/******************************************************************************
 *
 * Purpose:  Implementation of IO interface using Win32 API.
 *
 ******************************************************************************
 * Copyright (c) 2009
 * PCI Geomatics, 90 Allstate Parkway, Markham, Ontario, Canada.
 *
 * SPDX-License-Identifier: MIT
 ****************************************************************************/

#ifdef TRACK_DISKIO
// Keep these includes on top or else nccltype.h will conflict
// with type definitions from pcidsk_config.h.
#include "syslow/hdiskio.hh"
#include "syslow/htimer.hh"
#endif

#ifdef PCIMAJORVERSION
#include "syslow/winunicode.hh"
#endif

#include "pcidsk_io.h"
#include "pcidsk_exception.h"
#include <windows.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <io.h>
#include <fcntl.h>
#include <direct.h>

using namespace PCIDSK;

class Win32IOInterface final: public IOInterfaces
{
    void   *Open( const std::string& filename, const std::string& access ) const override;
    uint64  Seek( void *io_handle, uint64 offset, int whence ) const override;
    uint64  Tell( void *io_handle ) const override;
    uint64  Read( void *buffer, uint64 size, uint64 nmemb, void *io_handle ) const override;
    uint64  Write( const void *buffer, uint64 size, uint64 nmemb, void *io_handle ) const override;
    int     Eof( void *io_handle ) const override;
    int     Flush( void *io_handle ) const override;
    int     Close( void *io_handle ) const override;

    // Dummy implementation for now
    static const char     *LastError();
};

typedef struct {
    HANDLE hFile;
    uint64 offset;
} FileInfo;

/************************************************************************/
/*                       GetDefaultIOInterfaces()                       */
/************************************************************************/

const IOInterfaces *PCIDSK::GetDefaultIOInterfaces()
{
    static Win32IOInterface singleton_win32_interface;

    return &singleton_win32_interface;
}

/************************************************************************/
/*                                Open()                                */
/************************************************************************/

void *
Win32IOInterface::Open( const std::string& filename, const std::string& access ) const

{
#ifdef TRACK_DISKIO
    HTimer oTimer;
#endif

    DWORD dwDesiredAccess, dwCreationDisposition, dwFlagsAndAttributes;
    HANDLE hFile;

    if( strchr(access.c_str(),'+') != NULL || strchr(access.c_str(),'w') != 0 )
        dwDesiredAccess = GENERIC_READ | GENERIC_WRITE;
    else
        dwDesiredAccess = GENERIC_READ;

    if( strstr(access.c_str(), "w") != NULL )
        dwCreationDisposition = CREATE_ALWAYS;
    else
        dwCreationDisposition = OPEN_EXISTING;

    dwFlagsAndAttributes = (dwDesiredAccess == GENERIC_READ) ?
                FILE_ATTRIBUTE_READONLY : FILE_ATTRIBUTE_NORMAL;

#ifdef PCIMAJORVERSION
    std::string oLongFilename = WINExtendedLengthPath(filename);

    hFile = CreateFile((UTFTranscode) oLongFilename, dwDesiredAccess,
                       FILE_SHARE_READ | FILE_SHARE_WRITE,
                       NULL, dwCreationDisposition,  dwFlagsAndAttributes, NULL);
#else
    hFile = CreateFileA(filename.c_str(), dwDesiredAccess,
                        FILE_SHARE_READ | FILE_SHARE_WRITE,
                        NULL, dwCreationDisposition,  dwFlagsAndAttributes, NULL);
#endif

    if( hFile == INVALID_HANDLE_VALUE )
    {
        ThrowPCIDSKException( "Open(%s,%s) failed:\n%s",
                              filename.c_str(), access.c_str(), LastError() );
    }

    FileInfo *fi = new FileInfo();
    fi->hFile = hFile;
    fi->offset = 0;

#ifdef TRACK_DISKIO
    HDiskIO::Open(filename, fi, oTimer.GetTimeInSeconds());
#endif

    return fi;
}

/************************************************************************/
/*                                Seek()                                */
/************************************************************************/

uint64
Win32IOInterface::Seek( void *io_handle, uint64 offset, int whence ) const

{
#ifdef TRACK_DISKIO
    HTimer oTimer;
#endif

    FileInfo *fi = static_cast<FileInfo *>(io_handle);
    uint32       dwMoveMethod, dwMoveHigh;
    uint32       nMoveLow;
    LARGE_INTEGER li;

    // seeks that do nothing are still surprisingly expensive with MSVCRT.
    // try and short circuit if possible.
    if( whence == SEEK_SET && offset == fi->offset )
        return 0;

    switch(whence)
    {
        case SEEK_CUR:
            dwMoveMethod = FILE_CURRENT;
            break;
        case SEEK_END:
            dwMoveMethod = FILE_END;
            break;
        case SEEK_SET:
        default:
            dwMoveMethod = FILE_BEGIN;
            break;
    }

    li.QuadPart = offset;
    nMoveLow = li.LowPart;
    dwMoveHigh = li.HighPart;

    SetLastError( 0 );
    SetFilePointer(fi->hFile, (LONG) nMoveLow, (PLONG)&dwMoveHigh,
                   dwMoveMethod);

    if( GetLastError() != NO_ERROR )
    {
        ThrowPCIDSKException( "Seek(" PCIDSK_FRMT_UINT64 ",%d): %s (%d)",
                              offset, whence,
                              LastError(), GetLastError() );
        return (uint64)-1;
    }

/* -------------------------------------------------------------------- */
/*      Update our offset.                                              */
/* -------------------------------------------------------------------- */
    if( whence == SEEK_SET )
        fi->offset = offset;
    else if( whence == SEEK_END )
    {
        LARGE_INTEGER   li;

        li.HighPart = 0;
        li.LowPart = SetFilePointer( fi->hFile, 0, (PLONG) &(li.HighPart),
                                     FILE_CURRENT );
        fi->offset = li.QuadPart;
    }
    else if( whence == SEEK_CUR )
        fi->offset += offset;

#ifdef TRACK_DISKIO
    HDiskIO::Seek(io_handle, oTimer.GetTimeInSeconds());
#endif

    return 0;
}

/************************************************************************/
/*                                Tell()                                */
/************************************************************************/

uint64 Win32IOInterface::Tell( void *io_handle ) const

{
    FileInfo *fi = static_cast<FileInfo *>(io_handle);

    return fi->offset;
}

/************************************************************************/
/*                                Read()                                */
/************************************************************************/

uint64 Win32IOInterface::Read( void *buffer, uint64 size, uint64 nmemb,
                               void *io_handle ) const

{
#ifdef TRACK_DISKIO
    HTimer oTimer;
#endif

    FileInfo *fi = static_cast<FileInfo *>(io_handle);

    errno = 0;

    DWORD       dwSizeRead;
    size_t      result;

    if( !ReadFile(fi->hFile, buffer, (DWORD)(size*nmemb), &dwSizeRead, NULL) )
    {
        result = 0;
    }
    else if( size == 0 )
        result = 0;
    else
        result = (size_t) (dwSizeRead / size);

    if( errno != 0 && result == 0 && nmemb != 0 )
        ThrowPCIDSKException( "Read(" PCIDSK_FRMT_UINT64 "): %s",
                              size * nmemb,
                              LastError() );

    fi->offset += size*result;

#ifdef TRACK_DISKIO
    HDiskIO::Read(io_handle, (uint64) size * nmemb, oTimer.GetTimeInSeconds());
#endif

    return result;
}

/************************************************************************/
/*                               Write()                                */
/************************************************************************/

uint64 Win32IOInterface::Write( const void *buffer, uint64 size, uint64 nmemb,
                                void *io_handle ) const

{
#ifdef TRACK_DISKIO
    HTimer oTimer;
#endif

    FileInfo *fi = static_cast<FileInfo *>(io_handle);

    errno = 0;

    DWORD       dwSizeRead;
    size_t      result;

    if( !WriteFile(fi->hFile, buffer, (DWORD)(size*nmemb), &dwSizeRead, NULL) )
    {
        result = 0;
    }
    else if( size == 0 )
        result = 0;
    else
        result = (size_t) (dwSizeRead / size);

    if( errno != 0 && result == 0 && nmemb != 0 )
        ThrowPCIDSKException( "Write(" PCIDSK_FRMT_UINT64 "): %s",
                                   size * nmemb,
                                   LastError() );

    fi->offset += size*result;

#ifdef TRACK_DISKIO
    HDiskIO::Write(io_handle, (uint64) size * nmemb, oTimer.GetTimeInSeconds());
#endif

    return result;
}

/************************************************************************/
/*                                Eof()                                 */
/************************************************************************/

int Win32IOInterface::Eof( void *io_handle ) const

{
    uint64       nCur, nEnd;

    nCur = Tell( io_handle );
    Seek( io_handle, 0, SEEK_END );
    nEnd = Tell( io_handle );
    Seek( io_handle, nCur, SEEK_SET );

    return (nCur == nEnd);
}

/************************************************************************/
/*                               Flush()                                */
/************************************************************************/

int Win32IOInterface::Flush( void *io_handle ) const

{
    FileInfo *fi = static_cast<FileInfo *>(io_handle);

    FlushFileBuffers( fi->hFile );

    return 0;
}

/************************************************************************/
/*                               Close()                                */
/************************************************************************/

int Win32IOInterface::Close( void *io_handle ) const

{
#ifdef TRACK_DISKIO
    HTimer oTimer;
#endif

    FileInfo *fi = static_cast<FileInfo *>(io_handle);

    int result = CloseHandle( fi->hFile ) ? 0 : -1;
    delete fi;

#ifdef TRACK_DISKIO
    HDiskIO::Close(io_handle, oTimer.GetTimeInSeconds());
#endif

    return result;
}

/************************************************************************/
/*                             LastError()                              */
/*                                                                      */
/*      Return a string representation of the last error.               */
/************************************************************************/

/* static */
const char *Win32IOInterface::LastError()

{
    return "";
}
