added env and used env in config for more robust builds

.env.example

@@ -0,0 +1,4 @@
+TARGET_USER=firstlast
+SYSTEM_STATE_VERSION=6
+SYSTEM_PRIMARY_USER=admin
+SYSTEM_ARCH=aarch64-darwin

.gitignore

@@ -0,0 +1 @@
+.env

configuration.nix

@@ -1,18 +1,23 @@
 { config, pkgs, ... }: 
 
+let 
+  system = builtins.getEnv "SYSTEM_ARCH";
+  stateVersion = builtins.getEnv "SYSTEM_STATE_VERSION";
+  primaryUser = builtins.getEnv "SYSTEM_PRIMARY_USER"; 
+in
 {
   imports = [
     ./cli-tools.nix
   ];
 
-  nixpkgs.hostPlatform = "aarch64-darwin";
+  nixpkgs.hostPlatform = system;
 
   nix.enable = false;
 
   nix.settings.experimental-features = "nix-command flakes";
 
-  system.stateVersion = 6;
-  system.primaryUser = "briannelson";
+  system.stateVersion = stateVersion;
+  system.primaryUser = primaryUser;
 
   environment.systemPackages = with pkgs; [
     ffmpeg

flake.nix

@@ -8,20 +8,24 @@
     nix-homebrew.url = "github:zhaofengli/nix-homebrew";
   };
 
-  outputs = inputs@{ self, nix-darwin, nixpkgs, nix-homebrew, ... }: {
-    darwinConfigurations."briannelson" = nix-darwin.lib.darwinSystem {
-      modules = [
-        ./configuration.nix
-        nix-homebrew.darwinModules.nix-homebrew
-        {
-          nix-homebrew = {
-            enable = true;
-            enableRosetta = true;
-            user = "briannelson";
-            autoMigrate = true;
-          };
-        }
-      ];
+  outputs = inputs@{ self, nix-darwin, nixpkgs, nix-homebrew, ... }: 
+    let
+      primaryUser = builtins.getEnv "SYSTEM_PRIMARY_USER";
+    in
+    {
+      darwinConfigurations.primaryUser = nix-darwin.lib.darwinSystem {
+        modules = [
+          ./configuration.nix
+          nix-homebrew.darwinModules.nix-homebrew
+          {
+            nix-homebrew = {
+              enable = true;
+              enableRosetta = true;
+              user = "briannelson";
+              autoMigrate = true;
+            };
+          }
+        ];
+      };
     };
-  };
 }