// SPDX-License-Identifier: LGPL-2.1-or-later

/****************************************************************************
 *   Copyright (c) 2019 Zheng Lei (realthunder) <realthunder.dev@gmail.com> *
 *                                                                          *
 *   This file is part of the FreeCAD CAx development system.               *
 *                                                                          *
 *   This library is free software; you can redistribute it and/or          *
 *   modify it under the terms of the GNU Library General Public            *
 *   License as published by the Free Software Foundation; either           *
 *   version 2 of the License, or (at your option) any later version.       *
 *                                                                          *
 *   This library  is distributed in the hope that it will be useful,       *
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of         *
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the          *
 *   GNU Library General Public License for more details.                   *
 *                                                                          *
 *   You should have received a copy of the GNU Library General Public      *
 *   License along with this library; see the file COPYING.LIB. If not,     *
 *   write to the Free Software Foundation, Inc., 59 Temple Place,          *
 *   Suite 330, Boston, MA  02111-1307, USA                                 *
 *                                                                          *
 ****************************************************************************/


#include <Base/Interpreter.h>

#include "AutoTransaction.h"
#include "Application.h"
#include "Document.h"
#include "Transactions.h"


FC_LOG_LEVEL_INIT("App", true, true)

using namespace App;

static int _TransactionLock;
static int _TransactionClosed;

AutoTransaction::AutoTransaction(const char* name, bool tmpName)
{
    auto& app = GetApplication();
    if (name && app._activeTransactionGuard >= 0) {
        if (!app.getActiveTransaction() || (!tmpName && app._activeTransactionTmpName)) {
            FC_LOG("auto transaction '" << name << "', " << tmpName);
            tid = app.setActiveTransaction(name);
            app._activeTransactionTmpName = tmpName;
        }
    }
    // We use negative transaction guard to disable auto transaction from here
    // and any stack below. This is to support user setting active transaction
    // before having any existing AutoTransaction on stack, or 'persist'
    // transaction that can out live AutoTransaction.
    if (app._activeTransactionGuard < 0) {
        --app._activeTransactionGuard;
    }
    else if (tid || app._activeTransactionGuard > 0) {
        ++app._activeTransactionGuard;
    }
    else if (app.getActiveTransaction()) {
        FC_LOG("auto transaction disabled because of '" << app._activeTransactionName << "'");
        --app._activeTransactionGuard;
    }
    else {
        ++app._activeTransactionGuard;
    }
    FC_TRACE("construct auto Transaction " << app._activeTransactionGuard);
}

AutoTransaction::~AutoTransaction()
{
    auto& app = GetApplication();
    FC_TRACE("before destruct auto Transaction " << app._activeTransactionGuard);
    if (app._activeTransactionGuard < 0) {
        ++app._activeTransactionGuard;
    }
    else if (!app._activeTransactionGuard) {
#ifdef FC_DEBUG
        FC_ERR("Transaction guard error");
#endif
    }
    else if (--app._activeTransactionGuard == 0) {
        try {
            // We don't call close() here, because close() only closes
            // transaction that we opened during construction time. However,
            // when _activeTransactionGuard reaches zero here, we are supposed
            // to close any transaction opened.
            app.closeActiveTransaction();
        }
        catch (Base::Exception& e) {
            e.reportException();
        }
        catch (...) {
        }
    }
    FC_TRACE("destruct auto Transaction " << app._activeTransactionGuard);
}

void AutoTransaction::close(bool abort)
{
    if (tid || abort) {
        GetApplication().closeActiveTransaction(abort, abort ? 0 : tid);
        tid = 0;
    }
}

void AutoTransaction::setEnable(bool enable)
{
    auto& app = GetApplication();
    if (!app._activeTransactionGuard) {
        return;
    }
    if ((enable && app._activeTransactionGuard > 0)
        || (!enable && app._activeTransactionGuard < 0)) {
        return;
    }
    app._activeTransactionGuard = -app._activeTransactionGuard;
    FC_TRACE("toggle auto Transaction " << app._activeTransactionGuard);
    if (!enable && app._activeTransactionTmpName) {
        bool close = true;
        for (auto& v : app.DocMap) {
            if (v.second->hasPendingTransaction()) {
                close = false;
                break;
            }
        }
        if (close) {
            app.closeActiveTransaction();
        }
    }
}

int Application::setActiveTransaction(const char* name, bool persist)
{

    if (!name || !name[0]) {
        name = "Command";
    }
    
    this->signalBeforeOpenTransaction(name);
    if (_activeTransactionGuard > 0 && getActiveTransaction()) {
        if (_activeTransactionTmpName) {
            FC_LOG("transaction rename to '" << name << "'");
            for (auto& v : DocMap) {
                v.second->renameTransaction(name, _activeTransactionID);
            }
        }
        else {
            if (persist) {
                AutoTransaction::setEnable(false);
            }
            return 0;
        }
    }
    else if (_TransactionLock) {
        if (FC_LOG_INSTANCE.isEnabled(FC_LOGLEVEL_LOG)) {
            FC_WARN("Transaction locked, ignore new transaction '" << name << "'");
        }
        return 0;
    }
    else {
        FC_LOG("set active transaction '" << name << "'");
        _activeTransactionID = 0;
        for (auto& v : DocMap) {
            v.second->_commitTransaction();
        }
        _activeTransactionID = Transaction::getNewID();
    }
    _activeTransactionTmpName = false;
    _activeTransactionName = name;
    if (persist) {
        AutoTransaction::setEnable(false);
    }
    return _activeTransactionID;
}

const char* Application::getActiveTransaction(int* id) const
{
    int tid = 0;
    if (Transaction::getLastID() == _activeTransactionID) {
        tid = _activeTransactionID;
    }
    if (id) {
        *id = tid;
    }
    return tid ? _activeTransactionName.c_str() : nullptr;
}

void Application::closeActiveTransaction(bool abort, int id)
{
    if (!id) {
        id = _activeTransactionID;
    }
    if (!id) {
        return;
    }

    if (_activeTransactionGuard > 0 && !abort) {
        FC_LOG("ignore close transaction");
        return;
    }

    if (_TransactionLock) {
        if (_TransactionClosed >= 0) {
            _TransactionLock = abort ? -1 : 1;
        }
        FC_LOG("pending " << (abort ? "abort" : "close") << " transaction");
        return;
    }

    FC_LOG("close transaction '" << _activeTransactionName << "' " << abort);
    _activeTransactionID = 0;

    TransactionSignaller signaller(abort, false);
    for (auto& v : DocMap) {
        if (v.second->getTransactionID(true) != id) {
            continue;
        }
        if (abort) {
            v.second->_abortTransaction();
        }
        else {
            v.second->_commitTransaction();
        }
    }
}

////////////////////////////////////////////////////////////////////////

TransactionLocker::TransactionLocker(bool lock)
    : active(lock)
{
    if (lock) {
        ++_TransactionLock;
    }
}

TransactionLocker::~TransactionLocker()
{
    if (active) {
        try {
            activate(false);
            return;
        }
        catch (Base::Exception& e) {
            e.reportException();
        }
        catch (Py::Exception&) {
            Base::PyException e;
            e.reportException();
        }
        catch (std::exception& e) {
            FC_ERR(e.what());
        }
        catch (...) {
        }
        FC_ERR("Exception when unlocking transaction");
    }
}

void TransactionLocker::activate(bool enable)
{
    if (active == enable) {
        return;
    }

    active = enable;
    if (active) {
        ++_TransactionLock;
        return;
    }

    if (--_TransactionLock != 0) {
        return;
    }

    if (_TransactionClosed) {
        bool abort = (_TransactionClosed < 0);
        _TransactionClosed = 0;
        GetApplication().closeActiveTransaction(abort);
    }
}

bool TransactionLocker::isLocked()
{
    return _TransactionLock > 0;
}