import { VecN } from '@holotope/core';
import { type ConstraintRow4 } from './constraint-row4.js';
import { type DistanceConstraintEvaluationN, type DistanceCoordinateEvaluationN } from './distance-coordinate-n.js';
import { RigidBody4 } from './rigid-body4.js';
/**
 * What every distance coordinate needs regardless of what it measures to:
 * an identity, one body, and the anchor on it. Variants extend this with a
 * second body, a fixed point, or a surface.
 */
export interface DistanceCoordinate4BaseOptions {
    /** Stable identity, so a solver can warm-start this coordinate. */
    readonly id: string;
    /** The body carrying the first anchor. */
    readonly bodyA: RigidBody4;
    /** Anchor position in `bodyA`'s local frame, not world space. */
    readonly localAnchorA: VecN | ArrayLike<number>;
    /** Coherent distance gradient used only when the two anchors coincide. */
    readonly directionHint?: VecN | ArrayLike<number>;
}
export type DistanceCoordinate4Options = DistanceCoordinate4BaseOptions & ({
    readonly bodyB: RigidBody4;
    readonly localAnchorB: VecN | ArrayLike<number>;
} | {
    readonly bodyB?: null;
    readonly worldAnchorB: VecN | ArrayLike<number>;
});
/** Reusable local/world anchor binding for one scalar distance coordinate. */
export declare class DistanceCoordinate4 {
    /** Stable identity, so a solver can warm-start this coordinate. */
    readonly id: string;
    /** The body carrying the first anchor. */
    readonly bodyA: RigidBody4;
    /** First anchor in `bodyA`'s local frame, not world space. */
    readonly localAnchorA: VecN;
    /**
     * The body carrying the second anchor, or null when it is pinned to the
     * world — which is what distinguishes a two-body joint from an anchor.
     */
    readonly bodyB: RigidBody4 | null;
    /**
     * The second anchor, read in `bodyB`'s local frame when there is one and in
     * world space otherwise. The frame follows `bodyB`, so the two cases cannot
     * be told apart from this field alone.
     */
    readonly anchorB: VecN;
    protected directionHint: VecN | undefined;
    constructor(options: DistanceCoordinate4Options);
    worldAnchorA(): VecN;
    worldAnchorB(): VecN;
    evaluation(): DistanceCoordinateEvaluationN;
    protected evaluateAnchors(anchorA: VecN, anchorB: VecN): DistanceCoordinateEvaluationN;
}
export interface DistanceJointConstraint4 extends ConstraintRow4 {
    readonly anchorA: VecN;
    readonly anchorB: VecN;
    readonly direction: VecN;
    readonly currentLength: number;
    readonly restLength: number;
    readonly positionError: number;
}
export type DistanceJoint4Options = DistanceCoordinate4Options & {
    /** Captures the construction-pose distance when omitted. */
    readonly restLength?: number;
};
/** Persistent local-anchor binding for a rigid R4 distance equality. */
export declare class DistanceJoint4 extends DistanceCoordinate4 {
    readonly restLength: number;
    constructor(options: DistanceJoint4Options);
    evaluation(): DistanceConstraintEvaluationN;
    constraint(): DistanceJointConstraint4;
}
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