#!/usr/bin/env bash

check_string_ps=""
if [[ -x "/usr/lib/postfix/master" ]] ; then
   check_string_ps="/usr/lib/postfix/master"
elif [[ -x "/usr/libexec/postfix/master" ]] ; then
   check_string_ps="/usr/libexec/postfix/master"
fi

postfix_init_script=""
if [[ -x "/etc/init.d/postfix" ]] ; then
   postfix_init_script="/etc/init.d/postfix"
fi

LOCK_DIR=`mktemp -d`


#---------------------------------------
#-----------------------------
# Base Function(s)
#-----------------------------
#---------------------------------------

fatal(){
   echo ""
   echo -e "   [ Fatal ] $*"
   echo ""
   echo -e "\tScript terminated.."
   echo ""
   rm -rf $LOCK_DIR
   exit 1
}

error (){
   echo ""
   echo -e "   [ Error ] $*"
   echo ""
}

warn (){
   echo ""
   echo -e "   [ Warn ]  $*"
   echo ""
}

info (){
   echo ""
   echo -e "   [ Info ]  $*"
   echo ""
}

ok (){
   echo ""
   echo -e "   [ Ok ]    $*"
   echo ""
}

trim() {
    local var="$*"
    var="${var#"${var%%[![:space:]]*}"}"   # remove leading whitespace characters
    var="${var%"${var##*[![:space:]]}"}"   # remove trailing whitespace characters
    echo -n "$var"
}


#---------------------------------------
#-----------------------------
# Check some prerequisites
#-----------------------------
#---------------------------------------

# - Running in a terminal?
# -
if [[ -t 1 ]] ; then
      terminal=true
      LOGGING=true
else
   terminal=false
   LOGGING=false
fi

if [[ -z $check_string_ps ]]; then
   fatal "$(basename $0): Postfix seems NOT to be installed"
fi

# - Systemd supported ?
# -
systemd=$(which systemd)
systemctl=$(which systemctl)

systemd_supported=false
if [[ -n "$systemd" ]] && [[ -n "$systemctl" ]] ; then
   systemd_supported=true
else
   if [[ ! -x $postfix_init_script ]]; then
      fatal "$(basename $0): Missing Postfix Init-Script!"
   fi
fi


#---------------------------------------
#-----------------------------
# Check if Postfix Mailservice is running
#-----------------------------
#---------------------------------------

if $LOGGING ; then
   echo -e "\n   Check if Postfix Mailservice is running.."
   echo -e "   ========================================="
fi
if ! ps ax | grep -e "\ ${check_string_ps}" | grep -v grep > /dev/null ; then
   error "Postfix Mailservice seems to be down! Trying to restart service now.."

   if $systemd_supported ; then
      $systemctl stop postfix > /dev/null 2> ${LOCK_DIR}/err_msg.log
      if [[ $? -ne 0 ]]; then
         error "$(cat ${LOCK_DIR}/err_msg.log)"
      fi
      sleep 10
      $systemctl start postfix > /dev/null 2> ${LOCK_DIR}/err_msg.log
      if [[ $? -ne 0 ]]; then
         error "$(cat ${LOCK_DIR}/err_msg.log)"
      fi
   else
      $postfix_init_script stop > /dev/null 2>&1
      if [[ $? -ne 0 ]]; then
         error "Stopping Postfix Mailservice failed!"
      fi
      sleep 10
      $postfix_init_script start > /dev/null 2>&1
      if [[ $? -ne 0 ]]; then
         error "Starting Postfix Mailservice failed!"
      fi
   fi


   if ! ps ax | grep -e "\ ${check_string_ps}" | grep -v grep > /dev/null ; then
      error "Restarting Postfix Mailservice failed!"
   else
      ok "Postfix Mailservice is up and running."
   fi
         
else
   if $LOGGING ; then
      ok "Postfix Mailservice is up and running."
   fi
fi

rm -rf $LOCK_DIR
exit 0