import graphene
from django.db.models import Prefetch, Value, CharField, Q
from django.db.models.functions import Concat
from graphene import relay, ObjectType
from graphene_django import DjangoObjectType
from graphene_django.filter import DjangoFilterConnectionField
from graphql_relay import to_global_id

from basicknowledge.models import BasicKnowledge
from basicknowledge.queries import InstrumentNode
from books.models import Module
from books.schema.queries import ModuleNode
from users.models import User, SchoolClass, SchoolClassMember


class SchoolClassNode(DjangoObjectType):
    pk = graphene.Int()
    members = graphene.List('users.schema.ClassMemberNode')

    class Meta:
        model = SchoolClass
        filter_fields = ['name']
        interfaces = (relay.Node,)

    def resolve_pk(self, *args, **kwargs):
        return self.id

    def resolve_members(self, info, **kwargs):
        return SchoolClassMember.objects.filter(school_class=self)


class UserNode(DjangoObjectType):
    pk = graphene.Int()
    permissions = graphene.List(graphene.String)
    selected_class = graphene.Field(SchoolClassNode)
    is_teacher = graphene.Boolean()
    old_classes = DjangoFilterConnectionField(SchoolClassNode)

    class Meta:
        model = User
        filter_fields = ['username', 'email']
        only_fields = ['username', 'email', 'first_name', 'last_name', 'school_classes', 'last_module', 'avatar_url',
                       'selected_class']
        interfaces = (relay.Node,)

    def resolve_pk(self, info, **kwargs):
        return self.id

    def resolve_permissions(self, info):
        return self.get_all_permissions()

    def resolve_selected_class(self, info):
        return self.selected_class()

    def resolve_is_teacher(self, info):
        return self.is_teacher()

    def resolve_school_classes(self, info):
        if self.selected_class() is None:  # then we don't have any class to return
            return []
        return SchoolClass.objects.filter(
            Q(schoolclassmember__active=True, schoolclassmember__user=self) | Q(pk=self.selected_class().pk)).distinct()

    def resolve_old_classes(self, info):
        return SchoolClass.objects.filter(schoolclassmember__active=False, schoolclassmember__user=self)


class ClassMemberNode(ObjectType):
    """
    We need to build this ourselves, because we want the active property on the node, because providing it on the
    Connection or Edge for a UserNodeConnection is difficult.
    """
    user = graphene.Field(UserNode)
    active = graphene.Boolean()
    first_name = graphene.String()
    last_name = graphene.String()
    is_teacher = graphene.Boolean()
    id = graphene.ID()

    def resolve_id(self, *args):
        return to_global_id('UserNode', self.user.pk)

    def resolve_active(self, *args):
        return self.active

    def resolve_first_name(self, *args):
        return self.user.first_name

    def resolve_last_name(self, *args):
        return self.user.last_name

    def resolve_user(self, info, **kwargs):
        return self.user

    def resolve_is_teacher(self, *args):
        return self.user.is_teacher()


class UsersQuery(object):
    me = graphene.Field(UserNode)
    all_users = DjangoFilterConnectionField(UserNode)
    my_activity = DjangoFilterConnectionField(ModuleNode)
    my_instrument_activity = DjangoFilterConnectionField(InstrumentNode)

    def resolve_me(self, info, **kwargs):
        return info.context.user

    def resolve_all_users(self, info, **kwargs):
        if not info.context.user.is_superuser:
            return User.objects.none()
        else:
            return User.objects.all()

    def resolve_my_activity(self, info, **kwargs):
        return Module.objects.all()

    def resolve_my_instrument_activity(self, info, **kwargs):
        return BasicKnowledge.objects.all()


class AllUsersQuery(object):
    me = graphene.Field(UserNode)
    all_users = DjangoFilterConnectionField(UserNode)

    def resolve_all_users(self, info, **kwargs):
        if not info.context.user.is_superuser:
            return User.objects.none()
        else:
            return User.objects.all()