import type { OwnershipScope, SessionRecord } from "./contracts.js";
/** Conversation thread lifecycle state. Archive is soft; deletion goes through persistence lifecycle. */
export type ConversationThreadState = "active" | "archived";
/** Well-known `SessionRecord.metadata` key marking conversation threads. */
export declare const CONVERSATION_METADATA_KEY = "prismConversation";
export declare const DEFAULT_MAX_CONVERSATION_CURSOR_BYTES: number;
export declare const HARD_MAX_CONVERSATION_CURSOR_BYTES: number;
export interface ConversationBranchRef {
    readonly leafId: string;
    readonly createdAt: string;
}
/**
 * Durable user-scoped conversation thread. A thread is an ownership-scoped session
 * branch plus metadata; content lives in session entries and the redacted event ledger.
 */
export interface ConversationThread extends OwnershipScope {
    readonly id: string;
    readonly title?: string;
    readonly state: ConversationThreadState;
    readonly createdAt: string;
    readonly updatedAt: string;
    /** Branch leaves recorded by the conversation service; the entry tree remains the content source of truth. */
    readonly branches: readonly ConversationBranchRef[];
    /** CAS write version (stored `SessionRecord.version`); undefined on legacy rows. */
    readonly version?: number;
    /** Host-supplied create metadata; never credentials or raw transcripts. */
    readonly metadata?: Readonly<Record<string, unknown>>;
}
/** Opaque thread-bound replay cursor; prevents replaying a cursor minted for another thread. */
export interface ConversationReplayCursor {
    readonly v: 1;
    readonly threadId: string;
    /** Opaque store keyset cursor; undefined means the start of the thread. */
    readonly cursor?: string;
}
export declare class ConversationError extends Error {
    readonly reason: string;
    readonly code = "ERR_PRISM_CONVERSATION";
    constructor(message: string, reason: string);
}
export declare function encodeConversationReplayCursor(cursor: ConversationReplayCursor): string;
export declare function decodeConversationReplayCursor(encoded: string, expectedThreadId: string, maxBytes?: number): ConversationReplayCursor;
/** Project a persisted session record into a conversation thread. Undefined for non-conversation sessions. */
export declare function conversationThreadFromRecord(record: SessionRecord): ConversationThread | undefined;
/** Serialize conversation marker metadata for `SessionRecord.metadata`. */
export declare function conversationMarkerMetadata(marker: {
    readonly title?: string;
    readonly state: ConversationThreadState;
    readonly branches?: readonly ConversationBranchRef[];
    readonly requestId?: string;
    readonly metadata?: Readonly<Record<string, unknown>>;
}): Readonly<Record<string, unknown>>;