/**
 *    Copyright (C) 2013 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.
 */

#include "mongo/platform/basic.h"

#include "mongo/s/commands/dbclient_multi_command.h"

#include "mongo/db/audit.h"
#include "mongo/db/client.h"
#include "mongo/db/dbmessage.h"
#include "mongo/db/wire_version.h"
#include "mongo/rpc/factory.h"
#include "mongo/rpc/request_builder_interface.h"
#include "mongo/s/client/shard_connection.h"
#include "mongo/s/write_ops/batched_command_request.h"
#include "mongo/stdx/memory.h"
#include "mongo/util/net/message.h"

namespace mongo {

using std::unique_ptr;
using std::deque;
using std::string;

namespace {

//
// For sanity checks of batch write operations
//

BatchedCommandRequest::BatchType getBatchWriteType(const BSONObj& cmdObj) {
    string cmdName = cmdObj.firstElement().fieldName();
    if (cmdName == "insert")
        return BatchedCommandRequest::BatchType_Insert;
    if (cmdName == "update")
        return BatchedCommandRequest::BatchType_Update;
    if (cmdName == "delete")
        return BatchedCommandRequest::BatchType_Delete;
    return BatchedCommandRequest::BatchType_Unknown;
}

bool isBatchWriteCommand(const BSONObj& cmdObj) {
    return getBatchWriteType(cmdObj) != BatchedCommandRequest::BatchType_Unknown;
}

bool hasBatchWriteFeature(DBClientBase* conn) {
    return conn->getMinWireVersion() <= BATCH_COMMANDS &&
        conn->getMaxWireVersion() >= BATCH_COMMANDS;
}
}

// THROWS
static void sayAsCmd(DBClientBase* conn, StringData dbName, const BSONObj& cmdObj) {
    auto requestBuilder =
        rpc::makeRequestBuilder(conn->getClientRPCProtocols(), conn->getServerRPCProtocols());
    BSONObj upconvertedCmd;
    BSONObj upconvertedMetadata;

    // Previous implementation had hardcoded flags of 0 - more specifically, writes
    // are never secondaryOk.
    std::tie(upconvertedCmd, upconvertedMetadata) =
        uassertStatusOK(rpc::upconvertRequestMetadata(cmdObj, 0));

    BSONObjBuilder metadataBob;
    metadataBob.appendElements(upconvertedMetadata);
    if (conn->getRequestMetadataWriter()) {
        conn->getRequestMetadataWriter()((haveClient() ? cc().getOperationContext() : nullptr),
                                         &metadataBob,
                                         conn->getServerAddress());
    }

    requestBuilder->setDatabase(dbName);
    requestBuilder->setCommandName(upconvertedCmd.firstElementFieldName());
    requestBuilder->setCommandArgs(upconvertedCmd);
    requestBuilder->setMetadata(metadataBob.done());

    // Send our command
    auto requestMsg = requestBuilder->done();
    conn->say(requestMsg);
}

// THROWS
static void recvAsCmd(DBClientBase* conn, Message* toRecv, BSONObj* result) {
    if (!conn->recv(*toRecv)) {
        // Confusingly, socket exceptions here are written to the log, not thrown.
        uasserted(17255,
                  "error receiving write command response, "
                  "possible socket exception - see logs");
    }

    auto reply = rpc::makeReply(toRecv);

    if (conn->getReplyMetadataReader()) {
        conn->getReplyMetadataReader()(reply->getMetadata(), conn->getServerAddress());
    }

    *result = reply->getCommandReply();
}

DBClientMultiCommand::DBClientMultiCommand(bool isConfig) : _isConfig(isConfig) {}

DBClientMultiCommand::~DBClientMultiCommand() {
    // Cleanup anything outstanding, do *not* return stuff to the pool, that might error
    for (deque<PendingCommand*>::iterator it = _pendingCommands.begin();
         it != _pendingCommands.end();
         ++it) {
        PendingCommand* command = *it;
        delete command;
    }

    _pendingCommands.clear();
}

void DBClientMultiCommand::addCommand(const ConnectionString& endpoint,
                                      StringData dbName,
                                      const BSONObj& request) {
    PendingCommand* command = new PendingCommand(endpoint, dbName, request);
    _pendingCommands.push_back(command);
}

void DBClientMultiCommand::sendAll() {
    for (deque<PendingCommand*>::iterator it = _pendingCommands.begin();
         it != _pendingCommands.end();
         ++it) {
        PendingCommand* command = *it;
        dassert(!command->conn);

        try {
            dassert(command->endpoint.type() == ConnectionString::MASTER ||
                    command->endpoint.type() == ConnectionString::CUSTOM);

            command->conn = stdx::make_unique<ShardConnection>(command->endpoint, "");

            DBClientBase* const actualConn =
                (!_isConfig ? command->conn->get() : command->conn->getRawConn());

            // Sanity check if we're sending a batch write that we're talking to a new-enough
            // server.
            massert(28563,
                    str::stream() << "cannot send batch write operation to server "
                                  << actualConn->toString(),
                    !isBatchWriteCommand(command->cmdObj) || hasBatchWriteFeature(actualConn));

            sayAsCmd(actualConn, command->dbName, command->cmdObj);
        } catch (const DBException& ex) {
            command->status = ex.toStatus();
            command->conn.reset();
        }
    }
}

int DBClientMultiCommand::numPending() const {
    return static_cast<int>(_pendingCommands.size());
}

Status DBClientMultiCommand::recvAny(ConnectionString* endpoint, BSONSerializable* response) {
    unique_ptr<PendingCommand> command(_pendingCommands.front());
    _pendingCommands.pop_front();

    *endpoint = command->endpoint;
    if (!command->status.isOK())
        return command->status;

    dassert(command->conn);

    try {
        // Holds the data and BSONObj for the command result
        Message toRecv;
        BSONObj result;

        DBClientBase* const actualConn =
            (!_isConfig ? command->conn->get() : command->conn->getRawConn());

        recvAsCmd(actualConn, &toRecv, &result);
        command->conn->done();
        command->conn.reset();

        string errMsg;
        if (!response->parseBSON(result, &errMsg) || !response->isValid(&errMsg)) {
            return Status(ErrorCodes::FailedToParse, errMsg);
        }
    } catch (const DBException& ex) {
        command->conn.reset();
        return ex.toStatus();
    }

    return Status::OK();
}

DBClientMultiCommand::PendingCommand::PendingCommand(const ConnectionString& endpoint,
                                                     StringData dbName,
                                                     const BSONObj& cmdObj)
    : endpoint(endpoint), dbName(dbName.toString()), cmdObj(cmdObj), status(Status::OK()) {}

DBClientMultiCommand::PendingCommand::~PendingCommand() = default;

}  // namespace mongo