/**
 * Keeps the conversation pinned to the newest message while the reader is at
 * the bottom, and gets out of the way the moment they scroll up.
 *
 * Two things follow from that rule. A reply arriving while the reader is up in
 * the history must not yank them down — it raises the "jump to latest" button
 * instead. And their own message always scrolls into view, because they just
 * pressed send and expect to see it.
 *
 * @implements {ReactiveController}
 */
export class ScrollController implements ReactiveController {
    /**
     * @param {LitElement & { messages: Message[] }} host
     * @param {{ behavior: () => 'smooth' | 'instant' }} options
     */
    constructor(host: LitElement & {
        messages: Message[];
    }, { behavior }: {
        behavior: () => "smooth" | "instant";
    });
    /** @returns {boolean} True when newer content arrived while scrolled up. */
    get hasUnseen(): boolean;
    /** @returns {boolean} */
    get atBottom(): boolean;
    hostDisconnected(): void;
    /**
     * Runs before the render, so a decision made here lands in the same frame.
     * Whether the conversation grew is knowable from the array alone; only the
     * scrolling itself has to wait for the DOM.
     */
    hostUpdate(): void;
    hostUpdated(): void;
    /**
     * @param {{ smooth?: boolean }} [options] Defaults to the theme's setting.
     */
    scrollToBottom({ smooth }?: {
        smooth?: boolean;
    }): void;
    #private;
}
import type { ReactiveController } from 'lit';
import type { LitElement } from 'lit';
import type { Message } from '../types.js';