/***
    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; // 64KiB, 1k iterations to max out 64MB/s disk, 2k iteration to make out 128MB/s disk, is this number still way too low? cpu go brr

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

    void WinFileStream::Init(HANDLE handle, const AuString &path)
    {
        this->handle_ = handle;
        this->path_ = path;
    }
    
    AuUInt64 WinFileStream::GetOffset()
    {
        LARGE_INTEGER distance {};
        LARGE_INTEGER pos {};

        if (this->handle_ == INVALID_HANDLE_VALUE)
        {
            SysPushErrorUninitialized();
            return 0;
        }

        if (SetFilePointerEx(this->handle_, distance, &pos, FILE_CURRENT) == INVALID_SET_FILE_POINTER)
        {
            AuLogWarn("SetFilePointerEx IO Error: 0x{:x}, {}", GetLastError(), path_);
            SysPushErrorIO();
            return 0;
        }

        return pos.QuadPart;
    }

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

        if (this->handle_ == INVALID_HANDLE_VALUE)
        {
            SysPushErrorUninitialized();
            return false;
        }

        distance.QuadPart = offset;

        if (SetFilePointerEx(this->handle_, distance, &pos, FILE_BEGIN) == INVALID_SET_FILE_POINTER)
        {
            AuLogWarn("SetFilePointerEx IO Error: 0x{:x}, {}", GetLastError(), path_);
            SysPushErrorIO();
            return false;
        }

        return true;
    }

    AuUInt64 WinFileStream::GetLength()
    {
        LARGE_INTEGER length;
        
        if (handle_ == INVALID_HANDLE_VALUE)
        {
            SysPushErrorUninitialized();
            return 0;
        }

        if (!GetFileSizeEx(this->handle_, &length))
        {
            SysPushErrorIO();
            return 0;
        }

        return length.QuadPart;
    }

    bool WinFileStream::Read(const Memory::MemoryViewStreamWrite &parameters)
    {
        if (this->handle_ == INVALID_HANDLE_VALUE)
        {
            SysPushErrorUninitialized();
            return {};
        }

        auto length = parameters.length;
        parameters.outVariable = 0;
        AuUInt64 offset {0};
        while (length)
        {
            DWORD read;

            int blockSize = AuMin(AuUInt(kFileCopyBlock), length);

            if (!::ReadFile(this->handle_, reinterpret_cast<char *>(parameters.ptr) + offset, blockSize, &read, NULL))
            {
                AuLogWarn("ReadFile IO Error: 0x{:x}, {}", GetLastError(), path_);
                SysPushErrorIO();
                return false;
            }
            
            if (read == 0)
            {
                break;
            }

            offset += read;
            length -= read;
        }

        if (!offset)
        {
            return false;
        }

        parameters.outVariable = offset;
        return true;
    }
    
    bool WinFileStream::Write(const Memory::MemoryViewStreamRead &parameters)
    {
        if (this->handle_ == INVALID_HANDLE_VALUE)
        {
            SysPushErrorUninitialized();
            return 0;
        }

        auto length = parameters.length;
        parameters.outVariable = 0;
        AuUInt offset {0};
        while (length)
        {
            DWORD written;

            int blockSize = AuMin(AuUInt(kFileCopyBlock), length);

            if (!::WriteFile(this->handle_, reinterpret_cast<const char *>(parameters.ptr) + offset, blockSize, &written, NULL))
            {
                SysPushErrorIO("WriteFileEx IO Error: 0x{:x}, {}", GetLastError(), this->path_);
                return false;
            }

            if (!written)
            {
                SysPushErrorIO();
                parameters.outVariable = offset;
                return true;
            }

            offset += written;
            length -= written;
        }

        if (!offset)
        {
            return false;
        }

        parameters.outVariable = offset;
        return true;
    }

    void WinFileStream::WriteEoS()
    {
        if (this->handle_ == INVALID_HANDLE_VALUE)
        {
            SysPushErrorUninitialized();
            return;
        }

        SetEndOfFile(this->handle_);
    }

    void WinFileStream::Close()
    {
        if ((this->handle_ != INVALID_HANDLE_VALUE) && 
            (this->bShouldDelete))
        {
            FILE_DISPOSITION_INFO rm {};
            rm.DeleteFile = true;
            if (!SetFileInformationByHandle(this->handle_, _FILE_INFO_BY_HANDLE_CLASS::FileDispositionInfo, &rm, sizeof(rm)))
            {
                SysPushErrorIO("Couldn't delete temporary file {}", this->path_);
            }
        }
        AuWin32CloseHandle(this->handle_);
    }

    void WinFileStream::Flush()
    {
        FlushFileBuffers(this->handle_);
    }

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

    HANDLE WinFileStream::GetHandle()
    {
        return this->handle_;
    }

    static IFileStream *OpenNewEx(const AuString &path, EFileOpenMode openMode, EFileAdvisoryLockLevel lock, bool bCheck)
    {
        try
        {
            auto pathex = NormalizePathRet(path);
            if (pathex.empty())
            {
                return nullptr;
            }

            auto win32Path = Locale::ConvertFromUTF8(pathex);
            if (win32Path.empty())
            {
                return nullptr;
            }

            HANDLE fileHandle;

            fileHandle = INVALID_HANDLE_VALUE;

            auto dwShare = NtLockAdvisoryToShare(lock);

            switch (openMode)
            {
            case EFileOpenMode::eRead:
            {
                fileHandle = CreateFileW(win32Path.c_str(), GENERIC_READ, dwShare, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
                break;
            }
            case EFileOpenMode::eReadWrite:
            {
                CreateDirectories(pathex, true);

                if (bCheck)
                {
                    fileHandle = ::CreateFileW(win32Path.c_str(),
                                               GENERIC_WRITE | GENERIC_READ,
                                               NULL,
                                               NULL,
                                               CREATE_NEW,
                                               FILE_ATTRIBUTE_NORMAL,
                                               NULL);
                }
                else
                {
                    fileHandle = CreateFileW(win32Path.c_str(), GENERIC_WRITE | GENERIC_READ, dwShare, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
                    if (fileHandle == INVALID_HANDLE_VALUE)
                    {
                        fileHandle = CreateFileW(win32Path.c_str(), GENERIC_WRITE, dwShare, NULL, CREATE_NEW, FILE_ATTRIBUTE_NORMAL, NULL);
                    }
                }
            
                break;
            }
            case EFileOpenMode::eWrite:
            {
                CreateDirectories(pathex, true);

                if (bCheck)
                {
                    fileHandle = ::CreateFileW(win32Path.c_str(),
                                               GENERIC_WRITE,
                                               NULL,
                                               NULL,
                                               CREATE_NEW,
                                               FILE_ATTRIBUTE_NORMAL,
                                               NULL);
                }
                else
                {
                    fileHandle = CreateFileW(win32Path.c_str(), GENERIC_WRITE | FILE_READ_ATTRIBUTES, dwShare, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
                    if (fileHandle == INVALID_HANDLE_VALUE)
                    {
                        fileHandle = CreateFileW(win32Path.c_str(), GENERIC_WRITE, dwShare, NULL, CREATE_NEW, FILE_ATTRIBUTE_NORMAL, NULL);
                    }
                }
                break;
            }
            }

            if (fileHandle == INVALID_HANDLE_VALUE)
            {
                SysPushErrorIO("Invalid filepath, couldn't open: {}", path);
                return nullptr;
            }

            auto stream = _new WinFileStream();
            if (!stream)
            {
                CloseHandle(fileHandle);
                return nullptr;
            }

            stream->Init(fileHandle, pathex);
            return stream;
        }
        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