use ExtUtils::MakeMaker;
PDL::Core::Dev->import(); # for trylink

@subdirs = ("PGPLOT", "LUT", "IIS", "Karma", "PLplot", "Limits");

# we try and build unless WITH_3D == 0
$t = $PDL::Config{WITH_3D};
if ( defined($t) and $t == 0 ) {
   print "\n   WITH_3D: Not building TriD or OpenGL. Turn on WITH_3D if this is incorrect.\n\n";
} else {
   # Do we have the xdpyinfo command in PATH?
   use File::Find;
   my $have_xdpyinfo_command = 0;
   print "\n   WITH_3D: Looking for xdpyinfo to check GLX ";
   find( sub { -f && /^xdpyinfo(.exe)?$/i
         && ++$have_xdpyinfo_command && print "."; }, (split ':', $ENV{PATH}) );

   # If yes, run it to check for working GLX extension
   my $have_glx_extension = 0;
   if ($have_xdpyinfo_command) {
      print "\n   WITH_3D: Found xdpyinfo, now checking for GLX extension\n";
      $have_glx_extension = grep /^\s*GLX\s*$/, qx{xdpyinfo};
      if ($have_glx_extension) {
         print "   WITH_3D: Found GLX ($have_glx_extension match)\n";
      }
   }

    # If no GLX we won't choose to build TriD or OpenGL
    unless ($have_glx_extension or $t) {
       print "\n   WITH_3D: No GLX extension found for this X server, won't build TriD or OpenGL\n".
       "   WITH_3D: Turn on WITH_3D if this is incorrect.\n\n";
       $PDL::Config{WITH_3D} = 0;
    } else {
       # Working GLX so continue with automated check for libraries and includes
       print  "\n   WITH_3D: Trying OpenGL initial OPENGL_LIB configuration ->$PDL::Config{OPENGL_LIBS}<-\n\n";

       $PDL::Config{OPENGL_LIBS} = guessogllibs($PDL::Config{OPENGL_LIBS});

       if ( defined $PDL::Config{OPENGL_LIBS} ) {
          unshift @subdirs,"TriD";
          if ( $PDL::Config{OPENGL_LIBS} =~ /Mesa/ ) {
             $PDL::Config{OPENGL_DEFINE} .= ' -DGL_GLEXT_LEGACY';
          }
          $PDL::Config{WITH_3D} = 1;

          # hack for cygwin
          #
          # note: the current OpenGL implementation requires X windows in its
          # implementation, maybe we could eliminate the need for these hacks
          # by adding explicit X11 include locations for all cases
          #
          if ($^O eq 'cygwin' and not defined $PDL::Config{OPENGL_INC}) {
             $PDL::Config{OPENGL_INC} = '-I/usr/X11R6/include -I/usr/X11R6/include/GL';
          }

          if ($^O eq 'cygwin' and not defined $PDL::Config{OPENGL_DEFINE}) {
             $PDL::Config{OPENGL_DEFINE} =
             '-DGL_MESA_trace ' .
             '-DGLX_ARB_render_texture ' .
             '-DGLX_GLEXT_LEGACY ' .
             '-DGLX_MESA_agp_offset ' .
             '-DGLX_NV_vertex_array_range';
          }

          # hack for OS-X
          if ($^O eq "darwin" and not defined $PDL::Config{OPENGL_INC}) {
             $PDL::Config{OPENGL_INC} = "-I/usr/X11R6/include";
          }

          print "\n   WITH_3D: Success using $PDL::Config{OPENGL_LIBS} $PDL::Config{OPENGL_DEFINE}\n".
          "\n   WITH_3D: Set WITH_3D => 1 and build OpenGL and TriD\n\n";
       } else {
          warn "\n   WITH_3D: COULD NOT link OpenGL \n".
	  "    WITH_3D: Not building OpenGL and TriD options!  Turn on WITH_3D if this is incorrect.\n\n";
          $PDL::Config{WITH_3D}=0;
       }
    }
 }

#WriteMakefile(
#     'NAME' => 'PDL',
#     VERSION_FROM => '../Basic/Core/Version.pm',
#     DIR => [@subdirs]
#);
my @pm_names = qw (Graphics2D.pm State.pm);
my %pm = map { $h = '$(INST_LIBDIR)/';
	       $h .= 'PDL/' if $_ !~ /PDL.pm$/;
	       $h .= 'Graphics/' if $_ =~ /State.pm$/;
	       ( $_, $h . $_ );
	   } ( @pm_names);
my %man3pods = map { $h = '$(INST_MAN3DIR)/';
		     $h .= 'PDL::' if $_ !~ /PDL.pm$/;
		     ( $_, $h . substr($_,0,length($_)-3) . '.$(MAN3EXT)' ); 
		 } @pm_names;


WriteMakefile(
	      'NAME' => 'PDL',
	      VERSION_FROM => '../Basic/Core/Version.pm',
	      'PM'       => \%pm,
	      'MAN3PODS' => \%man3pods,
	      DIR => [@subdirs],
#	      LIBS => ['-lm'],  # corrected from LIB=>..., then commented out
	     );

sub guessogllibs{
  my $libs=shift;
  use Config;
  my $have_GL;
  my $mmpre = {MakeMaker => 1}; # preprocess by MakeMaker

  if(defined $libs){
	 if (trylink $libs,
		  '', 'char glBegin(); glBegin();',
		  libs($libs), $mmpre) {
		return $libs;
	 }else{
      undef $libs;
		warn "     User specified OpenGL configuration $libs did not work"
		  ."\n     trying to guess...\n\n";
	 }
  }
  if (trylink( 'libGL',
		'', 'char glBegin(); glBegin();',
		libs('-lGL'), $mmpre)) {
	 $libs = libs('-lGLU -lGL');
  } elsif (trylink ('libMesaGL',
			  '', 'char glBegin(); glBegin();',
			  libs('-lMesaGL'), $mmpre)) {
	 $libs = libs('-lMesaGLU -lMesaGL');
  } elsif (trylink ('libMesaGL with pthread',
			  '', 'char glBegin(); glBegin();',
			  libs('-lMesaGL -lpthread'), $mmpre)) {
	 $libs = libs('-lMesaGLU -lMesaGL -lpthread');
  }

  # Add -lm to libs (Seems to be needed on Linux and Solaris, and shouldn't hurt for others)
  # [only do if we've actually found anything]
  $libs .= ' -lm' if defined $libs and $libs !~ /\-lm\b/;
  return $libs;
}

sub libs ($) {
  require ExtUtils::MakeMaker;
  require ExtUtils::Liblist;
  my ($libs) = @_;
  my $lpath = '-L/usr/X11R6/lib -L/usr/lib/mesa';
  my $extra = '-lXext -lX11 -lm';
  return ${[ExtUtils::Liblist->ext("$lpath $libs $extra")]}[0];
}