/**
*    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/pch.h"

#include "mongo/base/init.h"
#include "mongo/base/status.h"
#include "mongo/bson/util/builder.h"
#include "mongo/client/dbclientinterface.h"
#include "mongo/db/auth/action_set.h"
#include "mongo/db/auth/resource_pattern.h"
#include "mongo/db/auth/authorization_session.h"
#include "mongo/db/catalog/collection.h"
#include "mongo/db/cloner.h"
#include "mongo/db/commands.h"
#include "mongo/db/commands/copydb.h"
#include "mongo/db/commands/copydb_getnonce.h"
#include "mongo/db/commands/rename_collection.h"
#include "mongo/db/db.h"
#include "mongo/db/dbhelpers.h"
#include "mongo/db/index_builder.h"
#include "mongo/db/instance.h"
#include "mongo/db/jsobj.h"
#include "mongo/db/kill_current_op.h"
#include "mongo/db/namespace_string.h"
#include "mongo/db/repl/oplog.h"
#include "mongo/db/repl/oplogreader.h"
#include "mongo/db/pdfile.h"
#include "mongo/db/operation_context_impl.h"
#include "mongo/db/storage_options.h"

namespace mongo {

    /* Usage:
     * admindb.$cmd.findOne( { copydb: 1, fromhost: <connection string>, fromdb: <db>,
     *                         todb: <db>[, username: <username>, nonce: <nonce>, key: <key>] } );
     *
     * The "copydb" command is used to copy a database.  Note that this is a very broad definition.
     * This means that the "copydb" command can be used in the following ways:
     *
     * 1. To copy a database within a single node
     * 2. To copy a database within a sharded cluster, possibly to another shard
     * 3. To copy a database from one cluster to another
     *
     * Note that in all cases both the target and source database must be unsharded.
     *
     * The "copydb" command gets sent by the client or the mongos to the destination of the copy
     * operation.  The node, cluster, or shard that recieves the "copydb" command must then query
     * the source of the database to be copied for all the contents and metadata of the database.
     *
     *
     *
     * When used with auth, there are two different considerations.
     *
     * The first is authentication with the target.  The only entity that needs to authenticate with
     * the target node is the client, so authentication works there the same as it would with any
     * other command.
     *
     * The second is the authentication of the target with the source, which is needed because the
     * target must query the source directly for the contents of the database.  To do this, the
     * client must use the "copydbgetnonce" command, in which the target will get a nonce from the
     * source and send it back to the client.  The client can then hash its password with the nonce,
     * send it to the target when it runs the "copydb" command, which can then use that information
     * to authenticate with the source.
     *
     * NOTE: mongos doesn't know how to call or handle the "copydbgetnonce" command.  See
     * SERVER-6427.
     *
     * NOTE: Since internal cluster auth works differently, "copydb" currently doesn't work between
     * shards in a cluster when auth is enabled.  See SERVER-13080.
     */
    class CmdCopyDb : public Command {
    public:
        CmdCopyDb() : Command("copydb") { }

        virtual bool adminOnly() const {
            return true;
        }

        virtual bool slaveOk() const {
            return false;
        }

        virtual bool isWriteCommandForConfigServer() const { return false; }

        virtual Status checkAuthForCommand(ClientBasic* client,
                                           const std::string& dbname,
                                           const BSONObj& cmdObj) {
            return copydb::checkAuthForCopydbCommand(client, dbname, cmdObj);
        }

        virtual void help( stringstream &help ) const {
            help << "copy a database from another host to this host\n";
            help << "usage: {copydb: 1, fromhost: <connection string>, fromdb: <db>, todb: <db>"
                 << "[, slaveOk: <bool>, username: <username>, nonce: <nonce>, key: <key>]}";
        }

        virtual bool run(OperationContext* txn,
                         const string& dbname,
                         BSONObj& cmdObj,
                         int,
                         string& errmsg,
                         BSONObjBuilder& result,
                         bool fromRepl) {

            string fromhost = cmdObj.getStringField("fromhost");
            bool fromSelf = fromhost.empty();
            if ( fromSelf ) {
                /* copy from self */
                stringstream ss;
                ss << "localhost:" << serverGlobalParams.port;
                fromhost = ss.str();
            }

            CloneOptions cloneOptions;
            cloneOptions.fromDB = cmdObj.getStringField("fromdb");
            cloneOptions.logForRepl = !fromRepl;
            cloneOptions.slaveOk = cmdObj["slaveOk"].trueValue();
            cloneOptions.useReplAuth = false;
            cloneOptions.snapshot = true;
            cloneOptions.mayYield = true;
            cloneOptions.mayBeInterrupted = false;

            string todb = cmdObj.getStringField("todb");
            if ( fromhost.empty() || todb.empty() || cloneOptions.fromDB.empty() ) {
                errmsg = "parms missing - {copydb: 1, fromhost: <connection string>, "
                         "fromdb: <db>, todb: <db>}";
                return false;
            }

            // SERVER-4328 todo lock just the two db's not everything for the fromself case
            scoped_ptr<Lock::ScopedLock> lk( fromSelf ?
                                             static_cast<Lock::ScopedLock*>( new Lock::GlobalWrite() ) :
                                             static_cast<Lock::ScopedLock*>( new Lock::DBWrite( todb ) ) );

            Cloner cloner;
            string username = cmdObj.getStringField( "username" );
            string nonce = cmdObj.getStringField( "nonce" );
            string key = cmdObj.getStringField( "key" );
            if ( !username.empty() && !nonce.empty() && !key.empty() ) {
                uassert( 13008, "must call copydbgetnonce first", authConn_.get() );
                BSONObj ret;
                {
                    dbtemprelease t;
                    if ( !authConn_->runCommand( cloneOptions.fromDB,
                                                 BSON( "authenticate" << 1 << "user" << username
                                                       << "nonce" << nonce << "key" << key ), ret ) ) {
                        errmsg = "unable to login " + ret.toString();
                        return false;
                    }
                }
                cloner.setConnection( authConn_.release() );
            }
            else if (!fromSelf) {
                // If fromSelf leave the cloner's conn empty, it will use a DBDirectClient instead.

                ConnectionString cs = ConnectionString::parse(fromhost, errmsg);
                if (!cs.isValid()) {
                    return false;
                }
                DBClientBase* conn = cs.connect(errmsg);
                if (!conn) {
                    return false;
                }
                cloner.setConnection(conn);
            }
            Client::Context ctx(todb);
            return cloner.go(txn, ctx, fromhost, cloneOptions, NULL, errmsg );
        }

    } cmdCopyDB;

} // namespace mongo