import asyncio

import fastapi
from starlette.responses import PlainTextResponse
import logging
import uvicorn
from opentelemetry.instrumentation.starlette import StarletteInstrumentor

logging.basicConfig(level=logging.DEBUG)
logging.getLogger().setLevel(logging.DEBUG)
logging.getLogger("opentelemetry.exporter").setLevel(logging.DEBUG)

sub_app = fastapi.FastAPI()

@sub_app.get("/home")
def sub_home():
    return PlainTextResponse("sub hi")

app = fastapi.FastAPI(root_path="/root")

app.mount("/sub", app=sub_app)

import asyncio

import starlette.applications as applications
from starlette.responses import PlainTextResponse
from starlette.routing import Route, Mount
import logging
from opentelemetry.instrumentation.starlette import StarletteInstrumentor

logging.basicConfig(level=logging.DEBUG)
logging.getLogger().setLevel(logging.DEBUG)
logging.getLogger("opentelemetry.exporter").setLevel(logging.DEBUG)

def sub_home(_):
    return PlainTextResponse("sub hi")


sub_app = applications.Starlette(routes=[Route("/home", sub_home)])

app = applications.Starlette(
    routes=[
        Mount("/sub", app=sub_app),
    ],
)
# I required the starlette app to be instrumented manually, well nevertheless this is not the point here
StarletteInstrumentor().instrument_app(app)

def get_host_port_url_tuple(scope):
    """Returns (host, port, full_url) tuple."""
    server = scope.get("server") or ["0.0.0.0", 80]
    port = server[1]
    server_host = server[0] + (":" + str(port) if str(port) != "80" else "")
    # To get the correct virtual url path within the hosting application (e.g also in a subapplication scenario)
    # we have to remove the root_path from the path
    # see:
    # - https://asgi.readthedocs.io/en/latest/specs/www.html#http-connection-scope (see: root_path and path)
    # - https://asgi.readthedocs.io/en/latest/specs/www.html#wsgi-compatibility (see: PATH_INFO)
    #       PATH_INFO can be derived by stripping root_path from path
    #       -> that means that the path should contain the root_path already, so prefixing it again is not necessary
    # - https://wsgi.readthedocs.io/en/latest/definitions.html#envvar-PATH_INFO
    #
    # From investigation it seems (that at least for fastapi), the path is already correctly set. That means
    # that root_path is already included in the path, so we can use it directly for full path.
    # old way: full_path = scope.get("root_path", "") + scope.get("path", "")
    full_path = scope.get("path", "")
    http_url = scope.get("scheme", "http") + "://" + server_host + full_path
    return server_host, port, http_url