#!/bin/bash

function helpexit() {
    echo 'Create or append md5sum list of files
Usage: md5sum-update [-r] [list name]
  -r recursive
  list name is md5sums.txt by default

  Check files with "md5sum -m m5sums.txt"
  '
    exit
}

recursive=0
list_name="md5sums.txt"
for ((i=1; i<=${#@}; i++)) {
    [[ "${!i}" = "-h" ]] && helpexit
    [[ "${!i}" = "--help" ]] && helpexit
    [[ "${!i}" = "-r" ]] && { recursive=1; continue; }
    list_name="${!i}"
}
set -e
echo "Updating: $list_name"
test -f "$list_name" || touch "$list_name"

_update() {
  if [ "$file" = "$list_name" ]; then
    return
  fi
  if test -d "$file"; then
    echo "$file is a directory"
    return
  fi
  if test -f "$file"; then
    if grep -q "  $file$" "$list_name"; then
      echo "$file: exist"
    else
      echo "$file: new"
      md5sum "$file" >> "$list_name"
    fi
  fi
}

shopt -s globstar
shopt -s nullglob

if [[ "$recursive" -eq 1 ]]; then
  for file in **; do
    _update
  done
else
  for file in *; do
    _update
  done
fi


sort -k 2 -o "$list_name" "$list_name"