// Hex → RGB
export function hexToRgb(hex) {
  const h = hex.replace('#', '');
  if (!/^[0-9a-fA-F]{3}$/.test(h) && !/^[0-9a-fA-F]{6}$/.test(h)) return null;
  const n = parseInt(h.length === 3
    ? h.split('').map(c => c + c).join('')
    : h, 16);
  return { r: (n >> 16) & 255, g: (n >> 8) & 255, b: n & 255 };
}

// RGB → Hex
export function rgbToHex({ r, g, b }) {
  return '#' + [r, g, b].map(v => v.toString(16).padStart(2, '0')).join('');
}

// RGB → HSL (h: 0-360, s: 0-100, l: 0-100)
export function rgbToHsl({ r, g, b }) {
  r /= 255; g /= 255; b /= 255;
  const max = Math.max(r, g, b), min = Math.min(r, g, b);
  let h = 0, s = 0;
  const l = (max + min) / 2;
  if (max === min) {
    // h and s remain 0 (achromatic)
  } else {
    const d = max - min;
    s = l > 0.5 ? d / (2 - max - min) : d / (max + min);
    switch (max) {
      case r: h = ((g - b) / d + (g < b ? 6 : 0)) / 6; break;
      case g: h = ((b - r) / d + 2) / 6; break;
      case b: h = ((r - g) / d + 4) / 6; break;
    }
  }
  return { h: Math.round(h * 360), s: Math.round(s * 100), l: Math.round(l * 100) };
}

// HSL → RGB
export function hslToRgb({ h, s, l }) {
  s /= 100; l /= 100;
  const k = n => (n + h / 30) % 12;
  const a = s * Math.min(l, 1 - l);
  const f = n => l - a * Math.max(-1, Math.min(k(n) - 3, Math.min(9 - k(n), 1)));
  return { r: Math.round(f(0) * 255), g: Math.round(f(8) * 255), b: Math.round(f(4) * 255) };
}

// HSL → Hex
export function hslToHex(hsl) {
  return rgbToHex(hslToRgb(hsl));
}

// Hex → HSL
export function hexToHsl(hex) {
  return rgbToHsl(hexToRgb(hex));
}

// Harmonien — Input: HSL, Output: Objekt mit Arrays von HSL-Objekten
export function getHarmonies(hsl) {
  const rotate = deg => ({ ...hsl, h: (hsl.h + deg + 360) % 360 });
  return {
    komplementaer:      [rotate(180)],
    analog:             [rotate(-30), rotate(30)],
    triade:             [rotate(120), rotate(240)],
    splitKomplementaer: [rotate(150), rotate(210)],
  };
}