/**
*    Copyright (C) 2008 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 "mongo/db/commands.h"
#include "mongo/db/concurrency/d_concurrency.h"
#include "mongo/db/repl/bgsync.h"
#include "mongo/db/repl/master_slave.h"  // replSettings
#include "mongo/db/repl/replication_coordinator_global.h"
#include "mongo/db/operation_context.h"

namespace mongo {

    using std::string;
    using std::stringstream;

namespace repl {

    // operator requested resynchronization of replication (on a slave or secondary). {resync: 1}
    class CmdResync : public Command {
    public:
        virtual bool slaveOk() const {
            return true;
        }
        virtual bool adminOnly() const {
            return true;
        }
        virtual bool isWriteCommandForConfigServer() const { return true; }
        virtual void addRequiredPrivileges(const std::string& dbname,
                                           const BSONObj& cmdObj,
                                           std::vector<Privilege>* out) {
            ActionSet actions;
            actions.addAction(ActionType::resync);
            out->push_back(Privilege(ResourcePattern::forClusterResource(), actions));
        }

        void help(stringstream& h) const {
            h << "resync (from scratch) a stale slave or replica set secondary node.\n";
        }

        CmdResync() : Command("resync") { }
        virtual bool run(OperationContext* txn,
                         const string& dbname,
                         BSONObj& cmdObj,
                         int,
                         string& errmsg,
                         BSONObjBuilder& result,
                         bool fromRepl) {

            ScopedTransaction transaction(txn, MODE_X);
            Lock::GlobalWrite globalWriteLock(txn->lockState());

            ReplicationCoordinator* replCoord = getGlobalReplicationCoordinator();
            if (getGlobalReplicationCoordinator()->getSettings().usingReplSets()) {
                const MemberState memberState = replCoord->getMemberState();
                if (memberState.startup()) {
                    return appendCommandStatus(result, Status(ErrorCodes::NotYetInitialized,
                                                              "no replication yet active"));
                }
                if (memberState.primary() ||
                        !replCoord->setFollowerMode(MemberState::RS_STARTUP2)) {
                    return appendCommandStatus(result, Status(ErrorCodes::NotSecondary,
                                                              "primaries cannot resync"));
                }
                BackgroundSync::get()->setInitialSyncRequestedFlag(true);
                return true;
            }

            // below this comment pertains only to master/slave replication
            if ( cmdObj.getBoolField( "force" ) ) {
                if ( !waitForSyncToFinish(txn, errmsg ) )
                    return false;
                replAllDead = "resync forced";
            }
            // TODO(dannenberg) replAllDead is bad and should be removed when masterslave is removed
            if (!replAllDead) {
                errmsg = "not dead, no need to resync";
                return false;
            }
            if ( !waitForSyncToFinish(txn, errmsg ) )
                return false;

            ReplSource::forceResyncDead( txn, "client" );
            result.append( "info", "triggered resync for all sources" );

            return true;
        }

        bool waitForSyncToFinish(OperationContext* txn, string &errmsg) const {
            // Wait for slave thread to finish syncing, so sources will be be
            // reloaded with new saved state on next pass.
            Timer t;
            while ( 1 ) {
                if ( syncing == 0 || t.millis() > 30000 )
                    break;
                {
                    Lock::TempRelease t(txn->lockState());
                    relinquishSyncingSome = 1;
                    sleepmillis(1);
                }
            }
            if ( syncing ) {
                errmsg = "timeout waiting for sync() to finish";
                return false;
            }
            return true;
        }
    } cmdResync;
} // namespace repl
} // namespace mongo