v2 / grouping for date headers

[qeepcologne]

This is not about adding the date headers in the ui - there are plenty of options to add.
But needing a grouping with a differnt treshold (e.g. daily for the date headers and every minute for the bubble nips).

[demchenkoalex]

Could you elaborate? I don’t quite understand how you can group date headers separately from the message bubbles - they’re displayed above the bubbles, right? 🤷

[intelryzen]

Could you elaborate? I don’t quite understand how you can group date headers separately from the message bubbles - they’re displayed above the bubbles, right? 🤷

Perhaps what the author means is that the grouping of the speech bubbles refers to minute-based groups rather than the interval between each bubble. Below is a temporary patch reflecting that requirement.

static bool isLastMessageInMinute({
    required List<Message> messages,
    required Message message,
    required int index,
  }) {
    bool isLastMessageInMinute = true;

    if (index < messages.length - 1) {
      final nextMessage = messages[index + 1];
      
      if (nextMessage.createdAt != null && message.createdAt != null) {
        final currentMinute = DateTime(
          message.createdAt!.year,
          message.createdAt!.month,
          message.createdAt!.day,
          message.createdAt!.hour,
          message.createdAt!.minute,
        );

        final nextMinute = DateTime(
          nextMessage.createdAt!.year,
          nextMessage.createdAt!.month,
          nextMessage.createdAt!.day,
          nextMessage.createdAt!.hour,
          nextMessage.createdAt!.minute,
        );
        
        isLastMessageInMinute =
            currentMinute != nextMinute ||
            message.authorId != nextMessage.authorId;
      }
    }

    return isLastMessageInMinute;
  }

[demchenkoalex]

Hmm, I still don’t understand. As far as I remember, I compare the current message to the previous one to calculate the time difference - not on a minute-by-minute basis.

Do you mean the requirement is to group messages strictly by time (e.g. every minute)?

[intelryzen]

Yes, exactly. Messages should be strictly grouped by each minute, rather than calculating the time difference between consecutive messages. For instance, a message sent at 2:05:59.999 and another at 2:06:00.000 must belong to separate groups.

[qeepcologne]

exactly, requirement is to group:

• messages by exact minute and user (nip + date below last message of the group)
  see example added by: intelryzen above.

• date header by exact date (header on top the first message of the group, user doesn't mater)

grouping by exact minute is required for the date header, otherwise messages are grouped in the same group that are divided into different dates when date difference is <1 minute around midnight.

i think current grouping by timestamp difference is also useful if timestamp is displayed on every message.

---

i tried to hack date headers back myself _chatController.operationsStream.listen but thats lots of pain and feels hacky:

• need to implement all operations (calculate headers at set, scroll up (paging): insert and maybe remove first of existing list, insert at bottom: insert if different to last message date, remove: if exist, maybe move down to next message)
• the messages itself are immutable
• storing in seperate list: message index changes at every operation
• complete recaculation performs very bad (especially because there is no bulk insert and remove)
  the problem with the grouping still exist, grouped messages may be divided by date header.

[qeepcologne]

@intelryzen now i am trying like you with similar function isFirstMessageInDate to caculate Headers on the fly.

bool isFirstMessageInDate({required List<Message> messages, required Message message, required int index}) {
  bool isFirstMessageInDate = true;

  if (index > 0) {
    final lastMessage = messages[index - 1];

    if (lastMessage.createdAt != null && message.createdAt != null) {
      final currentDate = DateTime(message.createdAt!.year, message.createdAt!.month, message.createdAt!.day);
      final lastDate = DateTime(lastMessage.createdAt!.year, lastMessage.createdAt!.month, lastMessage.createdAt!.day);

      isFirstMessageInDate = currentDate != lastDate;
    }
  }

  return isFirstMessageInDate;
}