Fix correct username not being set

Rather than set username in flake.nix, set a default value in
default.nix (since it's always called), and set appropriate values in
personal.nix (pixelifytica) and work.nix (elitherl), since the two
files are mutually exclusive and only one or the other will be
imported.

default.nix

@@ -1,4 +1,8 @@
-{username, ...}: {
+{
+  config,
+  lib,
+  ...
+}: {
   imports = [
     # Programs
     ./programs/desktop/default.nix
@@ -14,8 +18,8 @@
   programs.home-manager.enable = true;
   nixpkgs.config.allowUnfree = true;
   home = {
-    inherit username;
-    homeDirectory = "/home/${username}";
+    username = lib.mkDefault "pixelifytica";
+    homeDirectory = "/home/${config.home.username}";
     stateVersion = "23.05";
   };
 }

flake.nix

@@ -38,12 +38,10 @@
     ...
   }: let
     defaultExtraSpecialArgs = {
-      system ? "x86_64-linux",
-      hostname ? "Atlas",
-      username ? "pixelifytica",
-      ...
+      hostname,
+      system,
     }: rec {
-      inherit hostname username;
+      inherit hostname;
       inherit (plasma-manager.packages.${system}) rc2nix;
       accentColourName = "base0D";
       altAccentColourName = "base0C";
@@ -90,52 +88,57 @@
       };
     homeConfigurations = {
       # Server
-      "pixelifytica@Legion" = home-manager.lib.homeManagerConfiguration {
-        pkgs = import nixpkgs {system = "x86_64-linux";};
-        modules = defaultModules;
-        extraSpecialArgs = defaultExtraSpecialArgs {
-          system = "x86_64-linux";
+      "pixelifytica@Legion" = let
         hostname = "Legion";
-        };
+        system = "x86_64-linux";
+      in
+        home-manager.lib.homeManagerConfiguration {
+          pkgs = import nixpkgs {inherit system;};
+          modules = defaultModules;
+          extraSpecialArgs = defaultExtraSpecialArgs {inherit hostname system;};
         };
       # Personal
-      "pixelifytica@Northstar" = home-manager.lib.homeManagerConfiguration {
-        pkgs = import nixpkgs {system = "x86_64-linux";};
+      "pixelifytica@Northstar" = let
+        hostname = "Northstar";
+        system = "x86_64-linux";
+      in
+        home-manager.lib.homeManagerConfiguration {
+          pkgs = import nixpkgs {inherit system;};
           modules =
             defaultModules
             ++ [
               ./personal.nix
               {programs.plasma.configFile.kcminputrc."Libinput/1739/52759/SYNA32AA:00 06CB:CE17 Touchpad".NaturalScroll = true;}
             ];
-        extraSpecialArgs = defaultExtraSpecialArgs {
-          system = "x86_64-linux";
-          hostname = "Northstar";
+          extraSpecialArgs = defaultExtraSpecialArgs {inherit hostname system;};
         };
-      };
-      "pixelifytica@Vanguard" = home-manager.lib.homeManagerConfiguration {
-        pkgs = import nixpkgs {system = "x86_64-linux";};
-        modules = defaultModules ++ [./personal.nix];
-        extraSpecialArgs = defaultExtraSpecialArgs {
-          system = "x86_64-linux";
+      "pixelifytica@Vanguard" = let
         hostname = "Vanguard";
-        };
+        system = "x86_64-linux";
+      in
+        home-manager.lib.homeManagerConfiguration {
+          pkgs = import nixpkgs {inherit system;};
+          modules = defaultModules ++ [./personal.nix];
+          extraSpecialArgs = defaultExtraSpecialArgs {inherit hostname system;};
         };
       # Work
-      "elitherl@Tone" = home-manager.lib.homeManagerConfiguration {
-        pkgs = import nixpkgs {system = "x86_64-linux";};
-        modules = defaultModules ++ [./work.nix];
-        extraSpecialArgs = defaultExtraSpecialArgs {
-          system = "x86_64-linux";
+      "elitherl@Tone" = let
         hostname = "Tone";
-        };
-      };
-      "elitherl@Scorch" = home-manager.lib.homeManagerConfiguration {
-        pkgs = import nixpkgs {system = "x86_64-linux";};
-        modules = defaultModules ++ [./work.nix];
-        extraSpecialArgs = defaultExtraSpecialArgs {
         system = "x86_64-linux";
-          hostname = "Scorch";
+      in
+        home-manager.lib.homeManagerConfiguration {
+          pkgs = import nixpkgs {inherit system;};
+          modules = defaultModules ++ [./work.nix];
+          extraSpecialArgs = defaultExtraSpecialArgs {inherit hostname system;};
         };
+      "elitherl@Scorch" = let
+        hostname = "Scorch";
+        system = "x86_64-linux";
+      in
+        home-manager.lib.homeManagerConfiguration {
+          pkgs = import nixpkgs {inherit system;};
+          modules = defaultModules ++ [./work.nix];
+          extraSpecialArgs = defaultExtraSpecialArgs {inherit hostname system;};
         };
     };
   };

personal.nix

@@ -4,7 +4,9 @@
     ./programs/games/default.nix
     ./programs/streaming/default.nix
   ];
-  home.packages = with pkgs;
+  home = {
+    username = "pixelifytica";
+    packages = with pkgs;
     with kdePackages; [
       blender
       freecad
@@ -12,4 +14,5 @@
       ktorrent
       noson
     ];
+  };
 }

work.nix

@@ -4,12 +4,15 @@
   pkgs,
   ...
 }: {
-  home.packages = with pkgs; [
+  home = {
+    username = "elitherl";
+    packages = with pkgs; [
       twinkle
       teams-for-linux
       (writeShellScriptBin "ukaea-vpn-connect"
         "sudo ${openfortivpn}/bin/openfortivpn -c ${./ukaea-vpn.conf}")
     ];
+  };
   programs = {
     git.userEmail = config.accounts.email.accounts.outlook.address;
     firefox.policies.Homepage.URL = "https://nucleus.ukaea.uk";