/***
    Copyright (C) 2023 J Reece Wilson (a/k/a "Reece"). All rights reserved.

    File: AuIOHandle.Unix.cpp
    Date: 2023-8-11
    Author: Reece
***/
#include <RuntimeInternal.hpp>
#include "AuIOHandle.hpp"
#include "AuIOHandle.Unix.hpp"

#include "FS/FS.hpp"
#include "FS/FileAdvisory.Unix.hpp"
#include "FS/FileStream.Unix.hpp"

#include <fcntl.h>
#include <unistd.h>
#include <sys/stat.h>

namespace Aurora::IO
{
    AuUInt64 AFileHandle::DupHandle(AuUInt64 uOSHandle, bool bWriteAccess)
    {
        int fd = dup(uOSHandle);

        if (fd < 0)
        {
            return 0;
        }

        return AuUInt64(fd);
    }

    void AFileHandle::CloseHandle(AuUInt64 uOSHandle)
    {
        int fd = (int)uOSHandle;
        if (fd < 0)
        {
            return;
        }

        ::close(fd);
    }

    struct UnixIOHandle final : AFileHandle
    {
        bool InitFromPath(HandleCreate create) override
        {
            int iFileDescriptor { -1 };

            if (create.path.empty())
            {
                SysPushErrorArg("Cannot open an IO handle to the provided empty path");
                return false;
            }

            if (!FS::EFileOpenModeIsValid(create.eMode))
            {
                SysPushErrorParam("Invalid open mode");
                return false;
            }

            if (!FS::EFileAdvisoryLockLevelIsValid(create.eAdvisoryLevel))
            {
                SysPushErrorParam("Invalid lock mode");
                return false;
            }

            auto pathex = FS::NormalizePathRet(create.path);
            if (pathex.empty())
            {
                SysPushErrorMemory();
                return false;
            }

            if (create.bAsyncHandle ||
                create.bDirectIOMode)
            {
                this->bDirectIO = true;
            }

            switch (create.eMode)
            {
            case FS::EFileOpenMode::eRead:
            {

                break;
            }
            case FS::EFileOpenMode::eReadWrite:
            case FS::EFileOpenMode::eWrite:
            {
                if (create.bAlwaysCreateDirTree)
                {
                    FS::CreateDirectories(pathex, true);
                }

                if (create.bFailIfNonEmptyFile)
                {
                    if (AuFS::FileExists(pathex.c_str()))
                    {
                        SysPushErrorResourceExists("File {} already exists", create.path);
                        return false;
                    }
                }
               
                break;
            }
            };

            iFileDescriptor = ::open(pathex.c_str(),
                                     (create.eMode == FS::EFileOpenMode::eRead ? O_RDONLY : (O_RDWR | O_CREAT)) | O_CLOEXEC | (this->bDirectIO ? O_DIRECT : 0),
                                     0664);

            if (iFileDescriptor < 0)
            {
                SysPushErrorIO("Couldn't open file: {} ({}) {}", path, pathex, errno);
                return false;
            }

            if (!FS::ApplyDumbAdvisoryLock(iFileDescriptor, create.eAdvisoryLevel))
            {
                SysPushErrorIO("Couldn't open file: {}. File node (not section) is locked.", path);
                ::close(iFileDescriptor);
                return false;
            }

            if (create.bFailIfNonEmptyFile)
            {
                if (FS::PosixGetLength(iFileDescriptor))
                {
                    SysPushErrorResourceExists("File {} already exists", create.path);
                    ::close(iFileDescriptor);
                    return false;
                }
            }
       
            switch (create.eMode)
            {
            case FS::EFileOpenMode::eRead:
            {
                this->uOSReadHandle = AuUInt64(iFileDescriptor);
                break;
            }
            case FS::EFileOpenMode::eReadWrite:
            {
                this->uOSWriteHandle = AuUInt64(iFileDescriptor);
                this->uOSReadHandle = AuUInt64(iFileDescriptor);
                break;
            }
            case FS::EFileOpenMode::eWrite:
            {
                this->uOSWriteHandle = AuUInt64(iFileDescriptor);
                break;
            }
            };

            this->bIsAsync = create.bAsyncHandle;

            this->path = create.path;

            return this->IsValid();
        }

        bool IsFile() override;
        bool IsTTY() override;
        bool IsPipe() override;

        AuOptionalEx<bool> optIsFile {};
        AuOptionalEx<bool> optIsPipe {};
        AuOptionalEx<bool> optIsTTY {};
    };

    bool UnixIOHandle::IsFile()
    {
        bool bIsFile {};
        struct stat st;
        int iFileDescriptor {};

        if (auto file = this->optIsFile)
        {
            return file.value();
        }

        if (auto optHandle = this->GetOSHandleSafe())
        {
            iFileDescriptor = (int)optHandle.value();
        }
        else
        {
            SysPushErrorUninitialized();
            return false;
        }

        if (::fstat(iFileDescriptor, &st) != 0)
        {
            SysPushErrorIO("fstat failed");
            return false;
        }

        bIsFile = S_ISREG(st.st_mode);
        this->optIsFile = bIsFile;
        return bIsFile;
    }

    bool UnixIOHandle::IsTTY()
    {
        bool bIsTTY {};
        int iFileDescriptor {};

        if (auto file = this->optIsTTY)
        {
            return file.value();
        }

        if (auto optHandle = this->GetOSHandleSafe())
        {
            iFileDescriptor = (int)optHandle.value();
        }
        else
        {
            SysPushErrorUninitialized();
            return false;
        }

        bIsTTY = ::isatty(iFileDescriptor);
        this->optIsTTY = bIsTTY;
        return bIsTTY;
    }

    bool UnixIOHandle::IsPipe()
    {
        bool bIsPipe {};
        struct stat st;
        int iFileDescriptor {};

        if (auto file = this->optIsPipe)
        {
            return file.value();
        }

        if (auto optHandle = this->GetOSHandleSafe())
        {
            iFileDescriptor = (int)optHandle.value();
        }
        else
        {
            SysPushErrorUninitialized();
            return false;
        }

        if (::fstat(iFileDescriptor, &st) != 0)
        {
            SysPushErrorIO("fstat failed");
            return false;
        }

        bIsPipe = S_ISFIFO(st.st_mode);
        this->optIsPipe = bIsPipe;
        return bIsPipe;
    }

    AUKN_SYM IIOHandle *IOHandleNew()
    {
        return _new UnixIOHandle();
    }

    AUKN_SYM void IOHandleRelease(IIOHandle *pIOHandle)
    {
        AuSafeDelete<UnixIOHandle *>(pIOHandle);
    }

    AUROXTL_INTERFACE_SOO_SRC_EX(AURORA_SYMBOL_EXPORT, IOHandle, UnixIOHandle)
}