// @flow
import type { TimingFunction } from '../types/timingFunction'

const functionsMap = {
  back: 'cubic-bezier(0.175,  0.885, 0.320, 1.275)',
  cubic: 'cubic-bezier(0.215,  0.610, 0.355, 1.000)',
  circ: 'cubic-bezier(0.075,  0.820, 0.165, 1.000)',
  expo: 'cubic-bezier(0.190,  1.000, 0.220, 1.000)',
  quad: 'cubic-bezier(0.250,  0.460, 0.450, 0.940)',
  quart: 'cubic-bezier(0.165,  0.840, 0.440, 1.000)',
  quint: 'cubic-bezier(0.230,  1.000, 0.320, 1.000)',
  sine: 'cubic-bezier(0.390,  0.575, 0.565, 1.000)',
}

/**
 * String to represent common easing functions as demonstrated here: (github.com/jaukia/easie).
 *
 * @example
 * // Styles as object usage
 * const styles = {
 *   'transitionTimingFunction': easeOut('quad')
 * }
 *
 * // styled-components usage
 *  const div = styled.div`
 *   transitionTimingFunction: ${easeOut('quad')};
 * `
 *
 * // CSS as JS Output
 *
 * 'div': {
 *   'transitionTimingFunction': 'cubic-bezier(0.250,  0.460, 0.450, 0.940)',
 * }
 */
export default function easeOut(functionName: string): TimingFunction {
  return functionsMap[functionName.toLowerCase().trim()]
}