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

    File: ProcessSectionView.NT.hpp
    Date: 2022-08-09
    Author: Reece
***/
#include <Source/RuntimeInternal.hpp>
#include "ProcessSectionView.NT.hpp"
#include "Process.hpp"
#include <Source/IO/FS/FileStream.NT.hpp>
#include "ProcessSectionFileMapView.NT.hpp"
#include <Source/IO/IPC/IPCHandle.hpp>
#include <Windows.h>

namespace Aurora::Process
{
    AuSPtr<IProcessSectionMapView> ProcessSectionView::Allocate(AuUInt length)
    {
        HANDLE hFileMap;

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

        hFileMap = ::CreateFileMappingA(INVALID_HANDLE_VALUE,
                                        nullptr,
                                        PAGE_READWRITE,
                                     #if defined(AURORA_IS_64BIT)
                                        AuBitsToHigher(length),
                                        AuBitsToLower(length),
                                     #else
                                        0,
                                        length,
                                     #endif
                                        nullptr);
        if ((hFileMap == INVALID_HANDLE_VALUE) ||
            (!hFileMap))
        {
            SysPushErrorIO("Couldn't create file map");
            return {};
        }

        auto map = ::MapViewOfFile(hFileMap,
                                   SECTION_MAP_READ | SECTION_MAP_WRITE,
                                   0,
                                   0,
                                   length);
        if (!map)
        {
            SysPushErrorIO("Couldn't create allocation of section");
            AuWin32CloseHandle(hFileMap);
            return {};
        }

        auto newObject = AuMakeShared<ProcessSectionFileMapView>(AuUInt(map), hFileMap);
        if (!newObject)
        {
            SysPushErrorMem();
            AuWin32CloseHandle(hFileMap);
            return {};
        }

        return newObject;
    }

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

    AuSPtr<IProcessSectionMapView> ProcessSectionView::MapFileByObject(const AuSPtr<AuFS::IFileStream> &stream,
                                                                       AuUInt64 offset,
                                                                       AuUInt length,
                                                                       AuFS::EFileOpenMode mode,
                                                                       AuFS::EFileAdvisoryLockLevel processLockLevel)
    {
        HANDLE hFileMap;
        ULONG desiredAccess {}, pageAttributes {};

        if (!stream)
        {
            return {};
        }

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

        auto ok = AuStaticCast<AuFS::WinFileStream>(stream);
        if (processLockLevel != AuFS::EFileAdvisoryLockLevel::eNoSafety)
        {
            DWORD dwFlags {};
            OVERLAPPED overlapped {};

            if (processLockLevel == AuFS::EFileAdvisoryLockLevel::eBlockReadWrite)
            {
                dwFlags |= LOCKFILE_EXCLUSIVE_LOCK;
            }

            dwFlags |= LOCKFILE_FAIL_IMMEDIATELY;

            overlapped.Offset = AuBitsToLower(offset);
            overlapped.OffsetHigh = AuBitsToHigher(offset);

            if (!::LockFileEx(ok->GetHandle(),
                              dwFlags,
                              0,
                              AuBitsToLower(length),
                              AuBitsToHigher(length),
                              &overlapped))
            {
                SysPushErrorIO("No Lock");
                return {};
            }
        }
   
        switch (mode)
        {
        case AuFS::EFileOpenMode::eRead:
        {
            desiredAccess  = SECTION_MAP_READ;
            pageAttributes = PAGE_READONLY;
            break;
        }
        case AuFS::EFileOpenMode::eWrite:
        case AuFS::EFileOpenMode::eReadWrite:
        {
            desiredAccess  = SECTION_MAP_READ | SECTION_MAP_WRITE;
            pageAttributes = PAGE_READWRITE;
            break;
        }
        default:
            SysPushErrorGeneric();
            return {};
        };

        hFileMap = ::CreateFileMappingA(ok->GetHandle(),
                                        nullptr,
                                        pageAttributes,
                                     #if defined(AURORA_IS_64BIT)
                                        AuBitsToHigher(length),
                                        AuBitsToLower(length),
                                     #else
                                        0,
                                        length,
                                     #endif
                                        nullptr);
        if ((hFileMap == INVALID_HANDLE_VALUE) ||
            (!hFileMap))
        {
            SysPushErrorIO("Couldn't create file map. Is the requeted access mode too high for the given object?");
            return {};
        }

        auto map = ::MapViewOfFile(hFileMap,
                                   desiredAccess,
                                   AuBitsToHigher(offset),
                                   AuBitsToLower(offset),
                                   length);
        if (!map)
        {
            SysPushErrorIO("Couldn't create map of section");
            AuWin32CloseHandle(hFileMap);
            return {};
        }

        auto newObject = AuMakeShared<ProcessSectionFileMapView>(AuUInt(map), hFileMap);
        if (!newObject)
        {
            SysPushErrorMem();
            AuWin32CloseHandle(hFileMap);
            ::UnmapViewOfFile(map);
            return {};
        }

        return newObject;
    }

    AuSPtr<IProcessSectionMapView> ProcessSectionView::MapIPCMemory(const AuString &handleString,
                                                                    AuUInt64 offset,
                                                                    AuUInt length,
                                                                    AuFS::EFileOpenMode mode)
    {
        AuIPC::IPCHandle handle;
        HANDLE hFileMap;
        ULONG desiredAccess {}, pageAttributes {};

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

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

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

        auto actualLength = token->token.word;
        auto path         = token->token.ToNTPath();

        if (actualLength < offset + length)
        {
            SysPushErrorIO("Out of range");
            return {};
        }

        switch (mode)
        {
        case AuFS::EFileOpenMode::eRead:
        {
            desiredAccess  = SECTION_MAP_READ;
            pageAttributes = PAGE_READONLY;
            break;
        }
        case AuFS::EFileOpenMode::eWrite:
        case AuFS::EFileOpenMode::eReadWrite:
        {
            desiredAccess  = SECTION_MAP_READ | SECTION_MAP_WRITE;
            pageAttributes = PAGE_READWRITE;
            break;
        }
        default:
            SysPushErrorGeneric();
            return {};
        };

        hFileMap = ::OpenFileMappingA(desiredAccess,
                                       FALSE,
                                       path.c_str());
        if ((hFileMap == INVALID_HANDLE_VALUE) ||
            (!hFileMap))
        {
            SysPushErrorIO("Couldn't create IPC map (handle: {})", handleString);
            return {};
        }

        auto map = ::MapViewOfFile(hFileMap,
                                   desiredAccess,
                                   AuBitsToHigher(offset),
                                   AuBitsToLower(offset),
                                   length);
        if (!map)
        {
            SysPushErrorIO("Couldn't create map of IPC section (handle: {})", handleString);
            AuWin32CloseHandle(hFileMap);
            return {};
        }

        auto newObject = AuMakeShared<ProcessSectionFileMapView>(AuUInt(map), hFileMap);
        if (!newObject)
        {
            SysPushErrorMem();
            AuWin32CloseHandle(hFileMap);
            ::UnmapViewOfFile(map);
            return {};
        }

        return newObject;
    }

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