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

    File: FS.NT.cpp
    Date: 2021-6-12
    Author: Reece
***/
#include <Source/RuntimeInternal.hpp>
#include "FS.hpp"
#include "FS.Generic.hpp"
#include <Source/Time/Time.hpp>

#if !defined(_AURUNTIME_GENERICFS)
namespace Aurora::IO::FS
{
    static const AuUInt64 kFileCopyBlock = 0xFFFF; // 64KiB

    bool _MkDir(const AuString &str)
    {
        return CreateDirectoryW(Locale::ConvertFromUTF8(str).c_str(), NULL);
    }

    AUKN_SYM bool FilesInDirectory(const AuString &string, AuList<AuString> &files)
    {
        if (IterateDirEntriesSTL(string, true, files))
        {
            return true;
        }

        // TODO: Implement a fast path for NT. std::filesystem is unusably slow 

        return false;
    }

    AUKN_SYM bool DirsInDirectory(const AuString &string, AuList<AuString> &dirs)
    {
        if (IterateDirEntriesSTL(string, false, dirs))
        {
            return true;
        }

        // TODO: Implement a fast path for NT. std::filesystem is unusably slow 

        return false;
    }

    AUKN_SYM bool WriteFile(const AuString &path, const void *data, AuUInt length)
    {
        bool status;
        size_t offset;
        HANDLE fileHandle;
        std::wstring win32Path;
        AuString pathNormalized;
        
        status         = false;
        pathNormalized = NormalizePathRet(path);
        win32Path      = Locale::ConvertFromUTF8(pathNormalized);

        if (!pathNormalized.empty())
        {
            return false;
        }

        if (!win32Path.empty())
        {
            return false;
        }

        CreateDirectories(pathNormalized, true);
        
        fileHandle = CreateFileW(win32Path.c_str(), GENERIC_WRITE, FILE_SHARE_WRITE, NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
        if (fileHandle == INVALID_HANDLE_VALUE)
        {
            SysPushErrorIO("Couldn't open handle: {}", path);
            return false;
        }

        offset = 0;
        while (length)
        {  
            DWORD written;

            int blockSize = AuMin(static_cast<AuUInt64>(kFileCopyBlock), static_cast<AuUInt64>(length));

            if (!::WriteFile(fileHandle, &reinterpret_cast<const char *>(data)[offset], blockSize, &written, NULL))
            {
                SysPushErrorIO();
                goto out;
            }
            
            if (written != blockSize)
            {
                SysPushErrorIO();
                goto out;
            }

            offset += written;
            length -= written;
        }
        
        status = true;

    out:
        AuWin32CloseHandle(fileHandle);
        return status;
    }

    AUKN_SYM bool ReadFile(const AuString &path, AuByteBuffer &buffer)
    {
        std::wstring win32Path;
        LARGE_INTEGER length;
        bool status;
        size_t offset;
        
        status    = false;
        offset    = 0;
        win32Path = Locale::ConvertFromUTF8(NormalizePathRet(path));

        if (!win32Path.empty())
        {
            return false;
        }

        auto fileHandle = CreateFileW(win32Path.c_str(), GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
        if (fileHandle == INVALID_HANDLE_VALUE)
        {
            SysPushErrorIO("Couldn't open handle: {}", path);
            return false;
        }

        if (!GetFileSizeEx(fileHandle, &length))
        {
            SysPushErrorIO();
            goto out;
        }

        if (!AuTryResize(buffer, length.QuadPart))
        {
            SysPushErrorMem();
            goto out;
        }

        while (length.QuadPart)
        {
            DWORD read;

            int blockSize = AuMin(static_cast<AuUInt64>(kFileCopyBlock), static_cast<AuUInt64>(length.QuadPart));

            if (!::ReadFile(fileHandle, &buffer[offset], blockSize, &read, NULL))
            {
                AuLogWarn("ReadFile IO Error: 0x{:x} {}", GetLastError(), path);
                SysPushErrorIO();
                goto out;
            }

            offset += read;
            length.QuadPart -= read;
        }
        
        status = true;

    out:
        AuWin32CloseHandle(fileHandle);
        return status;
    }

    AUKN_SYM bool FileExists(const AuString &path)
    {
        try
        {
            DWORD dwAttrib = GetFileAttributesW(Locale::ConvertFromUTF8(NormalizePathRet(path)).c_str());
            return ((dwAttrib != INVALID_FILE_ATTRIBUTES) &&
                   !(dwAttrib & FILE_ATTRIBUTE_DIRECTORY));
        }
        catch (...)
        {
            return false;
        }
    }

    AUKN_SYM bool DirExists(const AuString &path)
    {
        try
        {
            DWORD dwAttrib = GetFileAttributesW(Locale::ConvertFromUTF8(NormalizePathRet(path)).c_str());
            return ((dwAttrib != INVALID_FILE_ATTRIBUTES) &&
                    (dwAttrib & FILE_ATTRIBUTE_DIRECTORY));
        }
        catch (...)
        {
            return false;
        }
    }
    
    AUKN_SYM bool DirMk(const AuString &path)
    {
        try
        {
            return CreateDirectories(NormalizePathRet(path), false);
        }
        catch (...)
        {
            return false;
        }
    }

    AUKN_SYM bool Remove(const AuString &path)
    {
        try
        {
            return DeleteFileW(Locale::ConvertFromUTF8(NormalizePathRet(path)).c_str());
        }
        catch (...)
        {
            return false;
        }
    }

    AUKN_SYM bool Relink(const AuString &src, const AuString &dest)
    {
        try
        {
            return MoveFileW(Locale::ConvertFromUTF8(NormalizePathRet(src)).c_str(), Locale::ConvertFromUTF8(NormalizePathRet(dest)).c_str());
        }
        catch (...)
        {
            return false;
        }
    }

    AUKN_SYM bool Copy(const AuString &src, const AuString &dest)
    {
        try
        {
            return CopyFileW(Locale::ConvertFromUTF8(NormalizePathRet(src)).c_str(), Locale::ConvertFromUTF8(NormalizePathRet(dest)).c_str(), true);
        }
        catch (...)
        {
            return false;
        }
    }

    AUKN_SYM bool StatFile(const AuString &path, Stat &stat)
    {
        WIN32_FILE_ATTRIBUTE_DATA data;

        stat = {};

        if (!GetFileAttributesExW(Locale::ConvertFromUTF8(NormalizePathRet(path)).c_str(), GetFileExInfoStandard, &data))
        {
            stat.exists = false;
            return false;
        }

        stat.exists = true;
        stat.existsDirectory = data.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY;
        stat.existsFile      = !stat.existsDirectory;
        stat.symLink         = data.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT;

        stat.size = AuUInt64(data.nFileSizeLow) | (AuUInt64(data.nFileSizeHigh) << 32);

        stat.created  = Time::ConvertTimestamp(data.ftCreationTime);
        stat.modified = Time::ConvertTimestamp(data.ftLastWriteTime);
        stat.accessed = Time::ConvertTimestamp(data.ftLastAccessTime);
        return true;
    }
}
#endif