/**
 *    Copyright (C) 2013 10gen Inc.
 *
 *    This program is free software: you can redistribute it and/or  modify
 *    it under the terms of the GNU Affero General Public License, version 3,
 *    as published by the Free Software Foundation.
 *
 *    This program 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 Affero General Public License for more details.
 *
 *    You should have received a copy of the GNU Affero General Public License
 *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 *    As a special exception, the copyright holders give permission to link the
 *    code of portions of this program with the OpenSSL library under certain
 *    conditions as described in each individual source file and distribute
 *    linked combinations including the program with the OpenSSL library. You
 *    must comply with the GNU Affero General Public License in all respects
 *    for all of the code used other than as permitted herein. If you modify
 *    file(s) with this exception, you may extend this exception to your
 *    version of the file(s), but you are not obligated to do so. If you do not
 *    wish to do so, delete this exception statement from your version. If you
 *    delete this exception statement from all source files in the program,
 *    then also delete it in the license file.
 */

#include <boost/scoped_ptr.hpp>
#include <boost/thread/thread.hpp>

#include "mongo/s/config.h"
#include "mongo/s/config_server_checker_service.h"
#include "mongo/util/concurrency/mutex.h"
#include "mongo/util/exit.h"

namespace mongo {

namespace {

// Thread that runs dbHash on config servers for checking data consistency.
boost::scoped_ptr<boost::thread> _checkerThread;

// Protects _isConsistentFromLastCheck.
mutex _isConsistentMutex("ConfigServerConsistent");
bool _isConsistentFromLastCheck = true;

void checkConfigConsistency() {
    while (!inShutdown()) {
        bool isConsistent = configServer.ok(true);

        {
            scoped_lock sl(_isConsistentMutex);
            _isConsistentFromLastCheck = isConsistent;
        }

        sleepsecs(60);
    }
}
}

bool isConfigServerConsistent() {
    scoped_lock sl(_isConsistentMutex);
    return _isConsistentFromLastCheck;
}

bool startConfigServerChecker() {
    if (_checkerThread == NULL) {
        _checkerThread.reset(new boost::thread(checkConfigConsistency));
    }

    return _checkerThread != NULL;
}
}
