improve nip10.GetImmediateReply()

nip10/nip10.go

@@ -13,12 +13,43 @@ func GetThreadRoot(tags nostr.Tags) *nostr.Tag {
 }
 
 func GetImmediateReply(tags nostr.Tags) *nostr.Tag {
+	var root *nostr.Tag
+	var lastE *nostr.Tag
+
 	for i := len(tags) - 1; i >= 0; i-- {
 		tag := tags[i]
-		if len(tag) >= 4 && tag[0] == "e" && tag[3] == "reply" {
-			return &tag
+
+		if len(tag) < 2 {
+			continue
 		}
+		if tag[0] != "e" {
+			continue
+		}
+
+		if len(tag) >= 4 {
+			if tag[3] == "reply" {
+				return &tag
+			}
+			if tag[3] == "root" {
+				// will be used as our first fallback
+				root = &tag
+				continue
+			}
+			if tag[3] == "mention" {
+				// this invalidates this tag as a second fallback mechanism (clients that don't add markers)
+				continue
+			}
+		}
+
+		lastE = &tag // will be used as our second fallback (clients that don't add markers)
 	}
 
-	return tags.GetLast([]string{"e", ""})
+	// if we reached this point we don't have a "reply", but if we have a "root"
+	// that means this event is a direct reply to the root
+	if root != nil {
+		return root
+	}
+
+	// if we reached this point and we have at least one "e" we'll use that (the last)
+	return lastE
 }