// https://gist.github.com/pjdietz/e0545332e2fc67a9a460

const pad = (n: number): string => String(n).padStart(2, '0')

const timezoneOffset = (offset: number): string => {
  if (offset === 0) {
    return 'Z'
  }

  const sign = offset > 0 ? '-' : '+'
  const absOffset = Math.abs(offset)
  return `${sign}${pad(Math.floor(absOffset / 60))}:${pad(absOffset % 60)}`
}

/**
 * Format a local date as an RFC 3339 date with timezone
 * @param d
 */
const rfc3339 = () => {
  const date = new Date()

  return (
    date.getFullYear() +
    '-' +
    pad(date.getMonth() + 1) +
    '-' +
    pad(date.getDate()) +
    'T' +
    pad(date.getHours()) +
    ':' +
    pad(date.getMinutes()) +
    ':' +
    pad(date.getSeconds()) +
    timezoneOffset(date.getTimezoneOffset())
  )
}

export default rfc3339