"""P1-G 回归测试: runtime_config DB 回落 env + 解密失败生产环境抛出。

运行: pytest tests/test_p1_g_runtime_config.py -v
(纯函数测试,mock session,无真实 PG 依赖。)
"""
from __future__ import annotations

from unittest.mock import MagicMock, patch

import pytest

from src.core.config import settings
import src.core.runtime_config as rc


# ── 辅助:构造模拟 session ─────────────────────────────────────────
class _FakeRow:
    def __init__(self, value): self.value = value


class _FakeSession:
    def __init__(self, row=None, raise_on_get=None):
        self._row = row
        self._raise = raise_on_get

    async def __aenter__(self):
        return self

    async def __aexit__(self, *a):
        return None

    async def get(self, cls, key):
        if self._raise:
            raise self._raise
        return self._row


class _FakeSessionLocal:
    def __init__(self, row=None, raise_on_get=None):
        self._row = row
        self._raise = raise_on_get

    def __call__(self):
        return _FakeSession(self._row, self._raise)


# ── 测试 ──────────────────────────────────────────────────────────
class TestDBFallback:
    """P1-G:DB 故障时回落环境变量。"""

    @pytest.mark.asyncio
    async def test_db_error_falls_back_to_env(self):
        """DB 抛异常 → 回落 settings 同名属性。"""
        # 模拟 DB 连接失败
        fake = _FakeSessionLocal(raise_on_get=RuntimeError("DB down"))
        with patch.object(rc, "AsyncSessionLocal", fake):
            val = await rc.get_runtime_value("LLM_MODEL")
        # 应回落 settings.LLM_MODEL(有默认值 gpt-4o)
        assert val == settings.LLM_MODEL

    @pytest.mark.asyncio
    async def test_db_returns_none_falls_back_to_env(self):
        """DB 行不存在 → 回落 env。"""
        fake = _FakeSessionLocal(row=None)
        with patch.object(rc, "AsyncSessionLocal", fake):
            val = await rc.get_runtime_value("LLM_MODEL")
        assert val == settings.LLM_MODEL


class TestDecryptFailure:
    """P1-G:解密失败在生产环境必须抛出,不得被 except Exception 吞掉。"""

    @pytest.mark.asyncio
    async def test_decrypt_failure_raises_in_production(self):
        """P1-G:production + 解密失败 → 必须 raise ValueError(不得被吞)。"""
        from src.core import crypto

        # 模拟 DB 返回一个加密值,但解密会失败
        fake = _FakeSessionLocal(row=_FakeRow("enc:v1:corrupted_token"))

        with patch.object(rc, "AsyncSessionLocal", fake), \
             patch.object(crypto, "decrypt_value", side_effect=ValueError("解密失败")), \
             patch.object(settings, "APP_ENV", "production"):
            # P1-G:生产环境解密失败必须抛出,不得静默回落
            with pytest.raises(ValueError, match="解密失败"):
                await rc.get_setting_origin("LLM_API_KEY")

    @pytest.mark.asyncio
    async def test_decrypt_failure_falls_back_in_non_production(self):
        """非生产环境 + 解密失败 → 回落 env,不抛错。"""
        from src.core import crypto

        fake = _FakeSessionLocal(row=_FakeRow("enc:v1:corrupted_token"))

        with patch.object(rc, "AsyncSessionLocal", fake), \
             patch.object(crypto, "decrypt_value", side_effect=ValueError("解密失败")), \
             patch.object(settings, "APP_ENV", "development"):
            origin, val = await rc.get_setting_origin("LLM_API_KEY")
            # 非生产 → 回落 env(origin=env 或 none)
            assert origin in ("env", "none")