Add option to mark old chats as read on backfill

[skip cd]

backfill.go

@@ -546,6 +546,9 @@ func (portal *Portal) convertAndSendBackfill(ctx context.Context, source *User,
 			}
 		}
 	}
+	if unreadHoursThreshold := portal.bridge.Config.Bridge.Backfill.UnreadHoursThreshold; unreadHoursThreshold > 0 && !markRead && len(messages) > 0 {
+		markRead = messages[len(messages)-1].TimestampMs < time.Now().Add(-time.Duration(unreadHoursThreshold)*time.Hour).UnixMilli()
+	}
 	if portal.bridge.SpecVersions.Supports(mautrix.BeeperFeatureBatchSending) {
 		log.Info().Int("event_count", len(events)).Msg("Sending events to Matrix using Beeper batch sending")
 		portal.sendBackfillBeeper(ctx, source, events, metas, markRead, forward)
@@ -583,7 +586,7 @@ func (portal *Portal) sendBackfillLegacy(ctx context.Context, source *User, even
 
 func (portal *Portal) sendBackfillBeeper(ctx context.Context, source *User, events []*event.Event, metas []*BackfillPartMetadata, markRead, forward bool) {
 	var markReadBy id.UserID
-	if markRead {
+	if markRead && forward {
 		markReadBy = source.MXID
 	}
 	resp, err := portal.MainIntent().BeeperBatchSend(ctx, portal.MXID, &mautrix.ReqBeeperBatchSend{

config/bridge.go

@@ -59,11 +59,12 @@ type BridgeConfig struct {
 	CommandPrefix string `yaml:"command_prefix"`
 
 	Backfill struct {
-		Enabled           bool `yaml:"enabled"`
-		InboxFetchPages   int  `yaml:"inbox_fetch_pages"`
-		HistoryFetchPages int  `yaml:"history_fetch_pages"`
-		CatchupFetchPages int  `yaml:"catchup_fetch_pages"`
-		Queue             struct {
+		Enabled              bool `yaml:"enabled"`
+		InboxFetchPages      int  `yaml:"inbox_fetch_pages"`
+		HistoryFetchPages    int  `yaml:"history_fetch_pages"`
+		CatchupFetchPages    int  `yaml:"catchup_fetch_pages"`
+		UnreadHoursThreshold int  `yaml:"unread_hours_threshold"`
+		Queue                struct {
 			PagesAtOnce       int           `yaml:"pages_at_once"`
 			MaxPages          int           `yaml:"max_pages"`
 			SleepBetweenTasks time.Duration `yaml:"sleep_between_tasks"`

config/upgrade.go

@@ -101,6 +101,7 @@ func DoUpgrade(helper *up.Helper) {
 	helper.Copy(up.Int, "bridge", "backfill", "inbox_fetch_pages")
 	helper.Copy(up.Int, "bridge", "backfill", "history_fetch_pages")
 	helper.Copy(up.Int, "bridge", "backfill", "catchup_fetch_pages")
+	helper.Copy(up.Int, "bridge", "backfill", "unread_hours_threshold")
 	helper.Copy(up.Int, "bridge", "backfill", "queue", "pages_at_once")
 	helper.Copy(up.Int, "bridge", "backfill", "queue", "max_pages")
 	helper.Copy(up.Str, "bridge", "backfill", "queue", "sleep_between_tasks")

example-config.yaml

@@ -164,6 +164,9 @@ bridge:
         history_fetch_pages: 0
         # Same as above, but for catchup backfills (i.e. when the bridge is restarted).
         catchup_fetch_pages: 5
+        # Maximum age of chats to leave as unread when backfilling. 0 means all chats can be left as unread.
+        # If non-zero, chats that are older than this will be marked as read, even if they're still unread on Meta.
+        unread_hours_threshold: 0
         # Backfill queue settings. Only relevant for Beeper, because standard Matrix servers
         # don't support inserting messages into room history.
         queue: