"""In-memory ``PropertyOverridesReader`` over a pre-fetched snapshot.

The modelling_e2e handler reads each Property's overrides inside its write loop.
Reading them live keeps a second DB Session open alongside the per-Property write
Unit of Work; pre-fetching every Property's overrides up front (one read pass,
then the read Session is closed) lets the loop run on a single DB connection. This
serves those pre-fetched snapshots behind the same ``PropertyOverridesReader``
port — a Property with no pre-fetched entry resolves to no overrides, exactly as
the Postgres reader returns an empty snapshot for a Property with no rows.
"""

from __future__ import annotations

from collections.abc import Mapping

from repositories.property.property_overrides_reader import (
    PropertyOverridesReader,
    ResolvedPropertyOverrides,
)

_NO_OVERRIDES = ResolvedPropertyOverrides(rows=())


class InMemoryPropertyOverridesReader(PropertyOverridesReader):
    def __init__(
        self, by_property_id: Mapping[int, ResolvedPropertyOverrides]
    ) -> None:
        self._by_property_id = dict(by_property_id)

    def overrides_for(self, property_id: int) -> ResolvedPropertyOverrides:
        return self._by_property_id.get(property_id, _NO_OVERRIDES)