"""
Get login statistics for a samba server daemon (uses journald). Recommended
setup in /etc/smbd.conf is to set `logging = syslog@3 ...` (ensure smbd was
built with `configure --with-syslog`).
"""

import re
from systemd import journal

from logparse import config
from logparse.formatting import *
from logparse.load_parsers import Parser
from logparse.util import LogPeriod, resolve

class SmbdJournald(Parser):

    def __init__(self):

        super().__init__()
        self.name = "smbd_journald"
        self.info = "Get login statistics for a samba server."

    def parse_log(self):

        logger.debug("Starting smbd section")
        section = Section("smbd")

        j = journal.Reader()
        j.this_boot()
        j.log_level(journal.LOG_DEBUG)
        j.add_match(_COMM="smbd")

        messages = [entry["MESSAGE"] for entry in j if "MESSAGE" in entry]

        total_auths = 0     # total no. of logins for all users and all shares

        shares = {}         # file shares (each share is mapped to a list of
                            # user-hostname pairs)

        logger.debug("Found {0} samba logins".format(str(len(messages))))
        logger.debug("Parsing data")

        for msg in messages:  # one log file for each client

            if "connect to service" in msg:

                # Generate list of [('client', 'ip', 'share', 'user')]
                entry = re.search("(\w*)\s*\(ipv.:(.+):.+\) connect to service"
                    "(\S+) initially as user (\S+)", msg)

                try:
                    client, ip, share, user = entry.group(1,2,3,4)
                except:
                    logger.warning("Malformed log message: " + msg)
                    continue

                if not share in shares:
                    share_match = False
                    for pattern in config.prefs.get("smbd", "shares").split():
                        share_match = re.fullmatch(pattern, share) or share_match
                    if not share_match:
                        logger.debug("Ignoring share {0} due to config".format(share))
                        continue

                if (not client.strip()):
                    client = ip
                userhost = user + '@' + resolve(client, 
                        fqdn=config.prefs.get("smbd", "smbd-resolve-domains"))

                user_match = False
                for pattern in config.prefs.get("smbd", "users").split():
                    user_match = re.fullmatch(pattern, userhost) or user_match
                if not user_match:
                    logger.debug("Ignoring login to {0} by user {1} "
                        "due to config".format(share, userhost))
                    continue

                total_auths += 1
                if share in shares:
                    shares[share].append(userhost)
                else:
                    shares[share] = [userhost]

        # Format Data() objects

        section.append_data(Data(subtitle="Total of {0} authentications"
            .format(str(total_auths))))

        for share, logins in shares.items():
            share_data = Data()
            share_data.items = logins
            share_data.orderbyfreq()
            share_data.truncl(config.prefs.getint("logparse", "maxlist"))
            share_data.subtitle = share +  " ({0}, {1})".format(
                    plural("user", len(share_data.items)),
                    plural("login", len(logins)))
            section.append_data(share_data)
            logger.debug("Found {0} logins for share {1}".format(
                str(len(logins)), share))

        logger.info("Finished smbd section")
        return section