refactoring for iServer and isWorkstation: part 1

hosts/modules/nix.nix

@@ -0,0 +1,64 @@
+{
+  inputs,
+  lib,
+  hostType,
+  ...
+}:
+
+{
+  config = lib.mkMerge [
+    # Common configuration
+    {
+      nix = {
+        settings = {
+          auto-optimise-store = true;
+          connect-timeout = 10;
+          log-lines = 25;
+          min-free = 128000000;
+          max-free = 1000000000;
+          trusted-users = [ "@wheel" ];
+        };
+        extraOptions = "experimental-features = nix-command flakes";
+        gc = {
+          automatic = true;
+          options = "--delete-older-than 8d";
+        };
+      };
+
+      nixpkgs.config = {
+        allowUnfree = true;
+        enableParallelBuilding = true;
+        buildManPages = false;
+        buildDocs = false;
+      };
+
+      system.stateVersion = "22.11";
+    }
+
+    # Server specific configuration
+    (lib.mkIf hostType.isServer {
+      environment.etc."channels/nixpkgs".source = inputs.nixpkgs-stable.outPath;
+
+      nix = {
+        registry.nixpkgs.flake = inputs.nixpkgs-stable;
+        nixPath = [
+          "nixpkgs=/etc/channels/nixpkgs"
+          "/nix/var/nix/profiles/per-user/root/channels"
+        ];
+      };
+    })
+
+    # Workstation specific configuration
+    (lib.mkIf hostType.isWorkstation {
+      environment.etc."channels/nixpkgs".source = inputs.nixpkgs.outPath;
+
+      nix = {
+        registry.nixpkgs.flake = inputs.nixpkgs;
+        nixPath = [
+          "nixpkgs=${inputs.nixpkgs}"
+          "/nix/var/nix/profiles/per-user/root/channels"
+        ];
+      };
+    })
+  ];
+}