Add manager class to handle the metadata types of a document type easily

mayan/apps/metadata/classes.py

@@ -2,6 +2,8 @@ from django.utils.translation import ugettext_lazy as _
 
 from acls.classes import EncapsulatedObject
 
+from .models import DocumentTypeMetadataType, MetadataType
+
 
 class MetadataClass(object):
     def __init__(self, dictionary):
@@ -16,3 +18,32 @@ class MetadataClass(object):
 
 class MetadataObjectWrapper(EncapsulatedObject):
     source_object_name = u'metadata_object'
+
+
+class DocumentTypeMetadataTypeManager(object):
+    @staticmethod
+    @property
+    def factory(document_type):
+        instance = DocumentTypeMetadataTypeManager(document_type)
+        return instance
+
+    def __init__(self, document_type):
+        self.document_type = document_type
+
+    def filter(self, **kwargs):
+        return self.get_query_set(**kwargs)
+
+    def all(self):
+        return self.get_query_set()
+
+    def get_query_set(self, **kwargs):
+        try:
+            return MetadataType.objects.filter(pk__in=self.document_type.documenttypemetadatatype_set.filter(**kwargs).values_list('metadata_type', flat=True))
+        except self.document_type.documenttypemetadatatype_set.model.DoesNotExist:
+            return MetadataType.objects.none()
+
+    def add(self, metadata_type, required=False):
+        DocumentTypeMetadataType.objects.create(document_type=self.document_type, metadata_type= metadata_type, required=required)
+
+    def remove(self, metadata_type):
+        DocumentTypeMetadataType.objects.get(document_type=self.document_type, metadata_type= metadata_type).delete()