"""The flat-roof reclassify maps a stated depth onto its Table 16 thickness member,
leaves depthless / non-flat rows alone, and is idempotent (#1376 / ADR-0041)."""

from __future__ import annotations

from scripts.reclassify_flat_roof_thickness import flat_thickness_corrections


def test_flat_depth_rows_are_corrected_to_the_thickness_member() -> None:
    # Arrange — flat roofs with a real depth (currently on the age-band-default
    # value), alongside depthless flat rows and a pitched row that must be left.
    stored = [
        ("flat: 150mm", "Flat, insulated (assumed)"),
        ("flat: 50mm", "Flat, insulated (assumed)"),
        ("flat: unknown", "Flat, insulated (assumed)"),
        ("flat: as built", "Flat, insulated (assumed)"),
        ("flat: no insulation", "Flat, no insulation"),
        ("pitchednormalloftaccess: 100mm", "Pitched, 100 mm loft insulation"),
    ]

    # Act
    corrections = flat_thickness_corrections(stored)

    # Assert — only the flat-depth rows are re-mapped, to their thickness member.
    assert corrections == {
        "flat: 150mm": "Flat, 150 mm insulation",
        "flat: 50mm": "Flat, 50 mm insulation",
    }


def test_a_non_rung_depth_snaps_to_the_nearest_tabulated_rung() -> None:
    # RdSAP Table 16 uses the nearest tabulated thickness <= the stated depth.

    # Act / Assert
    assert flat_thickness_corrections(
        [("flat: 60mm", "Flat, insulated (assumed)")]
    ) == {"flat: 60mm": "Flat, 50 mm insulation"}


def test_already_corrected_flat_rows_need_no_change() -> None:
    # Act / Assert — idempotent.
    assert (
        flat_thickness_corrections([("flat: 150mm", "Flat, 150 mm insulation")]) == {}
    )