#!/usr/bin/env bash

working_dir="$(dirname $(realpath $0))"


# -------------
# - Some Variables
# -------------

LOCK_DIR="/tmp/$(basename $0).LOCK"

service_name="ntpsec"
alert_email_arr="root"
sender_address="check_${service_name}@$(hostname -f)"

check_string_ps="$(which ntpd)"

restart_needed=false

# -------------
# - Job is already running?
# -------------

# - If job already runs, stop execution..
# -
if mkdir "$LOCK_DIR" 2> /dev/null ; then

   ## - Remove lockdir when the script finishes, or when it receives a signal
   trap clean_up SIGHUP SIGINT SIGTERM

else

   datum="$(date +"%d.%m.%Y %H:%M")"

   msg="[ Error ]: A previos instance of \"`basename $0`\" seems already be running.\n\n           Exiting now.."

   echo ""
   echo "[ Error ]: A previos instance of that script \"`basename $0`\" seems already be running."
   echo ""
   echo -e "           Exiting now.."
   echo ""

   for _email in ${alert_email_arr[@]} ; do
      echo -e "To:${_email}\n${content_type}\nSubject:Error cronjob `basename $0` -- $datum\n${msg}\n" \
         | sendmail -F "Error `hostname -f`" -f $sender_address $_email
   done

   exit 1

fi


# -------------
# - Some functions
# -------------

clean_up() {

   # Perform program exit housekeeping
   rm -rf "$LOCK_DIR"
   exit $1
}

echononl(){
   if $terminal ; then
      echo X\\c > /tmp/shprompt$$
      if [ `wc -c /tmp/shprompt$$ | awk '{print $1}'` -eq 1 ]; then
         echo -e -n "$*\\c" 1>&2
      else
         echo -e -n "$*" 1>&2
      fi
      rm /tmp/shprompt$$
   fi
}

fatal(){
   echo ""
   if $terminal ; then
      echo -e "   [ \033[31m\033[1mFatal\033[m ]: $*"
      echo ""
      echo -e "   \033[31m\033[1mScript was interupted\033[m!"
   else
      echo "   [ Fatal ]: $*"
      echo ""
      echo "              Script was terminated...."
   fi
   echo ""
   clean_up 1
}

error (){
   echo ""
   if $terminal ; then
      echo -e "   [ \033[31m\033[1mError\033[m ]: $*"
   else
      echo "[ Error ]: $*"
   fi
   echo ""
}

warn (){
   echo ""
   if $terminal ; then
      echo -e "   [ \033[33m\033[1mWarning\033[m ]: $*"
   else
      echo "[ Warning ]: $*"
   fi
   echo ""
}

info (){
   if $terminal ; then
   	echo ""
      echo -e "   [ \033[32m\033[1mInfo\033[m ]: $*"
   	echo ""
   fi
}

echo_done() {
   if $terminal ; then
      echo -e "\033[75G[ \033[32mdone\033[m ]"
   fi
}
echo_failed(){
   if $terminal && $LOGGING ; then
      echo -e "\033[75G[ \033[1;31mfailed\033[m ]"
   fi
}
echo_skipped() {
   if $terminal && $LOGGING ; then
      echo -e "\033[75G[ \033[33m\033[1mskipped\033[m ]"
   fi
}


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

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

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

systemd_supported=false
if [[ -n "$systemd" ]] && [[ -n "$systemctl" ]] ; then
   systemd_supported=true
fi

# - Check How to start/stop service
# -
SYSTEMD_UNIT_FILE=""
SYSY_INIT_SCRIPT=""
if $systemd_supported ; then
   SYSTEMD_UNIT_FILE="$(systemctl list-unit-files \
      | grep -E "${service_name}.service" \
      | grep "enabled" \
      | cut -d' ' -f1)"
   if [[ -z "${SYSTEMD_UNIT_FILE}" ]]; then
	   SYSTEMD_UNIT_FILE="$(systemctl list-unit-files \
         | grep -E "${service_name}[^@]*\.service" \
         | grep "enabled" | cut -d' ' -f1)"
   fi
fi

if [[ -z "$SYSTEMD_UNIT_FILE" ]]; then
	SYSY_INIT_SCRIPT="$(service --status-all | awk '{print$4}' | grep ${service_name} | head -1)"
fi

if [[ -z "$SYSTEMD_UNIT_FILE" ]] && [[ -z "$SYSY_INIT_SCRIPT" ]] ; then
	fatal "Neither an init-script nor a service file for ${service_name} service found!"
fi


# -------------
# - Main Part of Script
# -------------

if $terminal ; then
	echo -e "\n   Check if ${service_name} service is running.."
	echo -e "   ==================================="
fi

PIDS="$(ps ax | grep -E "${check_string_ps}" | grep -v grep | awk '{print$1}')"
if [[ -z "$PIDS" ]]; then
   restart_needed=true
fi
   
if $restart_needed ;then

	error "${service_name} service seems to be down. Try to (re)start .."

	echononl "   Stop service '${service_name}' first .."
	if [[ -n "$SYSTEMD_UNIT_FILE" ]] ; then
		systemctl stop $SYSTEMD_UNIT_FILE > /dev/null 2>&1
		if [[ $? -eq 0 ]] ; then
			echo_done
		else
			echo_failed
		fi
	else
		/etc/init.d/$SYSY_INIT_SCRIPT stop > /dev/null 2>&1
		if [[ $? -eq 0 ]] ; then
			echo_done
		else
			echo_failed
		fi
	fi

	sleep 2

	echononl "   Start Service '${service_name}' (${SYSTEMD_UNIT_FILE}).."
	if [[ -n "$SYSTEMD_UNIT_FILE" ]] ; then
		systemctl start $SYSTEMD_UNIT_FILE > /dev/null 2>&1
		if [[ $? -eq 0 ]] ; then
			echo_done
		else
			echo_failed
		fi
	else
		/etc/init.d/$SYSY_INIT_SCRIPT start > /dev/null 2>&1
		if [[ $? -eq 0 ]] ; then
			echo_done
		else
			echo_failed
		fi
	fi


	declare -i count=0

   restart_sucessfully=false
	while [[ $count -lt 10 ]] && ! $restart_sucessfully ; do

		((count++))

		sleep 1

      NEW_PID="$(ps ax | grep -E "${check_string_ps}" | grep -v grep | awk '{print$1}')"
      if [[ -z "$NEW_PID" ]]; then
         continue
      fi
      restart_sucessfully=true
      break

	done

	if ! $restart_sucessfully ; then
		error "Restarting service '${service_name}' failed."
	else

		info "Service '${service_name}' was restarted and is now up and running.
             The new PID is $NEW_PID"

      if ! $terminal ; then
         echo ""
         echo "[ Success ]: Service '${service_name}' was restarted and is now up and running."
         echo "             The new PID is $NEW_PID"
         echo ""
      fi

	fi

else
	info "Service ${service_name} is up and running."
fi

clean_up 0