import { Context } from 'koishi';
export interface MessageItem {
    content: string;
    timestamp: number;
    messageId?: string;
}
export declare class HistoryService {
    private ctx;
    private readonly MAX_HISTORY;
    constructor(ctx: Context);
    add(groupId: string, userId: string, content: string, messageId?: string): Promise<void>;
    get(groupId: string, userId: string, limit: number): Promise<MessageItem[]>;
    private cleanup;
}