import { Context } from 'koishi';
import { Config } from '../config';
export declare class MailerService {
    private ctx;
    private logger;
    private config;
    constructor(ctx: Context, config: Config);
    recordViolation(userId: string, groupId: string, words: string[], content: string): Promise<void>;
    private sendImmediate;
    sendSummaryReport(hours: number): Promise<{
        success: boolean;
        count?: number;
        receivers?: number;
        error?: string;
    }>;
    private cleanupOldRecords;
    private createTransporter;
}