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

    File: FileStream.Unix.cpp
    Date: 2021-6-12
    Author: Reece
***/
#include <Source/RuntimeInternal.hpp>
#include "FS.hpp"
#include "FileStream.Generic.hpp"
#include "FileAdvisory.Unix.hpp"
#include <sys/types.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <Source/IO/AuIOHandle.hpp>

#if !defined(_AURUNTIME_GENERICFILESTREAM)

namespace Aurora::IO::FS
{
    static const AuUInt64 kFileCopyBlock = 0x4000; // 16KiB

    PosixFileStream::PosixFileStream() :
        reader_(AuUnsafeRaiiToShared(this)),
        writer_(AuUnsafeRaiiToShared(this)),
        sreader_(AuUnsafeRaiiToShared(this)),
        swriter_(AuUnsafeRaiiToShared(this))
    {

    }

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

    bool PosixFileStream::Init(AuSPtr<IIOHandle> pHandle)
    {
        AuCtorCode_t code;
        this->pHandle_ = pHandle;
        return true;
    }
    
    AuUInt64 PosixFileStream::GetOffset()
    {
        AU_LOCK_GUARD(this->mutex_);
       
        int fd {};
        if (auto pHandle = this->pHandle_)
        {
            if (!pHandle->IsFile())
            {
                SysPushErrorIOResourceRejected();
                return 0;
            }

            if (auto opt = pHandle->GetOSHandleSafe())
            {
                fd = opt.Value();
            }
            else
            {
                SysPushErrorInvalidFd();
                return 0;
            }
        }
        else
        {
            SysPushErrorUninitialized();
            return 0;
        }

        return PosixGetOffset(fd);
    }
    
    bool PosixFileStream::SetOffset(AuUInt64 offset)
    {
        AU_LOCK_GUARD(this->mutex_);

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

            if (auto opt = pHandle->GetOSHandleSafe())
            {
                fd = opt.Value();
            }
            else
            {
                SysPushErrorInvalidFd();
                return false;
            }
        }
        else
        {
            SysPushErrorUninitialized();
            return false;
        }

        return PosixSetOffset(fd, offset);
    }

    AuUInt64 PosixFileStream::GetLength()
    {
        AU_LOCK_GUARD(this->mutex_);

        int fd {};
        if (auto pHandle = this->pHandle_)
        {
            if (!pHandle->IsFile())
            {
                // Intentionally suppressed (for the moment)
                // I don't want to fill error stacks up under paths that can handle char-devs by reading until EoS
                // If we do, we could hit an always-throw on AuErrorStack-catch
                // Some users are completely unaware they can access/test the underlying handle
                // Returning zero will do
                return 0;
            }

            if (auto opt = pHandle->GetOSHandleSafe())
            {
                fd = opt.Value();
            }
            else
            {
                SysPushErrorInvalidFd();
                return 0;
            }
        }
        else
        {
            SysPushErrorUninitialized();
            return 0;
        }
        
        return PosixGetLength(fd);
    }

    bool PosixFileStream::Read(const Memory::MemoryViewStreamWrite &parameters)
    {
        AU_LOCK_GUARD(this->mutex_);
        
        parameters.outVariable = 0;
	
        if (!this->pHandle_)
        {
            SysPushErrorUninitialized();
            return 0;
        }

        int fd = (int)this->pHandle_->GetOSReadHandleSafe().ValueOr((AuUInt)-1);
        if (fd == -1)
        {
            SysPushErrorIOResourceRejected();
            return 0;
        }

        AuUInt uOffset {};
        AuUInt64 uLength = parameters.length;

        if (this->pHandle_->IsPipe())
        {
        #if defined(FIONREAD)
            int available {};
            if (::ioctl(fd, FIONREAD, &available) < 0)
            {
                return 0;
            }

            uLength = AuMin(uLength, available);
            if (!uLength)
            {
                return 0;
            }
        #endif
        }

        while (uLength)
        {
            AuUInt32 uRead;

            if (!PosixRead(fd,
                           &reinterpret_cast<char *>(parameters.ptr)[uOffset],
                           AuMin(kFileCopyBlock, uLength),
                           &uRead))
            {
                SysPushErrorNested("File Error: {}", this->path_);
                break;
            }
            
            if (uRead == 0)
            {
                break;
            }

            uOffset += uRead;
            uLength -= uRead;
        }
        
        parameters.outVariable = uOffset;
        return true;
    }
    
    bool PosixFileStream::Write(const Memory::MemoryViewStreamRead &parameters)
    {
        AU_LOCK_GUARD(this->mutex_);

        parameters.outVariable = 0;

        if (!this->pHandle_)
        {
            SysPushErrorUninitialized();
            return 0;
        }

        int fd = this->pHandle_->GetOSWriteHandleSafe().ValueOr((AuUInt)-1);
        if (fd == -1)
        {
            SysPushErrorUninitialized();
            return 0;
        }

        AuUInt length = parameters.length;
        AuUInt offset {0};
        while (length)
        {
            AuUInt32 written;

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

            if (!PosixWrite(fd, &reinterpret_cast<const char *>(parameters.ptr)[offset], blockSize, &written))
            {
                SysPushErrorNested("File Error: {}", this->pHandle_->GetPath());
                return false;
            }

            if (!written)
            {
                break;
            }

            offset += written;
            length -= written;
        }
        
        parameters.outVariable = offset;
        return true;
    }

    void PosixFileStream::Close()
    {
        AU_DEBUG_MEMCRUNCH;
        AU_LOCK_GUARD(this->mutex_);
        AuString path;

        if (AuExchange(this->bMadeTemporary, false) &&
            this->pHandle_)
        {
            path = this->pHandle_->GetPath();
        }

        AuResetMember(this->pHandle_);

        if (path.size())
        {
            Aurora::RuntimeWaitForSecondaryTick();
            PosixUnlink(path.c_str());
        }
    }

    bool PosixFileStream::IsFlushOnClose() const
    {
        AU_LOCK_GUARD(this->mutex_);

        if (auto &pHandle = this->pHandle_)
        {
            return pHandle->IsFlushOnClose();
        }
        else
        {
            return false;
        }
    }

    void PosixFileStream::SetFlushOnClose(bool bFlushOnClose)
    {
        AU_LOCK_GUARD(this->mutex_);

        if (auto &pHandle = this->pHandle_)
        {
            pHandle->SetFlushOnClose(bFlushOnClose);
        }
    }

    bool PosixFileStream::IsWriteEoSOnClose() const
    {
        AU_LOCK_GUARD(this->mutex_);

        if (auto &pHandle = this->pHandle_)
        {
            return pHandle->IsWriteEoSOnClose();
        }
        else
        {
            return false;
        }
    }

    void PosixFileStream::SetWriteEoSOnClose(bool bShouldWriteEoS)
    {
        AU_LOCK_GUARD(this->mutex_);

        if (auto &pHandle = this->pHandle_)
        {
            pHandle->SetWriteEoSOnClose(bShouldWriteEoS);
        }
    }

    void PosixFileStream::Flush()
    {
        AU_LOCK_GUARD(this->mutex_);

        if (!this->pHandle_)
        {
            SysPushErrorUninitialized();
            return;
        }

        int fd = this->pHandle_->GetOSWriteHandleSafe().ValueOr((AuUInt)-1);
        if (fd == -1)
        {
            SysPushErrorIOResourceRejected();
            return;
        }

        SysFlushHandle(fd);
    }

    void PosixFileStream::WriteEoS()
    {
        AU_LOCK_GUARD(this->mutex_);

        if (!this->pHandle_)
        {
            SysPushErrorUninitialized();
            return;
        }

        int fd = this->pHandle_->GetOSWriteHandleSafe().ValueOr((AuUInt)-1);
        if (fd == -1)
        {
            SysPushErrorIOResourceRejected();
            return;
        }
        
        PosixWriteEoS(fd);
    }

    void PosixFileStream::MakeTemporary()
    {
        this->bMadeTemporary = true;
    }
    
    int PosixFileStream::GetUnixHandle()
    {
        return this->pHandle_ ?
            (int)this->pHandle_->GetOSWriteHandleSafe().ValueOr(this->pHandle_->GetOSReadHandleSafe().ValueOr((AuUInt)-1)) :
            -1;
    }

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

    IO::IStreamReader *PosixFileStream::ToStreamReader()
    {
        return &this->reader_;
    }

    IO::IStreamWriter *PosixFileStream::ToStreamWriter()
    {
        return &this->writer_;
    }

    IO::ISeekingReader *PosixFileStream::ToStreamSeekingReader()
    {
        return &this->sreader_;
    }

    IO::ISeekingWriter *PosixFileStream::ToStreamSeekingWriter()
    {
        return &this->swriter_;
    }

    AUKN_SYM IFileStream *OpenBlockingFileStreamFromHandleNew(const AuSPtr<IIOHandle> &pIOHandle)
    {
        SysCheckArgNotNull(pIOHandle, {});

        auto pStream = _new PosixFileStream();
        SysCheckNotNullMemory(pStream, {});

        if (!AuStaticCast<AFileHandle>(pIOHandle)->pIPCPipe &&
             AuStaticCast<AFileHandle>(pIOHandle)->ShouldClone())
        {
            auto pIOHandle2 = AuMakeShared<AFileHandle>();
            SysCheckNotNullMemory(pIOHandle2, {});

            if (!pIOHandle2->InitFromPair(pIOHandle->GetOSReadHandleSafe(), pIOHandle->GetOSWriteHandle()))
            {
                SysPushErrorIOResourceFailure();
                return {};
            }

            pStream->Init(pIOHandle2);
        }
        else
        {
            pStream->Init(pIOHandle);
        }

        return pStream;
    }

    AUKN_SYM void OpenBlockingFileStreamFromHandleRelease(IFileStream *that)
    {
        AuSafeDelete<PosixFileStream *>(that);
    }

    static IFileStream *OpenNewEx(const AuROString &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 PosixFileStream();
            if (!pStream)
            {
                SysPushErrorMemory();
                return nullptr;
            }

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

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

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

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

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

    AUKN_SYM IFileStream *OpenReadNew(const AuROString &path, EFileAdvisoryLockLevel level)
    {
        return OpenNewEx(path, EFileOpenMode::eRead, level, false);
    }

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

    AUKN_SYM IFileStream *OpenWriteNew(const AuROString &path, EFileAdvisoryLockLevel level)
    {
        return OpenNewEx(path, EFileOpenMode::eWrite, level, false);
    }

    AUKN_SYM void OpenWriteRelease(IFileStream *that)
    {
        AuSafeDelete<PosixFileStream *>(that);
    }
}
#endif