import { Duration, formatDuration, intervalToDuration } from 'date-fns';
import { DURATION_SECONDS } from '../../../session/constants';
import { getForcedEnglishTimeLocale } from '../timeLocaleMap';
import { getTimeLocaleDictionary } from '../shared';

/**
 * We decided against localizing the abbreviated durations like 1h, 1m, 1s as most apps don't.
 * This function just replaces any long form of "seconds?" to "s", "minutes?" to "m", etc.
 *
 * Note:
 *  We don't replace to 'months' as it would be the same as 'minutes', so this function shouldn't be used for a string containing months or longer units in it.
 *
 *  Date-fns also doesn't support the 'narrow' syntax for formatDistanceStrict and even if it did, minutes are abbreviated as 'min' in english.
 *
 * @param unlocalized the string containing the units to abbreviate
 * @returns the string with abbreviated units
 */
const unlocalizedDurationToAbbreviated = (unlocalized: string): string => {
  return unlocalized
    .replaceAll(' weeks', 'w')
    .replaceAll(' week', 'w')
    .replaceAll(' days', 'd')
    .replaceAll(' day', 'd')
    .replaceAll(' hours', 'h')
    .replaceAll(' hour', 'h')
    .replaceAll(' minutes', 'm')
    .replaceAll(' minute', 'm')
    .replaceAll(' seconds', 's')
    .replaceAll(' second', 's');
};

/**
 * date-fns `intervalToDuration` takes a duration in ms.
 * This is a simple wrapper to avoid duplicating this (and not forget about it).
 *
 * Note:
 *  - date-fns intervalToDuration returns 14d, so this forces it to return 2w which we want to use.
 *  - this will throw if the duration is > 4 weeks
 *
 * @param seconds the seconds to get the durations from
 * @returns a date-fns `Duration` type with the fields set
 */
const secondsToDuration = (seconds: number): Duration => {
  assertIsValidExpirationTimerSeconds(seconds);
  const duration = intervalToDuration({ start: 0, end: new Date(seconds * 1000) });

  if (!duration) {
    throw new Error('intervalToDuration failed to convert duration');
  }

  if (duration.days) {
    duration.weeks = Math.floor(duration.days / 7);
    duration.days %= 7;
  }

  return duration;
};

function assertIsValidExpirationTimerSeconds(timerSeconds: number) {
  if (timerSeconds > DURATION_SECONDS.WEEKS * 4) {
    throw new Error('assertIsValidExpirationTimer is not design to handle >4 weeks durations ');
  }
}

/**
 * Format an expiring/disappearing message timer to its abbreviated form.
 * Note: we don't localize this, and cannot have a value > 4 weeks
 *
 * @param timerSeconds the timer to format, in seconds
 * @returns '1h' for a duration of 3600s.
 */
export const formatAbbreviatedExpireTimer = (timerSeconds: number) => {
  assertIsValidExpirationTimerSeconds(timerSeconds);
  if (timerSeconds <= 0) {
    return window.i18n('off');
  }

  const duration = secondsToDuration(timerSeconds);

  const unlocalized = formatDuration(duration, {
    locale: getForcedEnglishTimeLocale(), // we want this forced to english
  });

  return unlocalizedDurationToAbbreviated(unlocalized);
};

/**
 * Format an expiring/disappearing message timer to its full localized form.
 * Note: throws if the value is > 4 weeks
 *
 * @param timerSeconds the timer to format, in seconds
 * @returns '1hour' for a duration of 3600s.
 */
export const formatNonAbbreviatedExpireTimer = (timerSeconds: number) => {
  assertIsValidExpirationTimerSeconds(timerSeconds);

  if (timerSeconds <= 0) {
    return window.i18n('off');
  }

  const duration = secondsToDuration(timerSeconds);

  return formatDuration(duration, {
    locale: getTimeLocaleDictionary(), // we want the full form  to be localized
  });
};

/**
 * Format an expiring/disappearing message timer to its abbreviated form.
 * Note: we don't localize this, and cannot have a value > 4 weeks
 *
 * @param timerSeconds the timer to format, in seconds
 * @returns '1h 1s' for a duration of 3601s.
 */
export const formatAbbreviatedExpireDoubleTimer = (timerSeconds: number) => {
  if (timerSeconds > DURATION_SECONDS.WEEKS * 4) {
    throw new Error(
      'formatAbbreviatedExpireDoubleTimer is not design to handle >4 weeks durations '
    );
  }
  if (timerSeconds <= 0) {
    return ['0s'];
  }

  const duration = secondsToDuration(timerSeconds);

  const format: Array<keyof Duration> = [];
  if (duration.months || duration.years) {
    throw new Error("we don't support years or months to be !== 0");
  }
  if (duration.weeks && format.length < 2) {
    format.push('weeks');
  }
  if (duration.days && format.length < 2) {
    format.push('days');
  }
  if (duration.hours && format.length < 2) {
    format.push('hours');
  }
  if (duration.minutes && format.length < 2) {
    format.push('minutes');
  }
  if (duration.seconds && format.length < 2) {
    format.push('seconds');
  }

  const unlocalized = formatDuration(duration, {
    locale: getForcedEnglishTimeLocale(), // we want this forced to english
    delimiter: '#',
    format,
  });
  return unlocalizedDurationToAbbreviated(unlocalized).split('#');
};