import { type EventContextData, type EventProperties, utils } from '@farfetch/blackout-analytics';
import UniqueViewIdStorage from './uniqueViewIdStorage/UniqueViewIdStorage.js';
import type { ProcessedContextWeb } from './context.js';
/**
 * Helper class used by analytics to manage state that will
 * be added to the context of each event.
 */
export default class WebContextStateManager {
    uniqueViewIdStorage: UniqueViewIdStorage | null;
    previousUniqueViewId: ProcessedContextWeb[typeof utils.ANALYTICS_PREVIOUS_UNIQUE_VIEW_ID];
    currentUniqueViewId: ProcessedContextWeb[typeof utils.ANALYTICS_UNIQUE_VIEW_ID];
    lastFromParameter: ProcessedContextWeb[typeof utils.LAST_FROM_PARAMETER_KEY];
    lastPageLocation: string | undefined;
    /**
     * Initializes last page location with the document.referrer if it is
     * available.
     */
    constructor();
    /**
     * Updated last page location which will be used to calculate
     * the pageLocationReferrer context parameter. This is separate
     * from other state updates since it normally needs to be done after
     * the event is dispatched to analytics.
     */
    updateLastPageLocation(): void;
    /**
     * Gets the current snapshot of the managed state.
     *
     * @returns Current snapshot of the managed state.
     */
    getSnapshot(): {
        __uniqueViewId: string | null | undefined;
        __previousUniqueViewId: string | null | undefined;
        __lastFromParameter: string | null | undefined;
        pageLocationReferrer: string | undefined;
    };
    /**
     * Updates relevant state based on the passed page event that will be tracked.
     *
     * @param _event - Event name. Not used at the moment but added as it might be useful in the future.
     * @param properties - Properties of the event.
     * @param _eventContext - Event context. Not used at the moment but added as it might be useful in the future.
     */
    updateStateFromPageEvent(_event: string, properties?: EventProperties, _eventContext?: EventContextData): void;
    /**
     * Updates relevant state based on the track event that will be tracked.
     *
     * @param _event - Event name. Not used at the moment but added as it might be useful in the future.
     * @param properties - Properties of the event.
     * @param _eventContext - Event context. Not used at the moment but added as it might be useful in the future.
     */
    updateStateFromTrackEvent(_event: string, properties?: EventProperties | undefined, _eventContext?: EventContextData | undefined): void;
    /**
     * Initializes the uniqueViewId storage based on the referrer, in case the user
     * opens a link of the website in a new tab.
     * document.referrer will point to the original URL from the previous tab,
     * so we try to grab a uniqueViewId based on that to keep the user journey correct in terms of tracking.
     */
    initialize(): void;
}