from datetime import date

from sqlalchemy import select, func, Subquery, cast, CTE
from sqlalchemy.dialects.postgresql import TIMESTAMP

from models import PaymentRecord
from schemas.statistics import CommonProfitFilters
from services.base import BaseService
from services.statistics.common import generate_date_range


class PaymentStatisticsService(BaseService):
    date_from: date
    date_to: date

    @staticmethod
    def _fill_date_gaps(payments: Subquery, all_dates: CTE) -> Subquery:
        return (
            select(
                all_dates.c.date,
                (all_dates.c.expenses + func.coalesce(payments.c.expenses, 0)).label("expenses"),
            )
            .join(payments, all_dates.c.date == payments.c.date, isouter=True)
            .order_by(all_dates.c.date)
            .subquery()
        )

    def _get_payment_records_sub(self) -> Subquery:
        all_dates = generate_date_range(self.date_from, self.date_to, ["expenses"])

        expenses = (
            select(
                func.sum(PaymentRecord.amount).label("expenses"),
                cast(PaymentRecord.start_date, TIMESTAMP(timezone=False)).label("date"),
            )
            .group_by("date")
            .subquery()
        )

        expenses_with_filled_gaps = self._fill_date_gaps(expenses, all_dates)
        return expenses_with_filled_gaps

    @staticmethod
    def _apply_payments(deals_by_dates: Subquery, expenses_subquery: Subquery):
        return (
            select(
                deals_by_dates.c.date,
                deals_by_dates.c.deals_count,
                deals_by_dates.c.revenue,
                (func.coalesce(deals_by_dates.c.profit, 0) - func.coalesce(expenses_subquery.c.expenses, 0))
                .label("profit"),
                (deals_by_dates.c.expenses + expenses_subquery.c.expenses).label("expenses"),
            )
            .join(expenses_subquery, expenses_subquery.c.date == deals_by_dates.c.date)
        )

    def apply_payments(self, filters: CommonProfitFilters, deals_by_dates: Subquery):
        self.date_from, self.date_to = filters.date_range

        salary_expenses = self._get_payment_records_sub()
        deals_by_dates = self._apply_payments(deals_by_dates, salary_expenses)

        return deals_by_dates