#!/usr/bin/env bash

# Modes (0 = off/false, 1 = true/on)
ssl=0
www=0
cname=0
delete=0
awstats=0
reload=0
content=0

config_dir=/etc/nagios3/conf.d
config_file_web=$config_dir/web_services.cfg
init_script=/etc/init.d/nagios3

export params=''

function help() {
    echo $0': [-s|-W|-A|-r] <[-D] -w website> [-h hostname] [-c cname1,cname2,etc...] [-C /path!string]'
    echo -e "\t-s Add SSL monitoring"
    echo -e "\t-W Also add a monitor for the WWW record"
    echo -e "\t-D Delete the monitor(s) for the hostname/website provided"
    echo -e "\t-h Provide a hostname, useful for VHOSTs"
    echo -e "\t-c A comma seperated list of cnames to add monitors for"
    echo -e "\t-A Adds an AWSTATS monitor for this host"
    echo -e "\t-C Adds a Content check for string matching"
    echo -e "\t-r Reloads nagios after config files are updated"
}

function set-params() {
    # Array is: use, description, host_name, check_command
    params=("$1" "$2" "$3" "$4")
}

function set-http-params() {
    set-params 'http-vhost2' "URL: $1" $2 "check_http_vhost2!$2!$1"
}

function set-https-params() {
    set-params 'http-vhost' "SSL Cert: $1" $2 "check_ssl_cert!$1"
}

function set-awstats-params() {
    set-params 'check-termite' "AWSTATS: $1" "termite.fsf.org" "check_termite!$1"
}

function set-content-params() {
    set-params 'http-vhost' "URL Content: $1" $2 "check_http_string!$2!$3"
}

function write-config-header() {
    echo "# AUTOGENERATED CONFIG FOR HOST: $host:$website"
    echo "# User: $USER"
    echo "# Date: `date '+%D %T'`"
}

function write-config-footer() {
    echo "# END $host:$website"
}

function write-config-body() {
    echo "define service {"
    echo -e "\tuse\t\t\t${params[0]}"
    echo -e "\tdescription\t\t${params[1]}"
    echo -e "\thost_name\t\t${params[2]}"
    echo -e "\tcheck_command\t\t${params[3]}"
    echo "}"
    echo
}

function delete-monitors() {
    sed '/^# AUTOGENERATED CONFIG FOR HOST: '$host':'$website'$/,/^# END '$host':'$website'$/d' -i $config_file_web
}

# Process our args
while getopts "rADWw:h:sc:C:" opt; do
    case "${opt}" in
	s)
	    ssl=1
	    ;;
	h)
	    host=${OPTARG}
	    ;;
	w)
	    website=${OPTARG}
	    ;;
	W)
	    www=1
	    ;;
	c)
	    cnames=${OPTARG}
	    cname=1
	    ;;
	D)
	    delete=1
	    ;;
	A)
	    awstats=1
	    ;;
	r)
	    reload=1
	    ;;
	C)
	    content_data="${OPTARG}"
	    content=1
	    ;;
	*)
	    help
	    exit 1
    esac
done

# Print help and quit if website is not provided
if [ -z ${website} ]; then
    help
    exit 1
fi

# Set host_name to website if not provided
if [ -z ${host} ]; then
    host=$website
fi

# Confirm we have a valid hostname (could be better, but this is good enough I think)
grep -R "host_name[ 	]*$host" $config_dir &>/dev/null
if [ $? -ne 0 ]; then
    echo "Error: Could not find host \`$host' in nagios configs."
    exit 3
fi

# Prep CNAMEs (if provided) for a for loop by replacing the delimiter
if [ $cname -eq 1 ]; then
    if [ -z ${cnames} ]; then
	echo "Error: CNAMEs garbled."
	exit 2
    fi
    cnames=$(echo $cnames | sed 's/,/ /g')
fi

# Set our generic configs (these are overwritten as we go)
set-http-params $website $host

# Delete records on request
if [ $delete -eq 1 ]; then
    delete-monitors
else
    # Double check that a duplicate monitor does not exist (does nothing if it doesnt exist)
    delete-monitors

    # Basic HTTP check, include basic header
    write-config-header >> $config_file_web
    write-config-body >> $config_file_web

    # www CNAME, special request :D
    if [ $www -eq 1 ]; then
	set-http-params www.$website $host
	write-config-body >> $config_file_web
    fi

    # Additional CNAMEs if requested
    if [ $cname -eq 1 ]; then
	for name in $cnames; do
	    set-http-params $name.$website $host
	    write-config-body >> $config_file_web
	done
    fi
    
    # SSL cert check, if requeted
    if [ $ssl -eq 1 ]; then
	set-https-params $website $host
	write-config-body >> $config_file_web
    fi

    if [ $content -eq 1 ]; then
	set-content-params $website $host "$content_data"
	write-config-body >> $config_file_web
    fi

    # AWSTATS check, if requested
    if [ $awstats -eq 1 ]; then
	if [ $www -eq 1 ]; then
	    set-awstats-params www.$website
	else
	    set-awstats-params $website
	fi
	write-config-body >> $config_file_web
    fi

    # Write out our footer
    write-config-footer >> $config_file_web
fi

if [ $reload -eq 1 ]; then
    # Reload nagios if required
    $init_script reload
fi