## pip3 install irc##
from irc import client, connection
from time import time
from socket import socket
from configparser import ConfigParser
from time import sleep
from threading import Thread
from os import chdir, path

chdir(path.dirname(path.abspath(__file__)))
config = ConfigParser()
# Defaults
config['Global'] = {'check_delay': '5 * 60',  # every 5 min
                    'IRC_host': '127.1', 'IRC_port': '6667', 'IRC_bot_nickname': 'bot', 'IRC_admin_nickname': '',
                    'IRC_chat_name': '#main', 'attempts': '', 'attempts_delay': '', }

config.read('monitor.conf')


def on_connect(connection, event):
    connection.mode(config['Global']['IRC_bot_nickname'], '+B')
    connection.join(config['Global']['IRC_chat_name'])

def on_join(connection, event):
    connection.privmsg(config['Global']['IRC_chat_name'], 'Bot started')

def on_disconnect(connection, event):
    exit(1)


def check_port(host, port):
    s = socket()
    s.settimeout(1)
    for _ in range(int(config['Global']['attempts'])):
        if not s.connect_ex((host, int(port))): return True
        sleep(int(config['Global']['attempts_delay']))
    return False

def check_service(host, services):
    for service_name, service_port in services.items():
        result = check_port(host, service_port)
        if connection_states[host][service_name] != result:
            if result:
                irc.privmsg(config['Global']['IRC_chat_name'], '{} on {}  is up'
                            .format(service_name, host))
            else:
                irc.privmsg(config['Global']['IRC_chat_name'], '{}:{} on {} is down!'
                            .format(config['Global']['IRC_admin_nickname'], service_name, host))
            connection_states[host][service_name] = result
##
reactor = client.Reactor()
irc = reactor.server()
irc.connect(config['Global']['IRC_host'], int(config['Global']['IRC_port']), config['Global']['IRC_bot_nickname'])
irc.add_global_handler("welcome", on_connect)
irc.add_global_handler("join", on_join)
irc.add_global_handler('disconnect', on_disconnect)
Thread(target=reactor.process_forever).start() #start irc client in other thread
##
hosts = config._sections
check_delay = eval(config['Global']['check_delay'])

last_check = 0
connection_states = {}
for host, services in hosts.items():
    connection_states[host] = {}
    for service in services:
        connection_states[host][service] = True

try:
    while True:
        if time() - last_check >= check_delay:
            #print('Checking')
            for host, services in hosts.items():
                if host == 'Global': continue
                Thread(target=check_service, args=(host, services)).start()
            last_check = time()
        reactor.process_once(timeout=1)
except KeyboardInterrupt:
    irc.disconnect()