/**
 * spk.ts — JPL SPK Type 2 binary ephemeris reader
 *
 * Reads de440s.bsp (NAIF DAF/SPK format) to extract planet positions as
 * barycentric rectangular coordinates in the J2000.0 equatorial frame.
 *
 * Supported: SPK Type 2 only (Chebyshev polynomials, position only).
 *            DE440s uses Type 2 for all bodies.
 *
 * Format reference:
 *   https://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/req/daf.html
 *   https://naif.jpl.nasa.gov/pub/naif/toolkit_docs/C/req/spk.html
 *
 * Data source: NASA/JPL public domain
 *   https://ssd.jpl.nasa.gov/ftp/eph/planets/bsp/de440s.bsp
 */
import { type Vec3 } from './chebyshev.js';
/**
 * NAIF integer body codes present in de440s.bsp.
 * Positions are barycentric (relative to Solar System Barycenter = 0)
 * except 301/399 which are relative to the Earth-Moon Barycenter (3).
 */
export declare const NAIF: {
    readonly SSB: 0;
    readonly Mercury: 1;
    readonly Venus: 2;
    readonly EMB: 3;
    readonly Mars: 4;
    readonly Jupiter: 5;
    readonly Saturn: 6;
    readonly Uranus: 7;
    readonly Neptune: 8;
    readonly Pluto: 9;
    readonly Sun: 10;
    readonly Moon: 301;
    readonly Earth: 399;
};
interface SpkSegment {
    target: number;
    center: number;
    frame: number;
    type: number;
    startET: number;
    endET: number;
    initAddr: number;
    finalAddr: number;
}
export declare class SpkFile {
    private readonly buf;
    private readonly littleEnd;
    private readonly segments;
    constructor(filePath: string);
    private detectEndian;
    private readF64;
    private readI32;
    /** Parse the linked list of summary records and build segment index. */
    private parseSegments;
    /**
     * Get the barycentric position (and velocity) of a body at ephemeris time `et`.
     *
     * @param target  NAIF body ID (see NAIF constants above)
     * @param center  NAIF center body ID (must match a segment in the file)
     * @param et      Ephemeris time in seconds from J2000.0 TDB
     * @returns Vec3  Position in km, velocity in km/s (J2000 equatorial rectangular)
     */
    getState(target: number, center: number, et: number): Vec3;
    /**
     * Return geocentric J2000 equatorial rectangular position (km) + velocity (km/s).
     *
     * Computes: body_SSB − Earth_SSB using the available SSB and EMB segments.
     *
     * For de440s.bsp:
     *   Earth_SSB = EMB_SSB + Earth_EMB   (body 3 + body 399)
     *   Moon_SSB  = EMB_SSB + Moon_EMB    (body 3 + body 301)
     */
    getGeocentric(naifBody: number, et: number): Vec3;
    /**
     * Return solar-system-barycentric J2000 equatorial rectangular position (km)
     * and velocity (km/s) for a body.
     *
     * Light-time and aberration corrections require the body and the observer to
     * be evaluated at *different* epochs, so callers need the barycentric states
     * separately rather than a pre-differenced geocentric vector.
     *
     * For de440s.bsp:
     *   Earth_SSB = EMB_SSB + Earth_EMB   (body 3 + body 399)
     *   Moon_SSB  = EMB_SSB + Moon_EMB    (body 3 + body 301)
     */
    getBarycentric(naifBody: number, et: number): Vec3;
    private findSegment;
    /**
     * Evaluate a Type 2 segment at ephemeris time `et`.
     *
     * SPK Type 2 segment layout (all doubles, 1-indexed addresses in file):
     *   [initAddr … finalAddr-4]  : N coefficient records, each RSIZE doubles
     *   [finalAddr-3]             : INIT    (segment start, ET seconds)
     *   [finalAddr-2]             : INTLEN  (sub-interval length, seconds)
     *   [finalAddr-1]             : RSIZE   (doubles per record)
     *   [finalAddr]               : N       (number of records)
     */
    private evalSegment;
    /** Expose segment list for diagnostics. */
    get segmentList(): readonly SpkSegment[];
}
/**
 * Load (and cache) a SpkFile from the given path.
 * Subsequent calls with the same path return the cached instance.
 */
export declare function loadSpk(filePath: string): SpkFile;
/** Reset the singleton cache (useful for testing). */
export declare function resetSpkCache(): void;
export {};