#!/bin/bash

# config
max_usage=90
bar_width=50
# colors
white="\e[39m"
green="\e[1;32m"
red="\e[1;31m"
dim="\e[2m"
undim="\e[0m"

# disk usage: ignore zfs, squashfs & tmpfs
mapfile -t dfs < <(df -H -x zfs -x squashfs -x tmpfs -x devtmpfs -x overlay --output=target,pcent,size | tail -n+2)
printf "\ndisk usage:\n"

for line in "${dfs[@]}"; do
    # get disk usage
    usage=$(echo "$line" | awk '{print $2}' | sed 's/%//')
    used_width=$((($usage*$bar_width)/100))
    # color is green if usage < max_usage, else red
    if [ "${usage}" -ge "${max_usage}" ]; then
        color=$red
    else
        color=$green
    fi
    # print green/red bar until used_width
    bar="[${color}"
    for ((i=0; i<$used_width; i++)); do
        bar+="="
    done
    # print dimmmed bar until end
    bar+="${white}${dim}"
    for ((i=$used_width; i<$bar_width; i++)); do
        bar+="="
    done
    bar+="${undim}]"
    # print usage line & bar
    echo "${line}" | awk '{ printf("%-31s%+3s used out of %+4s\n", $1, $2, $3); }' | sed -e 's/^/  /'
    echo -e "${bar}" | sed -e 's/^/  /'
done