use strict;
use Tk;
require Tk::DirTree;
require Tk::DragDrop;
require Tk::DropSite;
require Tk::LabFrame;

my $CalTreeWidth = 30;
my $CalTreeHeight = 20;
my $selectionWidth = 30;
my $selectionHeight = 8;

my $p1 = MainWindow->new();
my (
    $CalTree,
    $listbox,
    );


      my $leftFrame = $p1->LabFrame(-label=>"System Configuration", -labelside=>"acrosstop")
        ->pack(-side=>"left",-fill=>'y', -anchor=>"nw");
      {
        my $CalTreeScrollBarY = $leftFrame->Scrollbar();
        my $CalTreeScrollBarX = $leftFrame->Scrollbar(-orient=>"horiz");
        $CalTree = $leftFrame->Tree(-yscrollcommand=>['set',$CalTreeScrollBarY],
                                    -xscrollcommand=>['set',$CalTreeScrollBarX],
                                    -width=>$CalTreeWidth,
                                    -height=>$CalTreeHeight,
                                    -drawbranch=>1,
                                    -selectmode=>"extended",
                                    -command=>\&addSelected);
        $CalTreeScrollBarY->configure(-command=> [yview=>$CalTree]);
        $CalTreeScrollBarX->configure(-command=> [xview=>$CalTree]);
        $CalTree->DragDrop(-event => '<B1-Motion>',
                           -text => "",
                           -sitetypes => qw(Local));
        $CalTree->DropSite(-droptypes => qw(Local),
                           -dropcommand => [\&removeSelected]);
        $CalTreeScrollBarX->pack(-side=>"bottom",-fill=>"x");
        $CalTree->pack(-side=>"left",-fill=>"both");
        $CalTreeScrollBarY->pack(-side=>"left",-fill=>"y");
      }
      {
        my $selFrame = $p1->LabFrame(-label=>"Selected Items", -labelside=>"acrosstop")
          ->pack(-fill=>"y", -expand=>1);
        my $listboxScrollBarY = $selFrame->Scrollbar();
        my $listboxScrollBarX = $selFrame->Scrollbar(-orient=>"horiz");
        $listbox = $selFrame->Tree(-width=>$selectionWidth,-height=>$selectionHeight,-drawbranch=>1,
                                   -command=>\&removeSelected,-selectmode=>"extended",
                                   -yscrollcommand=>['set',$listboxScrollBarY],
                                   -xscrollcommand=>['set',$listboxScrollBarX]
                                  );
        $listboxScrollBarY->configure(-command=> [yview=>$listbox]);
        $listboxScrollBarX->configure(-command=> [xview=>$listbox]);
        $listbox->DropSite(-droptypes => qw(Local),
                           -dropcommand => [\&addSelected]);
        $listbox->DragDrop(-event => '<B1-Motion>',
                           -text => "",
                           -sitetypes => qw(Local));
        $listboxScrollBarX->pack(-side=>"bottom",-fill=>"x");
        $listbox->pack(-side=>"left",-fill=>"both");
        $listboxScrollBarY->pack(-side=>"right",-fill=>"y");
      }

$CalTree->add("parent", -text=>"parent1111");
$CalTree->addchild("parent", -text=>"child1");
$CalTree->addchild("parent.0", -text=>"grandchild1");
$CalTree->addchild("parent.0", -text=>"grandchild2");
$CalTree->addchild("parent", -text=>"child2");
$CalTree->addchild("parent.1", -text=>"grandchild1");
$CalTree->addchild("parent.1", -text=>"grandchild2");
$CalTree->autosetmode();

MainLoop;

sub addSelected {
  print "InterncalCal.pm: addSelected()\n";
  foreach ($CalTree->info("selection")) {
    print "    Found selected: " . $CalTree->entrycget($_,"-text") . "\n";
    my $item = $CalTree->entrycget($_,"-text");
    if ($CalTree->info("parent",$_) eq ""){
      # has no parent, so selection must have been 'root'. In other words, 'select all'
      foreach($CalTree->info("children", $_)){
        my $parent = $CalTree->entrycget($_,"-text");
        next if ($CalTree->entrycget($_,"-state") eq "disabled");
        if (!$listbox->info("exists",$parent)){
          $listbox->add("$parent", -text=>$parent); # if parent does not exist, create him first
        }
        foreach($CalTree->info("children", $_)){
          my $no = 0;
          my $item = $CalTree->entrycget($_,"-text");
          foreach($listbox->info("children", $parent)){
            $no++ if ($listbox->entrycget($_,"-text") eq $item); #if both parent and child exist, no need to add again
          }
          if (!$no){
            $listbox->addchild($parent,-text=>$item); # add item if does not already exists
          }
        }
      }
      
    } else {
      my $parent = $CalTree->entrycget($CalTree->info("parent",$_), "-text");
      if ($parent =~ /\d{4}/){
        # since we are not tracking from root (which contains 4 digits, this item should be at the root of the selection list
        if (!$listbox->info("exists",$item)){ # add item to list if does not exist
          $listbox->add("$item", -text=>$item);
        }
        foreach my $child ($CalTree->info('children',$_)){ #add all of its children as well
          my $no = 0;
          my $childname = $CalTree->entrycget($child,"-text");
          foreach ($listbox->info('children',$item)){
            $no++ if ($listbox->entrycget($_,"-text") eq $childname);
          }
          if (!$no){
            $listbox->addchild($item,-text=>$childname);
          }
        }
      }
      else {
        if ($listbox->info("exists",$parent)){
          foreach($listbox->info("children", $parent)){
            return if ($listbox->entrycget($_,"-text") eq $item); #if both parent and child exist, no need to add again
          }
        } else {
          $listbox->add("$parent", -text=>$parent); # if parent does not exist, create him first
        }
        $listbox->addchild($parent,-text=>$item); # add item
      }
    }
  }
  $listbox->autosetmode();
}

sub removeSelected {
  print "InterncalCal.pm: removeSelected()\n";
  my @toplevel;
  foreach ($listbox->info("selection")){
    print "    Found selected: " . $listbox->entrycget($_,"-text") . "\n";
    # don't remove the top level ones until all the selected items underneath have been removed
    # this is a hack !!!
    if ($listbox->entrycget($_,"-text") !~ /\s/){
      push @toplevel, $_;
      next;
    }
    $listbox->delete("entry",$_);
  }
  $listbox->delete("entry",$_) foreach(@toplevel);
  $listbox->autosetmode();
}