import { AngularFireDatabase } from '@angular/fire/database';
import { Survey, SurveyDataInterface } from '../../classes';
import { Observable } from 'rxjs';
import { AuthService } from '../auth/auth.service';
import 'firebase/functions';
export declare type SurveyChange = {
    to: Partial<SurveyDataInterface>;
    from: Partial<SurveyDataInterface>;
    timestamp: number;
};
export declare class SurveyService {
    private db;
    private auth;
    constructor(db: AngularFireDatabase, auth: AuthService);
    private getSurveyDataFromChangeList;
    private eliminateDeadLeave;
    changes: SurveyChange[];
    data: Partial<SurveyDataInterface>;
    getLatest(survey_id: string): Observable<Partial<SurveyDataInterface>>;
    write(survey: Survey): Promise<string>;
}