1 files changed, 90 insertions, 0 deletions
diff --git a/comm/mailnews/base/src/TemplateUtils.jsm b/comm/mailnews/base/src/TemplateUtils.jsm
new file mode 100644
index 0000000000..fca56fca67
--- /dev/null
+++ b/comm/mailnews/base/src/TemplateUtils.jsm
@@ -0,0 +1,90 @@
+/* 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;
+}