from typing import List, Optional

from sqlalchemy.orm import Session

from app.models.category import Category
from app.schemas.category import CategoryCreate, CategoryUpdate


def get_category(db: Session, category_id: int) -> Optional[Category]:
    """
    Get a category by ID
    """
    return db.query(Category).filter(Category.id == category_id).first()


def get_category_by_user(
    db: Session, category_id: int, user_id: int
) -> Optional[Category]:
    """
    Get a category by ID for a specific user
    """
    return db.query(Category).filter(
        Category.id == category_id, Category.owner_id == user_id
    ).first()


def get_categories(
    db: Session, user_id: int, skip: int = 0, limit: int = 100
) -> List[Category]:
    """
    Get all categories for a user
    """
    return db.query(Category).filter(
        Category.owner_id == user_id
    ).offset(skip).limit(limit).all()


def create_category(
    db: Session, category_in: CategoryCreate, user_id: int
) -> Category:
    """
    Create a new category for a user
    """
    db_category = Category(
        **category_in.dict(),
        owner_id=user_id,
    )
    db.add(db_category)
    db.commit()
    db.refresh(db_category)
    return db_category


def update_category(
    db: Session, category_id: int, category_in: CategoryUpdate, user_id: int
) -> Optional[Category]:
    """
    Update a category
    """
    db_category = get_category_by_user(db, category_id, user_id)
    if not db_category:
        return None

    update_data = category_in.dict(exclude_unset=True)
    for field, value in update_data.items():
        setattr(db_category, field, value)

    db.add(db_category)
    db.commit()
    db.refresh(db_category)
    return db_category


def delete_category(
    db: Session, category_id: int, user_id: int
) -> Optional[Category]:
    """
    Delete a category
    """
    db_category = get_category_by_user(db, category_id, user_id)
    if not db_category:
        return None

    db.delete(db_category)
    db.commit()
    return db_category