#!/usr/bin/perl
use strict;
use warnings;
use PDF::API2;
use PDF::Table;

# #A4 Landscape
my $width     = 842;
my $height    = 595; 
my $pdftable = new PDF::Table;
my $pdf = new PDF::API2(-file => "tables_side_by_side_test.pdf");
$pdf->mediabox($width, $height); 

my $page = $pdf->page();
my $start_page_no = 1;
my $target_page_no;
my $y = 500;
# table A and B horiz
my $xA = 10;
my $xB = 500;
my $table_no = 1;

# create 10 table pairs
for my $t (1..10){

  $target_page_no = $start_page_no;
  
  my $caption = $page->text();
  $caption->font($pdf->corefont('Helvetica-Bold'), 10);
  $caption->translate($xA,$y+1);
  $caption->text("Table A $t");       
  my ($pageA,$spanA,$yA) = _table_a($page,$xA,$y);
  
  $target_page_no = $start_page_no;  
  $caption->translate($xB,$y+1);
  $caption->text("Table B $t");       
  my ($pageB,$spanB,$yB) = _table_a($page,$xB,$y);
  
  # determine which tables spans the most pages
  # to determine start of next table pair
  if ($spanA > $spanB) {
    $y = $yA;
    $page = $pageA;
  } elsif ($spanB > $spanA){
    $y = $yB;
    $page = $pageB;
  } else {
    $y = ($yA > $yB) ? $yB : $yA;
    $page = $pageA;
  }

  # move down but avoid starting too close
  # to bottom  
  $y = $y-30;
  if ($y < 10){
    $y = 500;
    $page = _new_page() unless $t == 10;
  }
  
  $start_page_no = $pdf->pages;
}
$pdf->saveas();

# create new page for only if target page
# exceed number of existing pages
sub _new_page {
  ++$target_page_no;
  if ($target_page_no > $pdf->pages){
    return $pdf->page; # create new 
  } else {
    return $pdf->openpage($target_page_no);
  }
}

sub _table_a {
  my ($page,$x,$y) = @_;
  my $pdftable = new PDF::Table;
  my ($next_page, $span, $new_y) = $pdftable->table(
     $pdf,
     $page,
     _data($table_no++),
     x => $x, # center main table on the page
     w => 200,
     start_y => $y, next_y  => 500,  
     start_h => $y, next_h  => 500, 
     new_page_func => \&_new_page,
     padding => 2,
     padding_right => 10,
     border        => 0,
     background_color_odd  => "#E0E0E0",
     background_color_even => "#FFFFFF",
  );
  return ($next_page,$span,$new_y);
};

sub _data {
  my $t = shift;
  my @rows=(['A','B','C']);
  my $n = 5+int rand(50);
  push @rows,[$t,$_,$n] for 1..$n;
  return \@rows;
}