"""断路器单元测试（task: Phase 2 可靠性增强）。

测试 check_circuit_breaker 纯函数——不启动整个下载流程，
直接构造 recent_results 列表验证触发逻辑。

覆盖场景：
  1. 35% 失败率 → 触发
  2. 25% 失败率 → 不触发
  3. 北交所 920xxx 的 fail 不计入 → 不触发
  4. 不足窗口 → 不触发
  5. 恰好 30% → 不触发（阈值是 > 0.30，不含等于）
"""
import os
import sys

import pytest

_SCRIPT_DIR = os.path.join(os.path.dirname(__file__), "..", "..", "scripts", "data_platform")
_SCRIPT_DIR = os.path.abspath(_SCRIPT_DIR)
if _SCRIPT_DIR not in sys.path:
    sys.path.insert(0, _SCRIPT_DIR)

from raw_redownload import (  # noqa: E402
    CIRCUIT_BREAKER_FAIL_RATE,
    CIRCUIT_BREAKER_WINDOW,
    KNOWN_UNSUPPORTED_PREFIX,
    check_circuit_breaker,
)


def _make_results(n_ok: int, n_fail: int, fail_prefix: str = "600") -> list:
    """构造 recent_results 列表：n_ok 个 ok + n_fail 个 fail。

    fail_prefix 控制失败码的前缀（用于测试北交所排除）。
    """
    ok_list = [("600001", True)] * n_ok
    fail_list = [(f"{fail_prefix}9999", False)] * n_fail
    return ok_list + fail_list


class TestCircuitBreakerTrigger:
    """断路器触发阈值测试。"""

    def test_35_percent_fail_triggers(self):
        """200 只里 70 只 fail（35%）→ 触发。"""
        results = _make_results(n_ok=130, n_fail=70)
        assert len(results) == 200
        assert check_circuit_breaker(results) is True

    def test_25_percent_fail_no_trigger(self):
        """200 只里 50 只 fail（25%）→ 不触发。"""
        results = _make_results(n_ok=150, n_fail=50)
        assert len(results) == 200
        assert check_circuit_breaker(results) is False

    def test_exactly_30_percent_no_trigger(self):
        """恰好 30%（60/200）→ 不触发（阈值是 > 0.30，不含等于）。"""
        results = _make_results(n_ok=140, n_fail=60)
        assert len(results) == 200
        fail_rate = 60 / 200
        assert fail_rate == pytest.approx(CIRCUIT_BREAKER_FAIL_RATE)
        assert check_circuit_breaker(results) is False

    def test_31_percent_triggers(self):
        """31% 失败率 → 触发（刚过阈值）。"""
        results = _make_results(n_ok=138, n_fail=62)
        assert len(results) == 200
        assert check_circuit_breaker(results) is True


class TestCircuitBreakerBjExclusion:
    """北交所码不计入断路器分母测试。"""

    def test_bj_fails_excluded_from_denominator(self):
        """北交所 920xxx 的 fail 不计入 → 不触发。

        200 只非北交所全部 ok + 100 只北交所全部 fail：
        有效分母=200，有效失败=0 → 0% → 不触发。
        """
        ok_list = [("600001", True)] * 200
        bj_fail_list = [("920001", False)] * 100
        results = ok_list + bj_fail_list
        assert check_circuit_breaker(results) is False

    def test_bj_fails_do_not_inflate_rate(self):
        """北交所 fail 混在 200 窗口内不抬高失败率。

        150 只非北交所 ok + 50 只北交所 fail = 200 只总数：
        有效分母=150（< 窗口 200）→ 不足窗口，不触发。
        """
        ok_list = [("600001", True)] * 150
        bj_fail_list = [("920001", False)] * 50
        results = ok_list + bj_fail_list
        assert check_circuit_breaker(results) is False

    def test_mixed_bj_and_normal_fails(self):
        """混合场景：200 非北交所（60 fail=30%）+ 50 北交所 fail。

        有效：200 非北交所，60 fail = 30%，恰好阈值（> 0.30 不含等于）→ 不触发。
        北交所 50 fail 被排除，不影响计算。
        """
        ok_normal = [("600001", True)] * 140
        fail_normal = [("600002", False)] * 60
        fail_bj = [("920001", False)] * 50
        results = ok_normal + fail_normal + fail_bj
        assert check_circuit_breaker(results) is False

    def test_all_bj_prefixes_excluded(self):
        """所有已知不支持前缀都排除：920/921/83/87。"""
        ok_list = [("600001", True)] * 200
        bj_fails = (
            [("920001", False)] * 30
            + [("921002", False)] * 30
            + [("830003", False)] * 30
            + [("870004", False)] * 30
        )
        results = ok_list + bj_fails
        assert check_circuit_breaker(results) is False


class TestCircuitBreakerWindow:
    """窗口大小边界测试。"""

    def test_insufficient_window_no_trigger(self):
        """不足 200 只 → 不触发（即使全部 fail）。"""
        results = [("600001", False)] * 199
        assert check_circuit_breaker(results) is False

    def test_exactly_window_triggers_if_high_fail(self):
        """恰好 200 只且失败率超阈值 → 触发。"""
        results = _make_results(n_ok=100, n_fail=100)
        assert len(results) == 200
        assert check_circuit_breaker(results) is True

    def test_empty_results_no_trigger(self):
        """空列表 → 不触发。"""
        assert check_circuit_breaker([]) is False

    def test_all_ok_no_trigger(self):
        """200 只全部 ok → 不触发。"""
        results = [("600001", True)] * 200
        assert check_circuit_breaker(results) is False


class TestCircuitBreakerConstants:
    """常量值校验（防止意外修改）。"""

    def test_window_is_200(self):
        assert CIRCUIT_BREAKER_WINDOW == 200

    def test_fail_rate_is_030(self):
        assert CIRCUIT_BREAKER_FAIL_RATE == 0.30

    def test_known_unsupported_prefixes(self):
        assert KNOWN_UNSUPPORTED_PREFIX == ("920", "921", "83", "87")