import os
import sys
import subprocess
import signal
from threading import Thread
from time import sleep
from json.decoder import JSONDecodeError
import aiohttp
import asyncio
import async_timeout

sanic_project_content_one = '''
from sanic import Sanic
from sanic import response

app = Sanic(__name__)


@app.route("/")
async def test(request):
    return response.json({"test": 1})


if __name__ == '__main__':
    app.run(host="127.0.0.1", port=8000, auto_reload=True)
'''

sanic_project_content_two = '''
from sanic import Sanic
from sanic import response

app = Sanic(__name__)


@app.route("/")
async def test(request):
    return response.json({"test": 2})


if __name__ == '__main__':
    app.run(host="127.0.0.1", port=8000, auto_reload=True)
'''

process_id = None


def execute_cmd(command):
    process = subprocess.Popen(command, shell=True)
    global process_id
    process_id = process.pid
    process.communicate()


class TestAutoReloading:

    def check_response(self, url, response):
        """Send http request and tries to take it's response as json.
        Returns a dictionary.
        """
        async def req(url, excepted_response):
            async with aiohttp.ClientSession() as session:
                with async_timeout.timeout(10):
                    async with session.get(url) as response:
                        try:
                            result = await response.json()
                        except JSONDecodeError:
                            result = {}
            return result == excepted_response

        loop = asyncio.get_event_loop()
        return loop.run_until_complete(req(url, response))

    def test_reloading_after_change_file(self, capsys):
        if os.name != 'posix':
            return

        with capsys.disabled():
            pass
        sanic_app_file_path = "simple_sanic_app.py"
        with open(sanic_app_file_path, "w") as _file:
            _file.write(sanic_project_content_one)

        cmd = ' '.join([sys.executable, sanic_app_file_path])
        thread = Thread(target=execute_cmd, args=(cmd,))
        thread.start()

        sleep(2)  # wait for completing server start process
        assert self.check_response("http://127.0.0.1:8000/", {"test": 1})

        with open(sanic_app_file_path, "w") as _file:
            _file.write(sanic_project_content_two)

        sleep(2)  # wait for completing server start process
        assert self.check_response("http://127.0.0.1:8000/", {"test": 2})

        thread.join(1)
        os.remove(sanic_app_file_path)

    def teardown_method(self, method):
        if process_id:
            root_proc_path = \
                "/proc/{pid}/task/{pid}/children".format(pid=process_id)
            if not os.path.isfile(root_proc_path):
                return
            with open(root_proc_path) as children_list_file:
                children_list_pid = children_list_file.read().split()
            for child_pid in children_list_pid:
                os.kill(int(child_pid), signal.SIGTERM)