from dataclasses import dataclass
from typing import List

from domain.condition.records.calico.calico_property import CalicoProperty


@dataclass(frozen=True)
class LoadReport:
    """The reconciliation a Calico load emits so nothing vanishes silently
    (ADR-0064): how many observations were loaded versus dropped, and why.

    ``loaded``, ``unmatched_to_portfolio`` and ``blank_placeholder`` account for
    the Calico rows. ``null_uprn`` is a portfolio-wide data-quality canary — the
    count of properties in the portfolio whose UPRN is null (expected: zero) —
    *not* a per-row drop reason, so it does not partition with the others: a
    Calico reference pointing at a null-UPRN property is reported both here and
    under ``unmatched_to_portfolio``.
    """

    loaded: int
    unmatched_to_portfolio: int
    null_uprn: int
    blank_placeholder: int

    @classmethod
    def from_calico_load(
        cls,
        properties: List[CalicoProperty],
        blank_placeholder_count: int,
        unmatched_reference_count: int,
        null_uprn_references: List[str],
    ) -> "LoadReport":
        loaded = sum(len(prop.assets) for prop in properties)
        return cls(
            loaded=loaded,
            unmatched_to_portfolio=unmatched_reference_count,
            null_uprn=len(null_uprn_references),
            blank_placeholder=blank_placeholder_count,
        )