/**
 * Geometry snapshot for a scrollable chat viewport.
 */
export type ScrollGeometry = {
    scrollTop: number;
    scrollHeight: number;
    clientHeight: number;
};
/**
 * The decision a scroll event implies for follow-bottom state.
 */
export type FollowBottomScrollDecision = {
    nextFollowingBottom: boolean;
    shouldEndLayoutPreservation: boolean;
    shouldScheduleSnapToBottom: boolean;
};
export type DecideFollowBottomAfterScrollArgs = {
    atBottom: boolean;
    wasFollowingBottom: boolean;
    preservingLayout: boolean;
    userScrolling: boolean;
    previousScrollTop: number;
    scrollTop: number;
    followBottomThresholdPx: number;
};
export declare const getMaxScroll: (geometry: Pick<ScrollGeometry, "scrollHeight" | "clientHeight">) => number;
export declare const isViewportAtBottom: (geometry: ScrollGeometry, followBottomThresholdPx: number) => boolean;
export declare const didMoveAwayFromBottom: ({ previousScrollTop, scrollTop, followBottomThresholdPx }: Pick<DecideFollowBottomAfterScrollArgs, "previousScrollTop" | "scrollTop" | "followBottomThresholdPx">) => boolean;
export declare const decideFollowBottomAfterScroll: (args: DecideFollowBottomAfterScrollArgs) => FollowBottomScrollDecision;