import { type SbbElementType } from '@sbb-esta/lyne-elements/core.js';
import { SbbDialogElement } from '@sbb-esta/lyne-elements/dialog.pure.js';
import { type CSSResultGroup, type TemplateResult } from 'lit';
/**
 * A hidden easter egg dialog rendering a canvas-based Snake game.
 *
 * Use the inherited `open()`, `close()` methods and the `isOpen` getter
 * to control the dialog. The dialog can also be triggered from any element
 * via the inherited `trigger` id-reference attribute. Score is exposed via
 * the readonly `score` getter.
 */
export declare class SbbEasterEggElement extends SbbDialogElement {
    static readonly elementName: string;
    static elementDependencies: SbbElementType[];
    static styles: CSSResultGroup;
    /** The current game score (number of food items eaten in the current run). */
    get score(): number;
    /** The highest score reached in the current dialog session. Reset on close. */
    get highScore(): number;
    private accessor _score;
    private accessor _highScore;
    private accessor _gameOver;
    private accessor _started;
    private _canvas;
    private _ctx;
    private _cellSize;
    private _snake;
    private _currentDir;
    private _nextDir;
    private _snakePresence;
    private _foodPixel;
    private _currentFoodIndex;
    private _currentSpeed;
    private _timerId;
    private _touchStart;
    private _touchEnd;
    private _trainImages;
    private _foodImages;
    private _gridImage;
    private _imagesReady;
    private _openAbortController;
    private _prevTailCell;
    private _ateFoodThisFrame;
    private _needsFullRedraw;
    constructor();
    disconnectedCallback(): void;
    protected handleOpening(): void;
    protected handleClosing(): void;
    private _initGame;
    private _loadImage;
    private _attachInputListeners;
    private _onTouchStart;
    private _onTouchEnd;
    private _handleSwipe;
    private _onKeydown;
    private _applyDirectionKey;
    private _resetGame;
    private _handleStartClick;
    private _startGame;
    private _stopGame;
    private _setGameOver;
    private _focusStartButton;
    private _updatePoints;
    private _hasCollided;
    private _placeFood;
    private _isReverse;
    private _idx;
    private _getSecondSnakeCellDir;
    private _update;
    private _clearTile;
    private _draw;
    private _getTrainHeadDir;
    private _getTrainTailDir;
    protected render(): TemplateResult;
}
declare global {
    interface HTMLElementTagNameMap {
        'sbb-easter-egg': SbbEasterEggElement;
    }
}