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

    File: AuProcessSectionView.Unix.hpp
    Date: 2022-08-10
    Author: Reece
***/
#include <Source/RuntimeInternal.hpp>
#include "AuProcessSectionView.Unix.hpp"
#include "Process.hpp"
#include <Source/IO/FS/FileStream.Unix.hpp>
#include "AuProcessSectionFileMapView.Unix.hpp"
#include <Source/IO/IPC/AuIPCHandle.hpp>
#include <Source/IO/IPC/AuIPCMemory.Unix.hpp>
#include <sys/mman.h>
#include <sys/stat.h>
#include <fcntl.h>

namespace Aurora::Process
{
    AuUInt ProcessSectionView::GetStart()
    {
        return AuNumericLimits<AuUInt>::min();
    }

    AuUInt ProcessSectionView::GetEnd()
    {
        return AuNumericLimits<AuUInt>::max();
    }

    AuSPtr<IProcessSectionMapView> ProcessSectionView::Allocate(AuUInt uLength)
    {
        if (!uLength)
        {
            SysPushErrorArg("invalid uLength");
            return {};
        }

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

        auto newObject = AuMakeShared<ProcessSectionFileMapView>(AuUInt(map),
                                                                 uLength,
                                                                 false);
        if (!newObject)
        {
            SysPushErrorMem();
            ::munmap(map, uLength);
            return {};
        }

        return newObject;
    }

    AuSPtr<IProcessSectionMapView> ProcessSectionView::MapFileByPath(const AuString &str,
                                                                     AuUInt64 uOffset,
                                                                     AuUInt uLength,
                                                                     AuFS::EFileOpenMode mode,
                                                                     AuFS::EFileAdvisoryLockLevel sectionLock)
    {
        auto file = AuFS::OpenShared(str, mode, AuFS::EFileAdvisoryLockLevel::eNoSafety);
        return file ? this->MapFileByObject(file, uOffset, uLength, mode, sectionLock) : AuSPtr<IProcessSectionMapView> {};
    }

    AuSPtr<IProcessSectionMapView> ProcessSectionView::MapFileByObject(const AuSPtr<AuFS::IFileStream> &stream,
                                                                       AuUInt64 uOffset,
                                                                       AuUInt uLength,
                                                                       AuFS::EFileOpenMode mode,
                                                                       AuFS::EFileAdvisoryLockLevel processLockLevel)
    {
        return this->MapFileByObjectEx(0, stream, uOffset, uLength, mode, processLockLevel);
    }

    AuSPtr<IProcessSectionMapView> ProcessSectionView::MapIPCMemory(const AuString &handleString,
                                                                    AuUInt64 uOffset,
                                                                    AuUInt uLength,
                                                                    AuFS::EFileOpenMode mode)
    {
        return this->MapIPCMemoryEx(0, handleString, uOffset, uLength, mode);
    }

    AuSPtr<IProcessSectionMapView> ProcessSectionView::AllocateEx(AuUInt uLength, AuUInt uOffset)
    {
        PageTable table {};
        table.NX = true;
        table.readable = true;
        table.writable = true;
        return this->AllocateEx2(uLength, uOffset, table);
    }
    
    AuSPtr<IProcessSectionMapView> ProcessSectionView::AllocateEx2(AuUInt uLength, AuUInt uOffset, PageTable permissions)
    {
        if (!uLength)
        {
            SysPushErrorArg("invalid uLength");
            return {};
        }

        AuUInt32 uProtFlags {};
        
        if (!permissions.NX)
        {
            uProtFlags |= PROT_EXEC;
        }
        
        if (permissions.writable)
        {
            uProtFlags |= PROT_WRITE;
        }

        if (permissions.readable)
        {
            uProtFlags |= PROT_READ;
        }

        auto map = ::mmap((void *)uOffset, uLength, uProtFlags, MAP_ANONYMOUS | MAP_PRIVATE | (uOffset ? MAP_FIXED : 0), 0, 0);
        if (map == MAP_FAILED)
        {
            SysPushErrorIO();
            return {};
        }

        auto newObject = AuMakeShared<ProcessSectionFileMapView>(AuUInt(map),
                                                                 uLength,
                                                                 false);
        if (!newObject)
        {
            SysPushErrorMem();
            ::munmap(map, uLength);
            return {};
        }

        return newObject;
    }

    AuSPtr<IProcessSectionMapView> ProcessSectionView::MapFileByPathEx(AuUInt viewOffset,
                                                                       const AuString &str,
                                                                       AuUInt64 uOffset,
                                                                       AuUInt uLength,
                                                                       Aurora::IO::FS::EFileOpenMode mode,
                                                                       Aurora::IO::FS::EFileAdvisoryLockLevel processLockLevel)
    {
        auto file = AuFS::OpenShared(str, mode, AuFS::EFileAdvisoryLockLevel::eNoSafety);
        return file ? this->MapFileByObjectEx(viewOffset, file, uOffset, uLength, mode, processLockLevel) : AuSPtr<IProcessSectionMapView> {};
    }

    AuSPtr<IProcessSectionMapView> ProcessSectionView::MapFileByObjectEx(AuUInt viewOffset,
                                                                         const AuSPtr<Aurora::IO::FS::IFileStream> &pStream,
                                                                         AuUInt64 uOffset,
                                                                         AuUInt uLength,
                                                                         Aurora::IO::FS::EFileOpenMode mode,
                                                                         Aurora::IO::FS::EFileAdvisoryLockLevel processLockLevel)
    {
        if (!pStream)
        {
            return {};
        }

        if (!uLength)
        {
            SysPushErrorArg("invalid uLength");
            return {};
        }

        auto ok = AuStaticCast<AuFS::PosixFileStream>(pStream);
        int fd = ::dup(ok->GetHandle());
        if (fd == -1)
        {
            SysPushErrorIO();
            return {};
        }

        // TODO (Reece): lock garbage

        int prot {};
        switch (mode)
        {
        case AuFS::EFileOpenMode::eRead:
        {
            prot = PROT_READ;
            break;
        }
        case AuFS::EFileOpenMode::eWrite:
        case AuFS::EFileOpenMode::eReadWrite:
        {
            prot = PROT_READ | PROT_WRITE;
            break;
        }
        default:
            SysPushErrorGeneric();
            return {};
        };

        auto map = ::mmap((void *)viewOffset, uLength, prot, MAP_SHARED | (viewOffset ? MAP_FIXED : 0), fd, uOffset);
        if (map == MAP_FAILED)
        {
            SysPushErrorIO();
            ::close(fd);
            return {};
        }

        auto newObject = AuMakeShared<ProcessSectionFileMapView>(AuUInt(map),
                                                                 uLength,
                                                                 true,
                                                                 fd);
        if (!newObject)
        {
            SysPushErrorMem();
            ::close(fd);
            ::munmap(map, uLength);
            return {};
        }

        return newObject;
    }

    AuSPtr<IProcessSectionMapView> ProcessSectionView::MapIPCMemoryEx(AuUInt viewOffset,
                                                                      const AuString &handleString,
                                                                      AuUInt64 uOffset,
                                                                      AuUInt uLength,
                                                                      Aurora::IO::FS::EFileOpenMode mode)
    {
        AuIPC::IPCHandle handle;

        if (!uLength)
        {
            SysPushErrorArg("invalid uLength");
            return {};
        }

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

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

        auto actualLength = val->token.word;
        auto path         = AuIPC::GetServerPath(val->token);

        if (actualLength < uOffset + uLength)
        {
            SysPushErrorIO("Out of range");
            return {};
        }

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

        // TODO (Reece): lock garbage ( ??? )

        int prot {};
        switch (mode)
        {
        case AuFS::EFileOpenMode::eRead:
        {
            prot = PROT_READ;
            break;
        }
        case AuFS::EFileOpenMode::eWrite:
        case AuFS::EFileOpenMode::eReadWrite:
        {
            prot = PROT_READ | PROT_WRITE;
            break;
        }
        default:
            SysPushErrorGeneric();
            return {};
        };

        auto map = ::mmap((void *)viewOffset, uLength, prot, MAP_SHARED | (viewOffset ? MAP_FIXED : 0), fd, uOffset);
        if (map == MAP_FAILED)
        {
            SysPushErrorIO();
            ::close(fd);
            return {};
        }

        auto newObject = AuMakeShared<ProcessSectionFileMapView>(AuUInt(map),
                                                                 uLength,
                                                                 true,
                                                                 fd);
        if (!newObject)
        {
            SysPushErrorMem();
            ::close(fd);
            ::munmap(map, val->token.word);
            return {};
        }

        return newObject;
    }

    AuList<AuPair<AuUInt, AuUInt>> ProcessSectionView::GetAllocations()
    {
        AU_LOCK_GUARD(this->spinlock);
        return allocations;
    }

    AUKN_SYM AuSPtr<IProcessSectionView> GetGlobalProcessSpace()
    {
        static ProcessSectionView gSingleton;
        return AuUnsafeRaiiToShared(&gSingleton);
    }
}