# built-ins
import secrets
import timeit
import statistics

# third-party
import pytest
import timeit

# internals
import main

# TODO: @pytest.mark.slow or something to exclude this test unless explicitly requested
def test_sha3_timing(echo):

    User = main.admin.User
    User.delete().where(User.name == 'test').execute()

    password = secrets.token_hex(32)
    u = User.register('test', password)

    times = {}
    #repeats = 10000
    repeats = 100000

    stmt = "User.login('test', password)"
    t = timeit.Timer(stmt, globals=locals())
    times['pw_correct'] = t.repeat(repeat=repeats, number=1)

    #for length in range(1, 32 + 1):
    #for length in [4, 8, 16, 32]:
    for length in [4, 32]:

        password_wrong = secrets.token_hex(length)
        stmt = "User.login('test', password_wrong)"

        t = timeit.Timer(stmt, globals=locals())
        times[f'pw_incorrect_{length}'] = t.repeat(repeat=repeats, number=1)

    #for length in range(1, 32 + 1):
    #for length in [4, 8, 16, 32]:
    for length in [4, 32]:

        password_wrong = secrets.token_hex(length)
        stmt = "User.login('doesnotexist', password_wrong)"

        t = timeit.Timer(stmt, globals=locals())
        times[f'user_incorrect_{length}'] = t.repeat(repeat=repeats, number=1)

    u.delete_instance()

    mins = []
    maxs = []
    spreads = []
    means = []
    medians = []

    echo("Timing sidechannel test:")
    for key, timings in times.items():

        mins.append(min(timings))
        maxs.append(max(timings))
        spreads.append(maxs[-1] - mins[-1])
        means.append(statistics.mean(timings))
        medians.append(statistics.median(timings))

        echo(f"{key}: min {min(timings)}, max {max(timings)}, spread {max(timings) - min(timings)}, mean {statistics.mean(timings)}, median {statistics.median(timings)}")

    spread_min = max(mins) - min(mins)
    spread_max = max(maxs) - min(maxs)
    spread_spread = max(spreads) - min(spreads)
    spread_mean = max(means) - min(means)
    spread_median = max(medians) - min(medians)

    echo(f"spread min: {spread_min}")
    echo(f"spread max: {spread_max}")
    echo(f"spread spread: {spread_spread}")
    echo(f"spread mean: {spread_mean}")
    echo(f"spread median: {spread_median}")

    assert spread_min < 0.001, "spread for minimum execution time too large"
    assert spread_max < 0.001, "spread for maximum execution time too large"
    assert spread_spread < 0.001, "spread for execution time spread too large"
    assert spread_mean < 0.01, "spread for mean execution time too large"
    assert spread_median < 0.01, "spread for median execution time too large"