Mine

  if ($text =~ /^([-.!]time\s*(.*))/ && $target eq "#testing123") {
    my $input = $1;
    my @data = split / /, $2;
    $flag = 0;
    if (is_valid_time($data[0])) {  
      $server->command("msg #testing123 Your time of $data[0] is |" . time_to_secs($data[0]) . "| seconds");
      $flag = 1;
    }
    if (!$flag) { $server->command("msg #testing123 Your input of $input is invalid"); }
  }

sub is_valid_time {
  if ($_[0] =~ /^\d\d?\d?(:\d\d?)?(:\d\d?)?(\.\d\d?)?$/) { return 1 }
}

sub time_to_secs {
  my @parts = split /:/, $_[0];
  if (!$#parts) { return $parts[0]; }
  if ($#parts == 1) { return $parts[0] * 60 + $parts[1]; }
  if ($#parts == 2) { return $parts[0] * 3600 + $parts[1] * 60 + $parts[2]; }
}