antongolub/iso8601

// @flow

import type {IParser} from '../interface'
import {correctOffset, getSignFactor} from './util'

// 4.3 Date and time of day
/**
 * @ignore
 */
const parser: IParser = {
  // (YYYYMMDD | YYYYDDD | YYYYWwwD) T? HHMMSSTZ
  // The expression shall either be completely in basic format or completely in extended format
  pattern: [
    /^(\d{4}|[\-+]\d{6})(?:(0[1-9]|1[012])(0[1-9]|[12]\d|30|31)|(00[1-9]|0[1-9]\d|[12]\d\d|3[0-5]\d|36[0-6])|W(0[1-9]|[1-4]\d|5[0-3])(\d))T(?:(24)|(24)(00)|(24)(00)(00))(?:(Z)|([\-+])(\d{2})(\d{2})?)?$/,
    /^(\d{4}|[\-+]\d{6})-(?:(0[1-9]|1[012])-(0[1-9]|[12]\d|30|31)|(00[1-9]|0[1-9]\d|[12]\d\d|3[0-5]\d|36[0-6])|W(0[1-9]|[1-4]\d|5[0-3])-(\d))T(?:(24)|(24):(00)|(24):(00):(00))(?:(Z)|([\-+])(\d{2})(?::(\d{2}))?)?$/,
    /^(\d{4}|[\-+]\d{6})(?:(0[1-9]|1[012])(0[1-9]|[12]\d|30|31)|(00[1-9]|0[1-9]\d|[12]\d\d|3[0-5]\d|36[0-6])|W(0[1-9]|[1-4]\d|5[0-3])(\d))T(?:((?:[01]\d|2[0-3])(?:\.\d+)?)|([01]\d|2[0-3])([0-5]\d(?:\.\d+)?)|([01]\d|2[0-3])([0-5]\d)((?:[0-5]\d|60)(?:\.\d+)?))(?:(Z)|([\-+])(\d{2})(\d{2})?)?$/,
    /^(\d{4}|[\-+]\d{6})-(?:(0[1-9]|1[012])-(0[1-9]|[12]\d|30|31)|(00[1-9]|0[1-9]\d|[12]\d\d|3[0-5]\d|36[0-6])|W(0[1-9]|[1-4]\d|5[0-3])-(\d))T(?:((?:[01]\d|2[0-3])(?:\.\d+)?)|([01]\d|2[0-3]):([0-5]\d(?:\.\d+)?)|([01]\d|2[0-3]):([0-5]\d):((?:[0-5]\d|60)(?:\.\d+)?))(?:(Z)|([\-+])(\d{2})(?::(\d{2}))?)?$/
  ],
  builder (parts): Date {
    const year = +parts[1]
    const hours = +(parts[7] || parts[8] || parts[10])
    const minutes = +(parts[9] || parts[11] || 0) + 60 * (hours - (hours | 0))
    const seconds = +(parts[12] || 0) + 60 * (minutes - (minutes | 0))
    const milliseconds = Math.round(1000 * (seconds - (seconds | 0)))
    let month = 0
    let day

    switch (true) {
      case parts[2] !== undefined:
        month = +parts[2] - 1
        day = +parts[3]
        break

      case parts[4] !== undefined:
        day = +parts[4]
        break

      default:
        // NOTE 2.2.10 calendar week number
        // "first calendar week of a year is that one which includes the first Thursday of that year"
        day = +parts[6] + 7 * +parts[5] - 7 * +(new Date(year, 0, 1).getDay() < 5) - new Date(year, 0, 1).getDay() + 1
    }

    if (parts[13]) { // Zulu time
      return new Date(Date.UTC(year, month, day, hours, minutes, seconds, milliseconds))
    }

    const date = new Date(year, month, day, hours, minutes, seconds, milliseconds)
    const offset = getSignFactor(parts[14]) * (+parts[15] * 60 + (+parts[16] || 0))

    correctOffset(date, offset)
    return date
  }
}

export default parser