#!/bin/sh
# (C) Tobias Wiese | GPLv2+
# This file is based on mail-service-notification.sh from Icinga used under GPLv2+ license
# Except of function urlencode which is Copyright (C) by Brian White (brian@aljex.com) used under MIT license
# Changes: The script was adapted to send Telegram Messages instead of mail.

PROG="$(basename $0)"
ICINGA2HOST="$(hostname)"

if [ -z "$(type curl)" ] ; then
	echo "curl not found in \$PATH. Consider installing it." 2>&1
	exit 1
fi

## Function helpers
urlencode() {
  local LANG=C i=0 c e s="$1"

  while [ $i -lt ${#1} ]; do
    [ "$i" -eq 0 ] || s="${s#?}"
    c=${s%"${s#?}"}
    [ -z "${c#[[:alnum:].~_-]}" ] || c=$(printf '%%%02X' "'$c")
    e="${e}${c}"
    i=$((i + 1))
  done
  echo "$e"
}

## Keep formatting in sync with telegram-host-notification.sh
for P in DATE HOSTNAME HOSTDISPLAYNAME SERVICENAME SERVICEDISPLAYNAME \
	SERVICEOUTPUT SERVICESTATE USERCHATID TYPE
do
	eval "PAR=\$${P}"

	if [ ! "$PAR" ] ; then
		echo "Required parameter '$P' is missing." >&2
		exit 1
	fi
done

## Build the notification message
NOTIFICATION_MESSAGE=`cat << EOF
[$SERVICESTATE] $SERVICEDISPLAYNAME on $HOSTDISPLAYNAME

$SERVICEOUTPUT
EOF
`

## Check whether author and comment was specified.
if [ -n "$COMMENT" ] ; then
	NOTIFICATION_MESSAGE="$NOTIFICATION_MESSAGE

Comment by $AUTHOR:
	$COMMENT"
fi

## Check whether Icinga Web 2 URL was specified.
if [ -n "$ICINGAWEB2URL" ] ; then
	NOTIFICATION_MESSAGE="$NOTIFICATION_MESSAGE

$ICINGAWEB2URL/monitoring/service/show?host=$(urlencode "$HOSTNAME")&service=$(urlencode "$SERVICENAME")"
fi

## Check whether verbose mode was enabled and log to syslog.
if [ "$VERBOSE" = "true" ] ; then
	logger "$PROG sends Telegram => $CHATID"
fi

## Send message via telegram
curl -X POST "https://api.telegram.org/bot${TOKEN}/sendMessage" \
	--data-urlencode "chat_id=$USERCHATID" \
	--data-urlencode "text=$NOTIFICATION_MESSAGE" \
	--data-urlencode "disable_web_page_preview=true"