#!/bin/bash

#
#/
#/ Usage:
#/ check-disk.sh --warning=<level> --critical=<level> --help
#/ 
#/ Checks the disk usage
#/ 
#/ Options:
#/  -w, --warning=<level>      The level of when to trigger a warning (level=loadavg/nproc)
#/  -c, --critical=<level>     The level of when to trigger a critical warning (level=loadavg/nproc)
#/  -h, --help                 Display this help message
#/ 
#/ Exit Codes:
#/  0 Everything OK
#/  1 Warning level exceeded
#/  2 Critical level exceeded
#/  3 Unknown status
#/


Usage() {
    grep '^#/' "${script_dir}/${script_name}" | sed 's/^#\/\w*//'
}

GetOptions() {
    # https://stackoverflow.com/a/29754866
    OPTIONS=w:c:h
    LONGOPTS=warning:,critical:,help

    # -use ! and PIPESTATUS to get exit code with errexit set
    # -temporarily store output to be able to check for errors
    # -activate quoting/enhanced mode (e.g. by writing out “--options”)
    # -pass arguments only via   -- "$@"   to separate them correctly
    ! PARSED=$(getopt --options=$OPTIONS --longoptions=$LONGOPTS --name "$0" -- "$@")
    if [[ ${PIPESTATUS[0]} -ne 0 ]]; then
        # e.g. return value is 1
        #  then getopt has complained about wrong arguments to stdout
        Usage
        exit 2
    fi

    # read getopt's output this way to handle the quoting right:
    eval set -- "$PARSED"

    # now enjoy the options in order and nicely split until we see --
    while true; do
        case "$1" in
            -w|--warning)
                warn="$2"
                shift 2
                ;;
            -c|--critical)
                crit="$2"
                shift 2
                ;;
            -h|--help)
                Usage
                exit 0
                ;;
            --)
                shift
                break
                ;;
            *)
                echo "DISK UNKNOWN - ${1} is not a valid parameter"
                exit 3
                ;;
        esac
    done
    if [ -z ${1+x} ]; then 
        echo "DISK UNKNOWN - Mountpoint not given"
        exit 3
    elif [ ! -d ${1} ]; then 
        echo "DISK UNKNOWN - Mountpoint is not a directory"
        exit 3
    else 
        disk=${1}
    fi
}
LC_NUMERIC="C"
warn=0.7
crit=0.9
disk='/'
script_name=$(basename "${0}")
script_dir=$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )
GetOptions "$@"

totalfull=$(df --output=size -B 1024 "${disk}" | tail -n 1 | xargs)
availfull=$(df --output=avail -B 1024 "${disk}" | tail -n 1 | xargs)
usedfull=$(df --output=used -B 1024 "${disk}" | tail -n 1 | xargs)

val=$(echo "${usedfull}/${totalfull}" | bc -l)

if (( $(echo "$val < ${warn}" | bc -l) )); then
    rval=0
    rmsg="OK"
elif (( $(echo "$val < ${crit}" | bc -l) )); then
    rval=1
    rmsg="WARNING"
else
    rval=2
    rmsg="CRITICAL"
fi
critfull=$(echo ${totalfull}\*${crit} | bc -l | awk '{ print int($1+0.5) }')
warnfull=$(echo ${totalfull}\*${warn} | bc -l | awk '{ print int($1+0.5) }')
minfull=0
maxfull=${totalfull}
unitfull="KiB"

used100=$(printf %.1f $(echo ${val}\*100 | bc -l))
crit100=$(printf %.1f $(echo ${crit}\*100 | bc -l))
warn100=$(printf %.1f $(echo ${warn}\*100 | bc -l))
min100=0
max100=100
unit100="%"

echo "DISK ${rmsg} - Used: ${usedfull} Available: ${availfull} Total: ${totalfull}|disk=${usedfull}${unitfull};$warnfull;$critfull;$minfull;$maxfull disk%=${used100}${unit100};$warn100;$crit100;$min100;$max100"
exit $rval