import * as R from 'ramda';
import * as tinycolor from 'tinycolor2';

export const RED = `rgba(255, 0, 0, 0.1)`;

/**
 * Creates a new tiny-color instance.
 * https://github.com/bgrins/TinyColor
 */
export function create(value: any) {
  return tinycolor(value);
}
export const black = () => create('black');
export const white = () => create('white');



/**
 * Takes a value of various types and converts it into a color.
 */
export function format(value: string | number | boolean | undefined): string | undefined {
  if (value === undefined) { return undefined; }
  if (value === true) { return RED; }
  if (R.is(Number, value)) { return toGrayAlpha(value as number); }
  return value as string;
}


/**
 * A number between -1 (black) and 1 (white).
 */
export function toGrayAlpha(value: number): string {
  if (value < -1) { value = -1; }
  if (value > 1) { value = 1; }

  // Black.
  if (value < 0) {
    return `rgba(0, 0, 0, ${Math.abs(value)})`;
  }

  // White.
  if (value > 0) {
    return `rgba(255, 255, 255, ${value})`;
  }

  return `rgba(0, 0, 0, 0.0)`; // Transparent.
}



/**
 * A number between -1 (black) and 1 (white).
 */
export function toGrayHex(value: number): string {
  if (value < -1) { value = -1; }
  if (value > 1) { value = 1; }

  // Black.
  if (value < 0) {
    return white().darken(Math.abs(value) * 100).toHexString();
  }

  // White.
  if (value > 0) {
    return black().lighten(value * 100).toHexString();
  }

  return white().toHexString();
}