from pathlib import Path
import importlib.util

import pytest
import yaml


HERE = Path(__file__).resolve().parent

spec = importlib.util.spec_from_file_location("concrete_beam2_calc", HERE / "calc.py")
assert spec is not None and spec.loader is not None
calc_module = importlib.util.module_from_spec(spec)
spec.loader.exec_module(calc_module)
compute = calc_module.compute


def load_input():
    with (HERE / "input.yaml").open(encoding="utf-8") as handle:
        return yaml.safe_load(handle)


@pytest.fixture
def result():
    return compute(load_input())


def test_example_demands(result):
    v = result["values"]
    assert v["self_weight_klf"] == pytest.approx(0.1)
    assert v["wu_klf"] == pytest.approx(0.7325)
    assert v["Mu_kipft"] == pytest.approx(23.44)
    assert v["Vu_kip"] == pytest.approx(5.86)


def test_example_flexure(result):
    v = result["values"]
    assert v["a_in"] == pytest.approx(1.519608, rel=1e-5)
    assert v["et"] == pytest.approx(0.017137, rel=1e-3)
    assert v["phi"] == pytest.approx(0.9)
    assert v["phiMn_kipft"] == pytest.approx(26.133456, rel=1e-5)
    assert result["checks"]["flexure"]["ok"] is True


def test_example_min_steel_and_shear(result):
    v = result["values"]
    assert v["As_min_in2"] == pytest.approx(0.384, rel=1e-4)
    assert v["phiVc_kip"] == pytest.approx(7.887205, rel=1e-4)
    assert result["checks"]["minimum_steel"]["ok"] is True
    assert result["checks"]["shear"]["ok"] is True


def test_alternate_units_match_default(result):
    alt = load_input()
    alt.update(
        {
            "span": "192 in",
            "tributary": "75 in",
            "fc": "3000 psi",
        }
    )
    converted = compute(alt)
    for key in ("span_ft", "tributary_ft", "fc_ksi", "Mu_kipft", "phiMn_kipft", "Vu_kip"):
        assert converted["values"][key] == pytest.approx(result["values"][key], rel=1e-6)


def test_wrong_dimension_is_rejected():
    bad = load_input()
    bad["span"] = "16 kip"
    with pytest.raises(ValueError, match="span"):
        compute(bad)