#!/usr/bin/perl 
#
# (c) Copyright 2005, 2007
#     Author: Åsmund Ødegård
#             RJ (contribution through http://billigites.blogspot.com)
#     
#     img-focalstat.pl is free software; you can redistribute it and/or modify
#     it under the terms of the GNU General Public License as published by
#     the Free Software Foundation; either version 2 of the License, or
#     (at your option) any later version.
#
#     img-focalstat.pl is distributed in the hope that it will be useful,
#     but WITHOUT ANY WARRANTY; without even the implied warranty of
#     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#     GNU General Public License for more details.
#
#     You should have received a copy of the GNU General Public License
#     along with img-focalstat.pl; if not, write to the Free Software
#     Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA


use File::Find;
use Getopt::Std;
use POSIX;

($#ARGV > -1 and $basedir = $ARGV[0]) or $basedir = ".";

getopts('s:b:o:n:ig',\%opts);

my $show=0;
my $bars=0;
my $numbars=10;
my $outputfile="bar.png";
my $include_nafocal=0;
$opts{s} and $show=1;
$opts{b} and $basedir = $opts{b};
$opts{g} and $bars=1;
$opts{o} and $outputfile=$opts{o};
$opts{n} and $numbars=$opts{n};
$opts{i} and $include_nafocal=1;
#print "base: " . $basedir . "\n";

my %allfocal = ();
my %focalcount = ();

sub findjpg {
   my $filename = $_;
   if ( $filename =~ /jpg$/i ) {
      $fullfilename = $File::Find::name;
      #print "Found jpg: " . $filename . "  ";
      #find focal-length:
      $focal = &findfocal($filename);
      if ( $include_nafocal or $focal != "n/a" ) {
         #print "Focal length: ${focal}mm \n";
         $focalcount{$focal} and ++$focalcount{$focal} or $focalcount{$focal} = 1;
         $allfocal{$focal} and $allfocal{$focal} .= ",$fullfilename" or $allfocal{$focal} = "$fullfilename";
         #print "So far: " . $focalcount{$focal} . " with this focallength\n";
         #print "These are the files: $allfocal{$focal}\n";
      }
   }
}

sub findfocal {
   # assume that we have a jpeg here.
   my $filename = $_;
   open (EXIF, "jhead \"$filename\"|") or die ("Can't run jhead on file\n");
   $focal="";
   while (<EXIF>) {
      /^Focal length :\s*(\d+.\d*).*/ and $focal = $1 and last;
   }
   close EXIF;
   $focal == "" and $focal = "n/a";
   $focal;
}

# find with side-effects, set the %allfocal and %focalcount
find(\&findjpg,$basedir);

foreach $key ( sort { $a <=> $b } keys %focalcount ) {
   print "$key: $focalcount{$key} pictures\n";
}


if ( $show ) {
   print "Show images with focallength $opts{s}\n";
   $cmd = "gthumb ";
   @imgs = split /,/,$allfocal{$opts{s}};
   foreach $img ( @imgs ) {
      $cmd .= "$img ";
   }
   print $cmd . "\n";
   system $cmd;
}


if ( $bars ) {
   # create a bar-plot using GD
   
   my $width = $numbars*55;
   use GD::Graph::bars;
   use GD::Graph::Data;
   use GD::Graph::colour qw(:colours :lists :files :convert);
   GD::Graph::colour::read_rgb("/etc/X11/rgb.txt") or die "cannot read colors";
   my $barplot = GD::Graph::bars->new($width,400);
   $barplot->set (
      x_label => 'focal lengths (in mm)',
      y_label => 'num pictures',
      title   => 'focal length statistics',
      transparent => 0,
      bgclr => 'DimGray',
   );
   my @focals = sort {$a <=> $b } (keys %focalcount);
   my $minfocal = $focals[0];
   my $maxfocal = $focals[$#focals];

   #print "minfocal: $minfocal, maxfocal: $maxfocal\n";

   my $step = ceil(($maxfocal - $minfocal)/$numbars);
   #print "Step will be $step\n";
   my @xdata;
   my @ydata;

   my $tmpfocal = $minfocal;
   my $focalsptr = 0;
   while ($tmpfocal <= $maxfocal) {
      my $upperb = $tmpfocal + $step;
      #print "Counting from $tmpfocal to $upperb: Adding for ";
      push @xdata,"$tmpfocal-$upperb";
      my $tmpcount = 0;
      while ($focalsptr <= $#focals and $focals[$focalsptr] <= $upperb) {
         #print "$focals[$focalsptr],";
         $tmpcount += $focalcount{$focals[$focalsptr]};
         $focalsptr += 1;
      }
      #print ": $tmpcount\n";
      push @ydata, $tmpcount;
      $tmpfocal += $step;
   }
   #my @bardata = (@xdata,@ydata);
   #my @bardata = (["20-30","30-40","40-50","50-60","60-70","70-80","80-90","90-100","100-200","200-300"],
   #               [ @ydata ]);

   if ( ! -e $outputfile ) {
      my $bardata = GD::Graph::Data->new( [[@xdata],[@ydata]] );

      my $values = $bardata->copy;
      $barplot->set(show_values => $values);

      my $plot = $barplot->plot($bardata) or die $barplot->error;
      open (IMG, ">$outputfile") or die $!;
      binmode IMG;
      print IMG $plot->png;
      close IMG;
   } else {
      print "File $outputfile exist, will not overwrite\n";
   }
}