"""
User Repository - Data Access Layer for User operations

Following Python Quick Start Guide:
- Repository layer contains ONLY database operations
- No business logic (that goes in services)
- Simple CRUD operations and queries
"""
from typing import Optional, List, Dict, Any
from app.core.database import db
from models import User


class UserRepository:
    """
    User repository - handles all User database operations.

    Responsibilities:
    - CRUD operations
    - Database queries
    - No business logic
    """

    def __init__(self, db_session=None):
        """Initialize repository with database session."""
        self.db = db_session or db.session

    def find_by_id(self, user_id: int) -> Optional[User]:
        """Find user by ID."""
        return User.query.get(user_id)

    def find_by_username(self, username: str) -> Optional[User]:
        """Find user by username."""
        return User.query.filter_by(username=username).first()

    def find_by_email(self, email: str) -> Optional[User]:
        """Find user by email."""
        return User.query.filter_by(email=email).first()

    def find_all(self, page: int = 1, per_page: int = 50) -> Any:
        """
        Find all users with pagination.

        Returns:
            Pagination object with users
        """
        return User.query.order_by(User.id.desc()).paginate(
            page=page,
            per_page=per_page,
            error_out=False
        )

    def count_all(self) -> int:
        """Count total users."""
        return User.query.count()

    def count_active(self) -> int:
        """Count active users."""
        return User.query.filter_by(is_active=True).count()

    def count_inactive(self) -> int:
        """Count inactive users."""
        return User.query.filter_by(is_active=False).count()

    def count_admins(self) -> int:
        """Count admin users."""
        return User.query.filter_by(is_admin=True).count()

    def create(self, user: User) -> User:
        """
        Create a new user.

        Args:
            user: User object to create

        Returns:
            Created user with ID
        """
        self.db.add(user)
        self.db.commit()
        return user

    def update(self, user: User) -> User:
        """
        Update an existing user.

        Args:
            user: User object with updated fields

        Returns:
            Updated user
        """
        self.db.commit()
        return user

    def delete(self, user: User) -> None:
        """
        Delete a user.

        Args:
            user: User object to delete
        """
        self.db.delete(user)
        self.db.commit()

    def rollback(self) -> None:
        """Rollback current transaction."""
        self.db.rollback()