#!/usr/bin/perl
#

use strict;
use GD;

my ($size, $imgfile, $file) = @ARGV;
open my $f, ">$file" or usage();
binmode $f;
my ($buf);
my $res;

my $image = GD::Image->new($imgfile);

my $width = $image->width;
my $height = $image->height;

my $limit = 200;
my $middlex = int($width / 2);
my $middley = int($height / 2);
print "$width $middlex, $height $middley\n";
my $index = $image->getPixel($middlex,$middley);
my ($r,$g,$b) = $image->rgb($index);

if ($r > $limit && $g > $limit && $b > $limit) {
    die "FATAL: pixel $middlex, $middley must not be white ($r, $g, $b)\n"
}
my @data;
my ($x, $y) = ($middlex, $middley);
#my @dir = ( [ 2, 0, ['00', '00'] ], [ -2, 0, ['01', '01']], [ 0, 2, ['11', '11']], [0, -2, ['10', '10']], [ 1, 0, ['00'] ], [ -1, 0, ['01'] ], [ 0, 1, ['11'] ], [ 0, -1, ['10']] );
my @dir = (
    [ 1, 0, ['00'] ], [ -1, 0, ['01'] ], [ 0, -1, ['11'] ], [ 0, 1, ['10']]
);

my %done;
my $prev = $dir[0];
while (@data < $size * 4) {
    my $sc = $size;
    my ($X, $Y);
    my $cmd;
    my @d = sort { rand 1 <=> rand 1 } @dir;
    for my $d ($prev, @d) {
	my ($dx, $dy, $c) = @$d;
	my ($nx, $ny) = ($x + $dx, $y + $dy);
	next if $nx > $width || $nx < 0 || $ny > $height || $ny < 0;
	my $index = $image->getPixel($nx,$ny);
	($r,$g,$b) = $image->rgb($index);
	#print "Testing $nx, $ny ($r, $g, $b): ";
	if ($r < $limit && $g < $limit & $b < $limit) {
	    if ($done{$nx}{$ny} <= $sc) {
		#	print "ok";
		$sc = $done{$nx}{$ny};
		$cmd = $c;
		$X = $nx;
		$Y = $ny;
		$prev = $d
	    }
	}
	#print "\n"
    }
    $X || $Y or die "FATAL: wrong pixel use ($X, $Y)";
    push @data, @$cmd;
    # mark the neighborhood
    $done{$X}{$Y} += 4;
    my $index = $image->getPixel($X+2,$Y);
    ($r,$g,$b) = $image->rgb($index);
    if ($r > $limit && $g > $limit && $b > $limit) {
	$done{$X+1}{$Y} += 2
    }
    my $index = $image->getPixel($X+2,$Y+2);
    ($r,$g,$b) = $image->rgb($index);
    if ($r > $limit && $g > $limit && $b > $limit) {
	$done{$X+1}{$Y+1} += 1;
    }
    my $index = $image->getPixel($X+2,$Y-2);
    ($r,$g,$b) = $image->rgb($index);
    if ($r > $limit && $g > $limit && $b > $limit) {
	$done{$X+1}{$Y-1} += 1;
    }
    my $index = $image->getPixel($X-2,$Y);
    ($r,$g,$b) = $image->rgb($index);
    if ($r > $limit && $g > $limit && $b > $limit) {
	$done{$X-1}{$Y} += 2;
    }
    my $index = $image->getPixel($X-2,$Y+2);
    ($r,$g,$b) = $image->rgb($index);
    if ($r > $limit && $g > $limit && $b > $limit) {
	$done{$X-1}{$Y+1} += 1;
    }
    my $index = $image->getPixel($X-2,$Y-2);
    ($r,$g,$b) = $image->rgb($index);
    if ($r < $limit && $g > $limit && $b > $limit) {
	$done{$X-1}{$Y-1} += 1;
    }
    my $index = $image->getPixel($X,$Y+2);
    ($r,$g,$b) = $image->rgb($index);
    if ($r > $limit && $g > $limit && $b > $limit) {
	$done{$X}{$Y+1} += 2;
    }
    my $index = $image->getPixel($X,$Y-2);
    ($r,$g,$b) = $image->rgb($index);
    if ($r > $limit && $g > $limit && $b > $limit) {
	$done{$X}{$Y-1} += 2;
    }
    $x = $X;
    $y = $Y;
    #print "$X, $Y ($r, $g, $b)\n";
}

# my $png_data = $image->png;
# open (DISPLAY,"| display -") || die;
# binmode DISPLAY;
# print DISPLAY $png_data;
# close DISPLAY;

my $im = new GD::Image($width,$height) || die;
my $black = $im->colorAllocate(0,0,0);       
my $white = $im->colorAllocate(255,255,255);       
my $x = $middlex;
my $y = $middley;

for (my $i; $i < @data; $i += 4) {
    my $cmd;
    for (my $j; $j < 4; $j++) { 
	my $n = $data[$i+$j];
	$cmd .= $n;
	if ($n eq '00') {
	    $x++
	} elsif ($n eq '01') {
	    $x--
	} elsif ($n eq '10') {
	    $y++	
	} elsif ($n eq '11') {
	    $y--
	}
	$im->setPixel($x,$y,$white)
    }
    my $val = unpack('C', pack('b8', $cmd));
    my $cal = $val ^ 0xaa;
    print $f pack('C', $cal);
}
my $png_data = $im->png;
open (DISPLAY,"| display -") || die;
binmode DISPLAY;
print DISPLAY $png_data;
close DISPLAY;

my $left = (($size * 4) - @data);
$buf = '00010001' x $left;
my $count = $left*8;
$res = pack("b$count", $buf);
print $f $res;
close $f;
exit;

# 00 right
# 01 left
# 10 bottom
# 11 top

my @data = (qw(
    # moon
01010101
01100110
01100110
01100110
01100110
01011001
01011001
01010110
01010110
01010101
10010101
01010101
10010101
01010101
01010111
01010111
01011101
01110111
01110111
01110111
01111111
01111111
01111111
11111111
11111101
11111101
11111111
11111111
11111111
11111100
11111111
11111111
11111100
11111111
11111100
11111100
11111100
11111100
11001100
11111100
11001100
11111100
11111100
11001100
11001100
11111111
01110111
01010110
01100110
01100110
01100110
10100110
01101010
01100110
01101010
10101010
10011010
01101010
10101010
10100110
10101010
10100110
10101010
10101010
10101010
10101010
10101010
10101010
10101010
10101000
10101010
10101010
10101000
10101010
10101000
10101000
10101000
10001000
10101000
10001000
10001000
10000000
10001000
10000000
10001000
10000000
10000000
10000000
00000000
10000000
00000000
00000011
00000011
00110011
00110011
00110011
00110011
11110011
11001100
11001100
11111100
11111100
11111111
11111100
11111111
11111111
00001000
00100010
00100010
00100010
00100010
00100010
00100010
00100010
00100010
00100010
00100010
00100010
00100010
00100010
00100010
00100010
00100010
00100010
00100010
00110011
00111111
11111111
11111111
11111111
11111101
11111111
11111111
11111111
11111111
11111111
11111101
11111111
11111111
11111111
11001111
11001111
11001100
11001100
11000000
11000000
11000000
11000000
11000000
11000000
11000000
11000000
11000000
11000000
11000000
11000000
11000000
10101001
10101001
10101001
10101001
10101001
00100010
00000011
11111100
11111100
11111100
11111100
11111100
10001000
10001010
10001000
10001010
10001000
10001010
00000011
11110111
01110111
01111111
01110111
01111111
11110000
00000000
00000000
00000011
00111101
11010101
01010101
01010101
01010101
11001100
11111100
11001100
11111100
11001100
11111111
11010111
01100110
10101001
10101001
10011001
10101001
10011001
10011011
11011101
11111101
11011101
11111101
11011101
11011101
10011001
00101010
10001000
10001000
10101000
10001000
10101000
11011101
11010101
11010101
11010101
11010101
11010101
11010101
11010101
11010101
11010101
11010101
11010101
11010101
11010101
11011101
11011111
11011101
11011111
11011111
11011111
11011111
11011111
11111111
11011111
11111111
11011111
11111111
11011111
11111111
11011101
11010101
01100110
01100110
01101010
01100110
01101010
01100110
01101010
01100110
01101010
01100110
01101010
01100110
01101010
01100110
01101010
01100110
01101010
01100101
01011101
01011101
01001101
01011101
01010101
01011101
01010101
01011101
01010101
01010101
01110101
01010101
01110101
01100110
10100010
10100010
10001000
10001010
10001000
10001010
10001000
10001010
10001000
10001010
10001000
10001010
10011010
10101001
10101010
10011010
10011001
10101001
10011001
10101001
10011001
10101001
10011001
10101001
10011001
10101001
10100010
10001000
00000011
00000000
00000011
00000000
00000011
00000000
00000011
00000000
00000011
00000000
00000011
00000000
00000010
10001000
)
);

# my $c;
# for (my $i; $i < 256; $i++) {
#    for (my $j; $j < 32; $j++) {
#        my $cal = $c ^ 0xaa;
#        print $f pack('C', $cal);
#    }
#    for (my $j; $j < 32; $j++) {
#        my $val = unpack('C', pack('b8', '00000000'));
#        my $cal = $val ^ 0xaa;
#        print $f pack('C', $cal);
#    }
#    $c++;
# }
my $im = new GD::Image(400,400) || die;
my $black = $im->colorAllocate(0,0,0);       
my $white = $im->colorAllocate(255,255,255);       
my $x = 200;
my $y = 200;
for (my $i; $i < @data; $i++) {
    foreach my $n ($data[$i] =~ /([01]{2})/g){
	if ($n eq '00') {
	    $x++
	} elsif ($n eq '01') {
	    $x--
	} elsif ($n eq '10') {
	    $y++	
	} elsif ($n eq '11') {
	    $y--
	}
	$im->setPixel($x,$y,$white)
    }
    my $val = unpack('C', pack('b8', $data[$i]));
    my $cal = $val ^ 0xaa;
    print $f pack('C', $cal);
}
my $png_data = $im->png;
open (DISPLAY,"| display -") || die;
binmode DISPLAY;
print DISPLAY $png_data;
close DISPLAY;

my $left = (16384 - @data);
$buf = '00010001' x $left;
my $count = $left*8;
$res = pack("b$count", $buf);
print $f $res;
close $f;
exit;

sub usage {
    print "\nusage:\n\n\t\tperl-kroete <size> <image file> <output file>\n\n";
    exit
}