refactor: mkHost load-all infrastructure and convert simple features

features/nix-settings.nix

@@ -0,0 +1,71 @@
+{
+  nixos =
+    { config, lib, ... }:
+    let
+      cfg = config.features.nix-settings;
+    in
+    {
+      options.features.nix-settings = {
+        enable = lib.mkEnableOption "nix settings";
+
+        towerCache.enable = lib.mkOption {
+          type = lib.types.bool;
+          default = true;
+
+        };
+
+        gc = {
+          dates = lib.mkOption {
+            type = lib.types.str;
+            default = "monthly";
+          };
+
+          olderThan = lib.mkOption {
+            type = lib.types.str;
+            default = "30d";
+          };
+        };
+
+        optimise.dates = lib.mkOption {
+          type = lib.types.listOf lib.types.str;
+          default = [ "monthly" ];
+        };
+      };
+
+      config = lib.mkIf cfg.enable {
+        nix = {
+          settings = {
+            experimental-features = [
+              "nix-command"
+              "flakes"
+            ];
+            download-buffer-size = 2 * 1024 * 1024 * 1024;
+            warn-dirty = false;
+            substituters =
+              [
+                "https://cache.nixos.org"
+                "https://nix-community.cachix.org?priority=45"
+              ]
+              ++ lib.optional cfg.towerCache.enable "http://tower:5000?priority=50";
+            trusted-public-keys =
+              [
+                "cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY="
+                "nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="
+              ]
+              ++ lib.optional cfg.towerCache.enable "matej.nix-1:TdbemLVYblvAxqJcwb3mVKmmr3cfzXbMcZHE5ILnZDE=";
+          };
+
+          gc = {
+            automatic = true;
+            dates = cfg.gc.dates;
+            options = "--delete-older-than ${cfg.gc.olderThan}";
+          };
+
+          optimise = {
+            automatic = true;
+            dates = cfg.optimise.dates;
+          };
+        };
+      };
+    };
+}