/**
 * Convert a value in range [0, max] to an RGB color using a smooth perceptually uniform gradient
 * This gradient goes from dark purple/blue (low values) to bright yellow/orange (high values)
 * Similar to the plasma colormap - attractive and perceptually linear
 */
export function valueToColor(value: number, max: number): string {
  const t = value / max;
  
  // Smooth gradient from dark purple-blue to bright yellow-orange
  // Carefully tuned for perceptual uniformity and attractiveness
  let r: number, g: number, b: number;
  
  // Red channel: smooth increase
  r = Math.floor(13 + 242 * Math.pow(t, 0.5));
  
  // Green channel: gentle S-curve for smoothness
  g = Math.floor(8 + 247 * Math.pow(t, 1.5));
  
  // Blue channel: decrease from purple to yellow
  b = Math.floor(135 * Math.pow(1 - t, 2));
  
  // Clamp values to valid range
  r = Math.min(255, Math.max(0, r));
  g = Math.min(255, Math.max(0, g));
  b = Math.min(255, Math.max(0, b));
  
  return `rgb(${r}, ${g}, ${b})`;
}

/**
 * Get an array of colors for the color bar
 */
export function getColorGradient(steps: number): string[] {
  const colors: string[] = [];
  for (let i = 0; i < steps; i++) {
    colors.push(valueToColor(i, steps - 1));
  }
  return colors;
}