refactor: hosts' systems & modules

lib/default.nix

@@ -0,0 +1,5 @@
+inputs: self: super:
+let
+  system = import ./system.nix inputs self super;
+in
+system

lib/system.nix

@@ -0,0 +1,66 @@
+inputs: self: super:
+let
+  inherit (self)
+    hasSuffix
+    filesystem
+    attrValues
+    filter
+    getAttrFromPath
+    hasAttrByPath
+    ;
+
+  collectModules = path: filesystem.listFilesRecursive path |> filter (hasSuffix ".nix");
+
+  collectInputModules =
+    packagePath:
+    (attrValues inputs) |> filter (hasAttrByPath packagePath) |> map (getAttrFromPath packagePath);
+
+  specialArgs = inputs // {
+    inherit inputs;
+    inherit self;
+  };
+
+  # All modules
+  modulesCommon = collectModules ../modules/common;
+  modulesLinux = collectModules ../modules/linux;
+  modulesDarwin = collectModules ../modules/darwin;
+
+  inputModulesNixos = collectInputModules [
+    "nixosModules"
+    "default"
+  ];
+  inputModulesDarwin = collectInputModules [
+    "darwinModules"
+    "default"
+  ];
+
+  # Overlays
+  overlays = collectInputModules [
+    "overlays"
+    "default"
+  ];
+
+  overlayModules = {
+    nixpkgs.overlays = overlays;
+  };
+in
+{
+  system =
+    os: configFile:
+    if os == "darwin" then
+      super.darwinSystem
+    else
+      super.nixosSystem {
+        inherit specialArgs;
+
+        modules =
+          [
+            overlayModules
+            configFile
+          ]
+          ++ modulesCommon
+          ++ (
+            if os == "darwin" then modulesDarwin ++ inputModulesDarwin else modulesLinux ++ inputModulesNixos
+          );
+      };
+}