nix: flake, package, nixos and home-manager modules

flake.nix

@@ -0,0 +1,61 @@
+{
+  description = "nyi fetch";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+  };
+
+  outputs =
+    {
+      self,
+      nixpkgs,
+    }:
+
+    let
+      systems = [
+        "x86_64-linux"
+        "aarch64-linux"
+        "aarch64-darwin"
+        "x86_64-darwin"
+      ];
+      forAllSystems = nixpkgs.lib.genAttrs systems;
+    in
+    {
+      packages = forAllSystems (
+        system:
+        let
+          pkgs = nixpkgs.legacyPackages.${system};
+        in
+        {
+          default = pkgs.callPackage ./nix/package.nix { };
+        }
+      );
+
+      devShells = forAllSystems (
+        system:
+        let
+          pkgs = nixpkgs.legacyPackages.${system};
+        in
+        {
+          default = pkgs.mkShell {
+            packages = with pkgs; [
+              cargo
+              rustc
+              clippy
+              rustfmt
+              rust-analyzer
+              fastfetch
+            ];
+          };
+        }
+      );
+
+      formatter = forAllSystems (system: nixpkgs.legacyPackages.${system}.nixfmt-tree);
+      overlays.default = final: prev: {
+        nyi = final.callPackage ./nix/package.nix { };
+      };
+
+      homeManagerModules.default = import ./nix/home-module.nix;
+      nixosModules.default = import ./nix/nixos-module.nix;
+    };
+}