#!/usr/bin/perl
#by monk zli034
use strict;
use Image::Magick;
use Cache::FileCache;

my @files = ();
my $folder = "c:\\photos";
my $FUZZ = 5; # permitted average deviation in the vector elements
my $CORRUPT = "CORRUPT"; # if defined, rename corrupt images into this dir
my $cache = Cache::FileCache->new;

unless (opendir(FOLDER, $folder)){
	print "Cannot opne folder $folder!\n";
	exit;	
}

@files = grep (!/^\.\.?$/, readdir(FOLDER));

closedir(FOLDER);

#print join("\n", @files), "\n";
sub warnif;
my	$write="ID,mean,stdv,class\n";        
foreach my $file (@files){
	#the first number of the photo file gives the
	#information of the type of the item.
	my $class;
	if ($file =~ /^1/){ $class = "first";}
	if ($file =~ /^2/){ $class = "second";}
	if ($file =~ /^3/){ $class = "third";}
	#print $file;
	my $image = Image::Magick->new;

	my $x = $image->Read($folder."\\".$file);
		#print $file;
		my @vector;
		
          #print "... skipping ($file)\n";
          #print "\n";
          my (@stat) = stat(_) or die "should not happen: $!"; # return 13 elements of file status.
          my $key = "@stat[0, 1, 9]"; # dev/ino/mtime
          print "$file is ", join("x",$image->Get('width', 'height')), "\n";
          warnif $image->Normalize();
          warnif $image->Resize(geometry => '4x4!');
          warnif $image->Set(magick => 'rgb');
          @vector = unpack "C*", $image->ImageToBlob();
          print "vector ", @vector, "\n";
          $cache->set($key, [@vector]);
          my $mean = mean(@vector);
          my $stdv = std_dev($mean, @vector);
        	print "mean $mean \n";
			print "standard deviation $stdv \n";       
			#$write=$write.$file.",".$mean.",".$stdv.",".$class."\n"; 
			foreach my $element (@vector){
			$write=$write.$element.",";      
		}
		$write = $write.$class."\n";
}


  #Output result--------------------------------------------------
  open(OUTFILE, ">testdata.csv") or die "Can't open testdata.csv: $!";
  print OUTFILE $write;
  close OUTFILE;


use Carp qw(carp);
sub warnif {
    	my $value = shift;
        carp $value if $value;
}

sub mean {
  my $result;
  foreach (@_) { $result += $_ }
  return $result / @_;
}
sub std_dev {
  my ($mean, @vector) = @_;
  my @elem_squared;
  foreach my $element(@vector) {
    push (@elem_squared, ($element **2));
  }
  return sqrt( mean(@elem_squared) - ($mean ** 2));
}