"""cache.py 本地层（不碰 Redis）：TTL 过期、容量淘汰、熔断冷却恢复。"""
from __future__ import annotations

import pytest

import app.cache as cache_mod
from app import cache


class _FakeClock:
    """替换 cache 命名空间里的 time（不影响全局 time 模块）。"""

    def __init__(self):
        self.now = 1000.0

    def monotonic(self) -> float:
        return self.now

    def time(self) -> float:
        return self.now


@pytest.fixture(autouse=True)
def _reset_state():
    """每个用例干净的本地缓存状态。"""
    cache._local_store.clear()
    cache._local_bytes = 0
    cache._disabled_until = 0.0
    yield
    cache._local_store.clear()
    cache._local_bytes = 0
    cache._disabled_until = 0.0


def test_local_set_get_roundtrip():
    cache.local_set("k", '{"a":1}', ttl=60)
    assert cache.local_get("k") == '{"a":1}'


def test_local_get_miss():
    assert cache.local_get("nope") is None


def test_local_expiry(monkeypatch):
    clock = _FakeClock()
    monkeypatch.setattr(cache_mod, "time", clock)
    cache.local_set("k", "v", ttl=10)
    clock.now = 1005.0
    assert cache.local_get("k") == "v"
    clock.now = 1101.0  # 过期
    assert cache.local_get("k") is None
    assert "k" not in cache._local_store  # 过期读取顺手清理


def test_local_ttl_capped_at_120s():
    """本地层恒 ≤120s（多进程部署时最多比 Redis 多陈旧 120s 的约定）。"""
    base = cache.time.monotonic()
    cache.local_set("k", "v", ttl=99999)
    ent = cache._local_store["k"]
    assert ent[0] - base <= 120.0 + 5  # 相对当前 monotonic 的上限（留误差余量）


def test_local_entries_cap_evicts_oldest():
    for i in range(cache._LOCAL_MAX_ENTRIES + 5):
        cache.local_set(f"k{i}", "v", ttl=60)
    assert len(cache._local_store) <= cache._LOCAL_MAX_ENTRIES
    # 先插入的（最旧）被近似 LRU 淘汰
    assert cache.local_get("k0") is None
    assert cache.local_get(f"k{cache._LOCAL_MAX_ENTRIES + 4}") == "v"


def test_local_overwrite_releases_bytes():
    cache.local_set("k", "x" * 1000, ttl=60)
    before = cache._local_bytes
    cache.local_set("k", "y", ttl=60)
    assert cache._local_bytes < before
    assert cache.local_get("k") == "y"


def test_bail_cooldown_recovers(monkeypatch):
    """熔断 60s：期间 _client 为 None，到期自动放行（Redis 未配置时也返回 None，但不熔断）。"""
    clock = _FakeClock()
    monkeypatch.setattr(cache_mod, "time", clock)
    cache._bail()
    assert cache._disabled_until > clock.now
    clock.now += 59.0
    assert clock.monotonic() < cache._disabled_until  # 仍在熔断期
    clock.now += 2.0  # 越过 60s 冷却
    assert clock.monotonic() >= cache._disabled_until  # 恢复探测资格


def test_digest_stable_and_distinct():
    assert cache.digest("a", 1, None) == cache.digest("a", 1, None)
    assert cache.digest("a", 1) != cache.digest("a", 2)