import pytest

from custom_components.easee_solar_charging.const import (
    AMPS_TO_POWER_W,
    MAX_CHARGER_CURRENT_A,
    MIN_CHARGER_CURRENT_A,
    PHASES,
    VOLTAGE_V,
    solar_excess_to_charger_current,
)

# ---------------------------------------------------------------------------
# solar_excess_to_charger_current
# ---------------------------------------------------------------------------

def test_zero_excess_returns_zero():
    assert solar_excess_to_charger_current(0) == 0


def test_just_below_minimum_threshold_returns_zero():
    min_power = PHASES * VOLTAGE_V * MIN_CHARGER_CURRENT_A
    assert solar_excess_to_charger_current(min_power - 1) == 0


def test_exactly_at_minimum_threshold():
    min_power = PHASES * VOLTAGE_V * MIN_CHARGER_CURRENT_A
    assert solar_excess_to_charger_current(min_power) == MIN_CHARGER_CURRENT_A


def test_fractional_watts_floor():
    # 3 * 230 * 8 = 5520 W → 8 A; adding 229 W is still not enough for 9 A
    assert solar_excess_to_charger_current(PHASES * VOLTAGE_V * 8 + 229) == 8


def test_intermediate_value():
    assert solar_excess_to_charger_current(PHASES * VOLTAGE_V * 10) == 10


def test_clamps_at_maximum():
    assert solar_excess_to_charger_current(999_999) == MAX_CHARGER_CURRENT_A


def test_negative_excess_returns_zero():
    assert solar_excess_to_charger_current(-500) == 0


@pytest.mark.parametrize("amps", range(MIN_CHARGER_CURRENT_A, MAX_CHARGER_CURRENT_A + 1))
def test_round_trip(amps):
    """Power for N amps should convert back to exactly N amps."""
    assert solar_excess_to_charger_current(AMPS_TO_POWER_W[amps]) == amps


# ---------------------------------------------------------------------------
# AMPS_TO_POWER_W table
# ---------------------------------------------------------------------------

def test_table_covers_full_range():
    assert set(AMPS_TO_POWER_W) == set(range(MIN_CHARGER_CURRENT_A, MAX_CHARGER_CURRENT_A + 1))


def test_table_minimum_entry():
    assert AMPS_TO_POWER_W[MIN_CHARGER_CURRENT_A] == PHASES * VOLTAGE_V * MIN_CHARGER_CURRENT_A


def test_table_maximum_entry():
    assert AMPS_TO_POWER_W[MAX_CHARGER_CURRENT_A] == PHASES * VOLTAGE_V * MAX_CHARGER_CURRENT_A


def test_table_is_strictly_increasing():
    values = [AMPS_TO_POWER_W[a] for a in sorted(AMPS_TO_POWER_W)]
    assert values == sorted(values) and len(set(values)) == len(values)