#!/usr/bin/env bash

# ----------
# - Some script variables (Default values other variables see below)
# ----------

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

conf_file="${working_dir}/conf/${script_name%%.*}.conf"

LOCK_DIR="/tmp/${script_name%%.*}.LOCK"
log_file="${LOCK_DIR}/${script_name%%.*}.log"


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

usage() {


   [[ -n  "$1" ]] && error "$1"


   [[ $terminal ]] && echo -e "
\033[1mUsage:\033[m

   $(basename $0) [-c <integer>}

\033[1mDescription\033[m

   Script wwarns if disk usage exceeds a given or default value (percent)

\033[1mOptions\033[m

   -c <integer)
      a critical value in percent. if disc usage reaches this value, a warn e-mail
      to given e-mail adresse(s) will be send.

      Default e-mail adresse(s):
        ${DEFAULT_ALERT_EMAIL_ADDRESSES}

   -h
      Prints this help.

\033[1mFiles\033[m

   $conf_file: Configuration file

\033[1mExample:\033[m

   warn if disc usage exceeds 80%

      $(basename $0) -c 80

"

   clean_up 1

}


clean_up() {

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

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

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

ok (){
   if $terminal ; then
      echo ""
      echo -e "   [ \033[32m\033[1mOk\033[m ]    $*"
      echo ""
   fi
}
echo_done() {
   if $terminal ; then
      echo -e "\033[75G[ \033[32mdone\033[m ]"
   fi
}
echo_ok() {
   if $terminal ; then
      echo -e "\033[75G[ \033[32mok\033[m ]"
   fi
}
echo_warn() {
   if $terminal ; then
      echo -e "\033[75G[ \033[33mwarn\033[m ]"
   fi
}
echo_failed(){
   if $terminal ; then
      echo -e "\033[75G[ \033[1;31mfailed\033[m ]"
   fi
}
echo_skipped() {
   if $terminal ; then
      echo -e "\033[75G[ \033[90m\033[1mskipped\033[m ]"
   fi
}
echo_wait(){
   if $terminal ; then
      echo -en "\033[75G[ \033[5m\033[1m...\033[m ]"
   fi
}

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

blank_line() {
   if $terminal ; then
      echo ""
   fi
}

is_number() {

   return $(test ! -z "${1##*[!0-9]*}" > /dev/null 2>&1);

   # - also possible
   # -
   i#[[ ! -z "${1##*[!0-9]*}" ]] && return 0 || return 1
   #retuon $([[ ! -z "${1##*[!0-9]*}" ]])
}


# ----------
# - Some checks ..
# ----------

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


# ==========
# - Begin Main Script
# ==========

# ----------
# - Headline
# ----------

if $terminal ; then
   clear
   echo ""
   echo -e "\033[1m----------\033[m"
   echo -e "\033[32m\033[1mRunning script \033[m\033[1m$script_name\033[32m .. \033[m"
   echo -e "\033[1m----------\033[m"
fi



# ----------
#  Read Configurations from $conf_file
# ----------

# - Give your default values here
# -
DEFAULT_ADMIN_EMAIL="argus@oopen.de"

DEFAULT_COMPANY="O.OPEN"

DEFAULT_CONTENT_TYPE='Content-Type: text/plain;\n charset="utf-8"'
DEFAULT_SENDER_ADDRESS="${script_name%%.*}@$(hostname -f)"
DEFAULT_ALERT_EMAIL_ADDRESSES="ckubu@oopen.de"
DEFAULT_WARN_VALUE=85%

# - Print help?
# -
if [[ "$(trim $*)" = "--help" ]] || [[ "$(trim $*)" = "-help" ]] || [[ "$(trim $*)" = "help" ]] ; then
    usage
fi



if [[ -f "$conf_file" ]]; then
   source "$conf_file"
else
   warn_only_terminal  "No configuration file '$conf_file' present.\n
                Loading default values.."
fi

[[ -n "${WARN_VALUE}" ]] || WARN_VALUE="${DEFAULT_WARN_VALUE}"

[[ -n "${ADMIN_EMAIL}" ]] || ADMIN_EMAIL="${DEFAULT_ADMIN_EMAIL}"
[[ -n "${COMPANY}" ]] || COMPANY="${DEFAULT_COMPANY}"

[[ -n "${ALERT_EMAIL_ADDRESSES}" ]] || ALERT_EMAIL_ADDRESSES="${DEFAULT_ALERT_EMAIL_ADDRESSES}"
[[ -n "${CONTENT_TYPE}" ]] || CONTENT_TYPE="${DEFAULT_CONTENT_TYPE}"
[[ -n "${SENDER_ADDRESS}" ]] || SENDER_ADDRESS="${DEFAULT_SENDER_ADDRESS}"


WARN_VALUE="${WARN_VALUE%\%}"

if ! $(is_number ${WARN_VALUE}) ; then
   fatal "Given value for \033[1mWARN_VALUE\033[m (\033[1m${WARN_VALUE}\033[m) isn't a number!"
fi

SUBJECT="[ Warning ] Hard disk storage on $(hostname -f) exceeds ${WARN_VALUE}%"

# ----------
# - Read commandline parameter
# ----------

while getopts c:h opt ; do
   case $opt in
      c)    WARN_VALUE="${OPTARG}"
            WARN_VALUE="${WARN_VALUE%\%}"
            ;;
      h)    usage
            ;;
      \?)   usage ;;
   esac
done


# - Commandline parameter overwrites those given at configuration file
# -
if ! $(is_number ${WARN_VALUE}) ; then
   fatal "Given value for \033[1mWARN_VALUE\033[m at commandline option \033[1m-c\033[m (\033[1m${WARN_VALUE}\033[m) isn't a number!"
fi


if [[ -n "$(trim ${ALERT_EMAIL_ADDRESSES})" ]] ; then
   for _email in $ALERT_EMAIL_ADDRESSES ; do
      alert_email_arr+=("$_email")
   done
fi


# ----------
# - Jobhandling
# ----------

# - 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 1" 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 ""

   echo -e "To:${ADMIN_EMAIL}\n${CONTENT_TYPE}\nSubject:Error cronjob `basename $0` -- $datum\n${msg}\n" \
      | sendmail -F "Error `hostname -f`" -f ${SENDER_ADDRESS} ${ADMIN_EMAIL}

   exit 1

fi
blank_line

msg=""
found=false
while IFS='' read -r _line || [[ -n $_line ]] ; do

   read -ra _addr <<< "$_line"
    
   _device="${_addr[1]}"
   _dir="${_addr[2]}"

   _tmp_percent="${_addr[0]}"
   declare -i _percent="${_tmp_percent%\%}"


   if [[ ${_percent} -gt ${WARN_VALUE} ]] ; then

      #echo -e "\033[3G${_device}\033[15G -> ${_dir}\033[25G ${_percent}%"
      if [[ -z "${msg}" ]]; then
         msg="\n   The hard disk space on Device '${_device}' mounted at '${_dir}' is '${_percent}'% full!\n"
      else
         msg+="\n   The hard disk space on Device '${_device}' mounted at '${_dir}' is '${_percent}'% full!\n"
      fi

      if ! ${found} && ${terminal} ; then
         echo -e "   Host: \033[1m$(hostname -f)\033[m"
      fi
      warn_only_terminal "The hard disk space on Device \033[1m${_device}\033[m mounted at \033[1m${_dir}\033[m is \033[1;31m${_percent}% full!\033[m"

      found=true

   fi

done < <(df -H | grep -vE '^Dateisystem|Filesystem|tmpfs|cdrom|loop|udev' | awk '{ print $5 " " $1 " " $6 }')

if $found ; then

   if $(which lxc-ls > /dev/null) ; then

      _guest_machines="$(lxc-ls)"


      if [[ ${#_guest_machines} -gt 0 ]]; then

         if ${terminal}; then
            echo -e "   LX Guest Systems:"
         fi

         msg_guests="LX Guest Systems:"

         for _name in ${_guest_machines} ; do

            _state="$(lxc-info -n ${_name} | grep -i 'State:' | awk '{print$2}')"

            msg_guests="${msg_guests}\n   (${_state}:) ${_name}"

            if ${terminal}; then
               echo -e "      (${_state}:) ${_name}"
            fi

         done


      fi # if [[ ${#_guest_machines} -gt 0 ]]

   fi # if $(which lxc-ls > /dev/null)

   SUBJECT="[ Warning ] Hard disk usage (${_percent}%) on $(hostname -f) exceeds ${WARN_VALUE}%"
   SUBJECT_UTF8="$(echo "${SUBJECT}" | iconv -t UTF8)"
   SUBJECT_UTF8_ENCODED="=?utf-8?B?$(echo ${SUBJECT_UTF8} | base64  --wrap=0)?="

   for _email in ${alert_email_arr[@]} ; do
      echo -e "To:${_email}\n${CONTENT_TYPE}\nSubject:${SUBJECT_UTF8_ENCODED}\n\nHost: $(hostname -f)\n${msg}\n${msg_guests}" | /usr/sbin/sendmail -F "${COMPANY} -- hard disk usage" -f ${SENDER_ADDRESS} ${_email}
   done

else
   info "Harddisk usage on host \033[1m$(hostname -f)\033[m is fine."
fi

clean_up 0