/**
*  Copyright Mikael Högdahl - triyana@users.sourceforge.net
*
*  This source is distributed under the terms of the Q Public License version 1.0,
*  created by Trolltech (www.trolltech.com).
*/

#include "MHFileTransaction.h"
#include "MHFile.h"
#include "MHString.h"
#include "MHVector.h"
#include "MHUtil.h"

MHFileTransaction*  MHFileTransaction::aaTransaction = 0;



/**
*
*/
MHFileTransaction::MHFileTransaction () {
    aOrgFiles = new MHVector ();
    aNewFiles = new MHVector ();
}



/**
*
*/
MHFileTransaction::~MHFileTransaction () {
    aOrgFiles->Erase ();
    aNewFiles->Erase ();
    delete aOrgFiles;
    delete aNewFiles;
}



/**
*
*/
void MHFileTransaction::Begin () {
    if (MHFileTransaction::aaTransaction)
        throw "MHFileTransaction::Begin Exception, transaction already in progress";
    MHFileTransaction::aaTransaction = new MHFileTransaction ();
}



/**
*
*/
void MHFileTransaction::Check (bool rollback) {
    //  Rename all original files to backup names
    for (int f = 0; f < aOrgFiles->Size(); f++) {
        MHString* file1 = (MHString*) aOrgFiles->Get(f);
        MHString* file2 = (MHString*) aNewFiles->Get(f);
        MHString* file3 = new MHString(*file1);

        if (rollback) {
            *file3 += ".tmp.tmp";
            remove (file1->Get());
            rename (file3->Get(), file1->Get());
        }
        remove (file2->Get());
        delete file3;
    }
    aOrgFiles->Erase ();
    aNewFiles->Erase ();
}



/**
*
*/
bool MHFileTransaction::commit2 () {
    int f;

    //  Rename all original files to backup names
    for (f = 0; f < aOrgFiles->Size(); f++) {
        MHString*   file1  = (MHString*) aOrgFiles->Get(f);
        MHString*   file2  = new MHString(*file1);
        int         size1  = MHFile::Size (file1->Get());
        bool        exist1 = MHFile::Exist (file1->Get());

        #ifdef BUGG
            if (*file1 == "d") {
                printf ("Delete file d.tmp then press return to continue: ");
                getc(stdin);
            }
        #endif

        if (size1 >= 0) {
            *file2 += ".tmp.tmp";
            if (exist1 == true && rename (file1->Get(), file2->Get()) != 0) {
                Check (false);
                delete file2;
                return false;
            }
        }
        delete file2;
    }

    //  Rename all new file to original name
    for (f = 0; f < aOrgFiles->Size(); f++) {
        MHString*   file1   = (MHString*) aOrgFiles->Get(f);
        MHString*   file2   = (MHString*) aNewFiles->Get(f);

        if (rename (file2->Get(), file1->Get()) != 0) {
            Check (true);
            return false;
        }
    }

    //  Delete all tmp2 backup files
    for (f = 0; f < aOrgFiles->Size(); f++) {
        MHString* file1 = (MHString*) aOrgFiles->Get(f);

        *file1 += ".tmp.tmp";
        remove (file1->Get());
    }
    aOrgFiles->Erase ();
    aNewFiles->Erase ();
    return true;
}



/**
*
*/
bool MHFileTransaction::Commit () {
    if (!MHFileTransaction::aaTransaction)
        throw "MHFileTransaction::Commit Exception, no transaction in progress";
    bool ret = MHFileTransaction::aaTransaction->commit2();
    delete MHFileTransaction::aaTransaction;
    MHFileTransaction::aaTransaction = 0;
    return ret;
}



/**
*  Get filename. If transaction is under way return the tmp name otherwise return the original name
*/
void MHFileTransaction::getFileName (const char* orgName, MHString* newName, bool read) {
    MHString* org = new MHString (orgName);

    //  Check if file exist, if so return existing tmp name
    for (int f = 0; f < aOrgFiles->Size(); f++) {
        MHString* file = (MHString*) aOrgFiles->Get(f);

        if (*file == *org) {
            MHString* file2 = (MHString*) aNewFiles->Get(f);
            *newName = *file2;
            delete org;
            return;
        }
    }

    MHString* newTmp = new MHString (*org);
    *newTmp += ".tmp";

    if (read) {
        //  File name is wanted for read operation
        if (MHFile::Exist (newTmp->Get()))
            *newName = *newTmp;
        else
            *newName = orgName;
        delete org;
        delete newTmp;
    }
    else {
        //  File name is wanted for write operation
        aOrgFiles->Push (org);
        aNewFiles->Push (newTmp);
        *newName = *newTmp;
    }
}



/**
*
*/
void MHFileTransaction::rollback2 () {
    //  Remove all new files
    for (int f = 0; f < aOrgFiles->Size(); f++) {
        MHString* file1 = (MHString*) aOrgFiles->Get(f);
        MHString* file2 = new MHString(*file1);

        *file2 += ".tmp";
        if (MHFile::Size (file2->Get()) >= 0)
            remove (file2->Get());
        delete file2;
    }
    aOrgFiles->Erase ();
    aNewFiles->Erase ();
}



/**
*
*/
void MHFileTransaction::Rollback () {
    if (!MHFileTransaction::aaTransaction)
        throw "MHFileTransaction::Rollback Exception, no transaction in progress";
    MHFileTransaction::aaTransaction->rollback2();
    delete MHFileTransaction::aaTransaction;
    MHFileTransaction::aaTransaction = 0;
}