#! /usr/bin/perl -w
#
# yapfaq by Thomas Hochstein
# (Original author: Marc Brockschmidt)
#
# containing some code from tinews.pl
# Copyright (c) 2002-2024 Urs Janssen <urs@tin.org>,
#                         Marc Brockschmidt <marc@marcbrockschmidt.de>
# containing some code from pgpverify.pl
# Written April 1996, <tale@isc.org> (David C Lawrence)
# Currently maintained by Russ Allbery <eagle@eyrie.org>
#
# This script posts articles (e.g. FAQs) to Usenet newsgroups.
# Most people will use it in combination with cron(8).
# 
# Copyright (C) 2003 Marc Brockschmidt <marc@marcbrockschmidt.de>
# Copyright (c) 2010-2017, 2026 Thomas Hochstein <thh@thh.name>
#
# It can be redistributed and/or modified under the same terms under 
# which Perl itself is published.

my $VERSION = "1.0.0";
(my $NAME = $0) =~ s#^.*/##;

use utf8;
use strict;
use Encode qw(encode);
use POSIX qw(strftime);
use Net::Domain qw(hostfqdn);
use Net::NNTP;
use DateTime;   # CPAN
use Path::Tiny; # CPAN
use Getopt::Long qw(GetOptions);
Getopt::Long::config ('bundling');

use Data::Dumper;

# configuration #######################
# may be overwritten via ~/.yapfaqrc or command line
my %Config;

$Config{'datadir'}      = 'data/'; # path to data files (FAQs, ...)

$Config{'nntp-server'}  = 'news';  # your NNTP server name, may be set via $NNTPSERVER
$Config{'nntp-port'}    = 119;     # NNTP-port, may be set via $NNTPPORT
$Config{'nntp-user'}    = '';      # username for AUTHINFO
$Config{'nntp-pass'}    = '';      # password for AUTHINFO
$Config{'force-auth'}   = 0;       # set to 1 to force authentification
$Config{'starttls'}     = 0;       # set to 1 to use STARTTLS if possible

$Config{'verbose'}      = 0;       # set to 1 to get warning messages
$Config{'debug'}        = 0;       # set to 1 to get some debug output,
                                   # set to 2 for NNTP debug output

# Main program ########################

### read configuration
# from (first match counts)
#   $XDG_CONFIG_HOME/yapfaqrc
#   ~/.config/yapfaqrc
#   ~/.yapfaqrc
# if present
# taken and modified from tinews.pl
my $RCFILE = undef;
my (@try, %seen);

if ($ENV{'XDG_CONFIG_HOME'}) {
  push(@try, (glob("$ENV{'XDG_CONFIG_HOME'}/yapfaqrc"))[0]);
}
push(@try, (glob('~/.config/yapfaqrc'))[0], (glob('~/.yapfaqrc'))[0]);

foreach (grep { ! $seen{$_}++ } @try) { # uniq @try
  last if (open($RCFILE, '<', $_));
  $RCFILE = undef;
}
if (defined($RCFILE)) {
  while (defined($_ = <$RCFILE>)) {
    if (m/^([^#\s=]+)\s*=\s*(\S[^#]+)/io) {
      chomp($Config{lc($1)} = $2);
    }
  }
  close($RCFILE);
}

# these env-vars have higher priority (order is important)
# taken from tinews.pl
$Config{'nntp-server'} = $ENV{'NEWSHOST'} if ($ENV{'NEWSHOST'});
$Config{'nntp-server'} = $ENV{'NNTPSERVER'} if ($ENV{'NNTPSERVER'});
$Config{'nntp-port'}   = $ENV{'NNTPPORT'} if ($ENV{'NNTPPORT'});

### read commandline options
my ($OptProject,$OptForce,$OptTest,$OptNewsgroup,$OptOutput);
GetOptions ('p|project=s'   => \$OptProject,
            'f|force'       => \$OptForce,
            't|test'        => \$OptTest,
            'n|newsgroup=s' => \$OptNewsgroup,
            'o|output'      => \$OptOutput,
            'datadir=s'     => \$Config{'datadir'},
            'nntp-server=s' => \$Config{'nntp-server'},
            'nntp-port=s'   => \$Config{'nntp-port'},
            'nntp-user=s'   => \$Config{'nntp-user'},
            'nntp-pass=s'   => \$Config{'nntp-pass'},
            'starttls!'     => \$Config{'starttls'},
            'force-auth!'   => \$Config{'force-auth'},
            'v|verbose!'    => \$Config{'verbose'},
            'd|debug!'      => \$Config{'debug'},
            'c|config'      => \&ShowConf,
            'h|help'        => \&ShowPOD,
            'V|version'     => \&ShowVersion) or &ShowUsage;

### create list of @Projects from $Config{'datadir'} unless -p is set
my @Projects;
if (!$OptProject) {
  die "E: Data directory '" . $Config{'datadir'} . "' does not exist.\n" unless (-d $Config{'datadir'});
  @Projects = glob $Config{'datadir'} . '*.hdr';
  foreach (@Projects) {
    $_ =~ s#^.*/##;
    $_ =~ s/\.hdr$//;
  }
} else {
  push @Projects, $OptProject;
}

### iterate over @Projects
print "- Test mode, no status updates.\n" if $Config{'debug'};
foreach (@Projects) {
  # check for existence of project
  my $HeaderFile = $Config{'datadir'} . "$_.hdr";
  if (not -r $HeaderFile) {
    warn "W: Project '$_' does not exist ('$HeaderFile' not found).\n";
    next;
  }

  print "Project '$_' ...\n" if $Config{'verbose'} or $Config{'debug'};
  # generate posting and check for due date
  # @Posting will be empty ('') if not due
  my @Posting = &BuildPosting($_);
  next if !$#Posting;

  # save Message-ID
  my $LastMID;
  foreach (@Posting) {
    if (/^Message-ID: /) {
      ($LastMID = $_) =~ s/^Message-ID:\s+//;
      chomp ($LastMID);
      last;
    }
  }

  # sent to STDOUT due to --output
  if ($OptOutput) {
    print "- Print to STDTOUT.\n----->----->----->-----\n" if $Config{'debug'};
    foreach (@Posting) {
     print $_
    };
    print "-----<-----<-----<-----\n" if $Config{'debug'};
  # otherwise: post
  } else {
    next if !&PostNNTP(@Posting);
  }

  # update status
  &UpdateStatus($_, $LastMID) if !$OptTest;
}

### we're done
exit(0);

# subroutines #########################

### ------------------------------------------------------------------
### display version information and exit
sub ShowVersion {
  print "$NAME v$VERSION\n";
  print "Copyright (C) 2003 Marc Brockschmidt <marc\@marcbrockschmidt.de>\n";
  print "Copyright (c) 2010-2017, 2026 Thomas Hochstein <thh\@thh.name>\n";
  print "This program is free software; you may redistribute it ".
        "and/or modify it under the same terms as Perl itself.\n";
  exit(0);
};

### ------------------------------------------------------------------
### feed myself to perldoc and exit
sub ShowPOD {
  exec('perldoc', $0);
  exit(0);
};

### ------------------------------------------------------------------
### Show current configuration
sub ShowConf {
  print "$NAME v$VERSION\n";
  print "Current configuration:\n";
  foreach my $config (sort keys %Config) {
    printf("- %s: %s\n", $config, $Config{$config}) if $Config{$config};
  }
};

### ------------------------------------------------------------------
### display short usage information
sub ShowUsage {
  print "$NAME v$VERSION\n";
  print "Usage: " . $NAME . " [OPTIONS]\n";
  print " -p project          run on project only, don't use all projects\n";
  print " -f                  post unconditionally, even if project(s) is/are not due\n";
  print " -t                  don't update project status (test)\n";
  print " -n newsgroup        post only to newsgroup (for testing)\n";
  print " -o                  print to STDOUT (for testing or to pipe into inews)\n";
  print " --datadir path      override \$datadir\n";
  print " --nntp-server name  override \$nntp-server\n";
  print " --nntp-port port    override \$nntp-port\n";
  print " --nntp-user user    override \$nntp-user\n";
  print " --nntp-pass passwd  override \$nntp-pass\n";
  print " --[no-]starttls     override \$starttls\n";
  print " --[no-]force-auth   override \$force-auth\n";
  print " -v | --[no-]verbose override \$verbose\n";
  print " -d | --[no-]debug   override \$debug\n";
  print " -c                  show current configuration\n";
  print " -h                  show documentation\n";
  print " -V                  show version and copyright\n";
  exit 0;
}

### ------------------------------------------------------------------
### parse a YYYY-MM-DD construct to a DateTime object
sub ParseDate {
  my $Date = shift;
  die "E: '$Date' is not a valid date format.\n" unless $Date =~ /^\d\d\d\d-\d\d-\d\d$/;
  my ($Year, $Month, $Day) = split /-/, $Date;
  return DateTime->new(year  => $Year,
                       month => $Month,
                       day   => $Day,
                      );
}

### ------------------------------------------------------------------
### add a duration (in d,w,m,y) to a DateTime object
sub AddDuration {
  my($Date, $Duration) = @_;
  $Duration =~ /(\d+)(.)/;
  my ($Amount, $Timespan) = ($1, lc($2));
  if ($Timespan eq 'd') {
    $Date->add(days => $Amount);
  }
  elsif ($Timespan eq 'w') {
    $Date->add(days => $Amount * 7);
  }
  elsif ($Timespan eq 'm') {
    $Date->add(months => $Amount);
  }
  elsif ($Timespan eq 'y') {
    $Date->add(years => $Amount);
  }
  return $Date;
}

### ------------------------------------------------------------------
### return a hash of all headers (ignoring duplicate headers)
# taken and modified from tinews.pl
sub ParseHeaders {
  my @Headers = @_;
  my (%Header, $Label, $Value);
  foreach (@Headers) {
    s/\r?\n$//;

    last if /^$/;

    if (/^(\S+):[ \t](.+)/) {
      ($Label, $Value) = ($1, $2);
      # discard all duplicate headers
      next if $Header{lc($Label)};
      $Header{lc($Label)} = $Value;
    } elsif (/^\s/) {
      # continuation lines
      if ($Label) {
        s/^\s+/ /;
        $Header{lc($Label)} .= $_;
      } else {
        warn (sprintf("W: Non-header line: %s\n",$_));
      }
    } else {
      warn (sprintf("W: Non-header line: %s\n",$_));
    }
  }
  return %Header;
};

### ------------------------------------------------------------------
### open NNTP connection, authenticate and return a Net::NNTP-Object
# taken and modified from tinews.pl
sub ConnectNNTP {
  my $NNTP = Net::NNTP->new(
                            Host   => $Config{'nntp-server'},
                            Reader => 1,
                            Debug  => $Config{'debug'},
                            Port   => $Config{'nntp-port'},
                            SSL_verify_mode => 0,
                           )
    or die("E: Can't connect to ".$Config{'nntp-server'}.":".$Config{'nntp-port'}.".\n");

  my $NNTPMsg  = $NNTP->message();
  my $NNTPCode = $NNTP->code();

  if ($Config{'starttls'} && $NNTP->can_ssl()) {
   $NNTP->starttls;
  }

  if ($Config{'debug'}) {
    print '- Connected to ' . $NNTP->peerhost . ':' . $NNTP->peerport . "\n";
    if ($Config{'starttls'}) {
      printf("  SSL-Fingerprint: %s %s\n", split(/\$/, $NNTP->get_fingerprint));
    }
  }

  # no read and/or write access - give up
  if ($NNTPCode < 200 || $NNTPCode > 201) {
    $NNTP->quit();
  }

  # read access - try to authenticate
  if ($NNTPCode == 201 || $Config{'force-auth'}) {
    # no user/password
    if (!$Config{'nntp-user'} || !$Config{'nntp-pass'}) {
      $NNTP->quit();
      die('E: ' . $NNTPCode . ' ' . $NNTPMsg . "\n");
    }
    $NNTP = &AuthNNTP($NNTP);
  }

  # try posting; on failure, try to authenticate
  $NNTP->post();
  $NNTPCode = $NNTP->code();
  if ($NNTPCode == 480) {
    $NNTP = &AuthNNTP($NNTP);
    $NNTP->post();
  }

  return $NNTP;
}

### ------------------------------------------------------------------
### do AUTHINFO on a Net::NNTP-Object, die on failure
# taken and modified from tinews.pl
sub AuthNNTP {
  my $NNTP = shift;

  $NNTP->authinfo($Config{'nntp-user'}, $Config{'nntp-pass'});
  my $NNTPMsg  = $NNTP->message();
  my $NNTPCode = $NNTP->code();
  if ($NNTPCode != 281) { # auth failed
    $NNTP->quit();
    die('E: ' . $NNTPCode . ' ' . $NNTPMsg . "\n");
  }

  return $NNTP;
}

### ------------------------------------------------------------------
### build posting
# read and parser header and body from files
# read status file, check due date
sub BuildPosting {
  my $Project = shift;
  my $StatusFile = $Config{'datadir'} . "$Project.cfg";
  my $HeaderFile = $Config{'datadir'} . "$Project.hdr";
  my $BodyFile   = $Config{'datadir'} . "$Project.txt";
  if (not -r $BodyFile) {
    warn "W: '$BodyFile' not found.\n";
    return '';
  }

  # read status file, if available
  my($LastPosted, $LastMID);
  if (-r $StatusFile) {
    print "- Reading status ($Project.cfg).\n" if $Config{'debug'};
    my @Status = path($StatusFile)->lines_utf8;
    foreach (@Status) {
      # convert Windows line-endings to Unix
      s/\r//;
      if (/^Last-posted: /i) {
        chomp;
        ($LastPosted = $_) =~ s/^Last-posted:\s+//i;
      } elsif (/^Last-Message-ID: /i) {
        chomp;
        ($LastMID = $_) =~ s/^Last-Message-ID:\s+//i;
      }
    }
  } else {
    print "- No status file ($Project.cfg).\n" if $Config{'debug'};
  }

  print "- Reading headers ($Project.hdr) and body ($Project.txt).\n" if $Config{'debug'};
  my @Headers = path($HeaderFile)->lines_utf8;
  my @Body    = path($BodyFile)->lines_utf8;
  my %Header  = &ParseHeaders(@Headers);

  # check for mandatory headers
  if (!$Header{'from'} or !$Header{'subject'} or !$Header{'newsgroups'}) {
    warn "W: From, Subject or Newsgroups header missing from '$HeaderFile'.\n";
    return '';
  }

  # add Date:
  push @Headers, 'Date: ' . DateTime->now->strftime('%a, %d %b %Y %H:%M:%S %z') . "\n";
  # add missing Message-ID:
  push @Headers, 'Message-ID: <%n-%y-%m-%d@' . hostfqdn. ">\n" if (!$Header{'message-id'});
  # add User-Agent
  push @Headers, "User-Agent: $NAME/$VERSION\n";

  # parse pseudo headers from body
  my ($InRealBody,$LastModified,$PostingFrequency);
  foreach (@Body) {
    # convert Windows line-endings to Unix
    s/\r//;
    next if $InRealBody;
    $InRealBody++ if /^$/;
    $LastModified     = $1 if /^Last-modified:\s*(\S+)\s*$/i;
    $PostingFrequency = $1 if /^Posting-Frequency:\s*(\S+)\s*$/i;
  }
  # parse Posting-Frequency from pseudo-header
  if ($PostingFrequency) {
    print "- Posting-Frequency set to $PostingFrequency from pseudo-header.\n" if $Config{'debug'};
    if ($PostingFrequency eq 'daily') {
      $PostingFrequency = '1d';
    } elsif ($PostingFrequency eq 'weekly') {
      $PostingFrequency = '1w';
    } elsif ($PostingFrequency =~ /bi-?weekly/) {
      $PostingFrequency = '2w';
    } elsif ($PostingFrequency eq 'monthly') {
      $PostingFrequency = '1m';
    } elsif ($PostingFrequency =~ /bi-?monthly/) {
      $PostingFrequency = '2m';
    }
  }

  # parse placeholders in headers
  foreach (@Headers) {
    # convert Windows line-endings to Unix
    s/\r//;
    # drop empty header
    $_ = '' if /^$/;
    # Replace %LM placeholder in Subject: with the Last-modified: pseudo-header
    if (/^Subject: /) {
      if ($LastModified) {
        $_ =~ s/\%LM/$LastModified/g;
      } else {
        $_ =~ s/ ?[<\[{\(]?\%LM[>\]}\)]? ?//;
      }
    }
    # Replace placeholders in Message-ID:
    # %n  project name
    # %y  current year
    # %m  current month
    # %d  current day
    # %p  PID
    if (/^Message-ID: /i) {
      my $TDY = DateTime->now->strftime('%Y');
      my $TDM = DateTime->now->strftime('%m');
      my $TDD = DateTime->now->strftime('%d');
      $_ =~ s/\%n/$Project/g;
      $_ =~ s/\%y/$TDY/g;
      $_ =~ s/\%m/$TDM/g;
      $_ =~ s/\%d/$TDD/g;
      $_ =~ s/\%p/$$/g;
      # add random part in test mode
      if ($OptTest) {
        my $random = sprintf("%08X", rand(0xFFFFFFFF));
        $_ =~ s/</<test-$random-/;
      }
    }
    # create Expires: from time period
    if (/^Expires: /) {
      chomp;
      $_ =~ s/^Expires:\s+//;
      die "E: Illegal 'Expires: $_' in '$HeaderFile'.\n" if ($_ !~ /^\d+[dwmy]$/);
      $_ = 'Expires: ' . &AddDuration(DateTime->now,$_)->strftime('%a, %d %b %Y %H:%M:%S %z') . "\n";
    }
    # add Supersedes: if set
    if (/^Supersedes: /) {
      if ($LastMID && !$OptTest) {
        $_= "Supersedes: $LastMID\n";
      } else {
        $_ = '';
      }
    }
    # overwrite Newsgroups: if --newsgroup is set
    if ($OptNewsgroup && /^Newsgroups: /) {
      print "- 'Newsgroups: $OptNewsgroup' has been set.\n" if $Config{'debug'};
      $_= "Newsgroups: $OptNewsgroup\n";
    }
    # get Posting-Frequency
    if (/^Posting-Frequency: /i) {
      chomp;
      $_ =~ s/^Posting-Frequency:\s+//i;
      $PostingFrequency = $_;
      $_ = '';
      print "- Posting-Frequency set to $PostingFrequency.\n" if $Config{'debug'};
    }
  }

  # not due if Posting-Freqency is "none"
  if ($PostingFrequency =~ /none/) {
    print "... is disabled.\n" if $Config{'verbose'} or $Config{'debug'};
    return '';
  }
  
  # default to 1 month if no (valid) Posting-Frequency is set
  $PostingFrequency = '1m' if $PostingFrequency !~ /^\d+[dwmy]$/;

  # check if posting is due
  print "- Posting has been forced.\n" if $Config{'debug'} && $OptForce;
  if ($OptForce or (!$LastPosted) or ($LastPosted && &AddDuration(&ParseDate($LastPosted),$PostingFrequency) <= DateTime->now)) {
    print "... is due and will be posted.\n" if $Config{'verbose'} or $Config{'debug'};
  } else {
    print "... is not due.\n" if $Config{'verbose'} or $Config{'debug'};
    return '';
  }

  # return posting
  return @Headers, "\n", @Body;
}

### ------------------------------------------------------------------
### post via NNTP
# taken and modified from tinews.pl
sub PostNNTP {
  my @Posting = @_;

  my $NNTP = ConnectNNTP();
  my $NNTPMsg  = $NNTP->message();
  my $NNTPCode = $NNTP->code();
  print "- Post article.\n" if $Config{'debug'};
  if ($NNTPCode == 340) {
    $NNTP->datasend(@Posting);
    ## buggy Net::Cmd < 2.31
    $NNTP->set_status(200, "");
    $NNTP->dataend();
    $NNTPMsg  = $NNTP->message();
    $NNTPCode = $NNTP->code();
    if (! $NNTP->ok()) {
      $NNTP->quit();
      warn("W: Posting failed! Response from server:\n", $NNTPCode, ' ', $NNTPMsg);
      return 0;
    }
  } else {
    $NNTP->quit();
    warn("W: Posting failed! Response from server:\n", $NNTPCode, ' ', $NNTPMsg);
    return 0;
  }
  $NNTP->quit();
  print "- Done.\n" if $Config{'debug'};
  return 1;
}

### ------------------------------------------------------------------
### update status (last posted, last mid)
sub UpdateStatus {
  my ($Project, $LastMID) = @_;
  my $StatusFile = $Config{'datadir'} . "$Project.cfg";
  my @Status;

  push @Status, "Last-Posted: " . DateTime->now->strftime('%Y-%m-%d') . "\n";
  push @Status, "Last-Message-ID: $LastMID\n";

  $StatusFile = path($StatusFile);
  $StatusFile->spew_utf8(@Status);

  print "- Status updated.\n" if $Config{'debug'};
  return;
}