"""消息列表游标的真实数据库验证（文档 §3.8 游标分页、§16.1 非法游标 400）。

单元测试用替身证明了"校验 → 透传"这条链，但"游标真的改变返回哪一页"只有真实
MySQL 能证明：`before` 边界最终会变成一条 `id < :cursor` 的 SQL 条件，写错了（例如
方向反了、被当成 `id > :cursor`、或 Python 侧过滤丢掉跨页一致性）单元测试看不出来。

本用例只写自己的临时会话数据，结束时全部删除；不依赖 Worker，也不依赖常驻队列。
"""

from datetime import UTC, datetime
from uuid import uuid4

import httpx
import pytest
from sqlalchemy import delete

from app.api.dependencies.auth import build_request_context
from app.core.contracts import RequestContext
from app.infrastructure.db import SessionFactory
from app.main import create_app
from app.model.conversation import ConversationMessage

# 依赖真实 MySQL：必须打 integration marker，否则按 marker 过滤时会漏测这批用例。
pytestmark = pytest.mark.integration

CUSTOMER_ID = 9001  # tools/seed_test_rbac.py 造的数据


async def test_cursor_walks_pages_and_invalid_cursor_is_rejected() -> None:
    session_id = f"cursor-{uuid4()}"
    now = datetime.now(UTC).replace(tzinfo=None)
    async with SessionFactory() as session, session.begin():
        session.add_all([
            ConversationMessage(session_id=session_id, customer_id=CUSTOMER_ID,
                                portal="customer_chat", role="user", content=f"m{index}",
                                created_at=now)
            for index in range(3)
        ])

    context = RequestContext(user_id=str(CUSTOMER_ID), trace_id=str(uuid4()),
                             roles=("customer",), permissions=())
    application = create_app()
    application.dependency_overrides[build_request_context] = lambda: context
    path = f"/api/v1/conversations/{session_id}/messages"
    try:
        async with httpx.AsyncClient(transport=httpx.ASGITransport(app=application),
                                    base_url="http://test") as client:
            first = await client.get(path, params={"limit": 2})
            assert first.status_code == 200
            page = first.json()["data"]
            assert [item["content"] for item in page] == ["m2", "m1"]

            # 用上一页最后一条的 message_id 作游标：必须取到更旧的一页，而不是重复第一页。
            second = await client.get(path, params={"limit": 2, "cursor": page[-1]["message_id"]})
            assert [item["content"] for item in second.json()["data"]] == ["m0"]

            # 走到头：再往前没有数据，返回空集合而不是报错、也不是回到第一页。
            last = second.json()["data"][-1]["message_id"]
            third = await client.get(path, params={"limit": 2, "cursor": last})
            assert third.json()["data"] == []

            invalid = await client.get(path, params={"cursor": "abc"})
            assert invalid.status_code == 400
            assert invalid.json()["error"]["code"] == "INVALID_CURSOR"
    finally:
        async with SessionFactory() as session, session.begin():
            await session.execute(delete(ConversationMessage).where(
                ConversationMessage.session_id == session_id))