/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

var EXPORTED_SYMBOLS = ["PluralStringFormatter", "makeFriendlyDateAgo"];

var { PluralForm } = ChromeUtils.importESModule(
  "resource://gre/modules/PluralForm.sys.mjs"
);

function PluralStringFormatter(aBundleURI) {
  this._bundle = Services.strings.createBundle(aBundleURI);
}

PluralStringFormatter.prototype = {
  get(aStringName, aReplacements, aPluralCount) {
    let str = this._bundle.GetStringFromName(aStringName);
    if (aPluralCount !== undefined) {
      str = PluralForm.get(aPluralCount, str);
    }
    if (aReplacements !== undefined) {
      for (let i = 0; i < aReplacements.length; i++) {
        str = str.replace("#" + (i + 1), aReplacements[i]);
      }
    }
    return str;
  },
};

var gTemplateUtilsStrings = new PluralStringFormatter(
  "chrome://messenger/locale/templateUtils.properties"
);

const _dateFormatter = new Services.intl.DateTimeFormat(undefined, {
  dateStyle: "short",
});
const _dayMonthFormatter = new Services.intl.DateTimeFormat(undefined, {
  month: "long",
  day: "numeric",
});
const _timeFormatter = new Services.intl.DateTimeFormat(undefined, {
  timeStyle: "short",
});
const _weekdayFormatter = new Services.intl.DateTimeFormat(undefined, {
  weekday: "long",
});

/**
 * Helper function to generate a localized "friendly" representation of
 * time relative to the present.  If the time input is "today", it returns
 * a string corresponding to just the time.  If it's yesterday, it returns
 * "yesterday" (localized).  If it's in the last week, it returns the day
 * of the week. If it's before that, it returns the date.
 *
 * @param {Date} time - The time (better be in the past!)
 * @returns {string} A "human-friendly" representation of that time
 *   relative to now.
 */
function makeFriendlyDateAgo(time) {
  // TODO: use Intl.RelativeTimeFormat instead.
  // Figure out when today begins
  let now = new Date();
  let today = new Date(now.getFullYear(), now.getMonth(), now.getDate());

  // Get the end time to display
  let end = time;

  // Figure out if the end time is from today, yesterday,
  // this week, etc.
  let dateTime;
  let kDayInMsecs = 24 * 60 * 60 * 1000;
  let k6DaysInMsecs = 6 * kDayInMsecs;
  if (end >= today) {
    // activity finished after today started, show the time
    dateTime = _timeFormatter.format(end);
  } else if (today - end < kDayInMsecs) {
    // activity finished after yesterday started, show yesterday
    dateTime = gTemplateUtilsStrings.get("yesterday");
  } else if (today - end < k6DaysInMsecs) {
    // activity finished after last week started, show day of week
    dateTime = _weekdayFormatter.format(end);
  } else if (now.getFullYear() == end.getFullYear()) {
    // activity must have been from some time ago.. show month/day
    dateTime = _dayMonthFormatter.format(end);
  } else {
    // not this year, so show full date format
    dateTime = _dateFormatter.format(end);
  }
  return dateTime;
}