synapsecns/sanguine

import JSBI from 'jsbi'

import { BigintIsh, Rounding } from '../../constants'
import { Fraction } from './fraction'

const ONE_HUNDRED = new Fraction(JSBI.BigInt(100))

/**
 * Converts a fraction to a percent
 *
 * @param fraction the fraction to convert
 */
const toPercent = (fraction: Fraction): Percent =>
  new Percent(fraction.numerator, fraction.denominator)

export class Percent extends Fraction {
  /**
   * This boolean prevents a fraction from being interpreted as a Percent
   */
  public readonly isPercent: true = true

  add(other: Fraction | BigintIsh): Percent {
    return toPercent(super.add(other))
  }

  subtract(other: Fraction | BigintIsh): Percent {
    return toPercent(super.subtract(other))
  }

  multiply(other: Fraction | BigintIsh): Percent {
    return toPercent(super.multiply(other))
  }

  divide(other: Fraction | BigintIsh): Percent {
    return toPercent(super.divide(other))
  }

  public toSignificant(
    significantDigits: number = 5,
    format?: object,
    rounding?: Rounding
  ): string {
    return super
      .multiply(ONE_HUNDRED)
      .toSignificant(significantDigits, format, rounding)
  }

  public toFixed(
    decimalPlaces: number = 2,
    format?: object,
    rounding?: Rounding
  ): string {
    return super.multiply(ONE_HUNDRED).toFixed(decimalPlaces, format, rounding)
  }
}