#!/usr/bin/env bash
## /etc/icinga2/scripts/host-by-telegram.sh / 20170330
## Last updated 20190820
## Last tests used 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 $0`"
HOSTNAME="`hostname`"
TRANSPORT="curl"
LF=$'\n'
unset DEBUG

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

Usage() {
cat << EOF

host-by-mail 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$)
  -l HOSTALIAS (\$host.name$)
  -n HOSTDISPLAYNAME (\$host.display_name$)
  -o HOSTOUTPUT (\$host.output$)
  -p TELEGRAM_BOT (\$telegram_bot$)
  -q TELEGRAM_CHATID (\$telegram_chatid$)
  -r TELEGRAM_BOTTOKEN (\$telegram_bottoken$)
  -s HOSTSTATE (\$host.state$)
  -t NOTIFICATIONTYPE (\$notification.type$)

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: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 ;;
    h) Usage ;;
    i) HAS_ICINGAWEB2=$OPTARG ;;
    l) HOSTALIAS=$OPTARG ;;
    n) HOSTDISPLAYNAME=$OPTARG ;;
    o) HOSTOUTPUT=$OPTARG ;;
    p) TELEGRAM_BOT=$OPTARG ;;
    q) TELEGRAM_CHATID=$OPTARG ;;
    r) TELEGRAM_BOTTOKEN=$OPTARG ;;
    s) HOSTSTATE=$OPTARG ;;
    t) NOTIFICATIONTYPE=$OPTARG ;;
    v) VERBOSE=$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 "$HOSTSTATE" in
  UP)      HOSTSTATEICON=$'\xF0\x9F\x9F\xA9 ';;
  DOWN)    HOSTSTATEICON=$'\xF0\x9F\x9F\xA5 ';;
  UNKNOWN) HOSTSTATEICON=$'\xE2\x9D\x93\x0A ';;
  *)       HOSTSTATEICON="";;
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)$LF"
elif [ $ageInHours -gt 0 ]; then
	age="Since   ${ageInHours}h $(($ageInMin-$ageInHours*60))m ($LONGDATETIME)$LF"
elif [ $ageInMin -gt 0 ]; then
	age="Since   ${ageInMin}m $(($ageInSec-$ageInMin*60))s$LF"
elif [ $ageInSec -gt 5 ]; then
	age="Since   ${ageInSec}s$LF"
elif [ $ageInSec -lt 0 ]; then
	age="Since   $LONGDATETIME$LF"
fi

if [ "$HOSTALIAS" == "$HOSTDISPLAYNAME" ]; then
	HOSTALIAS2=""
else
	HOSTALIAS2=" ($HOSTALIAS)"
fi

## Build the message itself
NOTIFICATION_MESSAGE=$(cat << EOF
$HOSTSTATEICON<b>$HOSTDISPLAYNAME</b>$HOSTALIAS2 is $HOSTSTATE!
${age}Info      $HOSTOUTPUT
IPv4     <code>$HOSTADDRESS</code>
EOF
)

## Is this host IPv6 capable?
if [ -n "$HOSTADDRESS6" ] ; then
  NOTIFICATION_MESSAGE="$NOTIFICATION_MESSAGE
IPv6     <code>$HOSTADDRESS6</code>"
fi
## Are there any comments? Put them into the message!
if [ -n "$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 [ "$VERBOSE" == "true" ] ; then
  ## Build the message's subject
  SUBJECT="[$NOTIFICATIONTYPE] Host $HOSTDISPLAYNAME is $HOSTSTATE!"
  logger "$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