import type { ConversationLogEntryInput, ConversationLogMessage } from './types';
/**
 * 去重键：messageId 优先；无 messageId 时退到 (userId, timestamp, content)
 * 三元组——对齐 Character mergeMessages 的既有模式，使同一消息经监听与
 * 回填双通道到达时只落一条。
 */
export declare const messageKey: (message: ConversationLogEntryInput) => string;
/**
 * 单会话内存滚动日志。纪元（clearedAt）拦截清空之前的旧消息复活；
 * 无 timestamp 的实时消息以到达时钟与纪元比较，回填消息没有可靠到达
 * 时钟、由调用方直接丢弃（见 backfill）。
 */
export declare class ConversationMessageLog {
    private readonly capacity;
    private entries;
    private readonly knownKeys;
    private nextSeq;
    private clearedAt;
    constructor(capacity: number);
    append(items: readonly ConversationLogEntryInput[]): void;
    /** 清空条目并推进纪元；绑定与 seq 计数由使用方保留。 */
    clear(clearedAt?: number): void;
    lastN(count: number): ConversationLogMessage[];
    afterSeq(seq: number): ConversationLogMessage[];
    tailSeq(): number | null;
    private acceptedByEpoch;
}