from __future__ import annotations

import os
from collections.abc import AsyncIterator
from contextlib import asynccontextmanager

import pytest
import pytest_asyncio
from httpx import ASGITransport
from httpx import AsyncClient
from mcp import ClientSession
from mcp.client.streamable_http import streamable_http_client

from personal_mcp.web.app import create_app


@pytest_asyncio.fixture
async def client() -> AsyncIterator[AsyncClient]:
    """Provides an AsyncClient bound to a fresh application instance."""
    app = create_app()
    async with AsyncClient(
        transport=ASGITransport(app=app),
        base_url="http://testserver",
        timeout=10.0,
    ) as test_client:
        yield test_client


@pytest.fixture
def mcp_endpoint_url() -> str:
    """Provides the MCP endpoint URL for SDK-based client sessions."""
    return os.getenv("PERSONAL_MCP_TEST_HTTP_URL", "")


@pytest.fixture
def mcp_session_factory(mcp_endpoint_url: str):
    """Provides a context manager factory for MCP SDK sessions.

    Keeping stream/client/session enter and exit in the test task avoids
    cross-task cancel scope teardown errors from async generator fixtures.
    """
    if not mcp_endpoint_url:
        pytest.skip("Set PERSONAL_MCP_TEST_HTTP_URL to run SDK-backed MCP endpoint tests.")

    @asynccontextmanager
    async def create_session(*, initialize: bool = True) -> AsyncIterator[ClientSession]:
        async with (
            AsyncClient(timeout=10.0) as http_client,
            streamable_http_client(
                mcp_endpoint_url,
                http_client=http_client,
            ) as (read_stream, write_stream, _),
            ClientSession(read_stream, write_stream) as session,
        ):
            if initialize:
                await session.initialize()
            yield session

    return create_session