feat(claim): arbitration per mode (#5) — first claim wins except conspiracy (#23)

nestlog.go

@@ -119,6 +119,19 @@ func (s *MessageStore) ByMsgID(msgID string) (Message, bool) {
 	return Message{}, false
 }
 
+// FirstClaim returns the author of the first claim against a message, and
+// whether any claim exists.
+func (s *MessageStore) FirstClaim(nestID, referentID string) (string, bool) {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+	for _, m := range s.log[nestID] {
+		if m.Kind == "claim" && m.RefersTo == referentID {
+			return m.Author, true
+		}
+	}
+	return "", false
+}
+
 func (s *MessageStore) save(nestID string) error {
 	if err := os.MkdirAll(s.dir, 0o755); err != nil {
 		return err