From 7c1b016997d056b38cc2f04ece45e903a1cfdc92 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?David=20Barrag=C3=A1n=20Merino?=
 <david.barragan@kaleidos.net>
Date: Wed, 13 Nov 2013 23:42:37 +0100
Subject: [PATCH] Added type and changed_fields to the version serializer class

---
 greenmine/base/serializers.py | 39 +++++++++++++++++++++++++++++++++--
 1 file changed, 37 insertions(+), 2 deletions(-)

diff --git a/greenmine/base/serializers.py b/greenmine/base/serializers.py
index 76209f58..aa016ad6 100644
--- a/greenmine/base/serializers.py
+++ b/greenmine/base/serializers.py
@@ -3,6 +3,7 @@
 from rest_framework import serializers
 
 from reversion.models import Version
+import reversion
 
 
 class PickleField(serializers.WritableField):
@@ -20,14 +21,16 @@ class VersionSerializer(serializers.ModelSerializer):
     created_date = serializers.SerializerMethodField("get_created_date")
     content_type = serializers.SerializerMethodField("get_content_type")
     object_id = serializers.SerializerMethodField("get_object_id")
+    type_name = serializers.SerializerMethodField("get_type")
     user = serializers.SerializerMethodField("get_user")
     comment = serializers.SerializerMethodField("get_comment")
     fields = serializers.SerializerMethodField("get_object_fields")
+    changed_fields  = serializers.SerializerMethodField("get_changed_fields")
 
     class Meta:
         model = Version
-        fields = ("id", "created_date", "content_type", "object_id", "user", "comment",
-                  "fields")
+        fields = ("id", "created_date", "content_type", "object_id", "type",
+                  "type_name", "user", "comment", "fields", "changed_fields")
         read_only = fields
 
     def get_created_date(self, obj):
@@ -39,6 +42,9 @@ class VersionSerializer(serializers.ModelSerializer):
     def get_object_id(self, obj):
         return obj.object_id_int
 
+    def get_type(self, obj):
+        return obj.get_type_display()
+
     def get_object_fields(self, obj):
         return obj.field_dict
 
@@ -47,3 +53,32 @@ class VersionSerializer(serializers.ModelSerializer):
 
     def get_comment(self, obj):
         return obj.revision.comment
+
+    def get_object_old_fields(self, obj):
+        versions = reversion.get_unique_for_object(obj.object)
+        try:
+            return versions[versions.index(obj) + 1].field_dict
+        except IndexError:
+            return None
+
+    def get_changed_fields(self, obj):
+        new_fields = self.get_object_fields(obj)
+        old_fields = self.get_object_old_fields(obj)
+
+        changed_fields = {}
+        if old_fields:
+            for key in new_fields.keys() | old_fields.keys():
+                if key == "modified_date":
+                    continue
+
+                if old_fields.get(key, None) == new_fields.get(key, None):
+                    continue
+
+                changed_fields[key] = {
+                     "name": obj.object.__class__._meta.get_field_by_name(
+                                                       key)[0].verbose_name,
+                     "old": old_fields.get(key, None),
+                     "new": new_fields.get(key, None),
+                  }
+
+        return changed_fields