#!/bin/bash

function _help() {
  echo '
Usage: file-enumerate [-k] [-p #] [-o folder]

  Creates a folder "enumerated" and hard links all files in the current folder
  renamed with a number (d.ext).

  -k  Keep filename as is (d.filename)
  -p  Pad numbers, defaults to 4
  -o  Output older name, default: enumerated
'
exit
}
keep=false
pad=4
output=enumerated
for (( i=1; i<=$#; i++ )); do
    j=$(( i + 1 ))
    [[ "${!i}" = "-h" ]] && _help
    [[ "${!i}" = "--help" ]] && _help
    [[ "${!i}" = "-k" ]] && keep=true
    [[ "${!i}" = "-p" ]] && { pad=${!j}; i=$(( i + 1 )); }
    [[ "${!i}" = "-o" ]] && { output=${!j}; i=$(( i + 1 )); }
done

printf -v padstr "%%0%dd" $pad

_drive() {
    ls -1prt | grep -v "/$" | cat -n | while read n f; do
        printf -v padded $padstr $n
        if [[ $keep = true ]]; then
           printf -v outname "%s.%s" "$padded" "$f"
        else
           ext=${f##*.}
           if [[ "$ext" = "$f" ]]; then
               printf -v outname "%s" "$padded"
           else
               printf -v outname "%s.%s" "$padded" "$ext"
           fi
        fi
        printf "%30s -> %s\n" "$f" "$outname"
        cp -l "${f}" "${output}"/"$outname"
    done
}

mkdir -p "${output}"
_drive