v2raya: v2rayA should start after nftables

nixos/modules/services/networking/v2raya.nix

···
   config = mkIf config.services.v2raya.enable {
     environment.systemPackages = [ pkgs.v2raya ];
 
-    systemd.services.v2raya = {
-      unitConfig = {
-        Description = "v2rayA service";
-        Documentation = "https://github.com/v2rayA/v2rayA/wiki";
-        After = [ "network.target" "nss-lookup.target" "iptables.service" "ip6tables.service" ];
-        Wants = [ "network.target" ];
-      };
+    systemd.services.v2raya =
+      let
+        nftablesEnabled = config.networking.nftables.enable;
+        iptablesServices = [
+          "iptables.service"
+        ] ++ optional config.networking.enableIPv6 "ip6tables.service";
+        tableServices = if nftablesEnabled then [ "nftables.service" ] else iptablesServices;
+      in
+      {
+        unitConfig = {
+          Description = "v2rayA service";
+          Documentation = "https://github.com/v2rayA/v2rayA/wiki";
+          After = [
+            "network.target"
+            "nss-lookup.target"
+          ] ++ tableServices;
+          Wants = [ "network.target" ];
+        };
+
+        serviceConfig = {
+          User = "root";
+          ExecStart = "${getExe pkgs.v2raya} --log-disable-timestamp";
+          Environment = [ "V2RAYA_LOG_FILE=/var/log/v2raya/v2raya.log" ];
+          LimitNPROC = 500;
+          LimitNOFILE = 1000000;
+          Restart = "on-failure";
+          Type = "simple";
+        };
 
-      serviceConfig = {
-        User = "root";
-        ExecStart = "${getExe pkgs.v2raya} --log-disable-timestamp";
-        Environment = [ "V2RAYA_LOG_FILE=/var/log/v2raya/v2raya.log" ];
-        LimitNPROC = 500;
-        LimitNOFILE = 1000000;
-        Restart = "on-failure";
-        Type = "simple";
+        wantedBy = [ "multi-user.target" ];
+        path = with pkgs; [ iptables bash iproute2 ]; # required by v2rayA TProxy functionality
       };
-
-      wantedBy = [ "multi-user.target" ];
-      path = with pkgs; [ iptables bash iproute2 ]; # required by v2rayA TProxy functionality
-    };
   };
 
   meta.maintainers = with maintainers; [ elliot ];