from __future__ import annotations

from claire.hlc import HLC, HLCGenerator


def test_hlc_monotonic_within_same_wall_ms() -> None:
    """Two ticks in the same millisecond must bump the counter."""
    clock = [1_000_000_000_000]
    gen = HLCGenerator("m1", now_fn=lambda: clock[0])
    a = gen.tick()
    b = gen.tick()
    assert a < b
    assert a.wall_ms == b.wall_ms
    assert b.counter == a.counter + 1


def test_hlc_resets_counter_on_wall_advance() -> None:
    clock = [1_000_000_000_000]
    gen = HLCGenerator("m1", now_fn=lambda: clock[0])
    gen.tick()
    gen.tick()
    clock[0] += 50
    later = gen.tick()
    assert later.counter == 0
    assert later.wall_ms == 1_000_000_000_050


def test_hlc_update_pulls_forward_from_remote() -> None:
    """Receiving an HLC from a peer with a higher wall_ms pulls us forward."""
    clock = [1_000_000_000_000]
    gen = HLCGenerator("m1", now_fn=lambda: clock[0])
    remote = HLC(wall_ms=2_000_000_000_000, counter=5, machine_id="m2")
    new = gen.update(remote)
    assert new.wall_ms == remote.wall_ms
    assert new.counter == remote.counter + 1


def test_hlc_encode_decode_roundtrip() -> None:
    hlc = HLC(wall_ms=1716253199000, counter=42, machine_id="abc-123")
    assert HLC.decode(hlc.encode()) == hlc


def test_hlc_string_ordering_matches_tuple_ordering() -> None:
    """Critical: HLCs sort the same way as strings as they do as tuples."""
    a = HLC(wall_ms=1000, counter=1, machine_id="m1")
    b = HLC(wall_ms=1000, counter=2, machine_id="m1")
    c = HLC(wall_ms=1001, counter=0, machine_id="m1")
    encoded = sorted([c.encode(), b.encode(), a.encode()])
    assert encoded == [a.encode(), b.encode(), c.encode()]