import pytest
from bicycle_drive_train import BikeDriveTrain


@pytest.fixture(scope="module")
def drive_train():
    """
    list of front cog tooth counts. For example it could be initialized with [38,30]
    list of rear cog tooth counts. For example it could be initialized with [28, 23, 19, 16]
    """
    return BikeDriveTrain([38, 30], [28, 23, 19, 16])


def test_bike_drive_train(drive_train):
    assert drive_train.front_cogs == [38, 30]
    assert drive_train.rear_cogs == [28, 23, 19, 16]


def test_bike_drive_train_ratios(drive_train):
    # generate list of the gear ratios for the given front crank and rear cassette
    ratios = [(38, 28, 38 / 28),
              (38, 23, 38 / 23),
              (38, 19, 38 / 19),
              (38, 16, 38 / 16),
              (30, 28, 30 / 28),
              (30, 23, 30 / 23),
              (30, 19, 30 / 19),
              (30, 16, 30 / 16)
              ]

    for ratio in ratios:
        assert ratio in drive_train.gear_combinations_and_ratios


def test_bike_drive_train_ratio(drive_train):
    """
    If the drivetrain was initialized with the example values above and passed a target_ratio of 1.6
    It should return a data type that contains the information:
        Front: 30, Rear: 19, Ratio: 1.579
    """
    assert drive_train.get_gear_combination(1.6) == (30, 19, 30 / 19)


def test_bike_drive_train_shift_seq(drive_train):
    """
    For an example input the same as above plus: initial_gear_combination = [38, 28]

        1 - F:38 R:28 Ratio 1.357
        2 - F:30 R:28 Ratio 1.071
        3 - F:30 R:23 Ratio 1.304
        4 - F:30 R:19 Ratio 1.579
    """

    sequence = drive_train.get_shift_sequence(target_ratio=1.6, initial_gear_combination=[38, 28])

    assert sequence == [
        (38, 28, 38 / 28),
        (30, 28, 30 / 28),
        (30, 23, 30 / 23),
        (30, 19, 30 / 19)
    ]


def test_bike_drive_train_shift_seq_output(drive_train, capsys):
    drive_train.get_shift_sequence(target_ratio=1.6, initial_gear_combination=[38, 28])

    out, err = capsys.readouterr()
    assert out == "1 - F:38 R:28 Ratio 1.357\n2 - F:30 R:28 Ratio 1.071\n3 - F:30 R:23 Ratio 1.304\n4 - F:30 R:19 Ratio 1.579"