environment to module

default.nix

@@ -250,6 +250,7 @@ in
   imports = [
     ./mail-server/clamav.nix
     ./mail-server/users.nix
+    ./mail-server/environment.nix
   ];
 
   config = mkIf cfg.enable {
@@ -260,11 +261,6 @@ in
               certificateScheme certificateFile keyFile certificateDirectory virusScanning;
     };
 
-    environment = import ./mail-server/environment.nix {
-      inherit pkgs;
-      inherit (cfg) certificateScheme;
-    };
-
     networking = import ./mail-server/networking.nix {
       inherit (cfg) domain hostPrefix enableImap enablePop3;
     };

mail-server/environment.nix

@@ -14,10 +14,15 @@
 #  You should have received a copy of the GNU General Public License
 #  along with this program. If not, see <http://www.gnu.org/licenses/>
 
-{ pkgs, certificateScheme }:
+{ config, pkgs, lib, ... }:
 
+let
+  cfg = config.mailserver;
+in
 {
-  systemPackages = with pkgs; [
+  config = with cfg; lib.mkIf enable {
+    environment.systemPackages = with pkgs; [
       dovecot opendkim openssh postfix clamav rspamd rmilter
     ] ++ (if certificateScheme == 2 then [ openssl ] else []);
+  };
 }