import math
import random
from hyperloglog import HyperLogLog


def test_empty():
    h = HyperLogLog(p=10)
    assert h.count() == 0.0


def test_exact_small():
    h = HyperLogLog(p=12)
    n = 1000
    for i in range(n):
        h.add(i)
    est = h.count()
    assert abs(est - n) / n < 0.05, (est, n)


def test_large():
    h = HyperLogLog(p=14)
    n = 100_000
    for i in range(n):
        h.add(i)
    est = h.count()
    rel = abs(est - n) / n
    assert rel < 0.02, (est, n, rel)


def test_duplicates():
    h = HyperLogLog(p=12)
    for i in range(5000):
        h.add(i % 1000)
    est = h.count()
    assert abs(est - 1000) / 1000 < 0.05, est


def test_strings():
    h = HyperLogLog(p=12)
    words = [f"item-{i}" for i in range(2000)]
    for w in words:
        h.add(w)
    est = h.count()
    assert abs(est - 2000) / 2000 < 0.05, est


def test_merge():
    a = HyperLogLog(p=12)
    b = HyperLogLog(p=12)
    for i in range(0, 1000, 2):
        a.add(i)
    for i in range(1, 1000, 2):
        b.add(i)
    m = a.merge(b)
    est = m.count()
    assert abs(est - 1000) / 1000 < 0.05, est


def test_merge_precision_mismatch():
    try:
        HyperLogLog(p=10).merge(HyperLogLog(p=12))
    except ValueError:
        return
    raise AssertionError("expected ValueError")


def test_extend():
    h = HyperLogLog(p=10)
    h.extend(range(500))
    assert abs(h.count() - 500) / 500 < 0.06


def test_len():
    h = HyperLogLog(p=10)
    for i in range(300):
        h.add(i)
    assert isinstance(len(h), int)


def test_determinism():
    a = HyperLogLog(p=12)
    b = HyperLogLog(p=12)
    for i in range(1000):
        a.add(i); b.add(i)
    assert a.count() == b.count()


def test_invalid_p():
    for p in (3, 17):
        try:
            HyperLogLog(p=p)
        except ValueError:
            continue
        raise AssertionError("expected ValueError")


if __name__ == "__main__":
    import pytest
    raise SystemExit(pytest.main([__file__, "-q"]))