%% -*- erlang -*-
%% Config file for cl-application

%% This would have been nicer if it was an escript..
%% Start at the bottom and read upwards
{value, {port_env, PortEnv0}, Config0} = lists:keytake(port_env, 1, CONFIG).

GetEnv = fun(Var) -> 
		 case os:getenv(Var) of
		     [] -> false;
		     Other -> Other
		 end
	 end.

AddConf = fun(_Var, [], Config) -> Config;
	     (Var, Value, Config) -> 
		  lists:keystore(Var, 1, Config, {Var, Value})
	  end.

Error = fun(Format, Args) ->
		io:format("~n***ERROR:~n" ++ Format ++"~n~n",Args),
		throw(error)
	end.

ConcatDir = fun(Prefix, PostFix, Dir) ->
		    Prefix ++ filename:join(Dir, PostFix)
	    end.

SetupUnix = fun(OCLDir) ->
		    OCLINC_0 = "-I" ++ ConcatDir("", "include", OCLDir),
		    OCLINC = case os:type() of
				 {unix,  linux} -> %% Add nvidia-current for non standard installation locations
				     OCLINC_0 ++
					 " -I/usr/include/nvidia-current";
				 _  -> OCLINC_0
			     end,
		    OCLLIB = "-L" ++ ConcatDir("", "lib", OCLDir),
		    AddConf("OPENCL_LIBDIR", OCLLIB,
			    AddConf("OPENCL_INCDIR", OCLINC, PortEnv0))
	    end.
%% Windows stuff below
WinType = fun() -> 
		  case GetEnv("TERM") of
		      "msys"   -> mingw;
		      "cygwin" -> cygwin;
		      _ -> windows
		  end
	  end.

WinEnvPrefix = fun(_, mingw)   -> 
		       %% Both cl.exe and gcc.exe accepts Windows paths
		       [Full|_] = string:tokens(os:cmd("where sh"), "\r\n"),
		       filename:dirname(filename:dirname(Full));
		  (cl, cygwin) ->
		       io:format("WARNING: Cygwin not supported~n",[]),
		       os:cmd("cygdrive -m /");
		  (_, _) ->
		       ""
	       end.

WinSetupGCC = fun(OpenCLDir) ->
		      io:format("Using gcc as compiler~n"),
		      Dir = case filelib:is_dir(OpenCLDir) of
				true -> OpenCLDir;
				false -> 
				    EnvPrefix = WinEnvPrefix(gcc, WinType()),
				    ExtDir = EnvPrefix++OpenCLDir,
				    filelib:is_dir(ExtDir) orelse 
					Error("Could not find OpenCL Dir in:~n"
					      "  ~s~n  ~s~n"
					      " set OPENCL_DIR=/path/to/opencl", 
					      [OpenCLDir, ExtDir]),
				    ExtDir
			    end,
		      Inc = ConcatDir("-I", "include", Dir),
		      Type = case erlang:system_info(wordsize) of
				 4 -> "x86";
				 8 -> "x64"
			     end,
		      Lib = case filelib:is_dir(filename:join([Dir, "lib", Type])) of
				true  -> ConcatDir("-L", filename:join("lib", Type), Dir);
				false -> ConcatDir("-L", "lib", Dir)
			    end,
		      
		      E0 = AddConf("OPENCL_LIBDIR", Lib,
				   AddConf("OPENCL_INCDIR", Inc, PortEnv0)),
		      E1 = case erlang:system_info(wordsize) of
			       4 -> E0;
			       8 -> AddConf("WIN_TARGET", "-DWIN_X64", E0)
			   end,
		      CC = case GetEnv("CC") of
			       false -> "gcc";
			       EnvCC -> EnvCC
			   end,

		      GCCConf =[{"win32", "CC" , CC},
				{"win32", "DRV_CC_TEMPLATE",
				 "$CC -c $CFLAGS $DRV_CFLAGS $PORT_IN_FILES -o $PORT_OUT_FILE"},
				{"win32", "DRV_LINK_TEMPLATE",
				 "$CC $PORT_IN_FILES $LDFLAGS $DRV_LDFLAGS -o $PORT_OUT_FILE"},
				{"win32", "DRV_CFLAGS" , "-g -Wall $ERL_CFLAGS"},
				{"win32", "DRV_LDFLAGS", "-shared $ERL_LDFLAGS"},
				{"win32", "LDFLAGS", "$LDFLAGS $OPENCL_LIBDIR -lOpenCL"},
				{"win32", "ERL_LDFLAGS", ""}],
		      Replace = fun(New = {Os, Val, _}, Env) ->
					Add = fun({POs, PVal, _}, {_,Acc}) 
						    when POs =:= Os, Val =:= PVal ->
						      {true, [New|Acc]};
						 (Old,{Found,Acc}) -> {Found, [Old|Acc]}
					      end,
					case lists:foldl(Add, {false,[]}, Env) of
					    {true,  Repl} -> Repl;
					    {false, Repl} -> [New|Repl]
					end
				end,
		      lists:foldl(Replace, E1, GCCConf)
	      end.


Win32VerifyLinkCmd = fun() ->
			     LinkOut = os:cmd("link --version"),
			     case LinkOut of
				 "Microsoft" ++ _ -> ok;
				 _ -> 
				     Dir = filename:dirname(os:find_executable("cl.exe")),
				     Path = os:getenv("PATH"),
				     os:putenv("PATH", filename:nativename(Dir) ++ ";" ++ Path),
				     io:format("WARNING: Wrong link.exe (non Microsoft) found, "
					       "setting cl.exe's dir first in PATH~n", [])
			     end
		     end.

WinSetupCL = fun(OpenCLDir) ->
		     io:format("Using cl.exe as compiler~n"),
		     Win32VerifyLinkCmd(),
		     Dir = case filelib:is_dir(OpenCLDir) of
			       true -> OpenCLDir;
			       false -> 
				   EnvPrefix = WinEnvPrefix(cl, WinType()),
				   ExtDir = EnvPrefix++OpenCLDir,
				   filelib:is_dir(ExtDir) orelse 
				       Error("Could not find OpenCL Dir in:~n"
					     "  ~s~n  ~s~n"
					     " set OPENCL_DIR=/path/to/opencl", 
					     [OpenCLDir, ExtDir]),
				   ExtDir
			   end,
		     Inc = ConcatDir("/I ", "include", Dir),
		     Type = case erlang:system_info(wordsize) of
				4 -> "x86";
				8 -> "x64"
			    end,
		     Lib = case filelib:is_dir(filename:join([Dir, "lib", Type])) of
			       true  -> ConcatDir("", filename:join("lib", Type), Dir);
			       false -> ConcatDir("", "lib", Dir)
			   end,

		     E0 = AddConf("OPENCL_LIBDIR", Lib,
				  AddConf("OPENCL_INCDIR", Inc, PortEnv0)),
		     case erlang:system_info(wordsize) of
			 4 -> E0;
			 8 -> AddConf("WIN_TARGET", "-DWIN_X64", E0)
		     end
	     end.

SetupWin32 = fun(OpenCLDir) ->
		     %% Do we want to compile with Microsoft's toolchain
		     case os:find_executable("cl.exe") of
			 false ->
			     (os:find_executable("gcc") == false) andalso 
				 Error("No known compiler found",[]),
			     WinSetupGCC(OpenCLDir);
			 _ ->
			     case GetEnv("CC") of
				 "gcc"     -> WinSetupGCC(OpenCLDir);
				 "gcc.exe" -> WinSetupGCC(OpenCLDir);
				 "cc"      -> WinSetupGCC(OpenCLDir);
				 "cc.exe"  -> WinSetupGCC(OpenCLDir);
				 false     -> WinSetupCL(OpenCLDir);
				 Other     -> Error("No known compiler found: CC=~s",[Other])
			     end
		     end
	     end.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

OCLDir = case GetEnv("OPENCL_DIR") of
	     false -> 
		 case os:type() of
		     {unix,  _} -> [];
		     {darwin,_} -> [];
		     {win32, _} -> "/opt/local/"
		 end;
	     Dir -> Dir
	 end.

PortEnv = case os:type() of
	      {win32, _} -> %% Massage Windows paths 
		  SetupWin32(OCLDir);
	      _ ->
		  SetupUnix(OCLDir)
	  end.

%% io:format("Config ~p~n",[PortEnv]).
[{port_env, PortEnv}|Config0].