import uuid
from typing import Optional

from sqlalchemy import select, func, update
from sqlalchemy.ext.asyncio import AsyncSession

from app.models.alert import Alert


class AlertRepository:
    def __init__(self, session: AsyncSession):
        self.session = session

    async def get_by_id(self, id: uuid.UUID) -> Optional[Alert]:
        result = await self.session.execute(
            select(Alert).where(Alert.id == id)
        )
        return result.scalar_one_or_none()

    async def list_by_user(
        self, user_id: uuid.UUID, *, skip: int = 0, limit: int = 100
    ) -> list[Alert]:
        result = await self.session.execute(
            select(Alert)
            .where(Alert.user_id == user_id)
            .order_by(Alert.created_at.desc())
            .offset(skip)
            .limit(limit)
        )
        return list(result.scalars().all())

    async def count_by_user(self, user_id: uuid.UUID) -> int:
        result = await self.session.execute(
            select(func.count()).select_from(Alert).where(Alert.user_id == user_id)
        )
        return result.scalar_one()

    async def get_unread_by_user(self, user_id: uuid.UUID) -> list[Alert]:
        result = await self.session.execute(
            select(Alert).where(
                Alert.user_id == user_id,
                Alert.is_read == False,
            ).order_by(Alert.created_at.desc())
        )
        return list(result.scalars().all())

    async def mark_as_read(self, alert_id: uuid.UUID) -> bool:
        instance = await self.get_by_id(alert_id)
        if instance is None:
            return False
        instance.is_read = True
        await self.session.flush()
        return True

    async def create(self, **kwargs) -> Alert:
        instance = Alert(**kwargs)
        self.session.add(instance)
        await self.session.flush()
        return instance

    async def update(self, id: uuid.UUID, **kwargs) -> Optional[Alert]:
        instance = await self.get_by_id(id)
        if instance is None:
            return None
        for key, value in kwargs.items():
            if hasattr(instance, key):
                setattr(instance, key, value)
        await self.session.flush()
        return instance

    async def delete(self, id: uuid.UUID) -> bool:
        instance = await self.get_by_id(id)
        if instance is None:
            return False
        await self.session.delete(instance)
        await self.session.flush()
        return True