timerender: Revert extra changes to time in recent conversations.

In #25012, which was intended to only modify the buddy list, we
accidentally changed the rendering of times for several other code
paths, including recent conversations, that were using the
last_status_from_time function, whose name really suggested it only
was used for the buddy list.

Extract a new function with a better name for the more common relative
time use case.

web/src/recent_topics_ui.js

@@ -363,7 +363,7 @@ function format_conversation(conversation_data) {
     context.full_last_msg_date_time = timerender.get_full_datetime(time);
     context.conversation_key = get_key_from_message(last_msg);
     context.unread_count = message_to_conversation_unread_count(last_msg);
-    context.last_msg_time = timerender.last_seen_status_from_date(time);
+    context.last_msg_time = timerender.relative_time_string_from_date(time);
     context.is_private = last_msg.type === "private";
     let all_senders;
     let senders;

web/src/settings_exports.js

@@ -46,13 +46,13 @@ export function populate_exports_table(exports) {
             let deleted_timestamp = data.deleted_timestamp;
 
             if (failed_timestamp !== null) {
-                failed_timestamp = timerender.last_seen_status_from_date(
+                failed_timestamp = timerender.relative_time_string_from_date(
                     new Date(failed_timestamp * 1000),
                 );
             }
 
             if (deleted_timestamp !== null) {
-                deleted_timestamp = timerender.last_seen_status_from_date(
+                deleted_timestamp = timerender.relative_time_string_from_date(
                     new Date(deleted_timestamp * 1000),
                 );
             }
@@ -62,7 +62,7 @@ export function populate_exports_table(exports) {
                     id: data.id,
                     acting_user: people.get_full_name(data.acting_user_id),
                     // Convert seconds -> milliseconds
-                    event_time: timerender.last_seen_status_from_date(
+                    event_time: timerender.relative_time_string_from_date(
                         new Date(data.export_time * 1000),
                     ),
                     url: data.export_url,

web/src/timerender.ts

@@ -187,6 +187,53 @@ export function render_now(time: Date, today = new Date()): TimeRender {
     };
 }
 
+// Relative time rendering for use in most screens like Recent conversations.
+//
+// Current date is passed as an argument for unit testing
+export function relative_time_string_from_date(
+    last_active_date: Date,
+    current_date = new Date(),
+): string {
+    const minutes = differenceInMinutes(current_date, last_active_date);
+    if (minutes <= 2) {
+        return $t({defaultMessage: "Just now"});
+    }
+    if (minutes < 60) {
+        return $t({defaultMessage: "{minutes} minutes ago"}, {minutes});
+    }
+
+    const days_old = differenceInCalendarDays(current_date, last_active_date);
+    const hours = Math.floor(minutes / 60);
+
+    if (hours < 24) {
+        if (hours === 1) {
+            return $t({defaultMessage: "An hour ago"});
+        }
+        return $t({defaultMessage: "{hours} hours ago"}, {hours});
+    }
+
+    if (days_old === 1) {
+        return $t({defaultMessage: "Yesterday"});
+    }
+
+    if (days_old < 90) {
+        return $t({defaultMessage: "{days_old} days ago"}, {days_old});
+    } else if (
+        days_old > 90 &&
+        days_old < 365 &&
+        last_active_date.getFullYear() === current_date.getFullYear()
+    ) {
+        // Online more than 90 days ago, in the same year
+        return get_localized_date_or_time_for_format(last_active_date, "dayofyear");
+    }
+    return get_localized_date_or_time_for_format(last_active_date, "dayofyear_year");
+}
+
+// Relative time logic variant use in the buddy list, where every
+// string has "Active" init. This is hard to deduplicate with
+// relative_time_string_from_date because of complexities involved in i18n and
+// word order.
+//
 // Current date is passed as an argument for unit testing
 export function last_seen_status_from_date(
     last_active_date: Date,

web/tests/recent_topics.test.js

@@ -136,7 +136,7 @@ mock_esm("../src/stream_list", {
     handle_narrow_deactivated: noop,
 });
 mock_esm("../src/timerender", {
-    last_seen_status_from_date: () => "Just now",
+    relative_time_string_from_date: () => "Just now",
     get_full_datetime: () => "date at time",
 });
 mock_esm("../src/sub_store", {

web/tests/timerender.test.js

@@ -518,6 +518,61 @@ run_test("last_seen_status_from_date", () => {
     assert_same({hours: -24}, $t({defaultMessage: "Active yesterday"}));
 });
 
+run_test("relative_time_string_from_date", () => {
+    // Set base_date to March 1 2016 12.30 AM (months are zero based)
+    let base_date = new Date(2016, 2, 1, 0, 30);
+
+    function assert_same(duration, expected_status) {
+        const past_date = add(base_date, duration);
+        const actual_status = timerender.relative_time_string_from_date(past_date, base_date);
+        assert.equal(actual_status, expected_status);
+    }
+
+    assert_same({seconds: -20}, $t({defaultMessage: "Just now"}));
+
+    assert_same({minutes: -1}, $t({defaultMessage: "Just now"}));
+
+    assert_same({minutes: -2}, $t({defaultMessage: "Just now"}));
+
+    assert_same({minutes: -30}, $t({defaultMessage: "30 minutes ago"}));
+
+    assert_same({hours: -1}, $t({defaultMessage: "An hour ago"}));
+
+    assert_same({hours: -2}, $t({defaultMessage: "2 hours ago"}));
+
+    assert_same({hours: -20}, $t({defaultMessage: "20 hours ago"}));
+
+    assert_same({hours: -24}, $t({defaultMessage: "Yesterday"}));
+
+    assert_same({hours: -48}, $t({defaultMessage: "2 days ago"}));
+
+    assert_same({days: -2}, $t({defaultMessage: "2 days ago"}));
+
+    assert_same({days: -61}, $t({defaultMessage: "61 days ago"}));
+
+    assert_same({days: -300}, "May 6, 2015");
+
+    assert_same({days: -366}, "Mar 1, 2015");
+
+    assert_same({years: -3}, "Mar 1, 2013");
+
+    // Set base_date to May 1 2016 12.30 AM (months are zero based)
+    base_date = new Date(2016, 4, 1, 0, 30);
+
+    assert_same({days: -91}, "Jan 31");
+
+    // Set base_date to May 1 2016 10.30 PM (months are zero based)
+    base_date = new Date(2016, 4, 2, 23, 30);
+
+    assert_same({hours: -1}, $t({defaultMessage: "An hour ago"}));
+
+    assert_same({hours: -2}, $t({defaultMessage: "2 hours ago"}));
+
+    assert_same({hours: -12}, $t({defaultMessage: "12 hours ago"}));
+
+    assert_same({hours: -24}, $t({defaultMessage: "Yesterday"}));
+});
+
 run_test("set_full_datetime", () => {
     let time = date_2019;