#!/usr/bin/perl

use strict;
use Getopt::Long;
use IO::Handle;

STDERR->autoflush(1);
STDOUT->autoflush(1);

my $sequence_dir;
my $ab_dir;
my $dt = 1;
GetOptions (
  "sequence_dir=s"  => \$sequence_dir,
  "ab_dir=s"  => \$ab_dir,
  "dt=i" => \$dt,
);

print 'sequence_dir: ' . $sequence_dir . "\n";
print 'ab dir: ' . $ab_dir . "\n";
if (! $sequence_dir || ! $ab_dir || ! -e $sequence_dir) {
  print "usage: $0 --sequence_dir ... --ab_dir ... --dt 1\n";
  exit(1);
}
$sequence_dir .= "/";
$ab_dir .= "/";

mkdir($ab_dir);
mkdir($ab_dir . "A/");
mkdir($ab_dir . "B/");
mkdir($ab_dir . "A/train/");
mkdir($ab_dir . "B/train/");
mkdir($ab_dir . "A/val/");
mkdir($ab_dir . "B/val/");
mkdir($ab_dir . "A/test/");
mkdir($ab_dir . "B/test/");

our @files = ();

opendir DIR, $sequence_dir;
while (readdir DIR) {
  next if /^\./;
  push(@files, $_);
}
closedir DIR;

our @sequence = sort @files;

my $count = scalar(@sequence) - $dt;

print "$count images in sequence\n";

my $i; my $x; my $y; my $dir; my $id;
for ($i = 0; $i < $count; $i++) {
  $id = $i;
  if ( ($id % 10) == 5) {
    $dir = "test/";
  } elsif ( ($id % 10) == 8) {
    $dir = "val/";
  } else {
    $dir = "train/";
  }
  if ( $i && ($i % 1000) == 0) {
    print $id . "...\n";
  }

  #my $x = int(rand($w - $dw));
  #my $y = int(rand($h - $dh));
  my $a_frame = $sequence_dir . $sequence[$id];
  my $b_frame = $sequence_dir . $sequence[$id+$dt];
  my $fn = sprintf("frame_%05d.png", $i);
  #print "$fn $x $y $a_frame\n";
  system("ln", "-s", $a_frame, $ab_dir . "A/" . $dir . $fn);
  system("ln", "-s", $b_frame, $ab_dir . "B/" . $dir . $fn);
}
print $count . "\n";