"""Unit tests for BESS capacity degradation model."""

import pytest

from remodel_engine.generation.bess_state import simulate_bess_capacity
from remodel_engine.schemas.generation import BessConfig

BASE_CFG = BessConfig(
    capacity_mwh=500.0,
    power_mw=125.0,
    rte=0.85,
    design_cycles=6000.0,
    eol_soh=0.70,
)


def test_output_length() -> None:
    cycles = [365.0 * (i + 1) for i in range(25)]
    result = simulate_bess_capacity(BASE_CFG, cycles)
    assert len(result) == 25


def test_index_is_1_to_25() -> None:
    cycles = [365.0 * (i + 1) for i in range(25)]
    result = simulate_bess_capacity(BASE_CFG, cycles)
    assert list(result.index) == list(range(1, 26))


def test_capacity_decreases_with_cycles() -> None:
    cycles = [365.0 * (i + 1) for i in range(25)]
    result = simulate_bess_capacity(BASE_CFG, cycles)
    assert all(result.iloc[i] >= result.iloc[i + 1] for i in range(24))


def test_zero_cycles_gives_full_capacity() -> None:
    """Zero cumulative cycles → SOH = 1.0 → usable = nameplate."""
    result = simulate_bess_capacity(BASE_CFG, [0.0] * 25)
    assert all(abs(v - BASE_CFG.capacity_mwh) < 1e-9 for v in result)


def test_soh_floor_at_eol() -> None:
    """Very high cycle count should floor at eol_soh * nameplate."""
    extreme_cycles = [100_000.0] * 25
    result = simulate_bess_capacity(BASE_CFG, extreme_cycles)
    floor = BASE_CFG.capacity_mwh * BASE_CFG.eol_soh
    assert all(abs(v - floor) < 1e-9 for v in result)


def test_augmentation_increases_capacity() -> None:
    cfg = BessConfig(
        capacity_mwh=500.0,
        power_mw=125.0,
        augmentation_schedule=[(10, 200.0)],
    )
    cycles = [0.0] * 25
    result = simulate_bess_capacity(cfg, cycles)
    assert result.iloc[9] > result.iloc[8]  # year 10 > year 9


def test_wrong_cycles_length_raises() -> None:
    with pytest.raises(ValueError, match="25 entries"):
        simulate_bess_capacity(BASE_CFG, [365.0] * 10)