from typing import List
from sqlalchemy import and_, select
from sqlalchemy.orm import aliased
from sqlalchemy.exc import SQLAlchemyError
from orm.author import Author
from orm.notification import Notification as NotificationMessage, NotificationSeen
from services.auth import login_required
from services.db import local_session
from strawberry_sqlalchemy_mapper import StrawberrySQLAlchemyMapper
import strawberry
from strawberry.schema.config import StrawberryConfig

strawberry_sqlalchemy_mapper = StrawberrySQLAlchemyMapper()


@strawberry_sqlalchemy_mapper.type(NotificationMessage)
class Notification:
    id: int
    action: str  # create update delete join follow etc.
    entity: str  # REACTION SHOUT
    created_at: int
    payload: str  # JSON data
    seen: List[int]


@strawberry.type
class NotificationSeenResult:
    error: str = strawberry.field(default=None, name="error")


@strawberry.type
class NotificationsResult:
    notifications: List[Notification]
    unread: int
    total: int


def get_notifications(author, session, limit, offset) -> List[Notification]:
    NotificationSeenAlias = aliased(NotificationSeen)
    query = select(
        NotificationMessage,
        NotificationSeenAlias.viewer.label("seen")
    ).outerjoin(
        NotificationSeen,
        and_(NotificationSeen.viewer == author.id, NotificationSeen.notification == NotificationMessage.id),
    ).group_by(NotificationSeen.notification)
    if limit:
        query = query.limit(limit)
    if offset:
        query = query.offset(offset)

    notifications = []
    for n, seen in session.execute(query):
        ntf = Notification(
            id=n.id,
            payload=n.payload,
            entity=n.entity,
            action=n.action,
            created_at=n.created_at,
            seen=seen,
        )
        if ntf:
            notifications.append(ntf)
    return notifications


@strawberry.type
class Query:
    @strawberry.field
    @login_required
    async def load_notifications(self, info, limit: int = 50, offset: int = 0) -> NotificationsResult:
        user_id = info.context["user_id"]
        with local_session() as session:
            try:
                author = session.query(Author).filter(Author.user == user_id).first()
                if author:
                    notifications = get_notifications(author, session, limit, offset)
                    if notifications and len(notifications) > 0:
                        nr = NotificationsResult(
                            notifications=notifications,
                            unread=sum(1 for n in notifications if author.id in n.seen),
                            total=session.query(NotificationMessage).count()
                        )
                        return nr
            except Exception as ex:
                print(f"[resolvers.schema] {ex}")
        return NotificationsResult(
            notifications=[],
            total=0,
            unread=0
        )


@strawberry.type
class Mutation:
    @strawberry.mutation
    @login_required
    async def mark_notification_as_read(self, info, notification_id: int) -> NotificationSeenResult:
        user_id = info.context["user_id"]
        with local_session() as session:
            try:
                author = session.query(Author).filter(Author.user == user_id).first()
                if author:
                    ns = NotificationSeen(notification=notification_id, viewer=author.id)
                    session.add(ns)
                    session.commit()
            except SQLAlchemyError as e:
                session.rollback()
                print(f"[mark_notification_as_read] error: {str(e)}")
                nsr = NotificationSeenResult(error="cant mark as read")
                return nsr
        return NotificationSeenResult()

    @strawberry.mutation
    @login_required
    async def mark_all_notifications_as_read(self, info) -> NotificationSeenResult:
        user_id = info.context["user_id"]

        with local_session() as session:
            try:
                author = session.query(Author).filter(Author.user == user_id).first()
                if author:
                    nslist = get_notifications(author, session, None, None)
                    for n in nslist:
                        if author.id not in n.seen:
                            ns = NotificationSeen(viewer=author.id, notification=n.id)
                            session.add(ns)
                    session.commit()
            except SQLAlchemyError as e:
                session.rollback()
                print(f"[mark_all_notifications_as_read] error: {str(e)}")
                nsr = NotificationSeenResult(error="cant mark as read")
                return nsr
        return NotificationSeenResult()


schema = strawberry.Schema(query=Query, mutation=Mutation, config=StrawberryConfig(auto_camel_case=False))