import os
import re
import requests
import smtplib
import socket
import ssl
import random
import time

from datetime import datetime
from email.mime.text import MIMEText

DEBUG_LOG = os.environ["DEBUG_LOG"].lower() == "true"

IRC_SERVER = os.environ["IRC_SERVER"]
IRC_PORT = int(os.environ["IRC_PORT"])
USE_TLS = os.environ["IRC_USE_TLS"].lower() == "true"
IRC_NICK = os.environ["IRC_NICK"]
IRC_USER = IRC_NICK
IRC_REALNAME = IRC_NICK
IRC_CHANNEL = os.environ["IRC_CHANNEL"]

TOPIC_REGEX = os.environ["TOPIC_REGEX"]

SMTP_SERVER = os.environ["SMTP_SERVER"]
SMTP_PORT = int(os.environ["SMTP_PORT"])
SMTP_USER = os.environ["SMTP_USER"]
SMTP_PASS = os.environ["SMTP_PASS"]
EMAIL_TO = os.environ["EMAIL_TO"]

MIN_WAIT_TIME = int(os.environ["MIN_WAIT_TIME"])
MAX_WAIT_TIME = int(os.environ["MAX_WAIT_TIME"])

MIN_SLEEP_TIME = int(os.environ["MIN_SLEEP_TIME"])
MAX_SLEEP_TIME = int(os.environ["MAX_SLEEP_TIME"])

topic_pattern = re.compile(TOPIC_REGEX)

def log(level, msg):
    if level == "." and not DEBUG_LOG:
        return
    ts = datetime.utcnow().strftime("%Y-%m-%d %H:%M:%S UTC")
    print(f"[{ts}] [{level}] {msg}", flush=True)

def sendmail(subject, message):
    try:
        msg = MIMEText(message)
        msg["Subject"] = subject
        msg["From"] = SMTP_USER
        msg["To"] = EMAIL_TO

        with smtplib.SMTP(SMTP_SERVER, SMTP_PORT) as server:
            server.starttls()
            server.login(SMTP_USER, SMTP_PASS)
            server.send_message(msg)
        log("+", f"Email sent to {EMAIL_TO}")
    except Exception as e:
        log("!", f"Failed to send error email: {e}")

def connect_to_channel_and_check_topic():
    log("*", f"Connecting to {IRC_SERVER}:{IRC_PORT} {"with TLS" if USE_TLS else "plain"}")
    
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sock.settimeout(10)
    if USE_TLS:
        context = ssl.create_default_context()
        sock = context.wrap_socket(sock, server_hostname=IRC_SERVER)
    
    sock.connect((IRC_SERVER, IRC_PORT))
    
    # Send NICK and USER
    nick = f"NICK {IRC_NICK}\r\n".encode()
    log(".", nick)
    sock.sendall(nick)

    irc_user = f"USER {IRC_USER} 0 * :{IRC_REALNAME}\r\n".encode()
    log(".", irc_user)
    sock.sendall(irc_user)
    
    topic = None
    joined = False
    
    while True:
        data = sock.recv(4096)
        if not data:
            break
        lines = data.decode(errors="ignore").split("\r\n")
        for line in lines:
            if not line:
                continue
            log(".", f"< {line}")
            
            # Respond to PING
            if line.startswith("PING"):
                resp = line.replace("PING", "PONG")
                pong = f"{resp}\r\n".encode()
                sock.sendall(pong)
                log(".", pong)
            
            # Check for end of MOTD or welcome to join channel
            if " 001 " in line and not joined:
                # Join channel
                join = f"JOIN {IRC_CHANNEL}\r\n".encode()
                sock.sendall(join)
                log(".", join)
                joined = True
            
            # Capture topic sent by server upon joining
            # IRC servers send: :server 332 nick #channel :topic here
            if f" 332 {IRC_NICK} " in line:
                parts = line.split(":", 2)
                if len(parts) == 3:
                    topic = parts[2]
                    log("*", f"Channel topic on join: {topic}")

                    if topic_pattern.search(topic):
                        log("+", f"Found topic, sending mail to {EMAIL_TO}")
                        sendmail("IRC TOPIC BOT: Found topic", topic)
    
        # If we have the topic, we can disconnect after a random delay
        if topic is not None:
            wait_time = random.randint(MIN_WAIT_TIME, MAX_WAIT_TIME)
            log("*", f"Waiting for {wait_time} seconds before disconnecting")
            time.sleep(wait_time)
            bye = b"QUIT :Bye!\r\n"
            sock.sendall(bye)
            log(".", bye)
            sock.close()
            log("*", "Disconnected")
            return

def main():
    try:
        res = requests.get("https://api.ipify.org", timeout=10)
        res.raise_for_status()
        ip = res.text.strip()
        log("*", f"Public IP is {ip}")
    except Exception as e:
        log("!", f"Could not get public IP, {e}")

    while True:
        connect_to_channel_and_check_topic()
        sleep_time = random.randint(MIN_SLEEP_TIME, MAX_SLEEP_TIME)
        log("*", f"Sleeping for {sleep_time} seconds before reconnecting")
        time.sleep(sleep_time)

if __name__ == "__main__":
    main()