#!/usr/bin/env bash
## /etc/icinga2/scripts/service-by-telegram.sh / 20170330
## Last updated 20190820
## Last tests used icinga2-2.11.2-1.buster

# Copyright (C) 2018 Marianne M. Spiller <github@spiller.me>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

PROG="`basename $0`"
HOSTNAME="`hostname`"
TRANSPORT="curl"
unset DEBUG

if [ -z "`which $TRANSPORT`" ] ; then
  echo "$TRANSPORT not in \$PATH. Consider installing it."
  exit 1
fi

Usage() {
cat << EOF

service-by-telegram notification script for Icinga 2 by spillerm <github@spiller.me>

The following are mandatory:
  -4 HOSTADDRESS (\$address$)
  -6 HOSTADDRESS6 (\$address6$)
  -d LONGDATETIME (\$icinga.long_date_time$)
  -e SERVICENAME (\$service.name$)
  -l HOSTALIAS (\$host.name$)
  -n HOSTDISPLAYNAME (\$host.display_name$)
  -o SERVICEOUTPUT (\$service.output$)
  -p TELEGRAM_BOT (\$telegram_bot$)
  -q TELEGRAM_CHATID (\$telegram_chatid$)
  -r TELEGRAM_BOTTOKEN (\$telegram_bottoken$)
  -s SERVICESTATE (\$service.state$)
  -t NOTIFICATIONTYPE (\$notification.type$)
  -u SERVICEDISPLAYNAME (\$service.display_name$)

And these are optional:
  -b NOTIFICATIONAUTHORNAME (\$notification.author$)
  -c NOTIFICATIONCOMMENT (\$notification.comment$)
  -i HAS_ICINGAWEB2 (\$icingaweb2url$, Default: unset)
  -v (\$notification_logtosyslog$, Default: false)
  -D DEBUG enable debug output - meant for CLI debug only

EOF
exit 1;
}

while getopts 4:6:b:c:d:e:f:hi:l:n:o:p:q:r:s:t:u:v:D opt
do
  case "$opt" in
    4) HOSTADDRESS=$OPTARG ;;
    6) HOSTADDRESS6=$OPTARG ;;
    b) NOTIFICATIONAUTHORNAME=$OPTARG ;;
    c) NOTIFICATIONCOMMENT=$OPTARG ;;
    d) LONGDATETIME=$OPTARG ;;
    e) SERVICENAME=$OPTARG ;;
    h) Usage ;;
    i) HAS_ICINGAWEB2=$OPTARG ;;
    l) HOSTALIAS=$OPTARG ;;
    n) HOSTDISPLAYNAME=$OPTARG ;;
    o) SERVICEOUTPUT=$OPTARG ;;
    p) TELEGRAM_BOT=$OPTARG ;;
    q) TELEGRAM_CHATID=$OPTARG ;;
    r) TELEGRAM_BOTTOKEN=$OPTARG ;;
    s) SERVICESTATE=$OPTARG ;;
    t) NOTIFICATIONTYPE=$OPTARG ;;
    u) SERVICEDISPLAYNAME=$OPTARG ;;
    v) VERBOSE=$OPTARG ;;
    D) DEBUG=1; echo -e "\n**********************************************\nWARNING: DEBUG MODE, DEACTIVATE ASAP\n**********************************************\n" ;;
   \?) echo "ERROR: Invalid option -$OPTARG" >&2
       Usage ;;
    :) echo "Missing option argument for -$OPTARG" >&2
       Usage ;;
    *) echo "Unimplemented option: -$OPTARG" >&2
       Usage ;;
  esac
done


# make icon out of service state
case "$SERVICESTATE" in
  CRITICAL) SERVICESTATEICON=$'\xF0\x9F\x9F\xA5';;
  WARNING)  SERVICESTATEICON=$'\xF0\x9F\x9F\xA7';;
  OK)       SERVICESTATEICON=$'\xF0\x9F\x9F\xA9';;
  UNKNOWN)  SERVICESTATEICON=$'\xE2\x9D\x93\x0A';;
  *)        SERVICESTATEICON="[$SERVICESTATE]";;
esac


# convert date
dateInSec=$(date -d "$LONGDATETIME" +%s)
nowInSec=$(date +%s)
ageInSec=$(($nowInSec - $dateInSec))
ageInMin=$(($ageInSec/60))
ageInHours=$(($ageInMin/60))
ageInDays=$(($ageInHours/24))
if [ "${LONGDATETIME:0:10}" == "$(date +"%Y-%m-%d")" ]; then
	LONGDATETIME="${LONGDATETIME:11}"
fi

date=${LONGDATETIME#}
if   [ $ageInDays -gt 0 ]; then
	age=" since ${ageInDays}d $(($ageInHours-$ageInDays*24))h ($LONGDATETIME)"
elif [ $ageInHours -gt 0 ]; then
	age=" since ${ageInHours}h $(($ageInMin-$ageInHours*60))m ($LONGDATETIME)"
elif [ $ageInMin -gt 0 ]; then
	age=" since ${ageInMin}m $(($ageInSec-$ageInMin*60))s"
elif [ $ageInSec -gt 5 ]; then
	age=" since ${ageInSec}s"
elif [ $ageInSec -lt 0 ]; then
	age=" since $LONGDATETIME"
fi


## Build the message itself
NOTIFICATION_MESSAGE=$(cat << EOF
$SERVICESTATEICON <b>$SERVICEDISPLAYNAME</b> is ${SERVICESTATE}$age
Host: <b>$HOSTALIAS</b> (IPv4 <code>$HOSTADDRESS</code>
EOF
)

## Is this host IPv6 capable?
if [ -n "$HOSTADDRESS6" ] ; then
  NOTIFICATION_MESSAGE="$NOTIFICATION_MESSAGE, IPv6 <code>$HOSTADDRESS6</code>"
fi
NOTIFICATION_MESSAGE="$NOTIFICATION_MESSAGE)"

NOTIFICATION_MESSAGE="$NOTIFICATION_MESSAGE
More info: $SERVICEOUTPUT"

## Are there any comments? Put them into the message!
if [ -n "$NOTIFICATIONCOMMENT" ] ; then
  NOTIFICATION_MESSAGE="$NOTIFICATION_MESSAGE
Comment by $NOTIFICATIONAUTHORNAME:
  $NOTIFICATIONCOMMENT"
fi

## Are we using Icinga Web 2? Put the URL into the message!
if [ -n "$HAS_ICINGAWEB2" ] ; then
  NOTIFICATION_MESSAGE="$NOTIFICATION_MESSAGE
<a href='$HAS_ICINGAWEB2/monitoring/host/show?host=$HOSTALIAS'>$HAS_ICINGAWEB2</a>"
fi

## Are we verbose? Then put a message to syslog...
if [ "$VERBOSE" == "true" ] ; then
  SUBJECT="[$NOTIFICATIONTYPE] $SERVICEDISPLAYNAME on $HOSTDISPLAYNAME is $SERVICESTATE!"
  logger "$PROG sends $SUBJECT => Telegram Channel $TELEGRAM_BOT"
fi

## debug output or not?
if [ -z $DEBUG ];then
    CURLARGS="--silent --output /dev/null"
else
    CURLARGS=-v
    set -x
    echo -e "DEBUG MODE!"
fi

## And finally, send the message
/usr/bin/curl $CURLARGS \
    --data-urlencode "chat_id=${TELEGRAM_CHATID}" \
    --data-urlencode "text=${NOTIFICATION_MESSAGE}" \
    --data-urlencode "parse_mode=HTML" \
    --data-urlencode "disable_web_page_preview=true" \
    "https://api.telegram.org/bot${TELEGRAM_BOTTOKEN}/sendMessage"
set +x