package Tk::HistEntry;

use vars qw($VERSION);
$VERSION = '0.001';

use base  qw(Tk::Frame);
use Tk::widgets qw(Frame Entry);

Construct Tk::Widget 'HistEntry';

sub Populate {
  require Tk::Entry;
  # HistEntry constructor.
  #
  my($cw, $args) = @_;
  $cw->SUPER::Populate($args);
  # Advertised subwidgets:  entry.
  my $e = $cw->Entry();
  $e->pack('-expand' => 1, '-fill' => 'both');
  $cw->Advertise('entry' => $e );
  $cw->ConfigSpecs(DEFAULT => [$e]);
  $cw->Delegates(DEFAULT => $e);
  $cw->AddScrollbars($e) if (exists $args->{-scrollbars});
  $e->{history} = {
    hlist => [],
    place => 0,
  };
  $e->bind("<Key-Return>"=> [ \&addHistory  ]);
  $e->bind("<Key-Up>"    => [ \&upHistory   ]);
  $e->bind("<Key-Down>"  => [ \&downHistory ]);
} 

sub addHistory {
  my $entry = shift;
  my $hist  = $entry->{history};
  push @{$hist->{hlist}}, $entry->get() ;
  $hist->{place}++;
} 

sub upHistory {
  my $entry = shift;
  my $hist  = $entry->{history};
  if ($hist->{place} <= 0) {
    $hist->{place} = $#{$hist->{hlist}}
  } 
  else {
    $hist->{place}--;
  } 
  $entry->delete('0','end');
  $entry->insert('1',$hist->{hlist}[$hist->{place}]);
} 

sub downHistory {
  my $entry = shift;
  my $hist  = $entry->{history};
  $entry->delete('0','end');
  if ($hist->{place} == $#{$hist->{hlist}}) {
    $hist->{place} = -1;
    return
  } 
  $hist->{place}++;
  $entry->insert('1',$hist->{hlist}[$hist->{place}]);
} 
1;