"""A Property's planning protections, resolved from geospatial reference data.

Three distinct flags (never the legacy collapsed `restricted_measures` boolean
— ADR-0020): a conservation area, a listed building, a heritage building. They
gate retrofit measures differently — a conservation area blocks external work
only, while listed/heritage protect the fabric itself — so the
measure-specific interpretation (`blocks_external` / `blocks_internal`) lives
here as derived queries. Sourced onto the Property from the geospatial layer
(co-located with the coordinates); defaults to unrestricted.
"""

from dataclasses import dataclass


@dataclass(frozen=True)
class PlanningRestrictions:
    """The planning protections on a Property that gate wall insulation
    (ADR-0019). Defaults to unrestricted."""

    in_conservation_area: bool = False
    is_listed: bool = False
    is_heritage: bool = False

    @property
    def blocks_external(self) -> bool:
        """External wall insulation is blocked by any protection (it alters the
        external appearance / protected fabric)."""
        return self.in_conservation_area or self.is_listed or self.is_heritage

    @property
    def blocks_internal(self) -> bool:
        """Internal wall insulation is blocked only where the fabric itself is
        protected — a listed or heritage building, not a plain conservation
        area."""
        return self.is_listed or self.is_heritage