import { DominoValue } from '../game/DominoValue';
import { DOMINO_HEIGHT, DOMINO_WIDTH } from './trainLayout';
export type LineEndId = 'left' | 'right' | 'top' | 'bottom';
/** Degrees: 0 = +x (right), 90 = +y (down). */
export declare const LINE_END_ANGLES: Readonly<Record<LineEndId, number>>;
export interface LineArmData {
    readonly end: LineEndId;
    readonly dominoes: readonly DominoValue[];
}
export interface ComputeLineLayoutInput {
    readonly centerX: number;
    readonly centerY: number;
    /** Spinner or seed tile at the center (null = empty board). */
    readonly center: DominoValue | null;
    readonly arms: readonly LineArmData[];
    /**
     * Extra gap between the center tile's outer edge and the first arm tile.
     * Default 0 so arm tiles abut the spinner/seed.
     */
    readonly startGap?: number;
}
export interface LineArmPlacement {
    readonly end: LineEndId;
    /** Train origin — same as the center tile's center (DominoTrain leadGap reaches out). */
    readonly startX: number;
    readonly startY: number;
    readonly angle: number;
    /**
     * Distance from (startX, startY) to the center of the first arm tile so that
     * tile's near edge touches the center tile (plus optional startGap).
     */
    readonly leadGap: number;
    readonly dominoes: readonly DominoValue[];
    /** Hit-target / play-button anchor for this end. */
    readonly highlightX: number;
    readonly highlightY: number;
}
export interface LineLayoutResult {
    readonly centerX: number;
    readonly centerY: number;
    readonly center: DominoValue | null;
    readonly arms: readonly LineArmPlacement[];
    readonly width: number;
    readonly height: number;
}
/**
 * Half-extent of the center tile along a cardinal arm.
 * Spinner (double) is rendered upright; seed (non-double) is rendered on its side.
 */
export declare function centerHalfExtentAlongEnd(end: LineEndId, center: DominoValue | null): number;
/**
 * Place a classic spinner (or seed) at center with four cardinal arm starts.
 * Arm geometry is consumed by DominoTrain (same as Mexican Train spokes).
 *
 * Train origins sit at the center; `leadGap` is sized so the first arm tile
 * abuts the center tile (zero default gap).
 */
export declare function computeLineLayout(input: ComputeLineLayoutInput): LineLayoutResult;
export { DOMINO_WIDTH, DOMINO_HEIGHT };