Update app to use new hooks interface

Signed-off-by: Roberto Rosario <Roberto.Rosario@mayan-edms.com>

mayan/apps/document_signatures/apps.py

@@ -18,6 +18,10 @@ from mayan.celery import app
 from .handlers import (
     handler_unverify_key_signatures, handler_verify_key_signatures
 )
+from .hooks import (
+    hook_create_embedded_signature, hook_decrypt_document_version
+)
+
 from .links import (
     link_all_document_version_signature_verify, link_document_signature_list,
     link_document_version_signature_delete,
@@ -68,10 +72,10 @@ class DocumentSignaturesApp(MayanAppConfig):
         SignatureBaseModel = self.get_model(model_name='SignatureBaseModel')
 
         DocumentVersion.register_post_save_hook(
-            func=EmbeddedSignature.objects.create, order=1
+            func=hook_create_embedded_signature, order=1
         )
         DocumentVersion.register_pre_open_hook(
-            func=EmbeddedSignature.objects.open_signed, order=1
+            func=hook_decrypt_document_version, order=1
         )
 
         ModelPermission.register(

mayan/apps/document_signatures/hooks.py

@@ -0,0 +1,23 @@
+from __future__ import unicode_literals
+
+from django.apps import apps
+
+
+def hook_create_embedded_signature(document_version):
+    EmbeddedSignature = apps.get_model(
+        app_label='document_signatures', model_name='EmbeddedSignature'
+    )
+
+    EmbeddedSignature.objects.create(document_version=document_version)
+
+
+def hook_decrypt_document_version(document_version, file_object):
+    EmbeddedSignature = apps.get_model(
+        app_label='document_signatures', model_name='EmbeddedSignature'
+    )
+
+    return {
+        'file_object': EmbeddedSignature.objects.open_signed(
+            document_version=document_version, file_object=file_object
+        )
+    }

mayan/apps/document_signatures/managers.py

@@ -14,7 +14,7 @@ logger = logging.getLogger(__name__)
 
 
 class EmbeddedSignatureManager(models.Manager):
-    def open_signed(self, file_object, document_version):
+    def open_signed(self, document_version, file_object):
         for signature in self.filter(document_version=document_version):
             try:
                 return self.open_signed(