feat: Add pre-commit-hooks.nix

Author: avnik

.gitignore

@@ -1,4 +1,5 @@
 .direnv
+.pre-commit-config.yaml
 
 # docs-serve stuff
 /mkdocs.yml

flake.lock

@@ -24,6 +24,11 @@
       url = "github:zhaofengli/attic";
       inputs.nixpkgs.follows = "nixpkgs";
     };
+    pre-commit-hooks-nix = {
+      url = "github:cachix/pre-commit-hooks.nix";
+      inputs.nixpkgs.follows = "nixpkgs";
+      inputs.nixpkgs-stable.follows = "nixpkgs"; # prevent unnecessary download
+    };
   };
   outputs = inputs @ {flake-parts, ...}:
     flake-parts.lib.mkFlake {

flake.nix

@@ -1,6 +1,11 @@
-{inputs, ...}: {
+{
+  inputs,
+  lib,
+  ...
+}: {
   imports = [
     inputs.devshell.flakeModule
+    inputs.pre-commit-hooks-nix.flakeModule
   ];
 
   perSystem = {
@@ -15,12 +20,19 @@
           ❄️ Welcome to the {14}{bold}cardano.nix{reset} devshell ❄️
           $(type -p menu &>/dev/null && menu)
         '';
+        startup = {
+          pre-commit = lib.noDepEntry "eval ${config.pre-commit.installationScript}";
+        };
       };
       packages = with pkgs; [
         statix
         config.treefmt.build.wrapper
         reuse
       ];
     };
+    pre-commit.settings = {
+      hooks.treefmt.enable = true;
+      settings.treefmt.package = config.treefmt.build.wrapper;
+    };
   };
 }