Add a shareable pre-commit hook

flake.nix

@@ -1,11 +1,54 @@
 {
   description = "Shared Nix settings (NixOS, Home Manager etc)";
 
-  outputs = { self }: {
-    nixosModules = {
-      nix-settings = import ./modules/nix-settings.nix;
-      nix-gc = import ./modules/nix-gc.nix;
-      futureware = import ./modules/futureware.nix;
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs";
+    systems.url = "github:nix-systems/default";
+    git-hooks = {
+      url = "github:cachix/git-hooks.nix";
+      inputs.nixpkgs.follows = "nixpkgs";
     };
   };
+
+  outputs =
+    {
+      self,
+      nixpkgs,
+      systems,
+      git-hooks,
+      ...
+    }:
+    let
+      eachSystem = nixpkgs.lib.genAttrs (import systems);
+    in
+    {
+      nixosModules = {
+        nix-settings = import ./modules/nix-settings.nix;
+        nix-gc = import ./modules/nix-gc.nix;
+        futureware = import ./modules/futureware.nix;
+      };
+
+      lib.pre-commit = import ./pre-commit.nix;
+
+      checks = eachSystem (system: {
+        pre-commit-check = git-hooks.lib.${system}.run {
+          src = ./.;
+          inherit (self.lib.pre-commit) hooks;
+        };
+      });
+
+      devShells = eachSystem (
+        system:
+        let
+          pkgs = import nixpkgs { inherit system; };
+          inherit (self.checks.${system}.pre-commit-check) shellHook enabledPackages;
+        in
+        {
+          default = pkgs.mkShell {
+            packages = enabledPackages;
+            inherit shellHook;
+          };
+        }
+      );
+    };
 }