refactor(flake): split host guest and module assembly

flake/default.nix

@@ -0,0 +1,58 @@
+{
+  lib,
+  inputs,
+  self,
+}:
+let
+  # TODO: refactor the registry code
+  registryAssembly = import ./registry.nix { inherit lib self; };
+
+  util = import ../lib { inherit lib; };
+  mkModules = import ./module.nix { inherit util; };
+
+  modules = mkModules {
+    root = self + "/modules";
+  };
+
+  guestModules = guests.mkGuests {
+    root = self + "/guests";
+  };
+
+  #----------------------------------------------------------
+
+  collectedRegistry = registryAssembly.collect { hosts = self.nixosConfigurations; };
+
+  specialArgs = {
+    inherit
+      inputs
+      self
+      util
+      ;
+    registry = collectedRegistry;
+  };
+
+  guests = import ./guest.nix {
+    inherit
+      inputs
+      lib
+      specialArgs
+      registryAssembly
+      util
+      ;
+    repositoryModules = modules;
+  };
+
+  hosts = import ./host.nix {
+    inherit
+      inputs
+      lib
+      specialArgs
+      guestModules
+      registryAssembly
+      ;
+    repositoryModules = modules;
+  };
+in
+{
+  inherit (hosts) mkHosts;
+}