#!/usr/bin/env python
import contextlib
import random
import signal
import subprocess
import threading
import time

import requests
import sys

port = int(sys.argv[1])

NGROK_CLI = [
    'ngrok', 'start', '--none', '--region', 'eu',
]

own = None
web_addr = 'http://localhost:4040/api'
addr = 'localhost:%d' % port

# FIXME: this is for xdist to avoid workers running ngrok at the
#        exact same time, use lockfile instead
time.sleep(random.SystemRandom().randint(1, 10))
# try to find out if ngrok is running, and if it's not attempt
# to start it
try:
    requests.get(web_addr)
except requests.exceptions.ConnectionError:
    own = subprocess.Popen(NGROK_CLI, stdout=subprocess.DEVNULL)
    for _ in range(5):
        time.sleep(1)
        with contextlib.suppress(requests.exceptions.ConnectionError):
            requests.get(web_addr)
            break
    else:
        sys.exit("Unable to connect to ngrok")

requests.post(f'{web_addr}/tunnels', json={
    'name': str(port),
    'proto': 'http',
    'addr': addr,
    'schemes': ['https'],
    'inspect': True,
}).raise_for_status()


tunnel = f'{web_addr}/tunnels/{port}'
for _ in range(10):
    time.sleep(2)
    r = requests.get(tunnel)
    # not created yet, wait and retry
    if r.status_code == 404:
        continue
    # check for weird responses
    r.raise_for_status()

    print(r.json()['public_url'], flush=True)
    sys.stdout.close()
    break
else:
    sys.exit("ngrok tunnel creation failed (?)")

shutdown = threading.Event()
def cleanup(_sig, _frame):
    requests.delete(tunnel)
    for _ in range(10):
        time.sleep(1)
        r = requests.get(tunnel)
        # check if deletion is done
        if r.status_code == 404:
            break
        r.raise_for_status()
    else:
        raise sys.exit("ngrok tunnel deletion failed")

    r = requests.get(f'{web_addr}/tunnels')
    if not r.ok:
        sys.exit(f'{r.reason} {r.text}')
    # FIXME: if we started ngrok, we should probably wait for all tunnels to be
    #        closed then terminate ngrok? This is likely a situation where the
    #        worker which created the ngrok instance finished early...
    if own and not r.json()['tunnels']:
        # no more tunnels and we started ngrok -> try to kill it
        own.terminate()
        own.wait(30)
    shutdown.set()

# don't know why but signal.sigwait doesn't seem to take SIGTERM in account so
# we need the cursed version
signal.signal(signal.SIGTERM, cleanup)
signal.signal(signal.SIGINT, cleanup)

shutdown.wait()