/**
 * @author Theodore Kruczek.
 * @license MIT
 * @copyright (c) 2022-2025 Theodore Kruczek Permission is
 * hereby granted, free of charge, to any person obtaining a copy of this
 * software and associated documentation files (the "Software"), to deal in the
 * Software without restriction, including without limitation the rights to use,
 * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do
 * so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

import {
  Celestial,
  Degrees,
  ecf2eci,
  EciVec3,
  GreenwichMeanSiderealTime,
  jday,
  Kilometers,
  LlaVec3,
  MILLISECONDS_TO_DAYS,
  Radians,
  rae2ecf,
  RaeVec3,
  Sgp4,
  SpaceObjectType,
  StarObjectParams,
} from '../main.js';
import { BaseObject } from './BaseObject.js';

export class Star extends BaseObject {
  ra: Radians;
  dec: Radians;
  bf: string;
  h: string;
  pname: string;
  vmag?: number;

  constructor(info: StarObjectParams) {
    super(info);
    this.type = SpaceObjectType.STAR;

    this.ra = info.ra;
    this.dec = info.dec;

    this.pname = info.pname ?? '';
    this.bf = info.bf ?? '';
    this.h = info.h ?? '';
    this.vmag = info.vmag;
  }

  eci(lla: LlaVec3 = { lat: <Degrees>180, lon: <Degrees>0, alt: <Kilometers>0 }, date: Date = new Date()): EciVec3 {
    const rae = this.rae(lla, date);
    const { gmst } = Star.calculateTimeVariables_(date);

    // Arbitrary distance to enable using ECI coordinates
    return ecf2eci(rae2ecf(rae, { lat: <Degrees>0, lon: <Degrees>0, alt: <Kilometers>0 }), gmst);
  }

  rae(
    lla: LlaVec3<Degrees, Kilometers> = { lat: <Degrees>180, lon: <Degrees>0, alt: <Kilometers>0 },
    date: Date = new Date(),
  ): RaeVec3 {
    const starPos = Celestial.azEl(date, lla.lat, lla.lon, this.ra, this.dec);

    return { az: starPos.az, el: starPos.el, rng: <Kilometers>250000 };
  }

  private static calculateTimeVariables_(date: Date): { gmst: GreenwichMeanSiderealTime; j: number } {
    const j =
      jday(
        date.getUTCFullYear(),
        date.getUTCMonth() + 1,
        date.getUTCDate(),
        date.getUTCHours(),
        date.getUTCMinutes(),
        date.getUTCSeconds(),
      ) +
      date.getUTCMilliseconds() * MILLISECONDS_TO_DAYS;
    const gmst = Sgp4.gstime(j);

    return { gmst, j };
  }
}