#!/bin/sh

# vivc Vorbis comment editor front-end v0.2
# [cc] 2001 Greg Wooledge
# This program is in the public domain, and may be used without restrictions.

prog=`basename $0`
usage() {
	echo "usage: $prog oggfile [...]" 1>&2
	exit 1
}
[ $# -lt 1 ] && usage

ed=vi
[ -n "$EDITOR" ] && ed="$EDITOR"
[ -n "$VISUAL" ] && ed="$VISUAL"

if [ -w $PWD ]; then
    tmp=.vivc.$$
    tmpogg=.vivc.$$.ogg
else
    tmp=/tmp/vivc.$$
    tmpogg=/tmp/vivc.$$.ogg
fi

dosigs() {
	trap 'echo "$prog: killed by signal" 1>&2; rm -f $tmp $tmpogg; exit 1' \
		1 2 3 15
}
dosigs

dovc() {
	vorbiscomment -l "$1" >$tmp
	if [ $? -ne 0 ]; then
		echo "$prog: could not read vorbis comments from '$1'" 1>&2
		rm -f $tmp
		return 0
	fi

	"$ed" $tmp
	# Can't assume anything about the editor's return code.

	vorbiscomment -w "$1" $tmpogg <$tmp
	if [ $? -ne 0 ]; then
		echo "$prog: could not write temporary file '$tmpogg'" 1>&2
		rm -f $tmp $tmpogg
		return 0
	fi
	rm $tmp

	# ignore signals during this part
	trap '' 1 2 3 15
	mv "$1" "$1".bak
	mv $tmpogg "$1"
	if [ $? -ne 0 ]; then
		echo "$prog: could not replace file '$1' with new version" 1>&2
		echo "$prog: your original file is in '$1.bak'" 1>&2
		echo "$prog: your modified Ogg Vorbis file is in $tmpogg" 1>&2
		# do NOT rm $tmpogg!
		return 1	# fatal, do not continue
	fi
	rm "$1".bak
	# allow signals again
	dosigs
}

for file; do
	if [ ! -w "$file" ]; then
		echo "$prog: file '$file' is not writable, skipping"
		continue
	fi
	dovc "$file"
	rc=$?
	[ $rc -gt 0 ] && exit $rc
done

exit 0