from pathlib import Path
import sys

import pytest


SCRIPTS = Path(__file__).resolve().parents[1] / "scripts"
sys.path.insert(0, str(SCRIPTS))

from thermal_demand import (  # noqa: E402
    CapacityInputs,
    annual_heat_mwh,
    captured_heat_kw,
    heat_pump_case,
    size_modules,
)


def test_15kw_module_produces_about_100mwh_captured_heat():
    heat_kw = captured_heat_kw(15, load_factor=0.85, capture_factor=0.90)
    assert annual_heat_mwh(heat_kw) == pytest.approx(100.521)


def test_heat_pump_electricity_is_explicit():
    result = heat_pump_case(source_heat_kw=90, heating_cop=3)
    assert result.delivered_heat_kw == pytest.approx(135)
    assert result.heat_pump_input_kw == pytest.approx(45)


def test_capacity_rounds_down_to_15kw_modules():
    result = size_modules(
        CapacityInputs(
            contracted_compute_kw=400,
            verified_grid_headroom_kw=350,
            conservative_base_heat_kw=210,
            equipment_site_limit_kw=500,
            load_factor=0.85,
            capture_factor=0.90,
            initial_heat_fraction=0.70,
            module_kw=15,
        )
    )
    assert result.eligible_modules == 12
    assert result.eligible_it_kw == 180
    assert result.limiting_gate == "heat"


@pytest.mark.parametrize(
    "field",
    [
        "contracted_compute_kw",
        "verified_grid_headroom_kw",
        "conservative_base_heat_kw",
        "equipment_site_limit_kw",
    ],
)
def test_missing_capacity_gate_means_zero_eligible_modules(field):
    values = {
        "contracted_compute_kw": 100,
        "verified_grid_headroom_kw": 100,
        "conservative_base_heat_kw": 100,
        "equipment_site_limit_kw": 100,
    }
    values[field] = None
    result = size_modules(CapacityInputs(**values))
    assert result.eligible_modules == 0
    assert result.eligible_it_kw == 0
    assert result.limiting_gate == "missing_gate"