#!/bin/sh
#
# List and read news articles
#

export PAGER="less -F"

trap 'rm -f $tmpfile; exit' 0 1 2 3 13 15

# If any command line argument is given, list and read all articles,
# otherwise only unread ones
[ $# -ne 0 ] && { iflag=-i; nflag="-n all"; }

invalid() {
    echo "Invalid response"; sleep 1
}

tmpfile=$(mktemp ~/.lrn.XXXXXX) || exit 1

while :; do
    if [ -z "$group" ]; then
	readnews -C $iflag $nflag | nawk '
	/^[[:space:]]/ {
	    printf "%4d %s\n", ++n, $1
	}' >$tmpfile
	[ -s $tmpfile ] || exit
	n=0
	while read line; do
	    eval "group$n=\${line##* }"
	    n=$(($n + 1))
	done <$tmpfile
	${PAGER} $tmpfile
	printf "\nGroup: "
	read r || exit
	[ -z "$r" ] && continue
	case "$r" in [!0-9]*) invalid; continue;; esac
	[ $r -lt 1 -o $r -gt $n ] && { invalid; continue; }
	eval "group=\$group$(($r - 1))"
    fi
    readnews -n $group -l $iflag | sed -n '/^    /p' >$tmpfile
    [ -s $tmpfile ] || { group=; continue; }
    ${PAGER} $tmpfile
    printf "\nPress <Return> to read articles, EOF to return to the groups..."
    read r || { group=; continue; }
    readnews -n $group $iflag
done
.