Sort chats by timestamp when handling history sync

user.go

@@ -22,6 +22,7 @@ import (
 	"errors"
 	"fmt"
 	"net/http"
+	"sort"
 	"sync"
 	"time"
 
@@ -361,6 +362,22 @@ type portalToBackfill struct {
 	conv   *waProto.Conversation
 }
 
+type conversationList []*waProto.Conversation
+
+var _ sort.Interface = (conversationList)(nil)
+
+func (c conversationList) Len() int {
+	return len(c)
+}
+
+func (c conversationList) Less(i, j int) bool {
+	return c[i].GetConversationTimestamp() < c[j].GetConversationTimestamp()
+}
+
+func (c conversationList) Swap(i, j int) {
+	c[i], c[j] = c[j], c[i]
+}
+
 func (user *User) handleHistorySync(evt *waProto.HistorySync) {
 	if evt.GetSyncType() != waProto.HistorySync_RECENT && evt.GetSyncType() != waProto.HistorySync_FULL {
 		return
@@ -369,8 +386,25 @@ func (user *User) handleHistorySync(evt *waProto.HistorySync) {
 	maxAge := user.bridge.Config.Bridge.HistorySync.MaxAge
 	minLastMsgToCreate := time.Now().Add(-time.Duration(maxAge) * time.Second)
 	createRooms := user.bridge.Config.Bridge.HistorySync.CreatePortals
-	portalsToBackfill := make([]portalToBackfill, 0)
-	for _, conv := range evt.GetConversations() {
+
+	conversations := conversationList(evt.GetConversations())
+	sort.Sort(sort.Reverse(conversations))
+	portalsToBackfill := make(chan portalToBackfill, len(conversations))
+
+	var backfillWait sync.WaitGroup
+	backfillWait.Add(1)
+	go func() {
+		for ptb := range portalsToBackfill {
+			user.log.Debugln("Bridging history sync payload for", ptb.portal.Key.JID)
+			ptb.portal.backfill(user, ptb.conv.GetMessages())
+			if !ptb.conv.GetMarkedAsUnread() && ptb.conv.GetUnreadCount() == 0 {
+				user.markSelfReadFull(ptb.portal)
+			}
+		}
+		backfillWait.Done()
+	}()
+
+	for _, conv := range conversations {
 		jid, err := types.ParseJID(conv.GetId())
 		if err != nil {
 			user.log.Warnfln("Failed to parse chat JID '%s' in history sync: %v", conv.GetId(), err)
@@ -410,16 +444,11 @@ func (user *User) handleHistorySync(evt *waProto.HistorySync) {
 		} else if !user.bridge.Config.Bridge.HistorySync.Backfill {
 			user.log.Debugln("Backfill is disabled, not bridging history sync payload for", portal.Key.JID)
 		} else {
-			portalsToBackfill = append(portalsToBackfill, portalToBackfill{portal, conv})
-		}
-	}
-	for _, ptb := range portalsToBackfill {
-		user.log.Debugln("Bridging history sync payload for", ptb.portal.Key.JID)
-		ptb.portal.backfill(user, ptb.conv.GetMessages())
-		if !ptb.conv.GetMarkedAsUnread() && ptb.conv.GetUnreadCount() == 0 {
-			user.markSelfReadFull(ptb.portal)
+			portalsToBackfill <- portalToBackfill{portal, conv}
 		}
 	}
+	close(portalsToBackfill)
+	backfillWait.Wait()
 	user.log.Infofln("Finished handling history sync with type %s, chunk order %d, progress %d%%", evt.GetSyncType(), evt.GetChunkOrder(), evt.GetProgress())
 }