#!/bin/bash
# Thu Mar 11 02:13:02 EST 2004
# NAME: cjnews
# DESCRIPTION: [the beginnings of] a command-line news reader
# Copyright 2004, Chris F.A. Johnson
# Released under the terms of the GNU General Public License

## fill in necessary information here
host=$NNTPSERVER
port=119
user=
pass=
configfile=$HOME/.cjnewsrc

## or put it in $configfile, which will  be sourced
[ -f "$configfile" ] && . "$configfile"

## meassage header arrays
from[0]=
groups[0]=
subject[0]=
date[0]=
lines[0]=
msg_id[0]=
user_agent[0]=

tcpread() {
    while IFS= read -r line <&3
    do
      line=${line%$CR}
      case $line in
          .) break ;;
          *) printf "%s\n" "$line" ;;
      esac
    done
}

tcpcmd() {
    local IFS=${IFS}$'\r'
    cmd=$*
    echo $cmd >&3
    read ok msg <&3
    [ ${verbose:-0} -gt 0 ] && printf "%s\n" "$ok $msg"
    [ ${ok:-666} -lt 400 ]
}

quit() {
    tcpcmd quit
    [ ${verbose:-0} -gt 0 ] && echo Exit code: $1
    exit $(( $1 % 255 ))
}

commas() {
    _COMMAS=
    local left num decimal
    case $1 in
        *.*) num=${1%.*}
             decimal=${1#.}
             ;;
        *) num=$1
           decimal=
           ;;
    esac
    while :
    do
       case $num in
          ???|??|?) _COMMAS=${num}${_COMMAS:+,$_COMMAS}; break ;;
          *)
             left=${num%???}
             _COMMAS=${num#${left}}${_COMMAS:+,$_COMMAS}
             num=$left
             ;;
       esac
    done
    _COMMAS=${_COMMAS}${decimal:+.$decimal}
    [ ${SILENT_FUNCS:-0} -eq 1 ] || echo "$_COMMAS"
}

folder() {
     group "$@"
}

group() {
    [ -z "$1" ] && { printf "%s\n" "USAGE: $FUNCNAME [+]name.of.group"; return 192; }
    tcpcmd group "${1#+}" && group=${1#+} || return 192
    printf "\nGroup:%s\n" "$group"
    prompt=$group
    set $msg
    commas $1;   num=$_COMMAS
    commas $2; first=$_COMMAS
    commas $3;  last=$_COMMAS
    printf "%s messages: %s to %s\n" "$num" "$first" "$last"
}

stat() {
    [ -z "$1" ] && { printf "%s\n" "USAGE: $FUNCNAME NUMBER" >&2; return 192; }
    tcpcmd stat "${@}"
}

parse_header() {
    local IFS=$'\n'
    local line
    local msg_num=${1:-$msg_num}
    for line in ${header[$msg_num]}
    do
      case $line in
          From:*)       from[$msg_num]=${line#From: } ;;
          Newsgroups:*) groups[$msg_num]=${line#Newsgroups: } ;;
          Subject:*)    subject[$msg_num]=${line#Subject: } ;;
          Date:*)       date[$msg_num]=${line#Date: } ;;
          Lines:*)      lines[$msg_num]=${line#Lines: } ;;
          Message-ID:*) msg_id[$msg_num]=${line#Message-ID: } ;;
          User-Agent:*) user_agent[$msg_num]=${line#User-Agent: } ;;
          Path:*) ;;
          Organization:*) ;;
          X-Trace:*) ;;
          X-Complaints-To:*) ;;
          NNTP-Posting-Date:*) ;;
          NNTP-Posting-Host:*) nntp_host[$msg_num]=${line#NNTP-Posting-Host: } ;;
          Xref:*) ;;
      esac
    done
}

full_header() {
    echo "$NL${header[$msg_num]}$NL"
}

show_header() {
    printf "\n"
    printf "Newsgroups: %s\n" "${groups[$msg_num]}"
    printf "   Subject: %s\n" "${subject[$msg_num]}"
    printf "      From: %s\n" "${from[$msg_num]}"
    printf "      Date: %s\n" "${date[$msg_num]}"
    printf "     Lines: %s\n" "${lines[$msg_num]}"
    printf "\n"
}

head() {
    local msg_num=$1
    case $msg_num in
        *[^0-9]*|"") printf "%s\n" "USAGE: $FUNCNAME NUMBER" >&2
                     return 192
                     ;;
    esac
    tcpcmd head $msg_num && echo || return 192
    header[$msg_num]=`tcpread`
    parse_header $msg_num
    show_header $msg_num
}

body() {
    [ -z "$1" ] && { printf "%s\n" "USAGE: $FUNCNAME NUMBER"; return 192; }
    tcpcmd body "${@}" && echo || return 192
    tcpread
}

help() {
    echo "
       folder [+]GROUP  - select GROUP
       group  [+]GROUP  - select GROUP
       head   NUMBER    - retrieve the head of message no. NUMBER
       body   NUMBER    - retrieve message no. NUMBER
       stat   NUMBER    - get statistics for message no. NUMBER
       help             - show this screen
       quit             - exit $progname
"
}

SILENT_FUNCS=1
progname=${0##*/}
HISTFILE=$HOME/.cnewshist

[ -f "$HISTFILE" ] || touch $HISTFILE
history -r
CR=$'\r'
NL=$'\n'

exec 3<>/dev/tcp/$host/$port
read ok msg <&3
echo "$ok $line"
case $ok in
    200|201) echo "Connected to $host" ;;
    *) quit 192 ;;
esac

[ -n "$user" ] && tcpcmd authinfo simple $user $pass || quit $ok

while :
do
    read -ep "${prompt:-$host}:: " cmd

    ## there must be an easier way to use history in a script
    history -w
    history -s "$cmd"
    history -a
    history -c
    history -r

    case $cmd in
        q|Q|bye|quit) break ;;
        group* ) $cmd ;;
        folder*) $cmd ;;
        stat*) $cmd ;;
        head*) $cmd ;;
        body*) $cmd ;;
        *) help ;;
    esac
done

tempfile=$HOME/.cnews-histfile-$$
uniq "$HISTFILE" > $tempfile
mv -b $tempfile "$HISTFILE"

quit 0