#!/bin/bash

# stardate, date in hexadecimal or base36 or base62

# http://www.dcode.fr/base-n-convert

# dec to hex
hex () {
    var=$(printf '%x\n' "$1")
    echo ${var^^}
}

# hex to dec
dec () {
    var="$1"
    echo $((0x$var))
}

# epoch to time
ep2time () {
    date -d @"$1"
}

# https://en.wikipedia.org/wiki/Base36#bash_implementation
thirty () { 
    value="$1"
    result=""
    base36="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    while true; do
        result=${base36:((value%36)):1}${result}
        if [ $((value=${value}/36)) -eq 0 ]; then
            break
        fi
    done
    echo ${result}
}

# base 62
sixty () { 
    value="$1"
    result=""
    base62="0123456789aAbBcCdDeEfFgGhHiIjJkKlLmMnNoOpPqQrRsStTuUvVwWxXyYzZ"
    while true; do
        result=${base62:((value%62)):1}${result}
        if [ $((value=${value}/62)) -eq 0 ]; then
            break
        fi
    done
    echo ${result}
}

normal=$(date +%s) # epoch in seconds = shortest
#normal=$(date +%Y%m%d%H%M%S) # yyyymmddHHMMSS
#normal="441796964000000000" # seconds from big-bang

echo "$normal"; hex "$normal"; thirty "$normal"; sixty "$normal"
#ep2time "$normal"