from __future__ import annotations

from datetime import date
from decimal import Decimal

from mousehold_api import models
from mousehold_api.services.settlement import calculate_settlement
from mousehold_domain import FinancialEventStatus, FinancialEventType
from sqlalchemy.orm import Session


def test_equal_split_settlement(
    session: Session,
    household_setup: dict[str, str],
) -> None:
    event = models.FinancialEvent(
        household_id=household_setup["household_id"],
        payment_account_id=household_setup["account_a_id"],
        payer_user_id=household_setup["user_a_id"],
        event_type=FinancialEventType.EXPENSE,
        status=FinancialEventStatus.CONFIRMED,
        event_date=date(2026, 1, 1),
        amount=Decimal("120.00"),
        currency="EUR",
        merchant="Groceries",
    )
    session.add(event)
    session.flush()
    session.add_all(
        [
            models.SplitLine(
                event_id=event.id,
                user_id=household_setup["user_a_id"],
                share_amount=Decimal("60.00"),
            ),
            models.SplitLine(
                event_id=event.id,
                user_id=household_setup["user_b_id"],
                share_amount=Decimal("60.00"),
            ),
        ]
    )
    session.commit()

    summary = calculate_settlement(session, household_id=household_setup["household_id"])

    assert len(summary.suggested_transfers) == 1
    transfer = summary.suggested_transfers[0]
    assert transfer.from_user_id == household_setup["user_b_id"]
    assert transfer.to_user_id == household_setup["user_a_id"]
    assert transfer.amount == Decimal("60.00")


def test_shared_neutral_account_is_excluded(
    session: Session,
    household_setup: dict[str, str],
) -> None:
    event = models.FinancialEvent(
        household_id=household_setup["household_id"],
        payment_account_id=household_setup["shared_account_id"],
        payer_user_id=household_setup["user_a_id"],
        event_type=FinancialEventType.EXPENSE,
        status=FinancialEventStatus.CONFIRMED,
        event_date=date(2026, 1, 1),
        amount=Decimal("100.00"),
        currency="EUR",
    )
    session.add(event)
    session.flush()
    session.add_all(
        [
            models.SplitLine(
                event_id=event.id,
                user_id=household_setup["user_a_id"],
                share_amount=Decimal("50.00"),
            ),
            models.SplitLine(
                event_id=event.id,
                user_id=household_setup["user_b_id"],
                share_amount=Decimal("50.00"),
            ),
        ]
    )
    session.commit()

    summary = calculate_settlement(session, household_id=household_setup["household_id"])

    assert summary.included_event_ids == []
    assert summary.excluded_event_ids == [event.id]
    assert summary.suggested_transfers == []


def test_announced_and_outstanding_are_excluded_by_default(
    session: Session,
    household_setup: dict[str, str],
) -> None:
    event = models.FinancialEvent(
        household_id=household_setup["household_id"],
        payment_account_id=household_setup["account_a_id"],
        payer_user_id=household_setup["user_a_id"],
        event_type=FinancialEventType.EXPENSE,
        status=FinancialEventStatus.OUTSTANDING,
        event_date=date(2026, 1, 1),
        amount=Decimal("80.00"),
        currency="EUR",
    )
    session.add(event)
    session.flush()
    session.add(
        models.SplitLine(
            event_id=event.id, user_id=household_setup["user_b_id"], share_amount=Decimal("80.00")
        )
    )
    session.commit()

    default_summary = calculate_settlement(session, household_id=household_setup["household_id"])
    forecast_summary = calculate_settlement(
        session,
        household_id=household_setup["household_id"],
        include_announced=True,
    )

    assert default_summary.suggested_transfers == []
    assert forecast_summary.suggested_transfers[0].amount == Decimal("80.00")