From 94ea299c393c404662559fe6fb62df0cd2600fd4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?David=20Barrag=C3=A1n=20Merino?=
 <david.barragan@kaleidos.net>
Date: Wed, 17 Aug 2016 14:21:07 +0200
Subject: [PATCH] Add epics info in user_story_extra_info in task serializer

---
 taiga/projects/tasks/api.py         |  1 -
 taiga/projects/tasks/serializers.py | 14 +----------
 taiga/projects/tasks/utils.py       | 39 ++++++++++++++++++++++++++++-
 3 files changed, 39 insertions(+), 15 deletions(-)

diff --git a/taiga/projects/tasks/api.py b/taiga/projects/tasks/api.py
index 5f9a06ae..9584a17b 100644
--- a/taiga/projects/tasks/api.py
+++ b/taiga/projects/tasks/api.py
@@ -79,7 +79,6 @@ class TaskViewSet(OCCResourceMixin, VotedResourceMixin, HistoryResourceMixin,
     def get_queryset(self):
         qs = super().get_queryset()
         qs = qs.select_related("milestone",
-                               "user_story",
                                "project",
                                "status",
                                "owner",
diff --git a/taiga/projects/tasks/serializers.py b/taiga/projects/tasks/serializers.py
index 358b88ee..f0621581 100644
--- a/taiga/projects/tasks/serializers.py
+++ b/taiga/projects/tasks/serializers.py
@@ -29,18 +29,6 @@ from taiga.projects.notifications.mixins import WatchedResourceSerializer
 from taiga.projects.tagging.serializers import TaggedInProjectResourceSerializer
 from taiga.projects.votes.mixins.serializers import VoteResourceSerializerMixin
 
-class UserStoryExtraInfoSerializer(serializers.LightSerializer):
-    id = Field()
-    ref = Field()
-    subject = Field()
-
-    def to_value(self, instance):
-        if instance is None:
-            return None
-
-        return super().to_value(instance)
-
-
 class TaskListSerializer(VoteResourceSerializerMixin, WatchedResourceSerializer,
                          OwnerExtraInfoSerializerMixin, AssignedToExtraInfoSerializerMixin,
                          StatusExtraInfoSerializerMixin, BasicAttachmentsInfoSerializerMixin,
@@ -65,7 +53,7 @@ class TaskListSerializer(VoteResourceSerializerMixin, WatchedResourceSerializer,
     is_blocked = Field()
     blocked_note = Field()
     is_closed = MethodField()
-    user_story_extra_info = UserStoryExtraInfoSerializer(attr="user_story")
+    user_story_extra_info = Field()
 
     def get_milestone_slug(self, obj):
         return obj.milestone.slug if obj.milestone else None
diff --git a/taiga/projects/tasks/utils.py b/taiga/projects/tasks/utils.py
index d10dddab..d5775d19 100644
--- a/taiga/projects/tasks/utils.py
+++ b/taiga/projects/tasks/utils.py
@@ -25,8 +25,44 @@ from taiga.projects.votes.utils import attach_total_voters_to_queryset
 from taiga.projects.votes.utils import attach_is_voter_to_queryset
 
 
-def attach_extra_info(queryset, user=None, include_attachments=False):
+def attach_user_story_extra_info(queryset, as_field="user_story_extra_info"):
+    """Attach userstory extra info  as json column to each object of the queryset.
 
+    :param queryset: A Django user stories queryset object.
+    :param as_field: Attach the userstory extra info as an attribute with this name.
+
+    :return: Queryset object with the additional `as_field` field.
+    """
+
+    model = queryset.model
+    sql = """SELECT row_to_json(u)
+               FROM (SELECT "userstories_userstory"."id" AS "id",
+                            "userstories_userstory"."ref" AS "ref",
+                            "userstories_userstory"."subject" AS "subject",
+                            (SELECT json_agg(row_to_json(t))
+                               FROM (SELECT "epics_epic"."id" AS "id",
+                                            "epics_epic"."ref" AS "ref",
+                                            "epics_epic"."subject" AS "subject",
+                                            "epics_epic"."color" AS "color",
+                                            json_build_object('id', "projects_project"."id",
+                                                              'name', "projects_project"."name",
+                                                              'slug', "projects_project"."slug") AS "project"
+                                       FROM "epics_relateduserstory"
+                                 INNER JOIN "epics_epic"
+                                         ON "epics_epic"."id" = "epics_relateduserstory"."epic_id"
+                                 INNER JOIN "projects_project"
+                                         ON "projects_project"."id" = "epics_epic"."project_id"
+                                      WHERE "epics_relateduserstory"."user_story_id" = "{tbl}"."user_story_id"
+                                   ORDER BY "projects_project"."name", "epics_epic"."ref") t) AS "epics"
+               FROM "userstories_userstory"
+              WHERE "userstories_userstory"."id" = "{tbl}"."user_story_id") u"""
+
+    sql = sql.format(tbl=model._meta.db_table)
+    queryset = queryset.extra(select={as_field: sql})
+    return queryset
+
+
+def attach_extra_info(queryset, user=None, include_attachments=False):
     if include_attachments:
         queryset = attach_basic_attachments(queryset)
         queryset = queryset.extra(select={"include_attachments": "True"})
@@ -36,4 +72,5 @@ def attach_extra_info(queryset, user=None, include_attachments=False):
     queryset = attach_total_watchers_to_queryset(queryset)
     queryset = attach_is_voter_to_queryset(queryset, user)
     queryset = attach_is_watcher_to_queryset(queryset, user)
+    queryset = attach_user_story_extra_info(queryset)
     return queryset