fix: render error messages for invalid templates (#3088)

Currently direct templates can be created without the required
signatures fields for signers.

This means that the document can be fully signed by everyone but will
ultimately fail the sealing step which leaves the document in an
unrecoverable state.

apps/remix/app/routes/_recipient+/d.$token+/_index.tsx

@@ -7,6 +7,7 @@ import { getEnvelopeForDirectTemplateSigning } from '@documenso/lib/server-only/
 import { getTemplateByDirectLinkToken } from '@documenso/lib/server-only/template/get-template-by-direct-link-token';
 import { DocumentAccessAuth } from '@documenso/lib/types/document-auth';
 import { extractDocumentAuthMethods } from '@documenso/lib/utils/document-auth';
+import { getRecipientsWithMissingFields } from '@documenso/lib/utils/recipients';
 import { prisma } from '@documenso/prisma';
 import { Plural } from '@lingui/react/macro';
 import { UsersIcon } from 'lucide-react';
@@ -14,6 +15,7 @@ import { redirect } from 'react-router';
 import { match } from 'ts-pattern';
 
 import { Header as AuthenticatedHeader } from '~/components/general/app-header';
+import { DirectTemplateInvalidPageView } from '~/components/general/direct-template/direct-template-invalid-page';
 import { DirectTemplatePageView } from '~/components/general/direct-template/direct-template-page';
 import { DirectTemplateAuthPageView } from '~/components/general/direct-template/direct-template-signing-auth-page';
 import { DocumentSigningAuthPageView } from '~/components/general/document-signing/document-signing-auth-page';
@@ -70,8 +72,18 @@ const handleV1Loader = async ({ params, request }: Route.LoaderArgs) => {
     };
   }
 
+  const recipientsWithMissingFields = getRecipientsWithMissingFields(template.recipients, template.fields);
+
+  if (recipientsWithMissingFields.length > 0) {
+    return {
+      isAccessAuthValid: true,
+      isTemplateMissingSignatures: true,
+    } as const;
+  }
+
   return {
     isAccessAuthValid: true,
+    isTemplateMissingSignatures: false,
     template: {
       ...template,
       folder: null,
@@ -96,6 +108,7 @@ const handleV2Loader = async ({ params, request }: Route.LoaderArgs) => {
     .then((envelopeForSigning) => {
       return {
         isDocumentAccessValid: true,
+        isTemplateMissingSignatures: false,
         envelopeForSigning,
       } as const;
     })
@@ -108,6 +121,13 @@ const handleV2Loader = async ({ params, request }: Route.LoaderArgs) => {
         } as const;
       }
 
+      if (error.code === AppErrorCode.MISSING_SIGNATURE_FIELD) {
+        return {
+          isDocumentAccessValid: true,
+          isTemplateMissingSignatures: true,
+        } as const;
+      }
+
       throw new Response('Not Found', { status: 404 });
     });
 };
@@ -181,6 +201,10 @@ const DirectSigningPageV1 = ({ data }: { data: Awaited<ReturnType<typeof handleV
     return <DirectTemplateAuthPageView />;
   }
 
+  if (data.isTemplateMissingSignatures) {
+    return <DirectTemplateInvalidPageView />;
+  }
+
   const { template, directTemplateRecipient } = data;
 
   return (
@@ -235,6 +259,10 @@ const DirectSigningPageV2 = ({ data }: { data: Awaited<ReturnType<typeof handleV
     return <DocumentSigningAuthPageView email={''} emailHasAccount={true} />;
   }
 
+  if (data.isTemplateMissingSignatures) {
+    return <DirectTemplateInvalidPageView />;
+  }
+
   const { envelope, recipient } = data.envelopeForSigning;
 
   const { derivedRecipientAccessAuth } = extractDocumentAuthMethods({