export function hsvToRgb(
  h: number,
  s: number,
  v: number
): [number, number, number] {
  const c = v * s;
  const x = c * (1 - Math.abs(((h * 6) % 2) - 1));
  const m = v - c;

  let r = 0,
    g = 0,
    b = 0;

  if (h < 1 / 6) {
    r = c;
    g = x;
    b = 0;
  } else if (h < 2 / 6) {
    r = x;
    g = c;
    b = 0;
  } else if (h < 3 / 6) {
    r = 0;
    g = c;
    b = x;
  } else if (h < 4 / 6) {
    r = 0;
    g = x;
    b = c;
  } else if (h < 5 / 6) {
    r = x;
    g = 0;
    b = c;
  } else {
    r = c;
    g = 0;
    b = x;
  }

  return [
    Math.round((r + m) * 255),
    Math.round((g + m) * 255),
    Math.round((b + m) * 255),
  ];
}

export function rainbowColor(value: number): [number, number, number] {
  const phase = (value / 255.0) * 6;
  const segment = Math.floor(phase);
  const remainder = phase - segment;
  const t = remainder;
  const q = 1 - t;

  switch (segment % 6) {
    case 0:
      return [255, Math.round(t * 255), 0];
    case 1:
      return [Math.round(q * 255), 255, 0];
    case 2:
      return [0, 255, Math.round(t * 255)];
    case 3:
      return [0, Math.round(q * 255), 255];
    case 4:
      return [Math.round(t * 255), 0, 255];
    case 5:
      return [255, 0, Math.round(q * 255)];
    default:
      return [255, 255, 255];
  }
}

export function thermalColor(value: number): [number, number, number] {
  const t = value / 255.0;
  if (t < 0.25) {
    return [0, 0, Math.round(t * 4 * 255)];
  } else if (t < 0.5) {
    return [0, Math.round((t - 0.25) * 4 * 255), 255];
  } else if (t < 0.75) {
    return [
      Math.round((t - 0.5) * 4 * 255),
      255,
      Math.round((0.75 - t) * 4 * 255),
    ];
  } else {
    return [255, 255, Math.round((t - 0.75) * 4 * 255)];
  }
}

export function neonColor(value: number): [number, number, number] {
  const t = value / 255.0;
  const intensity = Math.pow(Math.sin(t * Math.PI), 2);
  const glow = Math.pow(intensity, 0.5);
  return [
    Math.round(glow * 255),
    Math.round(intensity * 255),
    Math.round(Math.pow(intensity, 2) * 255),
  ];
}

export function sunsetColor(value: number): [number, number, number] {
  const t = value / 255.0;
  if (t < 0.3) {
    return [Math.round(t * 3.33 * 255), 0, Math.round(t * 1.67 * 255)];
  } else if (t < 0.6) {
    const p = (t - 0.3) / 0.3;
    return [255, Math.round(p * 100), Math.round(50 * (1 - p))];
  } else {
    const p = (t - 0.6) / 0.4;
    return [255, Math.round(100 + p * 155), Math.round(p * 100)];
  }
}

export function oceanColor(value: number): [number, number, number] {
  const t = value / 255.0;
  if (t < 0.25) {
    return [0, Math.round(t * 2 * 255), Math.round(100 + t * 4 * 155)];
  } else if (t < 0.5) {
    const p = (t - 0.25) / 0.25;
    return [0, Math.round(128 + p * 127), 255];
  } else if (t < 0.75) {
    const p = (t - 0.5) / 0.25;
    return [Math.round(p * 100), 255, Math.round(255 - p * 100)];
  } else {
    const p = (t - 0.75) / 0.25;
    return [Math.round(100 + p * 155), 255, Math.round(155 + p * 100)];
  }
}

export function forestColor(value: number): [number, number, number] {
  const t = value / 255.0;
  if (t < 0.3) {
    return [Math.round(t * 2 * 255), Math.round(50 + t * 3 * 205), 0];
  } else if (t < 0.6) {
    const p = (t - 0.3) / 0.3;
    return [Math.round(150 - p * 100), 255, Math.round(p * 100)];
  } else {
    const p = (t - 0.6) / 0.4;
    return [Math.round(50 + p * 100), Math.round(255 - p * 100), Math.round(100 + p * 55)];
  }
}

export function copperColor(value: number): [number, number, number] {
  const t = value / 255.0;
  if (t < 0.4) {
    return [Math.round(t * 2.5 * 255), Math.round(t * 1.5 * 255), Math.round(t * 0.5 * 255)];
  } else if (t < 0.7) {
    const p = (t - 0.4) / 0.3;
    return [255, Math.round(153 + p * 102), Math.round(51 + p * 51)];
  } else {
    const p = (t - 0.7) / 0.3;
    return [255, 255, Math.round(102 + p * 153)];
  }
}

export function ditheredColor(value: number): [number, number, number] {
  const levels = 4;
  const step = 255 / (levels - 1);
  const quantized = Math.round(value / step) * step;
  const error = value - quantized;
  const dither = (Math.random() - 0.5) * 32;
  const final = Math.max(0, Math.min(255, quantized + error + dither));
  return [final, final, final];
}

export function paletteColor(value: number): [number, number, number] {
  const palette = [
    [0, 0, 0],
    [87, 29, 149],
    [191, 82, 177],
    [249, 162, 162],
    [255, 241, 165],
    [134, 227, 206],
    [29, 161, 242],
    [255, 255, 255],
  ];
  const index = Math.floor((value / 255.0) * (palette.length - 1));
  return palette[index] as [number, number, number];
}

export function calculateColorDirect(
  absValue: number,
  renderMode: string
): [number, number, number] {
  switch (renderMode) {
    case 'classic':
      return [absValue, (absValue * 2) % 256, (absValue * 3) % 256];

    case 'grayscale':
      return [absValue, absValue, absValue];

    case 'red':
      return [absValue, 0, 0];

    case 'green':
      return [0, absValue, 0];

    case 'blue':
      return [0, 0, absValue];

    case 'forest':
      return forestColor(absValue);

    case 'copper':
      return copperColor(absValue);

    case 'rainbow':
      return rainbowColor(absValue);

    case 'thermal':
      return thermalColor(absValue);

    case 'neon':
      return neonColor(absValue);

    case 'sunset':
      return sunsetColor(absValue);

    case 'ocean':
      return oceanColor(absValue);

    case 'dithered':
      return ditheredColor(absValue);

    case 'palette':
      return paletteColor(absValue);

    default:
      return [absValue, absValue, absValue];
  }
}