let clientAssignedQues = [];

    LoanStates.find({ _id: { $in: req.user.client.loanStates } }).exec((err, loanStates) => {
        if (err)
            return res._end(new ServiceError(err.message, ServiceError.STATUS.INTERNAL_SERVER_ERROR, ServiceError.CODE.ERROR_MONGODB_FIND));

        loanStates.forEach(state => {
            state.questionnaires.forEach(ques => {
                clientAssignedQues.push(ques);
            });
        });

        clientAssignedQues = _.concat(clientAssignedQues, req.user.client.createCustomerQuestionnaires);
        clientAssignedQues = _.uniq(clientAssignedQues);
        // console.log(clientAssignedQues);

        QuestionnaireClient.find({ client: req.user.client._id }).sort('createdAt').exec((err, questionnaires) => {
            if (err)
                return res._end(new ServiceError(err.message, ServiceError.STATUS.INTERNAL_SERVER_ERROR, ServiceError.CODE.ERROR_MONGODB_FIND));

            let existedQuestionnaires = [];
            questionnaires.forEach((item) => {
                existedQuestionnaires.push(item.questionnaireCard.toString())
            });

            let unusedQues = _.difference(clientAssignedQues, existedQuestionnaires);

            console.log(unusedQues);

            QuestionnaireModel.find({ _id: { $in: unusedQues } }).populate('business questionnaireCard')
                .exec((err, questionnaires) => {
                    if (err)
                        return res._end(new ServiceError(err.message, ServiceError.STATUS.INTERNAL_SERVER_ERROR, ServiceError.CODE.ERROR_MONGODB_FIND));

                    res._end({ questionnaires: questionnaires });
                });
        });
    });