from datetime import datetime

from sqlalchemy import and_, desc, func, select
from sqlalchemy.ext.asyncio import AsyncSession

from db.models import Metrics, MetricsQuery, Query, Url

###########################################################
# BLOCK FOR INTERACTION WITH DATABASE IN BUSINESS CONTEXT #
###########################################################


class UrlDAL:
    """Data Access Layer for operating user info"""

    def __init__(self, db_session: AsyncSession):
        self.db_session = db_session

    async def add_new_urls(self, add_values: list[Url]):
        for new_url in add_values:
            query = select(Url).where(Url.url == new_url.url)
            res = await self.db_session.execute(query)
            if res.scalar_one_or_none() is None:
                self.db_session.add(new_url)
            else:
                # If nessessary we can update data here
                pass

        await self.db_session.flush()
        return


class MetricDAL:
    """Data Access Layer for operating user info"""

    def __init__(self, db_session: AsyncSession):
        self.db_session = db_session

    async def get_last_metrics_date(self) -> datetime | None:
        query = (
            select(Metrics.date).group_by(Metrics.date).order_by(Metrics.date.desc())
        )
        result = await self.db_session.execute(query)
        if result is None:
            return None
        last_date = result.scalars().first()
        return last_date