Refine external signing flow and mobile PDF placement

backend/src/modules/invitations/invitations.service.js

@@ -183,12 +183,6 @@ const addInviteesToFlow = async (documentId, { invitees }, ownerUserId, context
     throw error;
   }
 
-  if (flow.status === 'completed') {
-    const error = new Error('La cadena ya fue completada. Crea una nueva si necesitas más firmas.');
-    error.statusCode = 409;
-    throw error;
-  }
-
   const { document } = await ensureOwnerCanInvite(documentId, ownerUserId);
   const existingInvitees = await invitationsRepository.listInvitationsByFlow(flow.id);
   const currentCount = existingInvitees.length;
@@ -198,11 +192,26 @@ const addInviteesToFlow = async (documentId, { invitees }, ownerUserId, context
     throw error;
   }
 
-  const existingEmails = new Set(existingInvitees.map((item) => String(item.invitee_email).toLowerCase()));
   const normalizedInvitees = invitees.map((invitee) => ({
     name: invitee.name.trim(),
     email: invitee.email.trim().toLowerCase(),
   }));
+  const payloadEmails = new Set();
+
+  for (const invitee of normalizedInvitees) {
+    if (payloadEmails.has(invitee.email)) {
+      const error = new Error(`El correo ${invitee.email} está repetido en la solicitud.`);
+      error.statusCode = 409;
+      throw error;
+    }
+    payloadEmails.add(invitee.email);
+  }
+
+  const existingEmails = new Set(
+    flow.status === 'completed'
+      ? []
+      : existingInvitees.map((item) => String(item.invitee_email).toLowerCase())
+  );
 
   for (const invitee of normalizedInvitees) {
     if (existingEmails.has(invitee.email)) {