#!/usr/bin/python3

import re
import dateutil.parser

import mailconfig
import utils

def scan_mail_log(logger, env):
	collector = {
		"other-services": set(),
		"imap-logins": { },
		"postgrey": { },
		"rejected-mail": { },
	}

	collector["real_mail_addresses"] = set(mailconfig.get_mail_users(env)) | set(alias[0] for alias in mailconfig.get_mail_aliases(env))

	with open("/var/log/mail.log") as log:
		for line in log:
			scan_mail_log_line(line.strip(), collector)

	if collector["imap-logins"]:
		logger.add_heading("Recent IMAP Logins")
		logger.print_block("The most recent login from each remote IP adddress is show.")
		for k in utils.sort_email_addresses(collector["imap-logins"], env):
			for ip, date in sorted(collector["imap-logins"][k].items(), key = lambda kv : kv[1]):
				logger.print_line(k + "\t" + str(date) + "\t" + ip)

	if collector["postgrey"]:
		logger.add_heading("Greylisted Mail")
		logger.print_block("The following mail was greylisted, meaning the emails were temporarily rejected. Legitimate senders will try again within ten minutes.")
		logger.print_line("recipient" + "\t" + "received" + "\t" + "sender" + "\t" + "delivered")
		for recipient in utils.sort_email_addresses(collector["postgrey"], env):
			for (client_address, sender), (first_date, delivered_date) in sorted(collector["postgrey"][recipient].items(), key = lambda kv : kv[1][0]):
				logger.print_line(recipient + "\t" + str(first_date) + "\t" + sender + "\t" + (("delivered " + str(delivered_date)) if delivered_date else "no retry"))

	if collector["rejected-mail"]:
		logger.add_heading("Rejected Mail")
		logger.print_block("The following incoming mail was rejected.")
		for k in utils.sort_email_addresses(collector["rejected-mail"], env):
			for date, sender, message in collector["rejected-mail"][k]:
				logger.print_line(k + "\t" + str(date) + "\t" + sender + "\t" + message)

	logger.add_heading("Other")
	logger.print_block("Unrecognized services in the log: " + ", ".join(collector["other-services"]))

def scan_mail_log_line(line, collector):
	m = re.match(r"(\S+ \d+ \d+:\d+:\d+) (\S+) (\S+?)(\[\d+\])?: (.*)", line)
	if not m: return

	date, system, service, pid, log = m.groups()
	date = dateutil.parser.parse(date)
	
	if service == "dovecot":
		scan_dovecot_line(date, log, collector)

	elif service == "postgrey":
		scan_postgrey_line(date, log, collector)

	elif service == "postfix/smtpd":
		scan_postfix_smtpd_line(date, log, collector)

	elif service in ("postfix/qmgr", "postfix/pickup", "postfix/cleanup",
			"postfix/scache", "spampd", "postfix/anvil", "postfix/master",
			"opendkim", "postfix/lmtp", "postfix/tlsmgr"):
		# nothing to look at
		pass

	else:
		collector["other-services"].add(service)

def scan_dovecot_line(date, log, collector):
	m = re.match("imap-login: Login: user=<(.*?)>, method=PLAIN, rip=(.*?),", log)
	if m:
		login, ip = m.group(1), m.group(2)
		if ip != "127.0.0.1": # local login from webmail/zpush
			collector["imap-logins"].setdefault(login, {})[ip] = date

def scan_postgrey_line(date, log, collector):
	m = re.match("action=(greylist|pass), reason=(.*?), (?:delay=\d+, )?client_name=(.*), client_address=(.*), sender=(.*), recipient=(.*)", log)
	if m:
		action, reason, client_name, client_address, sender, recipient = m.groups()
		key = (client_address, sender)
		if action == "greylist" and reason == "new":
			collector["postgrey"].setdefault(recipient, {})[key] = (date, None)
		elif action == "pass" and reason == "triplet found" and key in collector["postgrey"].get(recipient, {}):
			collector["postgrey"][recipient][key] = (collector["postgrey"][recipient][key][0], date)

def scan_postfix_smtpd_line(date, log, collector):
	m = re.match("NOQUEUE: reject: RCPT from .*?: (.*?); from=<(.*?)> to=<(.*?)>", log)
	if m:
		message, sender, recipient = m.groups()
		if recipient in collector["real_mail_addresses"]:
			# only log mail to real recipients
			collector["rejected-mail"].setdefault(recipient, []).append( (date, sender, message) )


if __name__ == "__main__":
	from status_checks import ConsoleOutput
	env = utils.load_environment()
	scan_mail_log(ConsoleOutput(), env)