Remove fallback quoted msgs in XMPP replies

bridge/xmpp/helpers.go

@@ -1,7 +1,9 @@
 package bxmpp
 
 import (
+	"bufio"
 	"regexp"
+	"strings"
 
 	"github.com/42wim/matterbridge/bridge/config"
 )
@@ -28,3 +30,23 @@ func (b *Bxmpp) cacheAvatar(msg *config.Message) string {
 	}
 	return ""
 }
+
+func trimLeadingQuotedLines(s string) string {
+	scanner := bufio.NewScanner(strings.NewReader(s))
+	var builder strings.Builder
+	skipping := true
+
+	for scanner.Scan() {
+		line := scanner.Text()
+		if skipping {
+			if strings.HasPrefix(line, "> ") {
+				// still skipping
+				continue
+			}
+			skipping = false
+		}
+		builder.WriteString(line + "\n")
+	}
+
+	return strings.TrimRight(builder.String(), "\n")
+}

bridge/xmpp/xmpp.go

@@ -347,6 +347,7 @@ func (b *Bxmpp) handleXMPP() error {
 				var parentID string
 				if res, ok := b.OriginIDs.Get(v.ReplyID); ok {
 					parentID, _ = res.(string)
+					v.Text = trimLeadingQuotedLines(v.Text)
 				}
 
 				rmsg := config.Message{