From 7b7cdb30fbc5a672b9554ef8138b4c7f3537b204 Mon Sep 17 00:00:00 2001
From: Tulir Asokan <tulir@maunium.net>
Date: Wed, 14 Aug 2024 17:46:36 +0300
Subject: [PATCH] backfill: ignore read up to ts if unread flag is false

---
 pkg/connector/backfill.go | 2 +-
 pkg/connector/chatsync.go | 8 ++------
 pkg/connector/client.go   | 1 +
 3 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/pkg/connector/backfill.go b/pkg/connector/backfill.go
index 7f2f419..6fd32f1 100644
--- a/pkg/connector/backfill.go
+++ b/pkg/connector/backfill.go
@@ -127,7 +127,7 @@ func (gc *GMClient) FetchMessages(ctx context.Context, params bridgev2.FetchMess
 		if meta != nil {
 			lastWrappedMsg := fetchResp.Messages[len(fetchResp.Messages)-1]
 			lastRawMsg := resp.Messages[len(resp.Messages)-1]
-			fetchResp.MarkRead = !meta.readUpToTS.Before(lastWrappedMsg.Timestamp) || meta.readUpTo == lastRawMsg.MessageID
+			fetchResp.MarkRead = !meta.unread || !meta.readUpToTS.Before(lastWrappedMsg.Timestamp) || meta.readUpTo == lastRawMsg.MessageID
 		}
 		gc.conversationMetaLock.Unlock()
 	} else {
diff --git a/pkg/connector/chatsync.go b/pkg/connector/chatsync.go
index 413dd5d..d052973 100644
--- a/pkg/connector/chatsync.go
+++ b/pkg/connector/chatsync.go
@@ -71,14 +71,10 @@ func (gc *GMClient) syncConversationMeta(v *gmproto.Conversation) (meta *convers
 		meta = &conversationMeta{}
 		gc.conversationMeta[v.ConversationID] = meta
 	}
+	meta.unread = v.Unread
 	if !v.Unread {
 		meta.readUpTo = v.LatestMessageID
-		newLastMsgTS := time.UnixMicro(v.LastMessageTimestamp)
-		// Don't allow read up to timestamp to move backwards.
-		// There are some weird race conditions where it causes backfills to be left unread.
-		if meta.readUpToTS.Before(newLastMsgTS) {
-			meta.readUpToTS = newLastMsgTS
-		}
+		meta.readUpToTS = time.UnixMicro(v.LastMessageTimestamp)
 	} else if meta.readUpTo == v.LatestMessageID {
 		meta.readUpTo = ""
 		meta.readUpToTS = time.Time{}
diff --git a/pkg/connector/client.go b/pkg/connector/client.go
index 4e778fb..e21a675 100644
--- a/pkg/connector/client.go
+++ b/pkg/connector/client.go
@@ -36,6 +36,7 @@ import (
 type conversationMeta struct {
 	markedSpamAt          time.Time
 	cancelPendingBackfill atomic.Pointer[context.CancelFunc]
+	unread                bool
 	readUpTo              string
 	readUpToTS            time.Time
 }