"""Shared write-time guard: a free day can never be `vacation`.

Extracted out of `PlanningService._reject_illegal_free_day` (restructure step
3b) so `DayAssertionService` — which now owns the hand-pin write path too,
see its module docstring — enforces the exact same rule instead of growing
its own copy. A free day (Saturday, Sunday, or Swedish red day, subject to a
workspace's `DayOverride`s — see `allocation_service.is_free_day`, the single
source of truth for "is this day free") can never be persisted as `vacation`,
and may be `sjukpenning`/`lagsta` only when the workspace opted in via
`Workspace.take_pl_on_red_days` (default False).
"""

from datetime import date

from app.entities.workspace import Workspace
from app.services.allocation_service import is_free_day
from app.utils.errors import ValidationError
from app.utils.holidays import get_swedish_holidays


def reject_illegal_free_day(
    workspace: Workspace | None,
    day_overrides: dict[date, bool],
    d: date,
    day_type: str,
) -> None:
    """Raise `ValidationError` iff `day_type` may not be planned on `d`.

    No-op for any `day_type` other than `sjukpenning`/`lagsta`/`vacation`
    (e.g. `'none'`, the exclusion-shaped assertion — excluding a day is
    always allowed, free or not) and a no-op entirely when `d` is not a free
    day in the first place.
    """
    if day_type not in ("vacation", "sjukpenning", "lagsta"):
        return

    holidays_map = get_swedish_holidays(d.year)
    if not is_free_day(d, holidays_map, day_overrides):
        return

    if day_type == "vacation":
        raise ValidationError(
            "Vacation cannot be planned on a free day (weekend or red day)",
            message_key="planning.rejection.vacationOnFreeDay",
            data={"date": d.isoformat()},
        )

    take_pl_on_red_days = workspace.take_pl_on_red_days if workspace is not None else False
    if not take_pl_on_red_days:
        raise ValidationError(
            "Parental leave cannot be planned on a free day unless the workspace "
            "setting take_pl_on_red_days is enabled",
            message_key="planning.rejection.parentalLeaveOnFreeDayDisabled",
            data={"date": d.isoformat()},
        )