import json
import sys
from collections.abc import Generator

import pytest
import uvicorn
from mcp.types import TextResourceContents

from fastmcp.client import Client
from fastmcp.client.transports import StreamableHttpTransport
from fastmcp.server.dependencies import get_http_request
from fastmcp.server.server import FastMCP
from fastmcp.utilities.tests import run_server_in_process


def fastmcp_server():
    """Fixture that creates a FastMCP server with tools, resources, and prompts."""
    server = FastMCP("TestServer")

    # Add a tool
    @server.tool()
    def greet(name: str) -> str:
        """Greet someone by name."""
        return f"Hello, {name}!"

    # Add a second tool
    @server.tool()
    def add(a: int, b: int) -> int:
        """Add two numbers together."""
        return a + b

    # Add a resource
    @server.resource(uri="data://users")
    async def get_users():
        return ["Alice", "Bob", "Charlie"]

    # Add a resource template
    @server.resource(uri="data://user/{user_id}")
    async def get_user(user_id: str):
        return {"id": user_id, "name": f"User {user_id}", "active": True}

    @server.resource(uri="request://headers")
    async def get_headers() -> dict[str, str]:
        request = get_http_request()

        return dict(request.headers)

    # Add a prompt
    @server.prompt()
    def welcome(name: str) -> str:
        """Example greeting prompt."""
        return f"Welcome to FastMCP, {name}!"

    return server


def run_server(host: str, port: int) -> None:
    try:
        app = fastmcp_server().streamable_http_app()
        server = uvicorn.Server(
            config=uvicorn.Config(
                app=app,
                host=host,
                port=port,
                log_level="error",
                lifespan="on",
            )
        )
        server.run()
    except Exception as e:
        print(f"Server error: {e}")
        sys.exit(1)
    sys.exit(0)


@pytest.fixture(scope="module")
def streamable_http_server() -> Generator[str, None, None]:
    with run_server_in_process(run_server) as url:
        yield f"{url}/mcp"


async def test_ping(streamable_http_server: str):
    """Test pinging the server."""
    async with Client(
        transport=StreamableHttpTransport(streamable_http_server)
    ) as client:
        result = await client.ping()
        assert result is True


async def test_http_headers(streamable_http_server: str):
    """Test getting HTTP headers from the server."""
    async with Client(
        transport=StreamableHttpTransport(
            streamable_http_server, headers={"X-DEMO-HEADER": "ABC"}
        )
    ) as client:
        raw_result = await client.read_resource("request://headers")
        assert isinstance(raw_result[0], TextResourceContents)
        json_result = json.loads(raw_result[0].text)
        assert "x-demo-header" in json_result
        assert json_result["x-demo-header"] == "ABC"