#! /usr/bin/perl -w
use strict;
use List::Util qw[max];

# read a  GIMP gpl palette file and write out a netpbm PPM image
# Liam Quin, https://www.delightfulcomputing.com/ 2021

my $inheader = 1;
my @colours;
my $max = 0;
while (<>) {
    chomp;
    if ($inheader) {
	if (m/^GIMP Palette/) {
	    next;
	}
	if (m/^NameL/) {
	    next;
	}
	if (m/^#/) {
	    $inheader = 0;
	    next;
	}
    } elsif (m/^\s*(\d+)\s+(\d+)\s+(\d+).*$/) {
	push @colours, [ $1, $2, $3 ];
	$max = max($max, $1, $2, $3);
    }
}

if (!@colours) {
    die "$0: no colours found";
}

if ($max <= 0) {
    die "$0: max value found is 0 which I think is an all-black palette";
}

# our image will be 1 pixel wide...
print "P3\n1 " . scalar(@colours) . "\n";
print "${max}\n";

# now the image data
foreach (@colours) {
    print $_->[0], " ", $_->[1], " ", $_->[2], "\n";
}