// SOLARGOD physical-data registry — radii, axial tilts, rotation, colors, texture
// paths, moon orbits. Radii are the brief §8 values (JPL). Tilts/rotation are
// canonical IAU/JPL phys_par values; every textured body has a flat-color
// procedural fallback so a missing texture degrades gracefully (brief §7).
//
// Fields: name, type, radiusKm, axialTiltDeg, rotationHours (neg = retrograde),
// color (fallback), texture (under CONFIG.textures.path, or null), parent,
// ephemId (planet → ephem.js key) | moonOrbit {aKm, periodDays (neg = retro)} |
// elements (small-body epoch elements). rings when present.

export const BODIES = {
  sun: {
    name: 'Sun', type: 'star', radiusKm: 695700, axialTiltDeg: 7.25,
    rotationHours: 609.12, color: '#ffdd88', texture: '2k_sun.jpg', parent: null,
  },
  mercury: {
    name: 'Mercury', type: 'planet', radiusKm: 2439.7, axialTiltDeg: 0.034,
    rotationHours: 1407.6, color: '#9c8b7a', texture: '2k_mercury.jpg',
    parent: 'sun', ephemId: 'mercury',
  },
  venus: {
    name: 'Venus', type: 'planet', radiusKm: 6051.8, axialTiltDeg: 177.36,
    rotationHours: -5832.5, color: '#d9b382', texture: '2k_venus_surface.jpg',
    parent: 'sun', ephemId: 'venus',
  },
  earth: {
    name: 'Earth', type: 'planet', radiusKm: 6371.0, axialTiltDeg: 23.44,
    rotationHours: 23.9345, color: '#4b7bd4', texture: '2k_earth_daymap.jpg',
    parent: 'sun', ephemId: 'earth',
  },
  mars: {
    name: 'Mars', type: 'planet', radiusKm: 3389.5, axialTiltDeg: 25.19,
    rotationHours: 24.6229, color: '#c1440e', texture: '2k_mars.jpg',
    parent: 'sun', ephemId: 'mars',
  },
  jupiter: {
    name: 'Jupiter', type: 'planet', radiusKm: 69911, axialTiltDeg: 3.13,
    rotationHours: 9.925, color: '#d8ca9d', texture: '2k_jupiter.jpg',
    parent: 'sun', ephemId: 'jupiter',
  },
  saturn: {
    name: 'Saturn', type: 'planet', radiusKm: 58232, axialTiltDeg: 26.73,
    rotationHours: 10.656, color: '#e3d9b0', texture: '2k_saturn.jpg',
    parent: 'sun', ephemId: 'saturn',
    rings: { innerKm: 74500, outerKm: 140220, texture: '2k_saturn_ring_alpha.png' },
  },
  uranus: {
    name: 'Uranus', type: 'planet', radiusKm: 25362, axialTiltDeg: 97.77,
    rotationHours: -17.24, color: '#b2e5e8', texture: '2k_uranus.jpg',
    parent: 'sun', ephemId: 'uranus',
    rings: { innerKm: 41000, outerKm: 51000, texture: null, color: '#8fa3a8' },
  },
  neptune: {
    name: 'Neptune', type: 'planet', radiusKm: 24622, axialTiltDeg: 28.32,
    rotationHours: 16.11, color: '#3f66d9', texture: '2k_neptune.jpg',
    parent: 'sun', ephemId: 'neptune',
  },

  // ---- moons (circular orbits in parent's equatorial plane; a[km], period[d]) ----
  moon: { name: 'Moon', type: 'moon', radiusKm: 1737.4, axialTiltDeg: 6.68,
    rotationHours: 655.728, color: '#bcbcbc', texture: '2k_moon.jpg',
    parent: 'earth', moonOrbit: { aKm: 384400, periodDays: 27.322 } },

  phobos: { name: 'Phobos', type: 'moon', radiusKm: 11.27, color: '#8a7c6e',
    texture: null, parent: 'mars', moonOrbit: { aKm: 9378, periodDays: 0.319 } },
  deimos: { name: 'Deimos', type: 'moon', radiusKm: 6.2, color: '#9a8c7a',
    texture: null, parent: 'mars', moonOrbit: { aKm: 23459, periodDays: 1.262 } },

  io:       { name: 'Io', type: 'moon', radiusKm: 1821.6, color: '#e8d24b',
    texture: null, parent: 'jupiter', moonOrbit: { aKm: 421700, periodDays: 1.769 } },
  europa:   { name: 'Europa', type: 'moon', radiusKm: 1560.8, color: '#c9b79c',
    texture: null, parent: 'jupiter', moonOrbit: { aKm: 671034, periodDays: 3.551 } },
  ganymede: { name: 'Ganymede', type: 'moon', radiusKm: 2634.1, color: '#9b8e7e',
    texture: null, parent: 'jupiter', moonOrbit: { aKm: 1070412, periodDays: 7.155 } },
  callisto: { name: 'Callisto', type: 'moon', radiusKm: 2410.3, color: '#6b5f52',
    texture: null, parent: 'jupiter', moonOrbit: { aKm: 1882709, periodDays: 16.689 } },

  mimas:     { name: 'Mimas', type: 'moon', radiusKm: 198.2, color: '#c8c8c8',
    texture: null, parent: 'saturn', moonOrbit: { aKm: 185539, periodDays: 0.942 } },
  enceladus: { name: 'Enceladus', type: 'moon', radiusKm: 252.1, color: '#f0f0f0',
    texture: null, parent: 'saturn', moonOrbit: { aKm: 238042, periodDays: 1.370 } },
  tethys:    { name: 'Tethys', type: 'moon', radiusKm: 531.1, color: '#d6d6d6',
    texture: null, parent: 'saturn', moonOrbit: { aKm: 294672, periodDays: 1.888 } },
  dione:     { name: 'Dione', type: 'moon', radiusKm: 561.4, color: '#cfcfcf',
    texture: null, parent: 'saturn', moonOrbit: { aKm: 377415, periodDays: 2.737 } },
  rhea:      { name: 'Rhea', type: 'moon', radiusKm: 763.8, color: '#c4c4c4',
    texture: null, parent: 'saturn', moonOrbit: { aKm: 527068, periodDays: 4.518 } },
  titan:     { name: 'Titan', type: 'moon', radiusKm: 2574.7, color: '#d9a441',
    texture: null, parent: 'saturn', moonOrbit: { aKm: 1221870, periodDays: 15.945 } },
  iapetus:   { name: 'Iapetus', type: 'moon', radiusKm: 734.5, color: '#8a7a5e',
    texture: null, parent: 'saturn', moonOrbit: { aKm: 3560851, periodDays: 79.33 } },

  miranda: { name: 'Miranda', type: 'moon', radiusKm: 235.8, color: '#b8bcc0',
    texture: null, parent: 'uranus', moonOrbit: { aKm: 129900, periodDays: 1.413 } },
  ariel:   { name: 'Ariel', type: 'moon', radiusKm: 578.9, color: '#c6cacd',
    texture: null, parent: 'uranus', moonOrbit: { aKm: 190900, periodDays: 2.520 } },
  umbriel: { name: 'Umbriel', type: 'moon', radiusKm: 584.7, color: '#7f8488',
    texture: null, parent: 'uranus', moonOrbit: { aKm: 266000, periodDays: 4.144 } },
  titania: { name: 'Titania', type: 'moon', radiusKm: 788.4, color: '#b0b4b8',
    texture: null, parent: 'uranus', moonOrbit: { aKm: 436300, periodDays: 8.706 } },
  oberon:  { name: 'Oberon', type: 'moon', radiusKm: 761.4, color: '#9aa0a4',
    texture: null, parent: 'uranus', moonOrbit: { aKm: 583500, periodDays: 13.46 } },

  // Triton is retrograde — encoded via the negative-period convention (brief §8).
  triton: { name: 'Triton', type: 'moon', radiusKm: 1353.4, color: '#d6cfc4',
    texture: null, parent: 'neptune', moonOrbit: { aKm: 354759, periodDays: -5.877 } },

  // ---- Pluto system (small-body epoch elements; texture-less spheres) ----
  pluto: {
    name: 'Pluto', type: 'dwarf', radiusKm: 1188.3, axialTiltDeg: 122.53,
    rotationHours: -153.2928, color: '#d9c8a9', texture: null, parent: 'sun',
    // JPL SBDB J2000 osculating elements (epoch 2451545.0 TDB).
    elements: { a: 39.48168677, e: 0.24880766, i: 17.14175, om: 110.30347,
                w: 113.76329, ma: 14.86012204, epoch: 2451545.0 },
  },
  charon: { name: 'Charon', type: 'moon', radiusKm: 606.0, color: '#b3a894',
    texture: null, parent: 'pluto', moonOrbit: { aKm: 19591, periodDays: 6.387 } },
};

// Ordered planet ids (draw / menu order).
export const PLANET_ORDER = ['mercury', 'venus', 'earth', 'mars', 'jupiter', 'saturn', 'uranus', 'neptune'];
// Moons grouped by parent.
export function moonsOf(parentId) {
  return Object.entries(BODIES)
    .filter(([, b]) => b.type === 'moon' && b.parent === parentId)
    .map(([id]) => id);
}