wip start on date separators

Author: gnprice

lib/model/message_list.dart

@@ -25,6 +25,12 @@ class MessageListRecipientHeaderItem extends MessageListItem {
   MessageListRecipientHeaderItem(this.message);
 }
 
+class MessageListDateSeparatorItem extends MessageListItem {
+  final Message message;
+
+  MessageListDateSeparatorItem(this.message);
+}
+
 /// A message to show in the message list.
 class MessageListMessageItem extends MessageListItem {
   final Message message;
@@ -118,6 +124,7 @@ mixin _MessageSequence {
           case MessageListDirection.older:       return -1;
         }
       case MessageListRecipientHeaderItem(:var message):
+      case MessageListDateSeparatorItem(:var message):
         return (message.id <= messageId) ? -1 : 1;
       case MessageListMessageItem(:var message): return message.id.compareTo(messageId);
     }
@@ -181,16 +188,19 @@ mixin _MessageSequence {
     final message = messages[index];
     final content = contents[index];
     bool canShareSender;
-    if (index > 0 && canShareRecipientHeader(messages[index - 1], message)) {
+    if (index == 0 || !haveSameRecipient(messages[index - 1], message)) {
+      items.add(MessageListRecipientHeaderItem(message));
+      canShareSender = false;
+    } else if (!messagesSameDay(messages[index - 1], message)) {
+      items.add(MessageListDateSeparatorItem(message));
+      canShareSender = false;
+    } else {
       assert(items.last is MessageListMessageItem);
       final prevMessageItem = items.last as MessageListMessageItem;
       assert(identical(prevMessageItem.message, messages[index - 1]));
       assert(prevMessageItem.isLastInBlock);
       prevMessageItem.isLastInBlock = false;
       canShareSender = (prevMessageItem.message.senderId == message.senderId);
-    } else {
-      items.add(MessageListRecipientHeaderItem(message));
-      canShareSender = false;
     }
     items.add(MessageListMessageItem(message, content,
       showSender: !canShareSender, isLastInBlock: true));
@@ -227,8 +237,16 @@ mixin _MessageSequence {
   }
 }
 
+// TODO cut this; update tests
 @visibleForTesting
 bool canShareRecipientHeader(Message prevMessage, Message message) {
+  if (!haveSameRecipient(prevMessage, message)) return false;
+  if (!messagesSameDay(prevMessage, message)) return false;
+  return true;
+}
+
+@visibleForTesting
+bool haveSameRecipient(Message prevMessage, Message message) {
   if (prevMessage is StreamMessage && message is StreamMessage) {
     if (prevMessage.streamId != message.streamId) return false;
     if (prevMessage.subject != message.subject) return false;
@@ -239,6 +257,7 @@ bool canShareRecipientHeader(Message prevMessage, Message message) {
   } else {
     return false;
   }
+  return true;
 
   // switch ((prevMessage, message)) {
   //   case (StreamMessage(), StreamMessage()):
@@ -248,12 +267,13 @@ bool canShareRecipientHeader(Message prevMessage, Message message) {
   //   default:
   //     return false;
   // }
+}
 
+bool messagesSameDay(Message prevMessage, Message message) {
   // TODO memoize [DateTime]s... also use memoized for showing date/time in msglist
   final prevTime = DateTime.fromMillisecondsSinceEpoch(prevMessage.timestamp * 1000);
   final time = DateTime.fromMillisecondsSinceEpoch(message.timestamp * 1000);
   if (!_sameDay(prevTime, time)) return false;
-
   return true;
 }
 

lib/widgets/message_list.dart

@@ -345,6 +345,10 @@ class _MessageListState extends State<MessageList> with PerAccountStoreAwareStat
             final header = RecipientHeader(message: data.message, narrow: widget.narrow);
             return StickyHeaderItem(allowOverflow: true,
               header: header, child: header);
+          case MessageListDateSeparatorItem():
+            final header = RecipientHeader(message: data.message, narrow: widget.narrow);
+            return StickyHeaderItem(allowOverflow: true,
+              header: header, child: Text("a new day")); // TODO
           case MessageListMessageItem():
             final header = RecipientHeader(message: data.message, narrow: widget.narrow);
             return MessageItem(