import TimeAgo from 'javascript-time-ago'

// English.
import en from 'javascript-time-ago/locale/en'

TimeAgo.addDefaultLocale(en)

// Create formatter (English).
const timeAgo = new TimeAgo('en-US')

timeAgo.format(new Date())
// "just now"

timeAgo.format(Date.now() - 60 * 1000)
// "1 minute ago"

timeAgo.format(Date.now() - 2 * 60 * 60 * 1000)
// "2 hours ago"

timeAgo.format(Date.now() - 24 * 60 * 60 * 1000)
// "1 day ago"

import ru from 'javascript-time-ago/locale/ru'
import de from 'javascript-time-ago/locale/de'
import es from 'javascript-time-ago/locale/es'

TimeAgo.addLocale(ru)
TimeAgo.addLocale(de)
TimeAgo.addDefaultLocale(es)

import ru from 'javascript-time-ago/locale/ru'
import de from 'javascript-time-ago/locale/de'
import es from 'javascript-time-ago/locale/es'

TimeAgo.addLocale(ru)
TimeAgo.addLocale(de)
TimeAgo.addLocale(es)

TimeAgo.setDefaultLocale('es')

TimeAgo.addDefaultLocale(en)
TimeAgo.addLocale(de)

// "de" language will be used, as it's the first one to match.
new TimeAgo(['ru-RU', 'de-DE', 'en-US'])

import TimeAgo from 'javascript-time-ago'

// Russian.
import ru from 'javascript-time-ago/locale/ru'

TimeAgo.addDefaultLocale(ru)

const timeAgo = new TimeAgo('ru-RU')

timeAgo.format(new Date())
// "только что"

timeAgo.format(Date.now() - 60 * 1000)
// "1 минуту назад"

timeAgo.format(Date.now() - 2 * 60 * 60 * 1000)
// "2 часа назад"

timeAgo.format(Date.now() - 24 * 60 * 60 * 1000)
// "1 день назад"

timeAgo.format(Date.now(), 'round')
// 0 seconds ago → "just now"

timeAgo.format(Date.now() - 1 * 1000, 'round')
// 1 second ago → "1 second ago"

timeAgo.format(Date.now() - 29 * 1000, 'round')
// 29 seconds ago → "29 seconds ago"

timeAgo.format(Date.now() - 30 * 1000, 'round')
// 30 seconds ago → "1 minute ago"

timeAgo.format(Date.now() - 1.5 * 60 * 1000, 'round')
// 1.5 minutes ago → "2 minutes ago"

timeAgo.format(Date.now(), 'round-minute')
// 0 seconds ago → "just now"

timeAgo.format(Date.now() - 29 * 1000, 'round-minute')
// 29 seconds ago → "just now"

timeAgo.format(Date.now() - 30 * 1000, 'round-minute')
// 30 seconds ago → "1 minute ago"

// The rest is same as "round" style.

timeAgo.format(new Date(), 'mini')
// 0 seconds ago → "0s"

timeAgo.format(new Date() - 1 * 1000, 'mini')
// 1 second ago → "1s"

timeAgo.format(Date.now() - 2 * 60 * 1000, 'mini')
// 2 minutes ago → "2m"

timeAgo.format(Date.now() - 3 * 60 * 60 * 1000, 'mini')
// 3 hours ago → "3h"

timeAgo.format(Date.now() - 4 * 24 * 60 * 60 * 1000, 'mini')
// 4 days ago → "4d"

timeAgo.format(Date.now() - 23 * 24 * 60 * 60 * 1000, 'mini')
// 23 days ago → "23d"

timeAgo.format(Date.now() - 5 * 30 * 24 * 60 * 60 * 1000, 'mini')
// 5 months ago → "5mo"

timeAgo.format(Date.now() - 12 * 30 * 24 * 60 * 60 * 1000, 'mini')
// 1 year ago → "1yr"

timeAgo.format(new Date(), 'mini-now')
// 0 seconds ago → "now"

timeAgo.format(new Date() - 1 * 1000, 'mini-now')
// 1 second ago → "1s"

// The rest is same as "mini" style.

timeAgo.format(new Date(), 'mini-minute')
// 0 seconds ago → "0m"

timeAgo.format(new Date() - 29 * 1000, 'mini-minute')
// 29 seconds ago → "0m"

timeAgo.format(new Date() - 30 * 1000, 'mini-minute')
// 30 seconds ago → "1m"

// The rest is same as "mini" style.

timeAgo.format(new Date(), 'mini-minute-now')
// 0 seconds ago → "now"

timeAgo.format(new Date() - 29 * 1000, 'mini-minute-now')
// 29 seconds ago → "now"

timeAgo.format(new Date() - 30 * 1000, 'mini-minute-now')
// 30 seconds ago → "1m"

// The rest is same as "mini" style.

timeAgo.format(new Date(), 'twitter')
// 0 seconds ago → "0s"

timeAgo.format(new Date() - 1 * 1000, 'twitter')
// 1 second ago → "1s"

timeAgo.format(Date.now() - 2 * 60 * 1000, 'twitter')
// 2 minutes ago → "2m"

timeAgo.format(Date.now() - 3 * 60 * 60 * 1000, 'twitter')
// 3 hours ago → "3h"

timeAgo.format(Date.now() - 4 * 24 * 60 * 60 * 1000, 'twitter')
// More than 24 hours ago → `month/day` ("Mar 4")

timeAgo.format(Date.now() - 364 * 24 * 60 * 60 * 1000, 'twitter')
// Another year → `month/day/year` ("Mar 5, 2017")

timeAgo.format(new Date(), 'twitter-now')
// 0 seconds ago → "now"

timeAgo.format(new Date() - 1 * 1000, 'twitter-now')
// 1 second ago → "1s"

// The rest is same as "twitter" style.

timeAgo.format(new Date(), 'twitter-minute')
// 0 seconds ago → "0m"

timeAgo.format(new Date() - 29 * 1000, 'twitter-minute')
// 29 seconds ago → "0m"

timeAgo.format(new Date() - 30 * 1000, 'twitter-minute')
// 30 seconds ago → "1m"

// The rest is same as "twitter" style.

timeAgo.format(new Date(), 'twitter-minute-now')
// 0 seconds ago → "now"

timeAgo.format(new Date() - 29 * 1000, 'twitter-minute-now')
// 29 seconds ago → "now"

timeAgo.format(new Date() - 30 * 1000, 'twitter-minute-now')
// 30 seconds ago → "1m"

// The rest is same as "twitter" style.

timeAgo.format(new Date(), 'twitter-first-minute')
// 0 seconds ago → ""

timeAgo.format(new Date() - 29 * 1000, 'twitter-first-minute')
// 29 seconds ago → ""

timeAgo.format(new Date() - 30 * 1000, 'twitter-first-minute')
// 30 seconds ago → "1m"

// The rest is same as "twitter" style.

import TimeAgo from 'javascript-time-ago'
import en from 'javascript-time-ago/locale/en'
import { round } from 'javascript-time-ago/steps'

TimeAgo.addDefaultLocale(en)

const customLabels = {
  second: {
    past: {
      one: "{0} second earlier",
      other: "{0} seconds earlier"
    },
    future: {
      one: "{0} second later",
      other: "{0} seconds later"
    }
  },
  ...
}

TimeAgo.addLabels('en', 'custom', customLabels)

const timeAgo = new TimeAgo('en-US')

const customStyle = {
  steps: round,
  labels: 'custom'
}

timeAgo.format(Date.now() - 10 * 1000, customStyle)
// "10 seconds earlier"

[
  {
    // "second" labels are used for formatting the output.
    formatAs: 'second'
  },
  {
    // This step is effective starting from 59.5 seconds.
    minTime: 60,
    // "minute" labels are used for formatting the output.
    formatAs: 'minute'
  },
  {
    // This step is effective starting from 59.5 minutes.
    minTime: 60 * 60,
    // "hour" labels are used for formatting the output.
    formatAs: 'hour'
  },
  …
]

minTime(
  date: number,        // The date argument, converted to a timestamp.
  {
    future: boolean,   // Is `true` if `date > now`, or if `date === now`
                       // and `future: true` option was passed to `.format()`.

    getMinTimeForUnit(unit: string, prevUnit: string?): number?
                       // Returns the `minTime` for a transition from a
                       // previous step with `formatAs: prevUnit` to a
                       // step with `formatAs: unit`.
                       // For example, if the previous step is `formatAs: "second"`,
                       // then `getMinTimeForUnit('minute')` returns `59.5`
                       // when `round` is "round", and `60` when `round` is "floor".
                       // A developer can also explicitly specify the previous step's unit:
                       // `getMinTimeForUnit('minute', 'second')`.
                       // Returns `undefined` if `unit` or `prevUnit` are not supported.
  }
): number

format(
  date: number,        // The date argument, converted to a timestamp.
  locale: string,      // The currently selected language. Example: "en".
  {
    formatAs(unit: string, value: number): string,
                       // A function that could be used to format `value` in `unit`s.
                       // Example: `formatAs('second', -2)`
                       // Outputs: "2 seconds ago"

    now: number,       // The current date timestamp.

    future: boolean    // Is `true` if `date > now`, or if `date === now`
                       // and `future: true` option was passed to `.format()`.
  }
): string?

import { minute, hour, day, week, month, year } from 'javascript-time-ago/steps'

// In seconds
minute === 60
hour === 60 * 60
day === 24 * 60 * 60
...

const customSteps = [{
  minTime: 5 * minute,
  ...
}]

timeAgo.format(Date.now() + 5 * 60 * 1000)
// "in 5 minutes"

// Without `future: true` option:

timeAgo.format(Date.now())
// "just now"

timeAgo.format(Date.now() + 5 * 60 * 1000)
// "in 5 minutes"

// With `future: true` option:

timeAgo.format(Date.now(), { future: true })
// "in a moment"

timeAgo.format(Date.now() + 5 * 60 * 1000, { future: true })
// "in 5 minutes" (no difference)

timeAgo.format(60 * 1000, { now: 0 })
// "1 minute ago"

getTimeToNextUpdate(
  date: number, // The date argument, converted to a timestamp.
  {
    getTimeToNextUpdateForUnit(unit: string): number?,
                       // Returns "time to next update" for a time unit.
                       // This is what the library calls internally
                       // when `formatAs` is configured for a `step`.
                       // Example: `getTimeToNextUpdateForUnit('minute')`.
                       // Can return `undefined` in edge cases:
                       // for example, when `unit` is "now".

    now: number,       // The current date timestamp.

    future: boolean    // Is `true` if `date > now`, or if `date === now`
                       // and `future: true` option was passed to `.format()`.
  }
): number?

const timeAgo = new TimeAgo('en-US')

let updateTimer

function render() {
  // Format the date.
  const [formattedDate, timeToNextUpdate] = timeAgo.format(date, {
    getTimeToNextUpdate: true
  })
  // Update the label.
  setFormattedDate(formattedDate)
  // Schedule next render.
  // `timeToNextUpdate` may be `undefined`, so provide a sensible default.
  updateTimer = setTimeout(render, getSafeTimeoutInterval(timeToNextUpdate || 60 * 1000))
}

// `setTimeout()` has a bug where it fires immediately
// when the interval is longer than about `24.85` days.
// https://stackoverflow.com/questions/3468607/why-does-settimeout-break-for-large-millisecond-delay-values
const SET_TIMEOUT_MAX_SAFE_INTERVAL = 2147483647
function getSafeTimeoutInterval(interval) {
  return Math.min(interval, SET_TIMEOUT_MAX_SAFE_INTERVAL)
}

new TimeAgo('en-US', { polyfill: false })

import IntlPolyfill from 'intl'

const locales = ['en', 'ru', ...]

if (typeof Intl === 'object') {
  if (!Intl.DateTimeFormat || Intl.DateTimeFormat.supportedLocalesOf(locales).length !== locales.length) {
    Intl.DateTimeFormat = IntlPolyfill.DateTimeFormat
  }
} else {
  global.Intl = IntlPolyfill
}

async function initIntl() {
  if (typeof Intl === 'object') {
    return
  }
  await Promise.all([
    import('intl'),
    import('intl/locale-data/jsonp/en'),
    import('intl/locale-data/jsonp/ru'),
    ...
  ])
}

initIntl().then(...)