#!/bin/sh
# env
# Written in 2019 by Lucas
# CC0 1.0 Universal/Public domain - No rights reserved
#
# To the extent possible under law, the author(s) have dedicated all
# copyright and related and neighboring rights to this software to the
# public domain worldwide. This software is distributed without any
# warranty. You should have received a copy of the CC0 Public Domain
# Dedication along with this software. If not, see
# <http://creativecommons.org/publicdomain/zero/1.0/>.

usage() {
	printf "Usage: %s [-T] rfc-number\n" "${0##*/}" >&2
	exit 1
}

tonumber() {
	printf "%u" "$1" 2>/dev/null
}

: ${RFCDIR:=~/doc/rfc}

torsocks=torsocks
while getopts T flag; do
	case $flag in
	T)	torsocks=
		;;
	*)	usage
		;;
	esac
done
shift $(($OPTIND - 1))

if [ $# -ne 1 ] || [ -z "$1" ] || ! n=$(tonumber "$1"); then
	usage
fi
rfcfile=$RFCDIR/rfc$n.txt
url=https://tools.ietf.org/rfc/rfc$n.txt

mkdir -p "$RFCDIR"
if [ ! -f "$rfcfile" ]; then
	if ! $torsocks ftp -Vo "$rfcfile" "$url"; then
		printf "%s: Couldn't fetch RFC %u\n" "${0##*/}" "$n" >&2
		exit 1
	fi
fi

${PAGER:-more} "$rfcfile"