hHandle = this->GetWin32Handle();

             if (hHandle == INVALID_HANDLE_VALUE)
             {
                 SysPushErrorInvalidFd();
                 return 0;
             }
        }
        else
        {
            SysPushErrorUninitialized();
            return 0;
        }

        if (::SetFilePointerEx(hHandle,
                               distance,
                               &pos,
                               FILE_CURRENT) == INVALID_SET_FILE_POINTER)
        {
            SysPushErrorIO("SetFilePointerEx IO Error: 0x{:x}, {}", GetLastError(), this->pHandle_ ? this->pHandle_->GetPath() : "");
            return 0;
        }

        return pos.QuadPart;
    }

    bool WinFileStream::SetOffset(AuUInt64 offset)
    {
        LARGE_INTEGER distance {};
        LARGE_INTEGER pos {};
        HANDLE hHandle {};

        if (auto pHandle = this->pHandle_)
        {
            if (!pHandle->IsFile())
            {
                SysPushErrorIOResourceRejected();
                return 0;
            }

            hHandle = this->GetWin32Handle();

            if (hHandle == INVALID_HANDLE_VALUE)
            {
                SysPushErrorInvalidFd();
                return 0;
            }
        }
        else
        {
            SysPushErrorUninitialized();
            return 0;
        }

        distance.QuadPart = offset;

        if (::SetFilePointerEx(hHandle, distance, &pos, FILE_BEGIN) == INVALID_SET_FILE_POINTER)
        {
            SysPushErrorIO("SetFilePointerEx IO Error: 0x{:x}, {}", GetLastError(), this->pHandle_ ? this->pHandle_->GetPath() : "");
            return false;
        }

        return true;
    }

    AuUInt64 WinFileStream::GetLength()
    {
        LARGE_INTEGER length;
        HANDLE hHandle {};

        if (auto pHandle = this->pHandle_)
        {
            if (!pHandle->IsFile())
            {
                SysPushErrorIOResourceRejected();
                return 0;
            }

            hHandle = this->GetWin32Handle();

            if (hHandle == INVALID_HANDLE_VALUE)
            {
                SysPushErrorInvalidFd();
                return 0;
            }
        }
        else
        {
            SysPushErrorUninitialized();
            return 0;
        }

        if (!::GetFileSizeEx(hHandle, &length))
        {
            SysPushErrorIO();
            return 0;
        }

        return length.QuadPart;
    }

    bool WinFileStream::Read(const Memory::MemoryViewStreamWrite &parameters)
    {
        if (!this->pHandle_)
        {
            SysPushErrorUninitialized();
            return 0;
        }

        auto hHandle = this->GetWin32Handle(true);
        HANDLE hEventHandle { INVALID_HANDLE_VALUE };

        if (hHandle == INVALID_HANDLE_VALUE)
        {
            SysPushErrorIOResourceRejected();
            return {};
        }

        bool bIsAsync = this->pHandle_->IsAsync();

        if (bIsAsync)
        {
            hEventHandle = ::CreateEventA(nullptr, false, false, nullptr);
        }

        parameters.outVariable = 0;

        AuUInt64 uLength = parameters.length;
        AuUInt64 uOffset {};
        while (uLength)
        {
            DWORD read {};

            auto blockSize = AuMin(AuUInt(kFileCopyBlock), uLength);

            if (this->pHandle_->IsAsync())
            {
                OVERLAPPED overlapped {};
                overlapped.hEvent = hEventHandle;

                if (!::ReadFile(hHandle,
                                reinterpret_cast<char *>(parameters.ptr) + uOffset,
                                blockSize,
                                NULL,
                                &overlapped) &&
                    ::GetLastError() != ERROR_IO_PENDING)
                {
                    SysPushErrorIO("ReadFile IO Error: 0x{:x}, {}", GetLastError(), this->pHandle_ ? this->pHandle_->GetPath() : "");
                    AuWin32CloseHandle(hEventHandle);
                    parameters.outVariable = uOffset;
                    return false;
                }

                ::WaitForSingleObject(hEventHandle, 0);

                if (!::GetOverlappedResult(hHandle, &overlapped, &read, true))
                {
                    if (::GetLastError() != ERROR_HANDLE_EOF)
                    {
                        AuWin32CloseHandle(hEventHandle);
                        parameters.outVariable = uOffset;
                        return false;
                    }
                }
            }
            else
            {
                if (!::ReadFile(hHandle,
                                reinterpret_cast<char *>(parameters.ptr) + uOffset,
                                blockSize,
                                &read,
                                NULL))
                {
                    SysPushErrorIO("ReadFile IO Error: 0x{:x}, {}", GetLastError(), this->pHandle_ ? this->pHandle_->GetPath() : "");
                    AuWin32CloseHandle(hEventHandle);
                    parameters.outVariable = uOffset;
                    return false;
                }
            }
       
            if (read == 0)
            {
                break;
            }

            uOffset += read;
            uLength -= read;
        }

        AuWin32CloseHandle(hEventHandle);
        parameters.outVariable = uOffset;
        return true;
    }
    
    bool WinFileStream::Write(const Memory::MemoryViewStreamRead &parameters)
    {
        auto optHandle = this->GetHandle()->GetOSWriteHandleSafe();
        if (!optHandle)
        {
            SysPushErrorIOResourceRejected();
            return false;
        }

        auto hHandle = (HANDLE)optHandle.value();
        HANDLE hEventHandle { INVALID_HANDLE_VALUE };

        if (hHandle == INVALID_HANDLE_VALUE)
        {
            SysPushErrorUninitialized();
            return 0;
        }

        bool bIsAsync = this->pHandle_->IsAsync();

        if (bIsAsync)
        {
            hEventHandle = ::CreateEventA(nullptr, false, false, nullptr);
        }
        parameters.outVariable = 0;

        AuUInt64 uLength = parameters.length;
        AuUInt64 uOffset {};
        while (uLength)
        {
            DWORD written {};

            auto uBlockSize = AuMin(AuUInt(kFileCopyBlock), uLength);

            if (bIsAsync)
            {
                OVERLAPPED overlapped {};
                overlapped.hEvent = hEventHandle;

                if (!::WriteFile(hHandle,
                                 reinterpret_cast<const char *>(parameters.ptr) + uOffset,
                                 uBlockSize,
                                 NULL,
                                 &overlapped) &&
                    ::GetLastError() != ERROR_IO_PENDING)
                {
                    SysPushErrorIO("WriteFile IO Error: 0x{:x}, {}", GetLastError(), this->pHandle_ ? this->pHandle_->GetPath() : "");
                    AuWin32CloseHandle(hEventHandle);
                    parameters.outVariable = uOffset;
                    return false;
                }

                ::WaitForSingleObject(hEventHandle, 0);

                if (!::GetOverlappedResult(hHandle, &overlapped, &written, true))
                {
                    AuWin32CloseHandle(hEventHandle);
                    parameters.outVariable = uOffset;
                    return false;
                }
            }
            else
            {
                if (!::WriteFile(hHandle, reinterpret_cast<const char *>(parameters.ptr) + uOffset, uBlockSize, &written, NULL))
                {
                    SysPushErrorIO("WriteFile IO Error: 0x{:x}, {}", GetLastError(), this->pHandle_ ? this->pHandle_->GetPath() : "");
                    parameters.outVariable = uOffset;
                    return false;
                }
            }

            if (!written)
            {
                SysPushErrorIO();
                parameters.outVariable = uOffset;

                AuWin32CloseHandle(hEventHandle);
                return true;
            }

            uOffset += written;
            uLength -= written;
        }

        AuWin32CloseHandle(hEventHandle);

        if (!uOffset)
        {
            return false;
        }

        parameters.outVariable = uOffset;
        return true;
    }

    void WinFileStream::WriteEoS()
    {
        auto hHandle = this->GetWin32Handle();

        if (hHandle == INVALID_HANDLE_VALUE)
        {
            SysPushErrorUninitialized();
            return;
        }

        SetEndOfFile(hHandle);
    }

    void WinFileStream::Close()
    {
        auto hHandle = this->GetWin32Handle();
        bool bDeleteFailed {};
        AuString path;

        if ((hHandle != INVALID_HANDLE_VALUE) && 
            (this->bShouldDelete))
        {
            FILE_DISPOSITION_INFO rm {};
            rm.DeleteFile = true;
            if (!(pSetFileInformationByHandle &&
                  pSetFileInformationByHandle(hHandle, _FILE_INFO_BY_HANDLE_CLASS::FileDispositionInfo, &rm, sizeof(rm))))
            {
                path = this->pHandle_ ? this->pHandle_->GetPath() : "";

                SysPushErrorIO("Couldn't delete temporary file {}", path);

                if (path.length())
                {
                    bDeleteFailed = true;
                }
            }
            else
            {
                bDeleteFailed = true;
            }
        }

        AuResetMember(this->pHandle_);

        // a bit of a hack for problematic NT-like platforms and Windows XP
        if (bDeleteFailed)
        {
            AuFS::Remove(path);
        }
    }

    void WinFileStream::Flush()
    {
        auto hHandle = this->GetWin32Handle();

        ::FlushFileBuffers(hHandle);
    }

    void WinFileStream::MakeTemporary()
    {
        this->bShouldDelete = true;
    }

    AuSPtr<IIOHandle> WinFileStream::GetHandle()
    {
        return this->pHandle_;
    }

    HANDLE WinFileStream::GetWin32Handle(bool bReadOnly)
    {
        if (auto pHandle = this->pHandle_)
        {
            if (bReadOnly)
            {
                return (HANDLE)pHandle->GetOSReadHandleSafe().ValueOr((AuUInt)INVALID_HANDLE_VALUE);
            }
            else
            {
                return (HANDLE)pHandle->GetOSWriteHandleSafe().ValueOr(pHandle->GetOSReadHandleSafe().ValueOr((AuUInt)INVALID_HANDLE_VALUE));
            }
        }

        return INVALID_HANDLE_VALUE;
    }

    AUKN_SYM AuSPtr<IFileStream> OpenBlockingFileStreamFromHandle(AuSPtr<IIOHandle> pIOHandle)
    {
        auto pStream = AuMakeShared<WinFileStream>();
        if (!pStream)
        {
            SysPushErrorMemory();
            return nullptr;
        }

        pStream->Init(pIOHandle);
        return pStream;
    }

    static IFileStream *OpenNewEx(const AuString &path,
                                  EFileOpenMode openMode,
                                  EFileAdvisoryLockLevel lock,
                                  bool bCheck)
    {
        try
        {
            auto pHandle = AuIO::IOHandleShared();
            if (!pHandle)
            {
                SysPushErrorMemory();
                return nullptr;
            }

            AuIO::IIOHandle::HandleCreate createhandle(path);
            createhandle.eAdvisoryLevel = lock;
            createhandle.eMode = openMode;
            createhandle.bFailIfNonEmptyFile = bCheck;
            createhandle.bDirectIOMode = false;
            createhandle.bAsyncHandle = false;

            if (!pHandle->InitFromPath(createhandle))
            {
                SysPushErrorNested();
                return nullptr;
            }

            auto pStream = _new WinFileStream();
            if (!pStream)
            {
                SysPushErrorMemory();
                return nullptr;
            }

            pStream->Init(pHandle);
            return pStream;
        }
        catch (...)
        {
            return nullptr;
        }
    }

    AUKN_SYM IFileStream *CreateNew(const AuString &path)
    {
        return OpenNewEx(path, EFileOpenMode::eWrite, EFileAdvisoryLockLevel::eBlockReadWrite, true);
    }

    AUKN_SYM void CreateRelease(IFileStream *that)
    {
        AuSafeDelete<WinFileStream *>(that);
    }

    AUKN_SYM IFileStream *OpenNew(const AuString &path, EFileOpenMode openMode, EFileAdvisoryLockLevel lock)
    {
        return OpenNewEx(path, openMode, lock, false);
    }

    AUKN_SYM void OpenRelease(IFileStream *that)
    {
        AuSafeDelete<WinFileStream *>(that);
    }

    AUKN_SYM IFileStream *OpenReadNew(const AuString &path, EFileAdvisoryLockLevel level)
    {
        return OpenNew(path, EFileOpenMode::eRead, level);
    }

    AUKN_SYM void OpenReadRelease(IFileStream * that)
    {
        AuSafeDelete<WinFileStream *>(that);
    }

    AUKN_SYM IFileStream *OpenWriteNew(const AuString &path, EFileAdvisoryLockLevel level)
    {
        return OpenNew(path, EFileOpenMode::eWrite, level);
    }

    AUKN_SYM void OpenWriteRelease(IFileStream *that)
    {
        AuSafeDelete<WinFileStream *>(that);
    }
}

#endif