import numpy as np
import pytest

from giant.materials import (
    MaterialProperties,
    MaterialPropertiesNotFilledError,
    UnknownMaterialError,
    get_material_properties,
    material_properties_array,
)


def test_get_material_properties_unknown_name_raises():
    with pytest.raises(UnknownMaterialError):
        get_material_properties("G4_Unobtainium")


def test_get_material_properties_unfilled_entry_raises():
    """G4_LYSO is not a stock Geant4 NIST material (confirmed against the
    vendored Geant4 11.4.1 build) and is the one entry still shipped unfilled."""
    with pytest.raises(MaterialPropertiesNotFilledError):
        get_material_properties("G4_LYSO")


def test_get_material_properties_returns_filled_entry_from_injected_table():
    table = {
        "G4_Pb": MaterialProperties(
            z_eff=82.0, a_eff=207.2, density=11.35, x0=0.5612, lambda_int=17.59
        )
    }
    props = get_material_properties("G4_Pb", table)
    assert props.z_eff == 82.0
    assert props.a_eff == 207.2
    assert props.density == 11.35
    assert props.x0 == 0.5612
    assert props.lambda_int == 17.59


def test_material_properties_array_shape_and_values():
    table = {
        "G4_Pb": MaterialProperties(82.0, 207.2, 11.35, 0.5612, 17.59),
        "G4_W": MaterialProperties(74.0, 183.84, 19.3, 0.3504, 9.95),
    }
    names = np.array(["G4_Pb", "G4_W", "G4_Pb"], dtype=object)
    arr = material_properties_array(names, table)
    assert arr.shape == (3, 5)
    assert arr.dtype == np.float32
    np.testing.assert_allclose(arr[0], [82.0, 207.2, 11.35, 0.5612, 17.59], rtol=1e-5)
    np.testing.assert_allclose(arr[1], [74.0, 183.84, 19.3, 0.3504, 9.95], rtol=1e-5)


def test_all_known_materials_present_in_stub_table():
    """Every material referenced elsewhere in the repo must at least have a
    stub entry (even if unfilled) -- an unknown name should never be the
    failure mode a physicist hits when populating the table."""
    from giant.materials import MATERIAL_PROPERTIES

    expected = {
        "G4_PbWO4",
        "G4_CESIUM_IODIDE",
        "G4_Pb",
        "G4_W",
        "G4_Cu",
        "G4_Fe",
        "G4_BRASS",
        "G4_POLYSTYRENE",
        "G4_PLASTIC_SC_VINYLTOLUENE",
        "G4_BGO",
        "G4_LYSO",
        "G4_AIR",
        "G4_lAr",
    }
    assert expected <= set(MATERIAL_PROPERTIES.keys())


def test_all_materials_filled_except_lyso():
    """G4_LYSO is the sole intentionally-unfilled entry (not a stock Geant4
    NIST material); every other known material has real Geant4-derived
    values -- see the module docstring for provenance."""
    from giant.materials import MATERIAL_PROPERTIES

    for name, props in MATERIAL_PROPERTIES.items():
        if name == "G4_LYSO":
            assert all(v is None for v in props)
        else:
            assert all(v is not None for v in props), f"{name} unexpectedly unfilled"


def test_elemental_material_z_eff_matches_atomic_number():
    """Single-element materials' z_eff must equal the element's real Z."""
    pb = get_material_properties("G4_Pb")
    assert pb.z_eff == pytest.approx(82.0)
    w = get_material_properties("G4_W")
    assert w.z_eff == pytest.approx(74.0)
    fe = get_material_properties("G4_Fe")
    assert fe.z_eff == pytest.approx(26.0)


def test_pbwo4_values_match_known_cms_ecal_reference():
    """PbWO4 (CMS ECAL crystal) has well-known reference values: X0~0.89cm,
    density 8.28 g/cm^3 -- sanity check the Geant4-derived numbers land there."""
    pbwo4 = get_material_properties("G4_PbWO4")
    assert pbwo4.density == pytest.approx(8.28)
    assert pbwo4.x0 == pytest.approx(0.89, abs=0.01)
    assert pbwo4.z_eff == pytest.approx(31.33, abs=0.01)