#!/usr/bin/python3

from subprocess import run
from textwrap import dedent
import os
import sys
import socket
import re
import signal

config = {
    "token": None,
    "nickname": 'ianmethyst',
    "channel": '#ianmethyst',
    "supress_own": True,
    "short_notification": True
}

HOST = 'irc.chat.twitch.tv'
PORT = 6667
MESSAGE_REGEX = r':(.*)!.*@.* PRIVMSG #(.*) :(.*)'

sock = socket.socket()
connected = False


def get_token_from_env():
    """Get OAUTH token from environment variables or exit"""

    try:
        config['token'] = os.environ['TWITCH_OAUTH']
    except KeyError:
        helpText = """
                Get your OAUTH token here: https://twitchapps.com/tmi/
                Then pass it as an environment variable:
                TWITCH_OAUTH=<token> {__file__}"
                """
        print(dedent(helpText))
        sys.exit(1)


def connect():
    """Connect to IRC and authenticate"""

    sock.connect((HOST, PORT))
    sock.send(f"PASS {config['token']}\n".encode('utf-8'))
    sock.send(f"NICK {config['nickname']}\n".encode('utf-8'))
    sock.send(f"JOIN {config['channel']}\n".encode('utf-8'))


def pong(resp):
    """Answer to server PING to keep socket connection alive"""

    if resp.startswith('PING'):
        sock.send("PONG\n".encode('utf-8'))
        return True
    return False


def wait_for_chat(resp):
    """Wait until all welcome and user list messages are received"""

    if "End of /NAMES list" in resp:
        global connected
        connected = True
        run(["notify-send",
            f"connected to {config['channel']} as {config['nickname']}"])


def handle_message(resp):
    """Parse the message and send it as a notification"""

    print(resp)
    user, channel, message = re.search(MESSAGE_REGEX, resp).groups()

    if user and channel and message:
        if config['short_notification']:
            notification_text = f"@{user}: {message}"
        else:
            notification_text = f"@{user} in #{channel}\n{message}"

        if not (config['supress_own'] and config['nickname'] == user):
            run(["notify-send", notification_text])


def handle_exit(sig, frame):
    """Close socket connection before exit"""

    print(f"Got {sig.name}, closing socket")
    sock.shutdown(socket.SHUT_RDWR)
    sock.close()
    sys.exit(0)


if __name__ == "__main__":
    # Register signal handlers
    signal.signal(signal.SIGINT, handle_exit)
    signal.signal(signal.SIGTERM, handle_exit)

    get_token_from_env()
    connect()

    while True:
        resp = sock.recv(2048).decode('utf-8')

        if len(resp) > 0:
            if not (pong(resp)):
                if connected:
                    handle_message(resp)
                else:
                    wait_for_chat(resp)