msglist [nfc]: Finish centralizing on MessageTimestampStyle

Author: chrisbobbe

lib/widgets/message_list.dart

@@ -1843,6 +1843,10 @@ class DateText extends StatelessWidget {
   Widget build(BuildContext context) {
     final messageListTheme = MessageListTheme.of(context);
     final zulipLocalizations = ZulipLocalizations.of(context);
+    final formattedTimestamp = MessageTimestampStyle.dateOnlyRelative.format(
+      timestamp,
+      now: ZulipBinding.instance.utcNow().toLocal(),
+      zulipLocalizations: zulipLocalizations)!;
     return Text(
       style: TextStyle(
         color: messageListTheme.labelTime,
@@ -1852,46 +1856,7 @@ class DateText extends StatelessWidget {
         //   https://developer.mozilla.org/en-US/docs/Web/CSS/font-variant-caps#all-small-caps
         fontFeatures: const [FontFeature.enable('c2sc'), FontFeature.enable('smcp')],
       ),
-      formatHeaderDate(
-        zulipLocalizations,
-        DateTime.fromMillisecondsSinceEpoch(timestamp * 1000),
-        now: ZulipBinding.instance.utcNow().toLocal()));
-  }
-}
-
-@visibleForTesting
-String formatHeaderDate(
-  ZulipLocalizations zulipLocalizations,
-  DateTime dateTime, {
-  required DateTime now,
-}) {
-  assert(!dateTime.isUtc && !now.isUtc,
-    '`dateTime` and `now` need to be in local time.');
-
-  if (dateTime.year == now.year &&
-      dateTime.month == now.month &&
-      dateTime.day == now.day) {
-    return zulipLocalizations.today;
-  }
-
-  final yesterday = now
-    .copyWith(hour: 12, minute: 0, second: 0, millisecond: 0, microsecond: 0)
-    .add(const Duration(days: -1));
-  if (dateTime.year == yesterday.year &&
-      dateTime.month == yesterday.month &&
-      dateTime.day == yesterday.day) {
-    return zulipLocalizations.yesterday;
-  }
-
-  // If it is Dec 1 and you see a label that says `Dec 2`
-  // it could be misinterpreted as Dec 2 of the previous
-  // year. For times in the future, those still on the
-  // current day will show as today (handled above) and
-  // any dates beyond that show up with the year.
-  if (dateTime.year == now.year && dateTime.isBefore(now)) {
-    return DateFormat.MMMd().format(dateTime);
-  } else {
-    return DateFormat.yMMMd().format(dateTime);
+      formattedTimestamp);
   }
 }
 
@@ -1985,9 +1950,9 @@ class SenderRow extends StatelessWidget {
   }
 }
 
-// TODO centralize on this for wherever we show message timestamps
 enum MessageTimestampStyle {
   none,
+  dateOnlyRelative,
   timeOnly,
 
   // TODO(#45): E.g. "Yesterday at 4:47 PM"; see details in #45
@@ -2007,6 +1972,40 @@ enum MessageTimestampStyle {
   full,
   ;
 
+  static String _formatDateOnlyRelative(
+    DateTime dateTime, {
+    required DateTime now,
+    required ZulipLocalizations zulipLocalizations,
+  }) {
+    assert(!dateTime.isUtc && !now.isUtc,
+      '`dateTime` and `now` need to be in local time.');
+
+    if (dateTime.year == now.year &&
+        dateTime.month == now.month &&
+        dateTime.day == now.day) {
+      return zulipLocalizations.today;
+    }
+
+    final yesterday = now
+      .copyWith(hour: 12, minute: 0, second: 0, millisecond: 0, microsecond: 0)
+      .add(const Duration(days: -1));
+    if (dateTime.year == yesterday.year &&
+        dateTime.month == yesterday.month &&
+        dateTime.day == yesterday.day) {
+      return zulipLocalizations.yesterday;
+    }
+
+    // If it is Dec 1 and you see a label that says `Dec 2`
+    // it could be misinterpreted as Dec 2 of the previous
+    // year. For times in the future, those still on the
+    // current day will show as today (handled above) and
+    // any dates beyond that show up with the year.
+    if (dateTime.year == now.year && dateTime.isBefore(now)) {
+      return DateFormat.MMMd().format(dateTime);
+    } else {
+      return DateFormat.yMMMd().format(dateTime);
+    }
+  }
   static final _timeOnlyFormat = DateFormat('h:mm aa', 'en_US');
   static final _lightboxFormat = DateFormat.yMMMd().add_Hms();
   static final _fullFormat = DateFormat.yMMMd().add_jm();
@@ -2023,6 +2022,9 @@ enum MessageTimestampStyle {
 
     switch (this) {
       case none:     return null;
+      case dateOnlyRelative:
+        return _formatDateOnlyRelative(asDateTime,
+          now: now, zulipLocalizations: zulipLocalizations);
       case timeOnly: return _timeOnlyFormat.format(asDateTime);
       case lightbox: return _lightboxFormat.format(asDateTime);
       case full: return _fullFormat.format(asDateTime);

test/widgets/message_list_test.dart

@@ -1638,35 +1638,39 @@ void main() {
     });
   });
 
-  group('formatHeaderDate', () {
-    final zulipLocalizations = GlobalLocalizations.zulipLocalizations;
-    final now = DateTime.parse("2023-01-10 12:00");
-    final testCases = [
-      ("2023-01-10 12:00", zulipLocalizations.today),
-      ("2023-01-10 00:00", zulipLocalizations.today),
-      ("2023-01-10 23:59", zulipLocalizations.today),
-      ("2023-01-09 23:59", zulipLocalizations.yesterday),
-      ("2023-01-09 00:00", zulipLocalizations.yesterday),
-      ("2023-01-08 00:00", "Jan 8"),
-      ("2022-12-31 00:00", "Dec 31, 2022"),
-      // Future times
-      ("2023-01-10 19:00", zulipLocalizations.today),
-      ("2023-01-11 00:00", "Jan 11, 2023"),
-    ];
-    for (final (dateTime, expected) in testCases) {
-      test('$dateTime returns $expected', () {
-        addTearDown(testBinding.reset);
-
-        withClock(Clock.fixed(now), () {
-          check(formatHeaderDate(
-            zulipLocalizations,
-            DateTime.parse(dateTime),
-            now: testBinding.utcNow().toLocal(),
-          ))
-            .equals(expected);
+  group('MessageTimestampStyle', () {
+    group('dateOnlyRelative', () {
+      final zulipLocalizations = GlobalLocalizations.zulipLocalizations;
+      final now = DateTime.parse("2023-01-10 12:00");
+      final testCases = [
+        ("2023-01-10 12:00", zulipLocalizations.today),
+        ("2023-01-10 00:00", zulipLocalizations.today),
+        ("2023-01-10 23:59", zulipLocalizations.today),
+        ("2023-01-09 23:59", zulipLocalizations.yesterday),
+        ("2023-01-09 00:00", zulipLocalizations.yesterday),
+        ("2023-01-08 00:00", "Jan 8"),
+        ("2022-12-31 00:00", "Dec 31, 2022"),
+        // Future times
+        ("2023-01-10 19:00", zulipLocalizations.today),
+        ("2023-01-11 00:00", "Jan 11, 2023"),
+      ];
+      for (final (dateTime, expected) in testCases) {
+        test('$dateTime returns $expected', () {
+          addTearDown(testBinding.reset);
+
+          withClock(Clock.fixed(now), () {
+            final timestamp = DateTime.parse(dateTime).millisecondsSinceEpoch ~/ 1000;
+            final result = MessageTimestampStyle.dateOnlyRelative.format(
+              timestamp,
+              now: testBinding.utcNow().toLocal(),
+              zulipLocalizations: zulipLocalizations);
+            check(result).equals(expected);
+          });
         });
-      });
-    }
+      }
+    });
+
+    // TODO others
   });
 
   group('MessageWithPossibleSender', () {