"""T-07 agent_service StateGraph 骨架（mock LLM，不依赖外网/真 key）。

FakeLLM 捕获收到的 messages 供断言（system 边界 + 历史窗口 + 本轮消息）；
降级路径（无 key）与免责声明护栏单独覆盖。图/LLM 缓存经 reset_cache 隔离。
"""

from __future__ import annotations

import pytest
from langchain_core.messages import AIMessage

from app.config.settings import settings
from app.service import agent_service


class FakeLLM:
    def __init__(self, reply: str = "模拟回复"):
        self.reply = reply
        self.calls: list[list] = []

    def invoke(self, messages):
        self.calls.append(list(messages))
        return AIMessage(content=self.reply)


@pytest.fixture()
def fake_llm(monkeypatch):
    llm = FakeLLM()
    monkeypatch.setattr(agent_service, "_llm", llm)
    monkeypatch.setattr(settings, "deepseek_api_key", "test-key")
    yield llm
    agent_service.reset_cache()


HISTORY = [
    {"role": "user", "content": "你好"},
    {"role": "assistant", "content": "您好，有什么可以帮您？"},
]


def test_chat_customer_appends_disclaimer(fake_llm):
    out = agent_service.chat("customer", HISTORY, "查一下我的持仓")
    assert out["has_disclaimer"] is True
    assert out["reply"].endswith(agent_service.CHAT_DISCLAIMER)
    assert "模拟回复" in out["reply"]


def test_chat_risk_also_disclaimer(fake_llm):
    out = agent_service.chat("risk", [], "今天有多少待审预警")
    assert out["has_disclaimer"] is True


def test_chat_advisor_no_disclaimer(fake_llm):
    out = agent_service.chat("advisor", [], "总结客户需求")
    assert out["has_disclaimer"] is False
    assert agent_service.CHAT_DISCLAIMER not in out["reply"]


def test_messages_compose_system_history_and_user(fake_llm):
    agent_service.chat("customer", HISTORY, "最新问题")
    msgs = fake_llm.calls[0]
    assert msgs[0].__class__.__name__ == "SystemMessage"
    assert "不得提供投资建议" in msgs[0].content  # customer 边界注入
    assert [m.__class__.__name__ for m in msgs[1:]] == ["HumanMessage", "AIMessage", "HumanMessage"]
    assert msgs[-1].content == "最新问题"


def test_role_boundary_per_agent_type(fake_llm):
    agent_service.chat("analyst", [], "聚合一下")
    system = fake_llm.calls[0][0]
    assert "只读" in system.content


def test_degraded_reply_without_api_key(monkeypatch):
    """key 缺失 → 降级固定提示（不抛异常，演示链路不断）。"""
    monkeypatch.setattr(settings, "deepseek_api_key", "")
    agent_service.reset_cache()
    out = agent_service.chat("customer", [], "在吗")
    assert "LLM 未配置" in out["reply"] and "在吗" in out["reply"]
    assert out["has_disclaimer"] is True  # 降级回复同样经 guard 护栏


def test_graph_skeleton_nodes():
    graph = agent_service.build_graph()
    assert {"llm", "guard"} <= set(graph.nodes)  # __start__ 为 LangGraph 内部节点


def test_unknown_agent_type_falls_back_customer_boundary(fake_llm):
    """未知 agent_type 兜底 customer 边界（fail-safe：最严声明口径）。"""
    out = agent_service.chat("unknown", [], "hi")
    assert out["has_disclaimer"] is True
    assert "不得提供投资建议" in fake_llm.calls[0][0].content