#!/usr/bin/perl
use strict;
use warnings;
use Tk;

use constant PI => 3.1415927;
my $Size = 100;

my @Weekdays = qw/Son Mon Die Mit Don Fre Sam/;
my ($HSec, $HMin, $HHour, $Date);
my $Mw = MainWindow->new;
my $HFace = $Mw->Canvas (-width => 2*$Size, -height => 2*$Size)->pack;
my $DText = $Mw->Label (-textvariable => \$Date)->pack;

$HFace->createLine (tc(0.9, $_), tc(1, $_)) for (0..11);

drawtime();
$Mw->repeat (1000, \&drawtime);
$Mw->MainLoop();

sub drawtime {
    my ($s, $m, $h, $dy, $mn, $yr, $wd) = (localtime())[0..6];
    $Date = sprintf("%s, %02d.%02d.%04d", $Weekdays[$wd], $dy, $mn+1, $yr+1900);
    $h+=$m/60;
    for ($HSec, $HMin, $HHour) {
        $HFace->delete($_) if $_;
    }
    $HSec  = $HFace->createLine ($Size, $Size, tc(0.88, $s/5));
    $HMin  = $HFace->createPolygon (tc(0.85, $m/5), tc(0.05, ($m/5+4)), tc(0.05, ($m/5-4)));
    $HHour = $HFace->createPolygon (tc(0.5, $h), tc(0.05, $h+4), tc(0.05, $h-4));
    $Mw->update;
}

sub tc {
    my ($scale, $time) = @_;
    return ($Size*$scale*sin($time*PI/6)+$Size,
           -$Size*$scale*cos($time*PI/6)+$Size);
}