/***
    Copyright (C) 2022 J Reece Wilson (a/k/a "Reece"). All rights reserved.

    File: AuIPCMemory.Unix.cpp
    Date: 2022-4-14
    Author: Reece
***/
#include <Source/RuntimeInternal.hpp>
#include "IPC.hpp"
#include "AuIPCHandle.hpp"
#include "AuIPCMemory.Unix.hpp"

#include <sys/mman.h>
#include <sys/stat.h>        /* For mode constants */
#include <fcntl.h>           /* For O_* constants */

#if defined(AURORA_IS_LINUX_DERIVED)
    #include "IPCMutexFutex.Linux.hpp" /* For import */
#endif

namespace Aurora::IO::IPC
{
    //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
    // Shared memory
    //////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

    AuString GetServerPath(const IPC::IPCToken &handle)
    {
        AuString path;
        path += "/AURORA_";
        path += AuToString(AuUInt32(handle.cookie));
        path += "_";
        path += AuToString(AuUInt32(handle.pid));
        return path;
    }

    IPCSharedMemoryImpl::IPCSharedMemoryImpl(int fd,
                                             void *pBase,
                                             const IPC::IPCHandle &handle,
                                             bool bOwns) :
        fd_(fd),
        pBase_(ptr),
        uLen_(handle.values[0].token.word),
        bOwns_(bOwns),
        handle_(handle)
    {

    }

    IPCSharedMemoryImpl::~IPCSharedMemoryImpl()
    {
        if (this->pBase_)
        {
            ::munmap(this->pBase_, this->uLen_);
        }

        int fd {-1};
        if ((fd = AuExchange(this->fd_, -1)) != -1)
        {
            ::close(fd);
        }
    }

    Memory::MemoryViewWrite IPCSharedMemoryImpl::GetMemory()
    {
        return AuMemoryViewWrite(this->pBase_, this->uLen_);
    }

    AuUInt IPCSharedMemoryImpl::GetLength()
    {
        return this->uLen_;
    }

    AuString IPCSharedMemoryImpl::ExportToString()
    {
        return this->handle_.ToString();
    }

    AUKN_SYM AuSPtr<IPCSharedMemory>      NewSharedMemory(AuUInt uLength)
    {
        IPC::IPCHandle handle;
        IPC::IPCToken token;
        token.pid = handle.pid;
        token.word = uLength;
        token.NewId();

        handle.PushId(EIPCHandleType::eIPCMemory, token);

        auto path = GetServerPath(token);
        int fd = ::shm_open(path.c_str(), O_RDWR | O_CREAT, S_IRUSR | S_IWUSR);
        if (fd == -1)
        {
            SysPushErrorIO();
            return {};
        }

        if (::ftruncate(fd, uLength) == -1)
        {
            SysPushErrorMem();
            ::close(fd);
            return {};
        }

        auto map = ::mmap(nullptr, uLength, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
        if (map == MAP_FAILED)
        {
            SysPushErrorIO();
            ::close(fd);
            return {};
        }

        auto pObject = AuMakeShared<IPCSharedMemoryImpl>(fd, map, handle, true);
        if (!pObject)
        {
            SysPushErrorMem();
            ::munmap(map, uLength);
            ::close(fd);
            return {};
        }

        return pObject;
    }

    AuSPtr<IPCSharedMemory> ImportSharedMemoryEx(const IPCToken &token)
    {
        auto path = GetServerPath(token);
        int fd = ::shm_open(path.c_str(), O_RDWR, S_IRUSR | S_IWUSR);
        if (fd == -1)
        {
            SysPushErrorIO();
            return {};
        }

        auto map = ::mmap(nullptr, token.word, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
        if (map == MAP_FAILED)
        {
            SysPushErrorIO();
            ::close(fd);
            return {};
        }

        IPC::IPCHandle handle;
        handle.PushId(EIPCHandleType::eIPCMemory, token);

        auto pObject = AuMakeShared<IPCSharedMemoryImpl>(fd, map, handle, false);
        if (!pObject)
        {
            SysPushErrorMem();
            ::munmap(map, token.word);
            ::close(fd);
            return {};
        }

        return pObject;
    }

    AUKN_SYM AuSPtr<IPCSharedMemory>      ImportSharedMemory(const AuString &handleString)
    {
        IPC::IPCHandle handle;

        if (!handle.FromString(handleString))
        {
            SysPushErrorParseError("Invalid handle: {}", handleString);
            return {};
        }

        auto val = handle.GetToken(IPC::EIPCHandleType::eIPCMemory, 0);
        if (!val)
        {
            SysPushErrorParseError("Invalid handle: {}", handleString);
            return {};
        }

        return ImportSharedMemoryEx(val->token);
    }
}