from typing import Optional, List
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession

from app.models.category import Category


class CategoryRepository:
    def __init__(self, db: AsyncSession):
        self.db = db

    async def get_by_id(self, category_id: int) -> Optional[Category]:
        result = await self.db.execute(select(Category).where(Category.id == category_id))
        return result.scalar_one_or_none()

    async def get_all(self, level: Optional[int] = None, parent_id: Optional[int] = None) -> List[Category]:
        query = select(Category)
        if level:
            query = query.where(Category.level == level)
        if parent_id:
            query = query.where(Category.parent_id == parent_id)
        query = query.order_by(Category.sort_order)
        result = await self.db.execute(query)
        return list(result.scalars().all())

    async def get_children(self, parent_id: int) -> List[Category]:
        result = await self.db.execute(
            select(Category)
            .where(Category.parent_id == parent_id)
            .order_by(Category.sort_order)
        )
        return list(result.scalars().all())

    async def create(self, data: dict) -> Category:
        category = Category(**data)
        self.db.add(category)
        await self.db.flush()
        return category

    async def update(self, category_id: int, data: dict) -> Optional[Category]:
        category = await self.get_by_id(category_id)
        if not category:
            return None
        for key, value in data.items():
            setattr(category, key, value)
        await self.db.flush()
        return category

    async def delete(self, category_id: int) -> bool:
        category = await self.get_by_id(category_id)
        if not category:
            return False
        await self.db.delete(category)
        return True