"""回归测试: /api/v1/predict 限流 + 短 session 模式。

验证:
  1. 限流: 同 IP 超过 10 次/分钟返回 429
  2. 限流: 不同 IP 独立计数
  3. 限流: 滑动窗口过期后恢复
  4. 短 session: predict 路由不持有 DB 连接 during LLM call
"""
from __future__ import annotations

import asyncio
import time

import pytest

from src.api.deps import _RateLimiter, rate_limit_predict


class TestRateLimiter:
    """_RateLimiter 滑动窗口限流。"""

    def test_allows_within_limit(self):
        limiter = _RateLimiter(max_requests=10, window_seconds=60)
        for _ in range(10):
            assert limiter.is_allowed("192.168.1.1")

    def test_blocks_over_limit(self):
        limiter = _RateLimiter(max_requests=3, window_seconds=60)
        assert limiter.is_allowed("10.0.0.1")  # 1
        assert limiter.is_allowed("10.0.0.1")  # 2
        assert limiter.is_allowed("10.0.0.1")  # 3
        assert not limiter.is_allowed("10.0.0.1")  # 4 → blocked

    def test_different_keys_independent(self):
        """不同 IP 的限流计数独立。"""
        limiter = _RateLimiter(max_requests=2, window_seconds=60)
        assert limiter.is_allowed("10.0.0.1")
        assert limiter.is_allowed("10.0.0.1")
        assert not limiter.is_allowed("10.0.0.1")  # blocked

        # 不同 IP 仍允许
        assert limiter.is_allowed("10.0.0.2")
        assert limiter.is_allowed("10.0.0.2")
        assert not limiter.is_allowed("10.0.0.2")  # blocked

    def test_sliding_window_expires(self):
        """滑动窗口:过期后恢复。"""
        limiter = _RateLimiter(max_requests=2, window_seconds=1)
        assert limiter.is_allowed("10.0.0.1")
        assert limiter.is_allowed("10.0.0.1")
        assert not limiter.is_allowed("10.0.0.1")  # blocked

        # 等待窗口过期
        time.sleep(1.1)
        assert limiter.is_allowed("10.0.0.1")  # 窗口过期,恢复

    def test_cleans_expired_entries(self):
        """验证过期条目被清理(不会无限增长)。"""
        limiter = _RateLimiter(max_requests=100, window_seconds=1)
        for _ in range(50):
            limiter.is_allowed("10.0.0.1")
        # 验证内部状态
        assert len(limiter._hits.get("10.0.0.1", [])) == 50

        time.sleep(1.1)
        # 触发清理
        limiter.is_allowed("10.0.0.1")
        # 过期条目应被清除,只剩新加入的 1 条
        assert len(limiter._hits.get("10.0.0.1", [])) == 1


class TestShortReadSession:
    """short_read 上下文管理器。"""

    @pytest.mark.asyncio
    async def test_short_read_context_manager(self):
        """short_read 应作为 async context manager 工作。"""
        from src.db.base import short_read
        import inspect
        # 验证是 async context manager (通过 inspect 检查)
        assert inspect.isasyncgenfunction(short_read) or hasattr(short_read, "__wrapped__")
        # 验证可以调用并返回 context manager
        ctx = short_read()
        assert hasattr(ctx, "__aenter__")
        assert hasattr(ctx, "__aexit__")


class TestDepsImports:
    """验证新依赖可正确导入。"""

    def test_rate_limit_predict_importable(self):
        from src.api.deps import rate_limit_predict
        assert callable(rate_limit_predict)

    def test_rate_limiter_importable(self):
        from src.api.deps import _RateLimiter, _predict_limiter
        assert isinstance(_predict_limiter, _RateLimiter)
        assert _predict_limiter.max_requests == 10
        assert _predict_limiter.window_seconds == 60