#!/usr/bin/env perl

use strict;
use warnings;
use Net::FTP;
use Getopt::Long;
use File::Path 'mkpath';
use Data::Dumper;

# User-input/Defaults. No error checking! Dangerous...
my $local_dir = '/tmp/FEC_data';
my $max_connections = 5;
my $help = 0;

GetOptions(
	   "d|directory=s"	 => \$local_dir,
	   "m|max-connections=i" => \$max_connections,
	   "h|help"		 => $help,
	  ) or &usage;

&usage if $help;

my $host = 'ftp.fec.gov';
my $remote_dir = 'FEC/electronic';
my (@modtime, @timeouts, $count, $child);

$count = 0;
$SIG{INT} = "interrupt";

mkpath ($local_dir, 1, 0775) unless -e $local_dir;

opendir(DIR, $local_dir) or die 'Could not open dir: ' . $!;
my @local_files = grep !/^\.?\.$/, readdir DIR;
close DIR;

my $ftp = Net::FTP->new($host,
			Debug => 0,
			Passive => 1)
  or die "Cannot connect to host: $@";
$ftp->login('anonymous', 'doesnt@matter.com')
  or die "Login failed ", $ftp->message;
$ftp->cwd($remote_dir)
  or die "Couldn't change directory ", $ftp->message;
my @files = $ftp->ls('.')
  or die "Couldn't get directory listening ", $ftp->message;
$ftp->close();
undef $ftp;


print 'Comparing files' . "\n";
@files = grep !${{map{$_,1} @local_files}}{$_}, @files;

#print Dumper(@files);

  my $pid;
my @pids;

while (my @smallchunks = splice @files, 0, int($#files/$max_connections)) {
  sleep 2;
  $pid = fork();
  if ($pid == 0) {
    my $ftp = Net::FTP->new($host,
			    Debug => 0,
			    Passive => 1,
			    Timeouts => '300')
      or die "Cannot connect to host: $@";
    $ftp->login('anonymous', 'doesnt@matter.com')
      or die "Login failed ", $ftp->message;
    $ftp->cwd($remote_dir)
      or die "Couldn't change directory ", $ftp->message;
    $ftp->binary();
    foreach my $file (@smallchunks) {
      print "Attempting to download: $file" . "\n";
      eval {$ftp->get($file) or warn "Failed to download: " . $file . " || ", $ftp->message};
      if ($@ =~ /Timeout/) {
	push @timeouts, $file;
      }
    }

    $ftp->quit;
    exit 0;
  } else {
    push @pids, $pid;
  }
}
do {$child = waitpid (-1,0);} while $child > 0;

waitpid($pid, 0) if $pid != 0;
print "All files downloaded I hope\n";

open(FB, ">/tmp/timeouts.txt");
map {print FB "$_"} @timeouts;
close FB;

sub usage {

  print <<'METADATA';

FEC Mass Downloader/Updater - downloads a shit ton of .fec files easily

Usage:
    ./dl_fec.pl [options]

    options are following :
    -h, --help             : display this help message
    -m, --max-connections  : maximum ftp connections (default: 7)
    -d, --directory        : Directory/folder to put downloaded files
                             (default: /tmp/FEC_Data, must be writable)

Example:
    ./dl_fec.pl
    ./dl_fec.pl -d /tmp/fec_temp -m 10
    ./dl_fec.pl --directory=/tmp/fec_temp --max-connections=10

METADATA
  exit 0;
}

sub interrupt {
  $count++;
  die if $count > 1;
}