#!/bin/sh
#
# datedirs - move dated files into a date-based directory hierarchy
#
# SPDX-FileCopyrightText: 2023 Daniel Kalak
# SPDX-License-Identifier: GPL-3.0-or-later
#
# This program moves files with a YYYY-mm-dd[._] date prefix to
# directories in a format sepcified on the command line. Files are only
# moved, not renamed. The program exits 1 on bad usage and 0 otherwise.

usage_quit() {
	cat <<- EOF >&2
	Usage: $(basename "$0") FORMAT
	Possible values for FORMAT:
	  y
	  y/m
	  y-m
	  y/m/d
	  y/m-d
	  y-m/d
	  y-m-d
	    m
	    m/d
	    m-d
	      d
	EOF
	exit 1
}

[ "$#" = 1 ] || usage_quit

case "$1" in
y    ) chars=1-4 ; flag=g ;;
y/m  ) chars=1-7 ; flag=g ;;
y-m  ) chars=1-7 ; flag=3 ;;
y/m/d) chars=1-10; flag=g ;;
y/m-d) chars=1-10; flag=1 ;;
y-m/d) chars=1-10; flag=2 ;;
y-m-d) chars=1-10; flag=3 ;;
  m  ) chars=6-7 ; flag=g ;;
  m/d) chars=6-10; flag=g ;;
  m-d) chars=6-10; flag=3 ;;
    d) chars=9-10; flag=g ;;
*)     usage_quit         ;;
esac

for f in [0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9][._]*
do
	dir="$(printf %s "$f" | cut -c "$chars" | sed 's/-/\//'"$flag")"
	mkdir -pv "$dir"
	mv -iv "$f" "$dir"
done