"""Challenge repository for data access operations."""
from typing import List, Optional
from sqlalchemy.orm import Session
from sqlalchemy import func
from backend.models.challenge import Challenge
from backend.repositories.base import BaseRepository


class ChallengeRepository(BaseRepository[Challenge]):
    """Repository for Challenge model operations."""

    def __init__(self, db: Session):
        """Initialize challenge repository."""
        super().__init__(Challenge, db)

    def get_by_user_id(self, user_id: int) -> List[Challenge]:
        """Get all challenges for a user ordered by display_order."""
        return self.db.query(Challenge).filter(
            Challenge.user_id == user_id
        ).order_by(Challenge.display_order.asc()).all()

    def get_by_user_and_id(self, user_id: int, challenge_id: int) -> Optional[Challenge]:
        """Get a challenge by user ID and challenge ID."""
        return self.db.query(Challenge).filter(
            Challenge.id == challenge_id,
            Challenge.user_id == user_id
        ).first()

    def get_max_display_order(self, user_id: int) -> Optional[int]:
        """Get the maximum display_order for a user."""
        return self.db.query(func.max(Challenge.display_order)).filter(
            Challenge.user_id == user_id
        ).scalar()