#!/usr/bin/perl -w

use strict;
use warnings;

use Tk;
use Tk::Canvas;

my $mw = MainWindow->new();
$mw->state('zoomed');

my $canvas =
        $mw->Canvas()->pack(-expand => 1, -fill => 'both');
        
my %coord_1 = (
        'a' => [100,100,'b'],
        'b' => [200,100,'c'],
        'c' => [200,200,'d'],
        'd' => [150,250,'e'],
        'e' => [100,200,'a'],
);

my %coord_2 = (
        'f' => [250,250,'g'],
        'g' => [300,200,'h'],
        'h' => [300,300,'i'],
        'i' => [250,350,'j'],
        'j' => [200,300,'f'],
);

drawPolygon($canvas, \%coord_1, 'yellow');
my $moving_pol =  drawPolygon($canvas, \%coord_2, 'lightblue');

$mw->bind('<Up>', sub{movePolygon($canvas,$moving_pol,0,-5);});
$mw->bind('<Down>', sub{movePolygon($canvas,$moving_pol,0,5);});
$mw->bind('<Left>', sub{movePolygon($canvas,$moving_pol,-5,0);});
$mw->bind('<Right>', sub{movePolygon($canvas,$moving_pol,5,0);});

Tk::MainLoop;

sub drawPolygon{
        my $widget      = shift;
        my $coord       = shift;
        my $color       = shift;
        
        my @coords;
        foreach my $point (sort keys %{$coord}){
                push(@coords, $coord->{$point}->[0], $coord->{$point}->[1]);
        }

        return  $widget->createPolygon(
                @coords,
                -fill => $color,
                -outline => 'black',
        );
}

sub movePolygon{
        my $widget      = shift;
        my $polygon = shift;
        my $x_move = shift;
        my $y_move = shift;
        
        foreach my $point (sort keys %coord_2){
                $coord_2{$point}->[0] += $x_move;
                $coord_2{$point}->[1] += $y_move;
        }

        $widget->move($polygon, $x_move, $y_move);
        
        if (PolygonsOverlap(\%coord_1,\%coord_2)){
                $widget->itemconfigure(
                        $polygon, 
                        -outline        => 'red',
                        -fill => 'lightgreen',
                );
        }else{
                $widget->itemconfigure(
                        $polygon, 
                        -outline        => 'black',
                        -fill => 'lightblue',
                );
        }
}

sub PolygonsOverlap{
        my %coord_1 = %{shift()};
        my %coord_2 = %{shift()};
        
        #################################
        # algorithmus zum testen, ob sich
        # die polygone überschneiden.
        #################################
}