// **************************************************************************
// * This file is part of the FreeFileSync project. It is distributed under *
// * GNU General Public License: http://www.gnu.org/licenses/gpl.html       *
// * Copyright (C) 2008-2011 ZenJu (zhnmju123 AT gmx.de)                    *
// **************************************************************************

#include "shadow.h"
#include <algorithm>
#include <string>
#include <comdef.h>
#include <zen/com_ptr.h>
#include <zen/com_error.h>

#define WIN32_LEAN_AND_MEAN
#include "windows.h"

#ifdef USE_SHADOW_XP
#include "xp/inc/vss.h"
#include "xp/inc/vswriter.h"
#include "xp/inc/vsbackup.h"

#elif defined USE_SHADOW_2003
#include "Server 2003/inc/vss.h"
#include "Server 2003/inc/vswriter.h"
#include "Server 2003/inc/vsbackup.h"
#else
adapt!
#endif

using namespace zen;


namespace
{
inline
void copyString(const std::wstring& input, wchar_t* buffer, size_t bufferSize)
{
    if (bufferSize > 0)
    {
        //size_t endPos = input.copy(buffer, bufferSize - 1);
        //buffer[endPos] = 0;
        const size_t maxSize = std::min(input.length(), bufferSize - 1);
        std::copy(input.begin(), input.begin() + maxSize, buffer);
        buffer[maxSize] = 0;
    }
}

inline
void writeErrorMsg(const wchar_t* input, HRESULT hr, wchar_t* output, unsigned int outputLen)
{
    copyString(generateErrorMsg(input, hr), output, outputLen);
}
}


bool shadow::createShadowCopy(const wchar_t* volumeName,
                              wchar_t*		 shadowVolName,
                              unsigned int   shadowBufferLen,
                              ShadowHandle*	 handle,
                              wchar_t*		 errorMessage,
                              unsigned int	 errorBufferLen)
{
    //MessageBox(0, L"backup err", L"", 0); */
    *handle    = 0;
    HRESULT hr = NULL;

    ComPtr<IVssBackupComponents> backupComp;
    if (FAILED(hr = CreateVssBackupComponents(backupComp.init())))
    {
        if (hr == E_ACCESSDENIED)
            writeErrorMsg(L"The caller does not have sufficient backup privileges or is not an administrator.", hr, errorMessage, errorBufferLen);
        else
            writeErrorMsg(L"Error calling \"CreateVssBackupComponents\".", hr, errorMessage, errorBufferLen);
        return false;
    }

    if (FAILED(hr = backupComp->InitializeForBackup()))
    {
        writeErrorMsg(L"Error calling \"InitializeForBackup\".", hr, errorMessage, errorBufferLen);
        return false;
    }

    if (FAILED(hr = backupComp->SetBackupState(false, false, VSS_BT_FULL)))
    {
        writeErrorMsg(L"Error calling \"SetBackupState\".", hr, errorMessage, errorBufferLen);
        return false;
    }

    ComPtr<IVssAsync> vssWriters;
    if (FAILED(hr = backupComp->GatherWriterMetadata(vssWriters.init())))
    {
        //this can happen if XP-version of VSS is used on Windows Vista (which needs at least VSS-Server2003 build)
        writeErrorMsg(L"Error calling \"GatherWriterMetadata\".", hr, errorMessage, errorBufferLen);
        return false;
    }

    //wait for shadow copy writers to complete
    if (FAILED(hr = vssWriters->Wait()))
    {
        writeErrorMsg(L"Error calling \"vssWriters->Wait\".", hr, errorMessage, errorBufferLen);
        return false;
    }

    vssWriters->QueryStatus(&hr, NULL); //check if the async operation succeeded...
    if (FAILED(hr))
    {
        writeErrorMsg(L"Error calling \"vssWriters->QueryStatus\".", hr, errorMessage, errorBufferLen);
        return false;
    }

    VSS_ID snapshotSetId = {0};
    if (FAILED(hr = backupComp->StartSnapshotSet(&snapshotSetId)))
    {
        writeErrorMsg(L"Error calling \"StartSnapshotSet\".", hr, errorMessage, errorBufferLen);
        return false;
    }

    VSS_ID SnapShotId = {0};
    if (FAILED(hr = backupComp->AddToSnapshotSet(const_cast<wchar_t*>(volumeName), GUID_NULL, &SnapShotId)))
    {
        writeErrorMsg(L"Error calling \"AddToSnapshotSet\".", hr, errorMessage, errorBufferLen);
        return false;
    }

    ComPtr<IVssAsync> vssPrepare;
    if (FAILED(hr = backupComp->PrepareForBackup(vssPrepare.init())))
    {
        writeErrorMsg(L"Error calling \"PrepareForBackup\".", hr, errorMessage, errorBufferLen);
        return false;
    }

    if (FAILED(hr = vssPrepare->Wait()))
    {
        writeErrorMsg(L"Error calling \"vssPrepare->Wait\".", hr, errorMessage, errorBufferLen);
        return false;
    }

    vssPrepare->QueryStatus(&hr, NULL); //check if the async operation succeeded...
    if (FAILED(hr))
    {
        writeErrorMsg(L"Error calling \"vssPrepare->QueryStatus\".", hr, errorMessage, errorBufferLen);
        return false;
    }

    ComPtr<IVssAsync> vssDoShadowCopy;
    if (FAILED(hr = backupComp->DoSnapshotSet(vssDoShadowCopy.init())))
    {
        writeErrorMsg(L"Error calling \"DoSnapshotSet\".", hr, errorMessage, errorBufferLen);
        return false;
    }

    if (FAILED(hr = vssDoShadowCopy->Wait()))
    {
        writeErrorMsg(L"Error calling \"vssDoShadowCopy->Wait\".", hr, errorMessage, errorBufferLen);
        return false;
    }

    vssDoShadowCopy->QueryStatus(&hr, NULL); //check if the async operation succeeded...
    if (FAILED(hr))
    {
        writeErrorMsg(L"Error calling \"vssDoShadowCopy->QueryStatus\".", hr, errorMessage, errorBufferLen);
        return false;
    }

    VSS_SNAPSHOT_PROP props;
    if (FAILED(hr = backupComp->GetSnapshotProperties(SnapShotId, &props)))
    {
        writeErrorMsg(L"Error calling \"GetSnapshotProperties\".", hr, errorMessage, errorBufferLen);
        return false;
    }

    //finally: write volume name of newly created shadow copy
    copyString(props.m_pwszSnapshotDeviceObject, shadowVolName, shadowBufferLen);

    VssFreeSnapshotProperties(&props);

    *handle = backupComp.release();

    return true;
}


void shadow::releaseShadowCopy(ShadowHandle handle)
{
    if (handle)
        handle->Release();
}