#!/usr/bin/env perl
use 5.014;
use strict;
use warnings;
use YAML;
use Cwd 'abs_path';
use Data::Dumper;
use GraphViz;
use Getopt::Long;

sub usage
{
  my $output = "usage: graph_flow.pl [-h] file_in.yml file_out.png\n";
  $output .= "Options:\n";
  $output .= "\t-h: this help\n";
  return $output
}

my $help = 0;
GetOptions ("h|help" => \$help)
  or die("Error in command line arguments\n".usage());

if($#ARGV!=1)
{
  die(usage());
}

my $g = GraphViz->new();
my $filename = abs_path($ARGV[0]);
my $outfilename = $ARGV[1];
my $ylog = YAML::LoadFile($filename);

my @prevs = ();
my $name = '';
my $action = '';
my $prev;
my $cont = 1;
$g->add_node(name => 'END', shape =>'box');

foreach my $i (@{$ylog->{'flow'}})
{
  foreach my $key (keys %{$i})
  {
    #print "$key\n";
    if(($action, $name) = ($key =~ m/(exit|start|end)\|(\w+)/))
    {
      if ($action eq "start")
      {
        $prev = $prevs[-1];

        if ($prev)
        {
          $g->add_node(name => $name);
          $g->add_edge( $prev => $name, label => $cont++);
        }
        else
        {
          $g->add_node(name => $name, shape=> 'diamond');
        }
        push(@prevs, $name);
      }
      else
      {
        pop(@prevs); # this is me.
        $prev = $prevs[-1];
        if ($action eq "end") { $g->add_edge($name => $prev, label => $cont++); }
        else { @prevs = ();  $g->add_edge($name => 'END', label => $cont++); }
      }
    }
  }
}
$g->as_png($outfilename);
#EOF