use File::Basename;
use File::Spec;
use Cwd;
use File::Path;
use File::Find;


if ($ARGV[0] =~ /^-h(.*)/i){
  print "Usage:: jarp.pl [<jarfile>]";
  exit 1;
}

my $java_home = $ENV{JAVA_HOME};
my $classdir = 'classes';
my $jasmdir = 'jasm';

# perform validations
die "Environment variable JAVA_HOME not defined." if not defined $java_home;


if (!-d $classdir){
  my $jarfile = $ARGV[0];
  die "Not a file: $jarfile" if !-f $jarfile;
  my $jarpath = File::Spec->rel2abs($jarfile);
  
  mkpath $classdir or die "Cannot create temporary directory $classdir: $!";

  my $curdir = getcwd;
  chdir $classdir or die "Cannot chdir to $classdir: $!";

  print "Unjarring $jarpath in directory $classdir ...\n";
  `$java_home/bin/jar xf $jarpath`;
  print "... done.\n";
  
  chdir $curdir or die "Cannot chdir to $curdir: $!";
} else {
  print "Found directory $classdir. Won't unjar $jarfile.\n";
}

my @classes = ();
my $dirlist = [];
print "Making list of classes ...\n";
find(\&visit_file, $classdir);
print "... done.\n";

for my $dir (@$dirlist){
  print $dir, "\n";
}
mkpath($dirlist);

my $index = 0;
for my $class (@classes){
  my $filename = "$jasmdir/$class";
  $filename =~ s/\./\//g;
  $filename .= ".jasm";
  `$java_home/bin/javap -classpath $classdir -c $class > $filename`;
  print "[$index] Disassembled: $filename\n";
  ++$index;
}

sub visit_file {
  if (-f $_){
    if ($File::Find::name =~ m!$classdir/(.*).class!){
      my $class = $1;
      $class =~ s/\//\./g;
      push @classes, $class;
    }
  } elsif (-d $_){
    if ($File::Find::name =~ m!$classdir/(.*)!){
      my $dir = "$jasmdir/$1";
      push @$dirlist, $dir if not grep { $_ eq $dir } @$dirlist;
    }
  }
}