#!/bin/bash

#Enable DEBUG to '1'
Debug='0'

# Mattermost incoming web-hook URL and user name
url='<incoming webbook uri>'	# example: httpsL//mattermost.example.com/hooks/ere5h9gfbbbk8gdxsei1tt8ewewechjsd
username='zabbix'
icon='<icon_url>'

## Values received by this script:
# To = $1 / Mattermost channel or user to send the message to, specified in the Zabbix web interface; "@username" or "#channel"
# Subject = $2 / subject of the message sent by Zabbix; by default, it is usually something like "(Problem|Resolved|Update): Lack of free swap space on Zabbix server"
# Message = $3 / message body sent by Zabbix; by default, it is usually approximately 4 lines detailing the specific trigger involved
# Alternate URL = $4 (optional) / alternative Slack.com web-hook URL to replace the above hard-coded one; useful when multiple groups have seperate Slack teams
# Proxy = $5 (optional) / proxy host including port (such as "example.com:8080")

to="${1}"
subject="${2}"

# The message that we want to send to Mattermost  is the "subject" value ($2 / $subject - that we got earlier)
#  followed by the message that Zabbix actually sent us ($3)
message="${subject}\n\n${3}"

# Change color emoji depending on the subject - Green (Resolved), Red (Problem)
if [[ "$subject" == *"Resolved"* ]]; then
        emoji=':smile:'
        color="#1BFF00"
elif [[ "$subject" == *"Problem"* ]]; then
        emoji=':frowning:'
        color="#ff2a00"
elif [[ "$subject" == *"Updated"* ]]; then
        color="#ccff00"
else
        # Default color
        emoji=':question:'
        color="#1258b5"
fi

# Replace the above hard-coded Mattermost web-hook URL entirely, if one was passed via the optional 4th parameter
url=${4-$url}

# Use optional 5th parameter as proxy server for curl
proxy=${5-""}
if [[ "$proxy" != '' ]]; then
    proxy="-x $proxy"
fi

## Debug
if [[ "$Debug" == "1" ]]; then
        echo "to - $to" >> /tmp/SortieMattermost.txt
        echo "sujet - $subject" >> /tmp/SortieMattermost.txt
        echo "message - $message" >> /tmp/SortieMattermost.txt
        echo "........." >> /tmp/SortieMattermost.txt
fi

# Build our JSON payload and send it as a POST request to the Mattermost incoming web-hook URL
payload="payload={\"icon_url\": \"$icon\", \"attachments\": [ {\"color\": \"${color}\", \"text\": \"${message}\"} ], \"channel\": \"${to}\", \"username\": \"${username}\", \"icon_emoji\": \"${emoji}\"}"

# Execute the HTTP POST request of the payload to Slack via curl, storing stdout (the response body)
return=$(curl $proxy -sm 5 --data-urlencode "${payload}" $url -A 'zabbix-mattermost-alertscript / https://github.com/vincent1890/zabbix-mattermost-alertscript/')

# If the response body was not what was expected from Slack ("ok"), something went wrong so print the Slack error to stderr and exit with non-zero
if [[ "$return" != 'ok' ]]; then
    >&2 echo "$return"
    exit 1
fi