import type { ArkmeConversationViewportSnapshot } from './conversation-memory-cache.js';
import { type ConversationViewportEntries } from '../conversation-viewport-state.js';
interface DurableViewports {
    read(account: string, surface: string, signal?: AbortSignal): Promise<unknown>;
    write(account: string, surface: string, entries: ConversationViewportEntries): Promise<unknown>;
}
/** Only geometry and stable row identities; no message bodies, credentials or server cursors. */
export declare class ConversationViewportPersistence {
    private readonly storage;
    private readonly durable?;
    private account;
    private key;
    private readonly values;
    private timer;
    private epoch;
    private hydration;
    private hydrationController;
    private readonly touched;
    private readonly durablePending;
    private readonly durableSaved;
    private durableFlight;
    constructor(storage?: () => Storage | undefined, durable?: DurableViewports | undefined);
    setScope(account: string | undefined, surface?: string): void;
    getViewport(source: string): ArkmeConversationViewportSnapshot | undefined;
    /** Host storage survives ephemeral Harness ports; hydrate before choosing the cache anchor. */
    hydrate(signal?: AbortSignal): Promise<void>;
    private rememberDurable;
    /** Single flight, latest snapshot per scope, no retry loop or per-scroll I/O. */
    settle(): Promise<void>;
    storeViewport(source: string, viewport: ArkmeConversationViewportSnapshot): void;
    flush: () => void;
}
export {};
//# sourceMappingURL=conversation-viewport-persistence.d.ts.map