def attach_extra_info(queryset, user=None):
    # Userstories prefetching
    UserStory = apps.get_model("userstories", "UserStory")
    us_queryset = UserStory.objects.select_related("milestone",
                                                   "project",
                                                   "status",
                                                   "owner",
                                                   "assigned_to",
                                                   "generated_from_issue")

    us_queryset = userstories_utils.attach_total_points(us_queryset)
    us_queryset = userstories_utils.attach_role_points(us_queryset)
    us_queryset = attach_total_voters_to_queryset(us_queryset)
    us_queryset = attach_watchers_to_queryset(us_queryset)
    us_queryset = attach_total_watchers_to_queryset(us_queryset)
    us_queryset = attach_is_voter_to_queryset(us_queryset, user)
    us_queryset = attach_is_watcher_to_queryset(us_queryset, user)

    queryset = queryset.prefetch_related(Prefetch("user_stories", queryset=us_queryset))
    queryset = attach_total_points(queryset)
    queryset = attach_closed_points(queryset)

    queryset = attach_total_voters_to_queryset(queryset)
    queryset = attach_watchers_to_queryset(queryset)
    queryset = attach_total_watchers_to_queryset(queryset)
    queryset = attach_is_voter_to_queryset(queryset, user)
    queryset = attach_is_watcher_to_queryset(queryset, user)
    return queryset

    def attach_watchers_attrs_to_queryset(self, queryset):
        qs = attach_watchers_to_queryset(queryset)
        qs = attach_total_watchers_to_queryset(queryset)
        if self.request.user.is_authenticated():
            qs = attach_is_watcher_to_queryset(qs, self.request.user)

        return qs

def attach_extra_info(queryset, user=None, include_attachments=False, include_tasks=False, epic_id=None):
    queryset = attach_total_points(queryset)
    queryset = attach_role_points(queryset)
    queryset = attach_epics(queryset)

    if include_attachments:
        queryset = attach_basic_attachments(queryset)
        queryset = queryset.extra(select={"include_attachments": "True"})

    if include_tasks:
        queryset = attach_tasks(queryset)
        queryset = queryset.extra(select={"include_tasks": "True"})

    if epic_id is not None:
        queryset = attach_epic_order(queryset, epic_id)
        queryset = queryset.extra(select={"include_epic_order": "True"})

    queryset = attach_total_attachments(queryset)
    queryset = attach_total_voters_to_queryset(queryset)
    queryset = attach_watchers_to_queryset(queryset)
    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_total_comments_to_queryset(queryset)
    return queryset

def tasks_to_csv(project, queryset):
    csv_data = io.StringIO()
    fieldnames = ["ref", "subject", "description", "user_story", "sprint", "sprint_estimated_start",
                  "sprint_estimated_finish", "owner", "owner_full_name", "assigned_to",
                  "assigned_to_full_name", "status", "is_iocaine", "is_closed", "us_order",
                  "taskboard_order", "attachments", "external_reference", "tags", "watchers", "voters",
                  "created_date", "modified_date", "finished_date"]

    custom_attrs = project.taskcustomattributes.all()
    for custom_attr in custom_attrs:
        fieldnames.append(custom_attr.name)

    queryset = queryset.prefetch_related("attachments",
                                         "custom_attributes_values")
    queryset = queryset.select_related("milestone",
                                       "owner",
                                       "assigned_to",
                                       "status",
                                       "project")

    queryset = attach_total_voters_to_queryset(queryset)
    queryset = attach_watchers_to_queryset(queryset)

    writer = csv.DictWriter(csv_data, fieldnames=fieldnames)
    writer.writeheader()
    for task in queryset:
        task_data = {
            "ref": task.ref,
            "subject": task.subject,
            "description": task.description,
            "user_story": task.user_story.ref if task.user_story else None,
            "sprint": task.milestone.name if task.milestone else None,
            "sprint_estimated_start": task.milestone.estimated_start if task.milestone else None,
            "sprint_estimated_finish": task.milestone.estimated_finish if task.milestone else None,
            "owner": task.owner.username if task.owner else None,
            "owner_full_name": task.owner.get_full_name() if task.owner else None,
            "assigned_to": task.assigned_to.username if task.assigned_to else None,
            "assigned_to_full_name": task.assigned_to.get_full_name() if task.assigned_to else None,
            "status": task.status.name if task.status else None,
            "is_iocaine": task.is_iocaine,
            "is_closed": task.status is not None and task.status.is_closed,
            "us_order": task.us_order,
            "taskboard_order": task.taskboard_order,
            "attachments": task.attachments.count(),
            "external_reference": task.external_reference,
            "tags": ",".join(task.tags or []),
            "watchers": task.watchers,
            "voters": task.total_voters,
            "created_date": task.created_date,
            "modified_date": task.modified_date,
            "finished_date": task.finished_date,
        }
        for custom_attr in custom_attrs:
            value = task.custom_attributes_values.attributes_values.get(str(custom_attr.id), None)
            task_data[custom_attr.name] = value

        writer.writerow(task_data)

    return csv_data

def epics_to_csv(project, queryset):
    csv_data = io.StringIO()
    fieldnames = ["id", "ref", "subject", "description", "owner", "owner_full_name",
                  "assigned_to", "assigned_to_full_name", "status", "epics_order",
                  "client_requirement", "team_requirement", "attachments", "tags",
                  "watchers", "voters", "created_date", "modified_date",
                  "related_user_stories"]

    custom_attrs = project.epiccustomattributes.all()
    for custom_attr in custom_attrs:
        fieldnames.append(custom_attr.name)

    queryset = queryset.prefetch_related("attachments",
                                         "custom_attributes_values",
                                         "user_stories__project")
    queryset = queryset.select_related("owner",
                                       "assigned_to",
                                       "status",
                                       "project")

    queryset = attach_total_voters_to_queryset(queryset)
    queryset = attach_watchers_to_queryset(queryset)

    writer = csv.DictWriter(csv_data, fieldnames=fieldnames)
    writer.writeheader()
    for epic in queryset:
        epic_data = {
            "id": epic.id,
            "ref": epic.ref,
            "subject": epic.subject,
            "description": epic.description,
            "owner": epic.owner.username if epic.owner else None,
            "owner_full_name": epic.owner.get_full_name() if epic.owner else None,
            "assigned_to": epic.assigned_to.username if epic.assigned_to else None,
            "assigned_to_full_name": epic.assigned_to.get_full_name() if epic.assigned_to else None,
            "status": epic.status.name if epic.status else None,
            "epics_order": epic.epics_order,
            "client_requirement": epic.client_requirement,
            "team_requirement": epic.team_requirement,
            "attachments": epic.attachments.count(),
            "tags": ",".join(epic.tags or []),
            "watchers": epic.watchers,
            "voters": epic.total_voters,
            "created_date": epic.created_date,
            "modified_date": epic.modified_date,
            "related_user_stories": ",".join([
                "{}#{}".format(us.project.slug, us.ref) for us in epic.user_stories.all()
            ]),
        }

        for custom_attr in custom_attrs:
            if not hasattr(epic, "custom_attributes_values"):
                continue
            value = epic.custom_attributes_values.attributes_values.get(str(custom_attr.id), None)
            epic_data[custom_attr.name] = value

        writer.writerow(epic_data)

    return csv_data

def attach_extra_info(queryset, user=None):
    queryset = attach_generated_user_stories(queryset)
    queryset = attach_total_voters_to_queryset(queryset)
    queryset = attach_watchers_to_queryset(queryset)
    queryset = attach_total_watchers_to_queryset(queryset)
    queryset = attach_is_voter_to_queryset(queryset, user)
    queryset = attach_is_watcher_to_queryset(queryset, user)
    return queryset

def issues_to_csv(project, queryset):
    csv_data = io.StringIO()
    fieldnames = ["ref", "subject", "description", "sprint", "sprint_estimated_start",
                  "sprint_estimated_finish", "owner", "owner_full_name", "assigned_to",
                  "assigned_to_full_name", "status", "severity", "priority", "type",
                  "is_closed", "attachments", "external_reference", "tags", "watchers",
                  "voters", "created_date", "modified_date", "finished_date"]

    custom_attrs = project.issuecustomattributes.all()
    for custom_attr in custom_attrs:
        fieldnames.append(custom_attr.name)

    queryset = queryset.prefetch_related("attachments",
                                         "generated_user_stories",
                                         "custom_attributes_values")
    queryset = queryset.select_related("owner",
                                       "assigned_to",
                                       "status",
                                       "project")
    queryset = attach_total_voters_to_queryset(queryset)
    queryset = attach_watchers_to_queryset(queryset)

    writer = csv.DictWriter(csv_data, fieldnames=fieldnames)
    writer.writeheader()
    for issue in queryset:
        issue_data = {
            "ref": issue.ref,
            "subject": issue.subject,
            "description": issue.description,
            "sprint": issue.milestone.name if issue.milestone else None,
            "sprint_estimated_start": issue.milestone.estimated_start if issue.milestone else None,
            "sprint_estimated_finish": issue.milestone.estimated_finish if issue.milestone else None,
            "owner": issue.owner.username if issue.owner else None,
            "owner_full_name": issue.owner.get_full_name() if issue.owner else None,
            "assigned_to": issue.assigned_to.username if issue.assigned_to else None,
            "assigned_to_full_name": issue.assigned_to.get_full_name() if issue.assigned_to else None,
            "status": issue.status.name if issue.status else None,
            "severity": issue.severity.name,
            "priority": issue.priority.name,
            "type": issue.type.name,
            "is_closed": issue.is_closed,
            "attachments": issue.attachments.count(),
            "external_reference": issue.external_reference,
            "tags": ",".join(issue.tags or []),
            "watchers": issue.watchers,
            "voters": issue.total_voters,
            "created_date": issue.created_date,
            "modified_date": issue.modified_date,
            "finished_date": issue.finished_date,
        }

        for custom_attr in custom_attrs:
            value = issue.custom_attributes_values.attributes_values.get(str(custom_attr.id), None)
            issue_data[custom_attr.name] = value

        writer.writerow(issue_data)

    return csv_data

def userstories_to_csv(project, queryset):
    csv_data = io.StringIO()
    fieldnames = ["ref", "subject", "description", "sprint", "sprint_estimated_start",
                  "sprint_estimated_finish", "owner", "owner_full_name", "assigned_to",
                  "assigned_to_full_name", "status", "is_closed"]

    roles = project.roles.filter(computable=True).order_by('slug')
    for role in roles:
        fieldnames.append("{}-points".format(role.slug))

    fieldnames.append("total-points")

    fieldnames += ["backlog_order", "sprint_order", "kanban_order",
                   "created_date", "modified_date", "finish_date",
                   "client_requirement", "team_requirement", "attachments",
                   "generated_from_issue", "external_reference", "tasks",
                   "tags", "watchers", "voters"]

    custom_attrs = project.userstorycustomattributes.all()
    for custom_attr in custom_attrs:
        fieldnames.append(custom_attr.name)

    queryset = queryset.prefetch_related("role_points",
                                         "role_points__points",
                                         "role_points__role",
                                         "tasks",
                                         "attachments",
                                         "custom_attributes_values")
    queryset = queryset.select_related("milestone",
                                       "project",
                                       "status",
                                       "owner",
                                       "assigned_to",
                                       "generated_from_issue")

    queryset = attach_total_voters_to_queryset(queryset)
    queryset = attach_watchers_to_queryset(queryset)

    writer = csv.DictWriter(csv_data, fieldnames=fieldnames)
    writer.writeheader()
    for us in queryset:
        row = {
            "ref": us.ref,
            "subject": us.subject,
            "description": us.description,
            "sprint": us.milestone.name if us.milestone else None,
            "sprint_estimated_start": us.milestone.estimated_start if us.milestone else None,
            "sprint_estimated_finish": us.milestone.estimated_finish if us.milestone else None,
            "owner": us.owner.username if us.owner else None,
            "owner_full_name": us.owner.get_full_name() if us.owner else None,
            "assigned_to": us.assigned_to.username if us.assigned_to else None,
            "assigned_to_full_name": us.assigned_to.get_full_name() if us.assigned_to else None,
            "status": us.status.name if us.status else None,
            "is_closed": us.is_closed,
            "backlog_order": us.backlog_order,
            "sprint_order": us.sprint_order,
            "kanban_order": us.kanban_order,
            "created_date": us.created_date,
            "modified_date": us.modified_date,
            "finish_date": us.finish_date,
            "client_requirement": us.client_requirement,
            "team_requirement": us.team_requirement,
            "attachments": us.attachments.count(),
            "generated_from_issue": us.generated_from_issue.ref if us.generated_from_issue else None,
            "external_reference": us.external_reference,
            "tasks": ",".join([str(task.ref) for task in us.tasks.all()]),
            "tags": ",".join(us.tags or []),
            "watchers": us.watchers,
            "voters": us.total_voters,
        }

        us_role_points_by_role_id = {us_rp.role.id: us_rp.points.value for us_rp in us.role_points.all()}
        for role in roles:
            row["{}-points".format(role.slug)] = us_role_points_by_role_id.get(role.id, 0)

        row['total-points'] = us.get_total_points()

        for custom_attr in custom_attrs:
            value = us.custom_attributes_values.attributes_values.get(str(custom_attr.id), None)
            row[custom_attr.name] = value

        writer.writerow(row)

    return csv_data

    def attach_watchers_attrs_to_queryset(self, queryset):
        qs = attach_watchers_to_queryset(queryset)
        if self.request.user.is_authenticated():
            qs = attach_is_watched_to_queryset(self.request.user, qs)

        return qs