#!/usr/bin/perl
use FileHandle;

my %depend = ();
my %minver = ();
my %config = ();
my $version, $level, $sublevel;

sub add_config($)
{
	my $arg=shift;

	if ($arg =~ m/^([A-Z0-9_]+)/) {
		$config{$1} = 1;
	}
}

sub check_deps($)
{
	my $arg=shift;
	$arg=$arg." ";

	while ($arg ne "") {
		if ($arg =~ m/^([A-Z0-9_]+) /) {
			my $val=$1;
			my $prev=$depend{$val};
			$depend { $val } = 1+$prev;
		}
		$arg =~ s/^[^ ]+ //;
	}
}

sub open_kconfig($$) {
	my ($dir,$file)=@_;
	my $in = new FileHandle;
	my $skip=0;

#print "opening $file\n";
	open $in,"$file";
	while (<$in>) {
#		if (m;^\s*source[\s\"]+drivers/media/(video|dvb)/Kconfig;) {
#			next;
#		}
		if (m|^\s*source[\s\"]+([^\n\s\"]+)[\n\s\"]|) {
			open_kconfig($dir,"$dir/$1");
			next;
		}
		if (m|^\s+depends on (.*)\n|) {
			check_deps ($1);
		}
		if (m|^\s+select (.*)\n|) {
			check_deps ($1);
		}
		if (m|^\s*config (.*)\n|) {
			my $key=$1;

			add_config ($1);

			my $min=$minver { $key };
			my $minversion, $minlevel, $minsublevel;
			if ($min =~ m/(\d+)\.(\d+)\.(\d+)/) {
				$minversion=$1;
				$minlevel=$2;
				$minsublevel=$3;
			} else {
				die "Minimum version for $key not found at versions.txt";
			}
			if ( ($version < $minversion) |
				($level < $minlevel) |
				($sublevel < $minsublevel) ) {
				$skip=1;
				printf "$key requires version $minversion.$minlevel.$minsublevel\n";

				print OUT "# $key disabled due to incorrect version\nconfig $key\n\ttristate\n\tdefault n\n\n";
				next;
			} else {
#				printf "OK: $key requires version $minversion.$minlevel.$minsublevel\n";
				$skip=0;
			}
		}

		s/^main(menu\s\"[^\"]+)/\1 - DON'T CHANGE IT!/;
		if (m/^[\w]/) {
			$skip=0;
		}
		if (!$skip) {
			print OUT $_;
		}
	}
	close $in;
}

sub parse_versions ()
{
	my $in = new FileHandle;
	my $ver;

	open $in,"versions.txt";
	while (<$in>) {
		if (m/\[([\d.]*)\]/) {
			$ver=$1;
			next;
		}
		s/\n//;
		if (m/^\s*([\w\d_]+)/) {
			$minver { $1 } = $ver;
#			printf ("%s=%s\n",$1,$ver);
		}
	}
	close $in;
}

parse_versions;

open IN,".version";
while (<IN>) {
	if (m/KERNELRELEASE\s*[:]*[=]+\s*(\d+)\.(\d+)\.(\d+)/) {
		$version=$1;
		$level=$2;
		$sublevel=$3;
	}
}
close IN;

printf "Preparing to compile for kernel version %d.%d.%d\n",$version,$level,$sublevel;

open OUT,">Kconfig";
print OUT "mainmenu \"V4L/DVB menu\"\n";

print OUT "source Kconfig.kern\n";
open_kconfig ("../linux","../linux/drivers/media/Kconfig");

close OUT;

while ( my ($key, $value) = each(%config) ) {
		delete $depend{$key};
}

open OUT,">Kconfig.kern";

print OUT "config MODULES\n\tboolean\n\tdefault y\n\n";

while ( my ($key, $value) = each(%depend) ) {
	print OUT "# $key with $value refs\nconfig $key\n\ttristate\n\tdefault m\n\n";
}
close OUT;