#!/usr/bin/env perl
use Cwd;
use File::Path;

my $CROSS	= defined($ENV{CROSS}) ? $ENV{CROSS} : -1;
my $IS_MSVC	= 0;
my $IS_MSWIN	= $^O eq "MSWin32";
my $AR		= defined($ENV{AR}) ? $ENV{AR} : "ar";
my $CC		= defined($ENV{CC}) ? $ENV{CC} : "gcc";
my $CFLAGS	= defined($ENV{CFLAGS}) ? $ENV{CFLAGS} : "";
my $LDFLAGS	= defined($ENV{LDFLAGS}) ? $ENV{LDFLAGS} : "";
my $LIBS	= defined($ENV{LIBS}) ? $ENV{LIBS} : "";
my $NUL		= "> /dev/null 2>&1";

sub path_translate {
	local($path) = @_;
	if($IS_MSWIN){
		$path =~ s/\//\\\\/g;
		return $path;
	}else{
		return $path;
	}
}

my %labels = ();
my @types = (
	"make"
);
my $type = $types[0];

if(defined($ENV{BACKEND})){
	$labels{$ENV{BACKEND}} = 1;
}

print("NishBox build script generator\n");
if(@ARGV == 1){
	$found = 0;
	$type = $ARGV[0];
	foreach(@types){
		if($_ eq $type){
			$found = 1;
			break;
		}
	}
	if(!$found){
		print("Not supported build script type\n");
		exit(1);
	}
}elsif(@ARGV != 0){
	print("Bad arguments, this script only needs build script type\n");
	print("Supported types:\n");
	foreach(@types){
		print("  $_");
		if($_ eq $types[0]){
			print(" (default)");
		}
		print("\n");
	}
	exit(1);
}
print("Generating for $type\n");
if($IS_MSWIN){
	print("Seems like you're building from Windows\n");
	$NUL = " > NUL:";
}

open(RULES, "<", "Rules") or die "Where is Rules";

print("Are we cross-compiling... ");

if($CROSS == -1){
	mkdir("test_conf");
	chdir("test_conf");
	open(SRC, ">", "test.c");
	print(SRC "int main(){}\n");
	close(SRC);
	if($IS_MSVC){
		$status = system("$CC /Fetest test.c $NUL");
	}else{
		$status = system("$CC -o test test.c $NUL");
	}
	if($status == 0){
		if($IS_MSWIN){
			$status = system("test.exe");
		}else{
			$status = system("./test");
		}
	}
	chdir("..");
	rmtree("test_conf");
	if($status == 0){
		$CROSS = 0;
	}else{
		$CROSS = 1;
	}
}

if($CROSS){
	$labels{C} = 1;
	print("yes");
}else{
	print("no");
}
print("\n");

if($IS_MSVC){
	$labels{M} = 1;
}

while($line = <RULES>){
	my $run = 1;

	my $optional	= "";
	my $label	= "";
	my $command	= "";
	my $arg		= "";
	if($line =~ /^#/){
		next;
	}
	$line =~ s/\n//g;
	if($line =~ /^(.)(....)([^\t ]+)$/){
		$optional	= $1;
		$label		= $2;
		$command	= $3;
	}elsif($line =~ /^(.)(....)([^\t ]+)[\t ]+(.+)$/){
		$optional	= $1;
		$label		= $2;
		$command	= $3;
		$arg		= $4;
	}
	while($label =~ /(.)/g){
		if(!($1 eq " ")){
			$run = $run && defined($labels{$1});
		}
	}
	if(!$run){
		next;
	}
	$optional = !($optional eq " ");
	if($command eq "CHECK"){
		my $status = 0;
		print("Checking if $arg exists... ");

		mkdir("test_conf");
		chdir("test_conf");
		open(SRC, ">", "test.c");
		print(SRC "#include <$arg>\n");
		close(SRC);
		if($IS_MSVC){
			$status = system("$CC /c $CFLAGS test.c $NUL");
		}else{
			$status = system("$CC -c $CFLAGS test.c $NUL");
		}
		chdir("..");
		rmtree("test_conf");

		if(defined($labels{D})){
			undef($labels{D});
		}
		if($status == 0){
			print("yes");
			$labels{D} = 1;
		}else{
			print("no");
		}

		print("\n");
		if($status != 0 && !$optional){
			print("Required header missing - generation aborted\n");
			exit(1);
		}
	}elsif($command eq "DEFINE"){
		if($IS_MSVC){
			$CFLAGS = "$CFLAGS /D$arg";
		}else{
			$CFLAGS = "$CFLAGS -D$arg";
		}
	}elsif($command eq "PKGCONF"){
		my $result = "";
		if($IS_MSVC){
			$result = `pkg-config --silence-errors --msvc-syntax --cflags $arg`;
			$result =~ s/\n$//g;
			$CFLAGS = "$CFLAGS $result";

			$result = `pkg-config --silence-errors --msvc-syntax --libs $arg`;
			$result =~ s/\n$//g;
			$LIBS = "$LIBS $result";
		}else{
			$result = `pkg-config --silence-errors --cflags $arg`;
			$result =~ s/\n$//g;
			$CFLAGS = "$CFLAGS $result";

			$result = `pkg-config --silence-errors --libs $arg`;
			$result =~ s/\n$//g;
			$LIBS = "$LIBS $result";
		}
	}elsif($command eq "LABEL"){
		$labels{$arg} = 1;
	}elsif($command eq "UNLABEL"){
		if(defined($labels{$arg})){
			undef($labels{$arg});
		}
	}elsif($command eq "INCREL" || $command eq "INCLUDE"){
		if($command eq "INCREL"){
			$arg = path_translate(Cwd::getcwd() . "/" . $arg);
		}else{
			$arg = path_translate($arg);
		}
		if($IS_MSVC){
			$CFLAGS = "$CFLAGS /I$arg";
		}else{
			$CFLAGS = "$CFLAGS -I$arg";
		}
	}elsif($command eq "LIBREL" || $command eq "LIBRARY"){
		if($command eq "LIBREL"){
			$arg = path_translate(Cwd::getcwd() . "/" . $arg);
		}else{
			$arg = path_translate($arg);
		}
		if($IS_MSVC){
			$LDFLAGS = "$LDFLAGS /LIBPATH $arg";
		}else{
			$LDFLAGS = "$LDFLAGS -L$arg";
		}
	}elsif($command eq "LINK"){
		if($IS_MSVC){
			$LIBS = "$LIBS $arg.lib";
		}else{
			$LIBS = "$LIBS -l$arg";
		}
	}elsif($command eq "COMPILE"){
		opendir(my $dh, $arg);
		my @l = grep(/\.c$/, readdir($dh));
		foreach(@l){
			print("$_\n");
		}
		closedir($dh);
	}
}

close(RULES);

print("----- Configuration result -----\n");
print("     AR: $AR\n");
print("     CC: $CC\n");
print(" CFLAGS: $CFLAGS\n");
print("LDFLAGS: $LDFLAGS\n");
print("   LIBS: $LIBS\n");
print("--------------------------------\n");