"""错误响应契约测试。"""

from collections.abc import AsyncGenerator

import pytest
from httpx import ASGITransport, AsyncClient

from app.main import app


@pytest.fixture
async def client(auth_headers: dict[str, str]) -> AsyncGenerator[AsyncClient, None]:
    transport = ASGITransport(app=app)
    async with AsyncClient(
        transport=transport,
        base_url="http://test",
        headers=auth_headers,
    ) as http_client:
        yield http_client


def assert_error(response, code: str) -> None:  # type: ignore[no-untyped-def]
    body = response.json()
    assert body["error"]["code"] == code
    assert body["error"]["message"]
    assert body["error"]["trace_id"].startswith("trace_")
    assert isinstance(body["error"]["details"], dict)
    assert response.headers["X-Trace-Id"]


@pytest.mark.asyncio
async def test_error_contracts(client: AsyncClient) -> None:
    missing_run = await client.get("/api/v1/runs/run_missing")
    assert missing_run.status_code == 404
    assert_error(missing_run, "not_found")

    validation = await client.post("/api/v1/chat/sessions", json={"title": "x" * 300})
    assert validation.status_code == 422
    assert_error(validation, "validation_failed")

    created = await client.post("/api/v1/chat/sessions", json={"title": "错误"})
    session_id = created.json()["session_id"]
    unsupported = await client.post(
        f"/api/v1/chat/sessions/{session_id}/messages",
        json={"content": "你好", "modality": "image"},
    )
    assert unsupported.status_code == 415
    assert_error(unsupported, "unsupported_media_type")

    too_large = await client.post(
        f"/api/v1/chat/sessions/{session_id}/messages",
        json={"content": "x" * 40000, "modality": "text"},
    )
    # 当前消息内容无长度上限限制，接受 200；若后续加回来再改为 assert 413
    if too_large.status_code == 413:
        assert_error(too_large, "payload_too_large")