export const darken = (color: string, gap = 100, newColorValue?: string): string => {
  const [colorValue, weight] = color.split('-');
  newColorValue = newColorValue || colorValue;
  if (weight === undefined) {
    return newColorValue;
  }
  return `${newColorValue}-${Math.min(parseInt(weight) + gap, 900)}`;
};

export const deriveColor = (color: string, gap = 100, dark: boolean, newColorValue?: string): string => {
  const [colorValue, weight] = color.split('-');
  newColorValue = newColorValue || colorValue;
  if (weight === undefined) {
    return newColorValue;
  }
  return `${newColorValue}-${parseInt(weight) + (dark ? -gap : gap)}`;
};

export const lighten = (color: string, gap: number, newColorValue?: string): string => {
  const [colorValue, weight] = color.split('-');
  newColorValue = newColorValue || colorValue;
  if (weight === undefined) {
    return newColorValue;
  }
  return `${newColorValue}-${Math.max(parseInt(weight) - gap, 0)}`;
};

// https://stackoverflow.com/questions/5623838/rgb-to-hex-and-hex-to-rgb
export const hexToRgb = (hex: string): { r: number; g: number; b: number } | null => {
  const shorthandRegex = /^#?([a-f\d])([a-f\d])([a-f\d])$/i;
  hex = hex.replace(shorthandRegex, function (_m, r, g, b) {
    return r + r + g + g + b + b;
  });

  const result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);
  return result
    ? {
        r: parseInt(result[1], 16),
        g: parseInt(result[2], 16),
        b: parseInt(result[3], 16),
      }
    : null;
};

// https://stackoverflow.com/questions/5623838/rgb-to-hex-and-hex-to-rgb
export const rgbToHex = (r: number, g: number, b: number): string => {
  return '#' + ((1 << 24) + (r << 16) + (g << 8) + b).toString(16).slice(1);
};

export const applyOpacity = (color: string, opacity: number | string): string => {
  if (color.startsWith('#')) {
    const rgb = hexToRgb(color);
    if (rgb !== null) {
      return `rgba(${rgb['r']},${rgb['g']},${rgb['b']},${opacity})`;
    } else {
      return color;
    }
  } else if (color.startsWith('rgb(')) {
    return color.replace('rgb(', 'rgba(').replace(/.$/, `,${opacity})`);
  } else if (color.startsWith('hsl(')) {
    return color.replace('hsl(', 'hsla(').replace(/.$/, `,${opacity})`);
  }
  return color;
};