import time

from fam_edge.model_adapters.circuit_breaker import CircuitBreaker


def test_closed_stays_closed_below_threshold():
    cb = CircuitBreaker(threshold=3, cooldown=1)
    cb.record_failure()
    cb.record_failure()
    assert not cb.is_open()
    assert cb.state == 'CLOSED'


def test_opens_at_threshold():
    cb = CircuitBreaker(threshold=3, cooldown=1)
    for _ in range(3):
        cb.record_failure()
    assert cb.is_open()
    assert cb.state == 'OPEN'


def test_half_open_after_cooldown_and_clears_stale_failures():
    """进入 HALF_OPEN 时应清空旧失败计数，探测调用失败一次不该立刻把它"凑数"重新 OPEN。"""
    cb = CircuitBreaker(threshold=3, cooldown=0.05)
    for _ in range(3):
        cb.record_failure()
    assert cb.is_open()
    time.sleep(0.1)
    # 冷却期已过，第一次 is_open() 调用把状态转为 HALF_OPEN 并放行一次探测
    assert cb.is_open() is False
    assert cb.state == 'HALF_OPEN'
    assert len(cb.failures) == 0
    # 探测失败一次：由于 deque 已清空，不应该只凭这一次失败就再次 OPEN
    # （state 仍是 HALF_OPEN，不是 OPEN，is_open() 只在 state=='OPEN' 时为 True）
    cb.record_failure()
    assert cb.state != 'OPEN'
    assert not cb.is_open()


def test_half_open_probe_success_closes():
    cb = CircuitBreaker(threshold=2, cooldown=0.05)
    cb.record_failure()
    cb.record_failure()
    time.sleep(0.1)
    assert cb.is_open() is False  # 触发 HALF_OPEN 转换
    cb.record_success()
    assert cb.state == 'CLOSED'
    assert len(cb.failures) == 0


def test_disabled_never_opens():
    cb = CircuitBreaker(threshold=1, cooldown=1, enabled=False)
    cb.record_failure()
    cb.record_failure()
    assert not cb.is_open()