#!/bin/sh

help() {
	echo "nx - create new script"
	echo "USAGE: nx <script_name>"
}

err() { printf '%s: %s\n' "$0" "$@" >&2; exit 1; }
warn() {
	printf '%s: %s [Y/n] ' "$0" "$@" >&2; read -r arg
	case "$arg" in ''|y|Y) ;; *) exit ;; esac
}

while getopts 'h' o; do case "$o" in
	h) help >&2; exit ;;
	*) err "invalid option -- '$OPTARG'" ;;
esac done
shift $((OPTIND - 1))

[ "$#" -lt 1 ] && help && exit 1
[ "$#" -gt 1 ] && err "too many arguments. Only one expected"


new_file() {
	cat << EOF > "$1"
#!/bin/sh

help() { echo "$1 -

USAGE:
	$1 [OPTION]...

OPTIONS:
	-h  show this help message"; }

err() { printf '$1: %s\n' "\$@" >&2; exit 1; }
while getopts 'h' o; do case "\$o" in
	h) help; exit ;;
	*) err "invalid option -- '\$OPTARG'" ;;
esac done
shift \$((OPTIND - 1))

[ "\$#" -lt 1 ] && help >&2 && exit 1

EOF

	chmod u+x -- "$1" || exit
}

file="$1"

if [ -f "$file" ]; then
	[ ! -w "$file" ] && chmod u+rw "$file"
	if [ -s "$file" ]; then
		warn "'$file' already exists, edit existing file?" || exit
	else
		warn "an empty file '$file' already exists, fill and edit?" &&
		new_file "$file"
	fi
elif [ -e "$file" ]; then
	err "'$file' already exists and is a non-regular file"
else
	new_file "$file"
fi

ls -lF --color -- "$file"

${EDITOR} "$file"