#!/usr/bin/env perl
# 20260219 ChatGPT
# $Id$
# $HeadURL$

# EXAMPLE:
#   perl fwd_positions_udp.pl \
#     --file /usr/local/src/sx1302_hal/util_net_downlink/uplinks_20260219_123102.csv \
#     --host ryzdesk --port 1777

use strict;
use warnings;
use IO::Socket::INET;
use Getopt::Long qw(GetOptions);

my ($file, $host, $port) = ("", "ryzdesk", 1777);
GetOptions(
  "file=s" => \$file,
  "host=s" => \$host,
  "port=i" => \$port,
) or die "bad args\n";

die "--file required\n" if !$file;

my $sock = IO::Socket::INET->new(
  PeerAddr => $host,
  PeerPort => $port,
  Proto    => "udp",
) or die "udp socket: $!\n";

£ Use tail -F so rotations keep working
open(my $fh, "-|", "tail", "-F", $file) or die "tail: $!\n";

$| = 1;

while (my $line = <$fh>) {
  chomp $line;

  £ Your CSV has the hex payload in field 16 (1-based) => index 15 (0-based)
  my @f = split(/,/, $line, -1);
  next if @f < 16;

  my $hex = $f[15] // "";
  $hex =~ s/[^0-9A-Fa-f]//g;
  next if $hex eq "";

  my $msg = pack("H*", $hex);   £ yields: "C,44.936454,-123.021923,65.40"
  $msg =~ s/\r?\n$//;

  £ sanity filter: must look like: X,lat,lon,alt
  next unless $msg =~ /^[A-Z],[+-]?\d+\.\d+,[+-]?\d+\.\d+,[+-]?\d+(\.\d+)?$/;

  $sock->send($msg."\n");
  print "$msg\n"; £ local visibility
}