import { SentMessageInfo } from 'nodemailer';
import { Subject } from 'rxjs';
import { KvDef } from '../core/kv';
import { EmailTmplConfigObject } from './email-tmpl.config';
import { EmailConfigObject } from './email.config';
import { MailInfo } from './email.interface';
import type { Attachment } from 'nodemailer/lib/mailer';
export declare class EmailHelper {
    static kvDef: KvDef;
    static tmplKvDef: KvDef;
    static getConfig(): Promise<EmailConfigObject>;
    static getTmplConfig(): Promise<EmailTmplConfigObject>;
    static sender: Subject<{
        email: MailInfo;
        cb: (info: MailInfo) => void;
    }>;
    private static sender$;
    private static transporter;
    private static emailTemplate;
    static init(): Promise<void>;
    static send(mailInfo: MailInfo): Promise<SentMessageInfo>;
    static sendByTemplateKey(key: string, { to, attachments, context }: {
        to: string[];
        attachments?: Attachment[];
        context?: Record<string, string>;
    }): Promise<MailInfo>;
    static sendByTemplate(template: string, data: any, { to, cc, bcc, subject, content, attachments }: MailInfo): Promise<any>;
}