/**
*    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.
*/

#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kCommand

#include "mongo/platform/basic.h"

#include <sstream>
#include <string>
#include <vector>

#include "mongo/db/auth/authorization_manager.h"
#include "mongo/db/auth/authorization_manager_global.h"
#include "mongo/db/auth/authorization_session.h"
#include "mongo/db/auth/privilege.h"
#include "mongo/db/auth/resource_pattern.h"
#include "mongo/db/catalog/apply_ops.h"
#include "mongo/db/catalog/document_validation.h"
#include "mongo/db/client.h"
#include "mongo/db/commands.h"
#include "mongo/db/commands/dbhash.h"
#include "mongo/db/db_raii.h"
#include "mongo/db/concurrency/write_conflict_exception.h"
#include "mongo/db/dbdirectclient.h"
#include "mongo/db/service_context.h"
#include "mongo/db/jsobj.h"
#include "mongo/db/matcher/matcher.h"
#include "mongo/db/operation_context_impl.h"
#include "mongo/db/op_observer.h"
#include "mongo/db/repl/oplog.h"
#include "mongo/db/repl/replication_coordinator_global.h"
#include "mongo/util/log.h"

namespace mongo {

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

    class ApplyOpsCmd : public Command {
    public:
        virtual bool slaveOk() const { return false; }
        virtual bool isWriteCommandForConfigServer() const { return true; }

        ApplyOpsCmd() : Command( "applyOps" ) {}
        virtual void help( stringstream &help ) const {
            help << "internal (sharding)\n{ applyOps : [ ] , preCondition : [ { ns : ... , q : ... , res : ... } ] }";
        }
        virtual void addRequiredPrivileges(const std::string& dbname,
                                           const BSONObj& cmdObj,
                                           std::vector<Privilege>* out) {
            // applyOps can do pretty much anything, so require all privileges.
            RoleGraph::generateUniversalPrivileges(out);
        }
        virtual bool run(OperationContext* txn,
                         const string& dbname,
                         BSONObj& cmdObj,
                         int,
                         string& errmsg,
                         BSONObjBuilder& result) {
            boost::optional<DisableDocumentValidation> maybeDisableValidation;
            if (shouldBypassDocumentValidationForCommand(cmdObj))
                maybeDisableValidation.emplace(txn);

            if ( cmdObj.firstElement().type() != Array ) {
                errmsg = "ops has to be an array";
                return false;
            }

            BSONObj ops = cmdObj.firstElement().Obj();

            {
                // check input
                BSONObjIterator i( ops );
                while ( i.more() ) {
                    BSONElement e = i.next();
                    if (!_checkOperation(e, errmsg)) {
                        return false;
                    }
                }
            }

            return appendCommandStatus(result, applyOps(txn, dbname, cmdObj, &result));
        }

    private:
        /**
         * Returns true if 'e' contains a valid operation.
         */
        bool _checkOperation(const BSONElement& e, string& errmsg) {
            if (e.type() != Object) {
                errmsg = str::stream() << "op not an object: " << e.fieldName();
                return false;
            }
            BSONObj obj = e.Obj();
            // op - operation type
            BSONElement opElement = obj.getField("op");
            if (opElement.eoo()) {
                errmsg = str::stream() << "op does not contain required \"op\" field: "
                                       << e.fieldName();
                return false;
            }
            if (opElement.type() != mongo::String) {
                errmsg = str::stream() << "\"op\" field is not a string: " << e.fieldName();
                return false;
            }
            // operation type -- see logOp() comments for types
            const char *opType = opElement.valuestrsafe();
            if (*opType == '\0') {
                errmsg = str::stream() << "\"op\" field value cannot be empty: " << e.fieldName();
                return false;
            }

            // ns - namespace
            // Only operations of type 'n' are allowed to have an empty namespace.
            BSONElement nsElement = obj.getField("ns");
            if (nsElement.eoo()) {
                errmsg = str::stream() << "op does not contain required \"ns\" field: "
                                       << e.fieldName();
                return false;
            }
            if (nsElement.type() != mongo::String) {
                errmsg = str::stream() << "\"ns\" field is not a string: " << e.fieldName();
                return false;
            }
            if (*opType != 'n' && nsElement.String().empty()) {
                errmsg = str::stream()
                    << "\"ns\" field value cannot be empty when op type is not 'n': "
                    << e.fieldName();
                return false;
            }
            return true;
        }
    } applyOpsCmd;

}