#!/bin/zsh -
#
#   Oliver Fromme  <olli@fromme.com>
#
#   BSD-style copyright and standard disclaimer applies.
#
#   This little script enables you to ``edit an ls'',
#   i.e. it will load a list of filenames into your
#   favourite editor (presumably vi).  Any changes to
#   the filenames will result in renaming the respective
#   files.
#
#   Notes:
#    - Do not change the numbers in the first column,
#      unless you know exactly what you're doing.
#    - If you remove an entire line, the corresponding
#      file will _not_ be deleted.  It just remains
#      untouched.
#    - You can use any character in filenames, with one
#      special case:  backslashes have to be specified
#      twice.
#    - If there are any filename collisions, you will
#      be asked if overwriting the first file is OK.
#    - Do not try to exchange the filenames of two or
#      more files.  It won't work.
#    - If you want to edit the filenames of certain
#      files only, you can specify them on the command
#      line (the default is ``*'').
#

if [[ "$VISUAL" != "" ]]; then
	VICMD="$VISUAL"
elif [[ "$EDITOR" != "" ]]; then
	VICMD="$EDITOR"
else
	VICMD="/usr/bin/vi"
fi

if [[ "x$1" == "x--" ]]; then
	shift
elif expr "x$1" : 'x-' >/dev/null; then
	echo "Usage: ${0:t} [file ...]" >&2
	exit 1
fi

#   Do not use a publicly writable directory such as /tmp,
#   which would be a security hole because of possible
#   race conditions!
TMP="$HOME/.${0:t}.$$.tmp"
Cleanup()
{
	rm -f "$TMP" "$TMP".new
	exit 1
}
trap Cleanup 1 2 3 15

if [[ $# -gt 0 ]]; then
	ls -d -- "$@" | awk '{printf "%04d %s\n", NR, $0}' > "$TMP"
else
	ls > "$TMP" | awk '{printf "%04d %s\n", NR, $0}' > "$TMP"
fi
cp "$TMP" "$TMP".new

$VICMD "$TMP".new

(
	cat "$TMP"
	echo "xxx"
	cat "$TMP".new
) \
| awk '{
	if ($1 == "xxx")
		new=1;
	else if (!new)
		old[$1] = substr($0, 6);
	else {
		new = substr($0, 6);
		if (old[$1] && new && old[$1] != new)
			printf "%s/%s\n", old[$1], new;
	}
}' \
| (
	IFS='/'
	while read OLD NEW; do
		mv -i -- "$OLD" "$NEW"
	done
)

rm -f "$TMP" "$TMP".new
exit 0

#--