"""作业 1 验收测试：LangGraph 最小图。

通过标准（对应迁移计划作业 1）：
- 同一会话（thread）轮数累计：1 → 2；
- 不同会话相互隔离：新 thread 的轮数从 1 开始；
- 不依赖 FastGPT 与真实模型，离线可重复执行。

注意：节点实现（src/agent/graph.py 中的 TODO）完成前，
本文件的测试会失败，属于预期状态。
"""

import pytest

from src.agent.graph import GraphDeps, build_graph, workflow_fake_llm


async def ask(graph, thread_id: str, text: str, llm=None) -> dict:
    # 只传本轮变化的字段；对已有 checkpoint 的 thread 传完整初始状态，
    # 其中的 turn_count=0 会覆盖已累计的值（LangGraph 输入按通道覆盖）。
    return await graph.ainvoke(
        {"session_id": thread_id, "input_text": text},
        config={"configurable": {"thread_id": thread_id}},
        context=GraphDeps(llm=llm or workflow_fake_llm()),
    )


@pytest.mark.asyncio
async def test_same_thread_accumulates_turns() -> None:
    graph = build_graph()

    first = await ask(graph, "thread-a", "你好")
    second = await ask(graph, "thread-a", "发生了交通事故")

    assert first["turn_count"] == 1
    assert second["turn_count"] == 2


@pytest.mark.asyncio
async def test_different_threads_are_isolated() -> None:
    graph = build_graph()

    await ask(graph, "thread-a", "你好")
    await ask(graph, "thread-a", "发生了交通事故")
    other = await ask(graph, "thread-b", "你好")

    assert other["turn_count"] == 1


@pytest.mark.asyncio
async def test_first_turn_is_welcome_stage() -> None:
    # 新会话首条消息：welcome 节点固定问候，返回 1001（对照工作流
    # work_start is_first_message → Assigned Reply#3），不调用模型
    graph = build_graph()
    result = await ask(graph, "thread-a", "你好")

    assert result["stage_code"] == "1001"
    assert result["response_text"].startswith("<state>1001</state>")
    assert result["turn_count"] == 1


@pytest.mark.asyncio
async def test_second_turn_keeps_stage_without_event() -> None:
    # 问候后的普通输入：脚手架版无事件则保持 1001，
    # 【继续办理】等事件经白名单进入 1002（见 test_transitions.py）
    graph = build_graph()
    await ask(graph, "thread-a", "你好")
    result = await ask(graph, "thread-a", "我出车祸了")

    assert result["stage_code"] == "1001"
    assert "我出车祸了" in result["response_text"]