#!/bin/bash

die () {
  echo >&2 "$@"
  exit 1
}

#
# Preparing
#

mkdir -p /tmp/docker-mailserver/tmp

#
# Users
#
if [ -f /tmp/docker-mailserver/postfix-accounts.cf ]; then
  echo "Regenerating postfix 'vmailbox' and 'virtual' for given users"
  echo "# WARNING: this file is auto-generated. Modify config/postfix-accounts.cf to edit user list." > /etc/postfix/vmailbox

  # Checking that /tmp/docker-mailserver/postfix-accounts.cf ends with a newline
  sed -i -e '$a\' /tmp/docker-mailserver/postfix-accounts.cf
  # Configuring Dovecot
  echo -n > /etc/dovecot/userdb
  chown dovecot:dovecot /etc/dovecot/userdb
  chmod 640 /etc/dovecot/userdb
  cp -a /usr/share/dovecot/protocols.d /etc/dovecot/
  # Disable pop3 (it will be eventually enabled later in the script, if requested)
  mv /etc/dovecot/protocols.d/pop3d.protocol /etc/dovecot/protocols.d/pop3d.protocol.disab
  sed -i -e 's/#ssl = yes/ssl = yes/g' /etc/dovecot/conf.d/10-master.conf
  sed -i -e 's/#port = 993/port = 993/g' /etc/dovecot/conf.d/10-master.conf
  sed -i -e 's/#port = 995/port = 995/g' /etc/dovecot/conf.d/10-master.conf
  sed -i -e 's/#ssl = yes/ssl = required/g' /etc/dovecot/conf.d/10-ssl.conf

  # Creating users
  # 'pass' is encrypted
  while IFS=$'|' read login pass
  do
    # Setting variables for better readability
    user=$(echo ${login} | cut -d @ -f1)
    domain=$(echo ${login} | cut -d @ -f2)
    # Let's go!
    echo "user '${user}' for domain '${domain}' with password '********'"
    echo "${login} ${domain}/${user}/" >> /etc/postfix/vmailbox
    # User database for dovecot has the following format:
    # user:password:uid:gid:(gecos):home:(shell):extra_fields
    # Example :
    # ${login}:${pass}:5000:5000::/var/mail/${domain}/${user}::userdb_mail=maildir:/var/mail/${domain}/${user}
    echo "${login}:${pass}:5000:5000::/var/mail/${domain}/${user}::" >> /etc/dovecot/userdb
    mkdir -p /var/mail/${domain}
    if [ ! -d "/var/mail/${domain}/${user}" ]; then
      maildirmake.dovecot "/var/mail/${domain}/${user}"
      maildirmake.dovecot "/var/mail/${domain}/${user}/.Sent"
      maildirmake.dovecot "/var/mail/${domain}/${user}/.Trash"
      maildirmake.dovecot "/var/mail/${domain}/${user}/.Drafts"
      echo -e "INBOX\nSent\nTrash\nDrafts" >> "/var/mail/${domain}/${user}/subscriptions"
      touch "/var/mail/${domain}/${user}/.Sent/maildirfolder"

    fi
    echo ${domain} >> /tmp/docker-mailserver/tmp/vhost.tmp
  done < /tmp/docker-mailserver/postfix-accounts.cf
else
  echo "==> Warning: 'config/docker-mailserver/postfix-accounts.cf' is not provided. No mail account created."
fi

#
# Aliases
#
if [ -f /tmp/docker-mailserver/postfix-virtual.cf ]; then
  # Copying virtual file
  cp /tmp/docker-mailserver/postfix-virtual.cf /etc/postfix/virtual
  while read from to
  do
    # Setting variables for better readability
    uname=$(echo ${from} | cut -d @ -f1)
    domain=$(echo ${from} | cut -d @ -f2)
    # if they are equal it means the line looks like: "user1     other@domain.tld"
    test "$uname" != "$domain" && echo ${domain} >> /tmp/docker-mailserver/tmp/vhost.tmp
  done < /tmp/docker-mailserver/postfix-virtual.cf
else
  echo "==> Warning: 'config/postfix-virtual.cf' is not provided. No mail alias/forward created."
fi

if [ -f /tmp/docker-mailserver/tmp/vhost.tmp ]; then
  cat /tmp/docker-mailserver/tmp/vhost.tmp | sort | uniq > /etc/postfix/vhost && rm /tmp/docker-mailserver/tmp/vhost.tmp
fi

echo "Postfix configurations"
touch /etc/postfix/vmailbox && postmap /etc/postfix/vmailbox
touch /etc/postfix/virtual && postmap /etc/postfix/virtual

# DKIM
# Check if keys are already available
if [ -e "/tmp/docker-mailserver/opendkim/KeyTable" ]; then
  mkdir -p /etc/opendkim
  cp -a /tmp/docker-mailserver/opendkim/* /etc/opendkim/
  echo "DKIM keys added for : `ls -C /etc/opendkim/keys/`"
else 
  grep -vE '^(\s*$|#)' /etc/postfix/vhost | while read domainname; do
    mkdir -p /etc/opendkim/keys/$domainname
    if [ ! -f "/etc/opendkim/keys/$domainname/mail.private" ]; then
      echo "Creating DKIM private key /etc/opendkim/keys/$domainname/mail.private"
      pushd /etc/opendkim/keys/$domainname
      opendkim-genkey --subdomains --domain=$domainname --selector=mail
      popd
      echo ""
      echo "DKIM PUBLIC KEY ################################################################"
      cat /etc/opendkim/keys/$domainname/mail.txt
      echo "################################################################################"
    fi
    # Write to KeyTable if necessary
    keytableentry="mail._domainkey.$domainname $domainname:mail:/etc/opendkim/keys/$domainname/mail.private"
    if [ ! -f "/etc/opendkim/KeyTable" ]; then
      echo "Creating DKIM KeyTable"
      echo "mail._domainkey.$domainname $domainname:mail:/etc/opendkim/keys/$domainname/mail.private" > /etc/opendkim/KeyTable
    else
      if ! grep -q "$keytableentry" "/etc/opendkim/KeyTable" ; then
        echo $keytableentry >> /etc/opendkim/KeyTable
      fi
    fi
    # Write to SigningTable if necessary
    signingtableentry="*@$domainname mail._domainkey.$domainname"
    if [ ! -f "/etc/opendkim/SigningTable" ]; then
      echo "Creating DKIM SigningTable"
      echo "*@$domainname mail._domainkey.$domainname" > /etc/opendkim/SigningTable
    else
      if ! grep -q "$signingtableentry" "/etc/opendkim/SigningTable" ; then
        echo $signingtableentry >> /etc/opendkim/SigningTable
      fi
    fi
  done
fi

echo "Changing permissions on /etc/opendkim"
# chown entire directory
chown -R opendkim:opendkim /etc/opendkim/
# And make sure permissions are right
chmod -R 0700 /etc/opendkim/keys/

# DMARC
# if there is no AuthservID create it
if [ `cat /etc/opendmarc.conf | grep -w AuthservID | wc -l` -eq 0 ]; then
  echo "AuthservID $(hostname)" >> /etc/opendmarc.conf
fi
if [ `cat /etc/opendmarc.conf | grep -w TrustedAuthservIDs | wc -l` -eq 0 ]; then
  echo "TrustedAuthservIDs $(hostname)" >> /etc/opendmarc.conf
fi
if [ ! -f "/etc/opendmarc/ignore.hosts" ]; then
  mkdir -p /etc/opendmarc/
  echo "localhost" >> /etc/opendmarc/ignore.hosts
fi

# SSL Configuration
case $DMS_SSL in
  "letsencrypt" )
    # letsencrypt folders and files mounted in /etc/letsencrypt
    if [ -e "/etc/letsencrypt/live/$(hostname)/cert.pem" ] \
    && [ -e "/etc/letsencrypt/live/$(hostname)/chain.pem" ] \
    && [ -e "/etc/letsencrypt/live/$(hostname)/privkey.pem" ]; then
      echo "Adding $(hostname) SSL certificate"
      # create combined.pem from (cert|chain|privkey).pem with eol after each .pem
      sed -e '$a\' -s /etc/letsencrypt/live/$(hostname)/{cert,chain,privkey}.pem > /etc/letsencrypt/live/$(hostname)/combined.pem

      # Postfix configuration
      sed -i -r 's/smtpd_tls_cert_file=\/etc\/ssl\/certs\/ssl-cert-snakeoil.pem/smtpd_tls_cert_file=\/etc\/letsencrypt\/live\/'$(hostname)'\/fullchain.pem/g' /etc/postfix/main.cf
      sed -i -r 's/smtpd_tls_key_file=\/etc\/ssl\/private\/ssl-cert-snakeoil.key/smtpd_tls_key_file=\/etc\/letsencrypt\/live\/'$(hostname)'\/privkey.pem/g' /etc/postfix/main.cf

      # Dovecot configuration
      sed -i -e 's/ssl_cert = <\/etc\/dovecot\/dovecot\.pem/ssl_cert = <\/etc\/letsencrypt\/live\/'$(hostname)'\/fullchain\.pem/g' /etc/dovecot/conf.d/10-ssl.conf
      sed -i -e 's/ssl_key = <\/etc\/dovecot\/private\/dovecot\.pem/ssl_key = <\/etc\/letsencrypt\/live\/'$(hostname)'\/privkey\.pem/g' /etc/dovecot/conf.d/10-ssl.conf

      echo "SSL configured with letsencrypt certificates"

    fi
    ;;

  "custom" )
    # Adding CA signed SSL certificate if provided in 'postfix/ssl' folder
    if [ -e "/tmp/postfix/ssl/$(hostname)-full.pem" ]; then
      echo "Adding $(hostname) SSL certificate"
      mkdir -p /etc/postfix/ssl
      cp "/tmp/postfix/ssl/$(hostname)-full.pem" /etc/postfix/ssl

      # Postfix configuration
      sed -i -r 's/smtpd_tls_cert_file=\/etc\/ssl\/certs\/ssl-cert-snakeoil.pem/smtpd_tls_cert_file=\/etc\/postfix\/ssl\/'$(hostname)'-full.pem/g' /etc/postfix/main.cf
      sed -i -r 's/smtpd_tls_key_file=\/etc\/ssl\/private\/ssl-cert-snakeoil.key/smtpd_tls_key_file=\/etc\/postfix\/ssl\/'$(hostname)'-full.pem/g' /etc/postfix/main.cf

      # Dovecot configuration
      sed -i -e 's/ssl_cert = <\/etc\/dovecot\/dovecot\.pem/ssl_cert = <\/etc\/postfix\/ssl\/'$(hostname)'-full\.pem/g' /etc/dovecot/conf.d/10-ssl.conf
      sed -i -e 's/ssl_key = <\/etc\/dovecot\/private\/dovecot\.pem/ssl_key = <\/etc\/postfix\/ssl\/'$(hostname)'-full\.pem/g' /etc/dovecot/conf.d/10-ssl.conf

      echo "SSL configured with CA signed/custom certificates"

    fi
    ;;

  "self-signed" )
    # Adding self-signed SSL certificate if provided in 'postfix/ssl' folder
    if [ -e "/tmp/postfix/ssl/$(hostname)-cert.pem" ] \
    && [ -e "/tmp/postfix/ssl/$(hostname)-key.pem"  ] \
    && [ -e "/tmp/postfix/ssl/$(hostname)-combined.pem" ] \
    && [ -e "/tmp/postfix/ssl/demoCA/cacert.pem" ]; then
      echo "Adding $(hostname) SSL certificate"
      mkdir -p /etc/postfix/ssl
      cp "/tmp/postfix/ssl/$(hostname)-cert.pem" /etc/postfix/ssl
      cp "/tmp/postfix/ssl/$(hostname)-key.pem" /etc/postfix/ssl
      # Force permission on key file
      chmod 600 /etc/postfix/ssl/$(hostname)-key.pem
      cp "/tmp/postfix/ssl/$(hostname)-combined.pem" /etc/postfix/ssl
      cp /tmp/postfix/ssl/demoCA/cacert.pem /etc/postfix/ssl

      # Postfix configuration
      sed -i -r 's/smtpd_tls_cert_file=\/etc\/ssl\/certs\/ssl-cert-snakeoil.pem/smtpd_tls_cert_file=\/etc\/postfix\/ssl\/'$(hostname)'-cert.pem/g' /etc/postfix/main.cf
      sed -i -r 's/smtpd_tls_key_file=\/etc\/ssl\/private\/ssl-cert-snakeoil.key/smtpd_tls_key_file=\/etc\/postfix\/ssl\/'$(hostname)'-key.pem/g' /etc/postfix/main.cf
      sed -i -r 's/#smtpd_tls_CAfile=/smtpd_tls_CAfile=\/etc\/postfix\/ssl\/cacert.pem/g' /etc/postfix/main.cf
      sed -i -r 's/#smtp_tls_CAfile=/smtp_tls_CAfile=\/etc\/postfix\/ssl\/cacert.pem/g' /etc/postfix/main.cf
      ln -s /etc/postfix/ssl/cacert.pem "/etc/ssl/certs/cacert-$(hostname).pem"

      # Dovecot configuration
      sed -i -e 's/ssl_cert = <\/etc\/dovecot\/dovecot\.pem/ssl_cert = <\/etc\/postfix\/ssl\/'$(hostname)'-combined\.pem/g' /etc/dovecot/conf.d/10-ssl.conf
      sed -i -e 's/ssl_key = <\/etc\/dovecot\/private\/dovecot\.pem/ssl_key = <\/etc\/postfix\/ssl\/'$(hostname)'-key\.pem/g' /etc/dovecot/conf.d/10-ssl.conf

      echo "SSL configured with self-signed/custom certificates"

    fi
    ;;

esac

#
# Override Postfix configuration
#
if [ -f /tmp/docker-mailserver/postfix-main.cf ]; then
  while read line; do
    postconf -e "$line"
  done < /tmp/docker-mailserver/postfix-main.cf
  echo "Loaded 'config/postfix-main.cf'"
else
  echo "'/tmp/postfix/main.cf' not provided. No extra postfix settings loaded."
fi

if [ ! -z "$SASL_PASSWD" ]; then
  echo "$SASL_PASSWD" > /etc/postfix/sasl_passwd
  postmap hash:/etc/postfix/sasl_passwd
  rm /etc/postfix/sasl_passwd
  chown root:root /etc/postfix/sasl_passwd.db
  chmod 0600 /etc/postfix/sasl_passwd.db
  echo "Loaded SASL_PASSWORD"
else
  echo "==> Warning: 'SASL_PASSWORD' is not provided. /etc/postfix/sasl_passwd not created."
fi

echo "Fixing permissions"
chown -R 5000:5000 /var/mail

echo "Creating /etc/mailname"
echo $(hostname -d) > /etc/mailname

echo "Configuring Spamassassin"
SA_TAG=${SA_TAG:="2.0"} && sed -i -r 's/^\$sa_tag_level_deflt (.*);/\$sa_tag_level_deflt = '$SA_TAG';/g' /etc/amavis/conf.d/20-debian_defaults
SA_TAG2=${SA_TAG2:="6.31"} && sed -i -r 's/^\$sa_tag2_level_deflt (.*);/\$sa_tag2_level_deflt = '$SA_TAG2';/g' /etc/amavis/conf.d/20-debian_defaults
SA_KILL=${SA_KILL:="6.31"} && sed -i -r 's/^\$sa_kill_level_deflt (.*);/\$sa_kill_level_deflt = '$SA_KILL';/g' /etc/amavis/conf.d/20-debian_defaults
test -e /tmp/spamassassin/rules.cf && cp /tmp/spamassassin/rules.cf /etc/spamassassin/

echo "Configuring fail2ban"
# enable filters
awk 'BEGIN{unit=0}{if ($1=="[postfix]" || $1=="[dovecot]" || $1=="[sasl]") {unit=1;}
      if ($1=="enabled" && unit==1) $3="true";
       else if ($1=="logpath" && unit==1) $3="/var/log/mail/mail.log";
      print;
      if (unit==1 && $1~/\[/ && $1!~/postfix|dovecot|sasl/) unit=0;
}' /etc/fail2ban/jail.conf > /tmp/jail.conf.new && mv /tmp/jail.conf.new /etc/fail2ban/jail.conf && rm -f /tmp/jail.conf.new

cat > /etc/fail2ban/filter.d/dovecot.conf << _EOF_
# Fail2Ban filter Dovecot authentication and pop3/imap server
#

[INCLUDES]

before = common.conf

[Definition]

_daemon = (auth|dovecot(-auth)?|auth-worker)

failregex = ^%(__prefix_line)s(pam_unix(\(dovecot:auth\))?:)?\s+authentication failure; logname=\S* uid=\S* euid=\S* tty=dovecot ruser=\S* rhost=<HOST>(\s+user=\S*)?\s*$
            ^%(__prefix_line)s(pop3|imap)-login: (Info: )?(Aborted login|Disconnected)(: Inactivity)? \(((no auth attempts|auth failed, \d+ attempts)( in \d+ secs)?|tried to use (disabled|disallowed) \S+ auth)\):( user=<\S*>,)?( method=\S+,)? rip=<HOST>, lip=(\d{1,3}\.){3}\d{1,3}(, session=<\w+>)?(, TLS( handshaking)?(: Disconnected)?)?\s*$
            ^%(__prefix_line)s(Info|dovecot: auth\(default\)): pam\(\S+,<HOST>\): pam_authenticate\(\) failed: (User not known to the underlying authentication module: \d+ Time\(s\)|Authentication failure \(password mismatch\?\))\s*$
            ^\s.*passwd-file\(\S*,<HOST>\): unknown user.*$
            (?: pop3-login|imap-login): .*(?:Authentication failure|Aborted login \(auth failed|Aborted login \(tried to use disabled|Disconnected \(auth failed).*rip=(?P<host>\S*),.*

## ^%(__prefix_line)spasswd-file\(\S*,<HOST>\): unknown user.*$
ignoreregex =
_EOF_


# increase ban time and find time to 3h
sed -i "/^bantime *=/c\bantime = 10800"     /etc/fail2ban/jail.conf
sed -i "/^findtime *=/c\findtime = 10800"   /etc/fail2ban/jail.conf

# avoid warning on startup
echo "ignoreregex =" >> /etc/fail2ban/filter.d/postfix-sasl.conf

# continue to write the log information in the newly created file after rotating the old log file
sed -i -r "/^#?compress/c\compress\ncopytruncate" /etc/logrotate.conf

# Setup logging
mkdir -p /var/log/mail && chown syslog:root /var/log/mail
touch /var/log/mail/clamav.log && chown -R clamav:root /var/log/mail/clamav.log
touch /var/log/mail/freshclam.log &&  chown -R clamav:root /var/log/mail/freshclam.log
sed -i -r 's|/var/log/mail|/var/log/mail/mail|g' /etc/rsyslog.d/50-default.conf
sed -i -r 's|LogFile /var/log/clamav/|LogFile /var/log/mail/|g' /etc/clamav/clamd.conf
sed -i -r 's|UpdateLogFile /var/log/clamav/|UpdateLogFile /var/log/mail/|g' /etc/clamav/freshclam.conf
sed -i -r 's|/var/log/clamav|/var/log/mail|g' /etc/logrotate.d/clamav-daemon
sed -i -r 's|/var/log/clamav|/var/log/mail|g' /etc/logrotate.d/clamav-freshclam
sed -i -r 's|/var/log/mail|/var/log/mail/mail|g' /etc/logrotate.d/rsyslog

echo "Starting daemons"
cron
/etc/init.d/rsyslog start

if [ "$SMTP_ONLY" != 1 ]; then
  # Here we are starting sasl and imap, not pop3 because it's disabled by default
  echo " * Starting dovecot services"
  /usr/sbin/dovecot -F -c /etc/dovecot/dovecot.conf &
fi

if [ "$ENABLE_POP3" = 1 -a "$SMTP_ONLY" != 1 ]; then
  echo "Starting POP3 services"
  mv /etc/dovecot/protocols.d/pop3d.protocol.disab /etc/dovecot/protocols.d/pop3d.protocol
  /usr/sbin/dovecot reload
fi

/etc/init.d/spamassassin start
/etc/init.d/clamav-daemon start
/etc/init.d/amavis start
/etc/init.d/opendkim start
/etc/init.d/opendmarc start
/etc/init.d/postfix start

if [ "$ENABLE_FAIL2BAN" = 1 ]; then
  echo "Starting fail2ban service"
  /etc/init.d/fail2ban start
fi

echo "Listing users"
/usr/sbin/dovecot user '*'

echo "Starting..."
tail -f /var/log/mail/mail.log