/**
 * Page context, dwell time, and inter-event engagement for GA4-style metrics.
 */
import type { EventPayload } from "../types";
import type { VTiltConfig } from "../types";
export interface PageleaveCaptureFn {
    (name: string, payload: EventPayload, options?: {
        skip_engagement?: boolean;
        skip_session_refresh?: boolean;
    }): void;
}
/**
 * Tracks time on current URL and milliseconds since last capture for engagement_time_msec.
 */
export declare class PageLifecycleTracker {
    private _pageEnterPerf;
    /** Null until first engagement-consuming event; then wall clock for next delta */
    private _lastCapturePerf;
    private readonly _bootPerf;
    private _prevUrl;
    private _prevPathname;
    private _prevTitle;
    /** Dedupe pagehide + visibility hidden for the same page */
    private _leaveEmittedForPageKey;
    /**
     * Call after a $pageview is sent (initial or SPA) to reset dwell timer and snapshot.
     */
    onAfterPageview(): void;
    /**
     * Milliseconds since last capture (or since boot on the first event). Does not advance the clock.
     */
    peekEngagementSinceLastCaptureMs(): number;
    /** Call after a capture is enqueued so the next peek measures from this point. */
    commitCaptureClock(): void;
    private _pageKey;
    /** Call when the tab becomes visible again so a later hide can emit another $pageleave. */
    clearLeaveDedupe(): void;
    /**
     * Fire $pageleave if enabled and not already emitted for this page.
     */
    tryCapturePageleave(config: VTiltConfig, capture: PageleaveCaptureFn, reason: string, extraProps?: EventPayload): void;
}