/**
 *    Copyright (C) 2014 MongoDB 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.
 */

#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kReplication

#include "mongo/platform/basic.h"

#include "mongo/db/repl/minvalid.h"

#include "mongo/db/concurrency/d_concurrency.h"
#include "mongo/db/concurrency/write_conflict_exception.h"
#include "mongo/db/dbhelpers.h"
#include "mongo/db/jsobj.h"
#include "mongo/db/operation_context.h"
#include "mongo/db/operation_context_impl.h"
#include "mongo/db/repl/oplog.h"
#include "mongo/util/assert_util.h"
#include "mongo/util/log.h"

namespace mongo {
namespace repl {

namespace {
    const char* initialSyncFlagString = "doingInitialSync";
    const BSONObj initialSyncFlag(BSON(initialSyncFlagString << true));
    const char* minvalidNS = "local.replset.minvalid";
} // namespace

    // Writes
    void clearInitialSyncFlag(OperationContext* txn) {
        MONGO_WRITE_CONFLICT_RETRY_LOOP_BEGIN {
            ScopedTransaction transaction(txn, MODE_IX);
            // TODO: Investigate correctness of taking MODE_IX for DB/Collection locks
            Lock::DBLock dblk(txn->lockState(), "local", MODE_X);
            Helpers::putSingleton(txn, minvalidNS, BSON("$unset" << initialSyncFlag));
        } MONGO_WRITE_CONFLICT_RETRY_LOOP_END(txn, "clearInitialSyncFlags", minvalidNS);

    }

    void setInitialSyncFlag(OperationContext* txn) {
        MONGO_WRITE_CONFLICT_RETRY_LOOP_BEGIN {
            ScopedTransaction transaction(txn, MODE_IX);
            Lock::DBLock dblk(txn->lockState(), "local", MODE_X);
            Helpers::putSingleton(txn, minvalidNS, BSON("$set" << initialSyncFlag));
        } MONGO_WRITE_CONFLICT_RETRY_LOOP_END(txn, "setInitialSyncFlags", minvalidNS);
    }

    void setMinValid(OperationContext* ctx, const OpTime& opTime) {
        MONGO_WRITE_CONFLICT_RETRY_LOOP_BEGIN {
            ScopedTransaction transaction(ctx, MODE_IX);
            Lock::DBLock dblk(ctx->lockState(), "local", MODE_X);
            Helpers::putSingleton(ctx,
                                  minvalidNS,
                                  BSON("$set" << BSON("ts" << opTime.getTimestamp() <<
                                                      "t" << opTime.getTerm())));

        } MONGO_WRITE_CONFLICT_RETRY_LOOP_END(ctx, "setMinValid", minvalidNS);
    }

    // Reads
    bool getInitialSyncFlag() {
        OperationContextImpl txn;
        MONGO_WRITE_CONFLICT_RETRY_LOOP_BEGIN {
            ScopedTransaction transaction(&txn, MODE_IS);
            Lock::DBLock dblk(txn.lockState(), "local", MODE_IS);
            Lock::CollectionLock lk(txn.lockState(), minvalidNS, MODE_IS);
            BSONObj mv;
            bool found = Helpers::getSingleton( &txn, minvalidNS, mv);

            if (found) {
                return mv[initialSyncFlagString].trueValue();
            }
            return false;
        } MONGO_WRITE_CONFLICT_RETRY_LOOP_END(&txn, "getInitialSyncFlags", minvalidNS);

        MONGO_UNREACHABLE;
    }

    OpTime getMinValid(OperationContext* txn) {
        MONGO_WRITE_CONFLICT_RETRY_LOOP_BEGIN {
            ScopedTransaction transaction(txn, MODE_IS);
            Lock::DBLock dblk(txn->lockState(), "local", MODE_IS);
            Lock::CollectionLock lk(txn->lockState(), minvalidNS, MODE_IS);
            BSONObj mv;
            bool found = Helpers::getSingleton(txn, minvalidNS, mv);
            if (found) {
                return extractOpTime(mv);
            }
            return OpTime();
        } MONGO_WRITE_CONFLICT_RETRY_LOOP_END(txn, "getMinValid", minvalidNS);
    }

}
}