#!/usr/bin/env python3

import os
import re
import socket
import sys
import time

from random import randrange

HOST = "127.0.0.1"  # Localhost
PORT = int(sys.argv[1])  # Port to listen on
LOG2FILE = False if len(sys.argv) < 3 else bool(int(sys.argv[2]))

import logging
logger = logging.getLogger('mdif')

if LOG2FILE:
    logging.basicConfig(filename=os.path.join(os.getcwd(), 'mdif_sim.log'), level=logging.INFO)


class MDIF:
    def __init__(self):
        self.delay = 1000

    def getDelay(self):
        return self.delay

    def setDelay(self, delay):
        self.delay = delay
        
with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:

    s.bind((HOST, PORT))
    s.listen()
    conn, addr = s.accept()
    with conn:

        def send(data: str):
            if data:
                logger.info(f'SENDING: "{data}"')
                return conn.sendall(f'{data}\r'.encode())
            else:
                logger.info(f'SENDING: ""')
                return conn.sendall(b'\r')

        def receive():
            data = conn.recv(1024)
            if data:
                # also removes terminator
                received = data.decode('ascii').rstrip()
            else:
                received = ''
            logger.info(f'RECEIVED: "{received}"')
            return received
        
        mdif = MDIF()

        while True:

            data = receive()

            if not data: # Empty implies client disconnected
                break    # Close Server

            try:

                if data == 'RMT 1':
                    send('')

                elif data == 'ECHO 0':
                    send('')

                elif data == 'DT':
                    send('%d' % mdif.getDelay())

                elif re.fullmatch(r'DT (\d+)', data):
                    new_delay = int(re.fullmatch(r'DT (\d+)', data).group(1))
                    mdif.setDelay(new_delay)
                    send('')

                else:
                    send('?2') # Bad command

            except Exception as e:
                logger.exception('Simulation Broke')
                send('?OV')