Initial commit to support workflow actions.

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

mayan/apps/document_states/classes.py

@@ -1,7 +1,17 @@
 from __future__ import unicode_literals
 
+from importlib import import_module
+import logging
+
+from django.apps import apps
+from django.utils import six
+from django.utils.encoding import force_text
+
 from common.classes import PropertyHelper
 
+__all__ = ('WorkflowAction',)
+logger = logging.getLogger(__name__)
+
 
 class DocumentStateHelper(PropertyHelper):
     @staticmethod
@@ -11,3 +21,51 @@ class DocumentStateHelper(PropertyHelper):
 
     def get_result(self, name):
         return self.instance.workflows.get(workflow__internal_name=name)
+
+
+class WorkflowActionMetaclass(type):
+    _registry = {}
+
+    def __new__(mcs, name, bases, attrs):
+        new_class = super(WorkflowActionMetaclass, mcs).__new__(
+            mcs, name, bases, attrs
+        )
+
+        if not new_class.__module__ == __name__:
+            mcs._registry[
+                '{}.{}'.format(new_class.__module__, name)
+            ] = new_class
+
+        return new_class
+
+
+class WorkflowActionBase(object):
+    fields = ()
+
+
+class WorkflowAction(six.with_metaclass(WorkflowActionMetaclass, WorkflowActionBase)):
+    @classmethod
+    def get(cls, name):
+        return cls._registry[name]
+
+    @classmethod
+    def get_all(cls):
+        return cls._registry
+
+    @staticmethod
+    def initialize():
+        for app in apps.get_app_configs():
+            try:
+                import_module('{}.workflow_actions'.format(app.name))
+            except ImportError as exception:
+                if force_text(exception) != 'No module named workflow_actions':
+                    logger.error(
+                        'Error importing %s workflow_actions.py file; %s',
+                        app.name, exception
+                    )
+
+    def get_form_schema(self, request=None):
+        return {
+            'fields': self.fields or (),
+            'widgets': getattr(self, 'widgets', {})
+        }