XEP-0461 Message Replies implementation

bridge/xmpp/xmpp.go

@@ -11,6 +11,7 @@ import (
 	"sync"
 	"time"
 
+	lru "github.com/hashicorp/golang-lru"
 	"github.com/jpillora/backoff"
 	"github.com/matterbridge-org/matterbridge/bridge"
 	"github.com/matterbridge-org/matterbridge/bridge/config"
@@ -26,18 +27,25 @@ type Bxmpp struct {
 	xc        *xmpp.Client
 	xmppMap   map[string]string
 	connected bool
+	cache     *lru.Cache
 	sync.RWMutex
 
 	avatarAvailability map[string]bool
 	avatarMap          map[string]string
 }
 
 func New(cfg *bridge.Config) bridge.Bridger {
+	newCache, err := lru.New(5000)
+	if err != nil {
+		cfg.Log.Fatalf("Could not create LRU cache: %v", err)
+	}
+
 	return &Bxmpp{
 		Config:             cfg,
 		xmppMap:            make(map[string]string),
 		avatarAvailability: make(map[string]bool),
 		avatarMap:          make(map[string]string),
+		cache:              newCache,
 	}
 }
 
@@ -124,19 +132,30 @@ func (b *Bxmpp) Send(msg config.Message) (string, error) {
 		return "", nil
 	}
 
+	// XEP-0461: populate reply fields if this message is a reply.
+	var replyID, replyTo string
+	if msg.ParentValid() {
+		if info, ok := b.cache.Get(msg.ParentID); ok {
+			si := info.(stanzaInfo)
+			replyID = si.stanzaID
+			replyTo = si.from
+		}
+	}
+
 	// Post normal message.
 	b.Log.Debugf("=> Sending message %#v", msg)
+	msgID := xid.New().String()
 	if _, err := b.xc.Send(xmpp.Chat{
-		Type:   "groupchat",
-		Remote: msg.Channel + "@" + b.GetString("Muc"),
-		Text:   msg.Username + msg.Text,
+		Type:    "groupchat",
+		Remote:  msg.Channel + "@" + b.GetString("Muc"),
+		Text:    msg.Username + msg.Text,
+		ID:      msgID,
+		ReplyID: replyID,
+		ReplyTo: replyTo,
 	}); err != nil {
 		return "", err
 	}
-
 	// Generate a dummy ID because to avoid collision with other internal messages
-	// However this does not provide proper Edits/Replies integration on XMPP side.
-	msgID := xid.New().String()
 	return msgID, nil
 }
 
@@ -277,6 +296,11 @@ func (b *Bxmpp) xmppKeepAlive() chan bool {
 	return done
 }
 
+type stanzaInfo struct {
+	stanzaID string
+	from     string
+}
+
 func (b *Bxmpp) handleXMPP() error {
 	b.startTime = time.Now()
 
@@ -300,6 +324,11 @@ func (b *Bxmpp) handleXMPP() error {
 			if v.Type == "groupchat" {
 				b.Log.Debugf("== Receiving %#v", v)
 
+				// XEP-0461: Cache StanzaID to use for Message Replies
+				if v.StanzaID.ID != "" {
+					b.cache.Add(v.ID, stanzaInfo{stanzaID: v.StanzaID.ID, from: v.Remote})
+				}
+
 				// Skip invalid messages.
 				if b.skipMessage(v) {
 					continue