"""SSE 契约测试。"""

from collections.abc import AsyncGenerator

import pytest
from httpx import ASGITransport, AsyncClient

from app.ai_provider.types.chat import ChatChunk
from app.application.agent.runtime import AgentTurnResult
from app.core.config import settings
from app.main import app


@pytest.fixture
async def client(
    monkeypatch: pytest.MonkeyPatch, auth_headers: dict[str, str]
) -> AsyncGenerator[AsyncClient, None]:
    _content = "你好，我是测试模型回复，会根据你的输入生成足够长的内容用于 SSE 分块验证。" * 4

    async def fake_run_agent_turn(*, on_chunk, **_kwargs: object):
        await on_chunk(ChatChunk(delta_content=_content))
        return AgentTurnResult(content=_content, reasoning="")

    monkeypatch.setattr("app.application.chat.send_message.run_agent_turn", fake_run_agent_turn)
    transport = ASGITransport(app=app)
    async with AsyncClient(
        transport=transport, base_url="http://test", headers=auth_headers
    ) as http_client:
        yield http_client


async def _completed_run(client: AsyncClient, content: str = "你好") -> str:
    created = await client.post("/api/v1/chat/sessions", json={"title": "SSE"})
    session_id = created.json()["session_id"]
    sent = await client.post(
        f"/api/v1/chat/sessions/{session_id}/messages",
        json={"content": content, "modality": "text"},
    )
    return str(sent.json()["run_id"])


@pytest.mark.asyncio
async def test_completed_run_stream_outputs_events(client: AsyncClient) -> None:
    run_id = await _completed_run(client)
    response = await client.get(f"/api/v1/runs/{run_id}/stream")
    assert response.status_code == 200
    text = response.text
    assert "event: run.started" in text
    assert "event: message.delta" in text
    assert "event: message.completed" in text
    assert "event: run.completed" in text


@pytest.mark.asyncio
async def test_completed_run_stream_outputs_chunked_message_deltas(client: AsyncClient) -> None:
    run_id = await _completed_run(client, content="你好" * 80)
    response = await client.get(f"/api/v1/runs/{run_id}/stream")
    assert response.status_code == 200
    text = response.text
    assert text.count("event: message.delta") >= 2
    assert "event: message.completed" in text
    assert "event: run.completed" in text


@pytest.mark.asyncio
async def test_stream_not_found_and_disabled(
    client: AsyncClient, monkeypatch: pytest.MonkeyPatch
) -> None:
    not_found = await client.get("/api/v1/runs/run_missing/stream")
    assert not_found.status_code == 404
    assert not_found.json()["error"]["code"] == "not_found"

    run_id = await _completed_run(client)
    monkeypatch.setattr(settings, "enable_sse", False)
    disabled = await client.get(f"/api/v1/runs/{run_id}/stream")
    assert disabled.status_code == 400
    assert disabled.json()["error"]["code"] == "invalid_request"