feat(flakeModules): Add git-hook module and dogfood it

Author: PetarKirov

.gitignore

@@ -13,3 +13,6 @@ matrix-*.json
 shardMatrix.json
 
 .vscode
+
+# Pre Commit
+.pre-commit-config.yaml

checks/default.nix

@@ -2,5 +2,6 @@
 {
   imports = [
     ./packages-ci-matrix.nix
+    ./pre-commit.nix
   ];
 }

checks/pre-commit.nix

@@ -0,0 +1,60 @@
+{ inputs, ... }:
+{
+  flake.flakeModules.git-hooks =
+    { config, ... }:
+    {
+      imports = [
+        # Import git-hooks flake-parts module
+        # docs: https://flake.parts/options/git-hooks-nix
+        inputs.git-hooks-nix.flakeModule
+      ];
+
+      config = {
+        perSystem =
+          { ... }:
+          {
+            devShells.pre-commit =
+              let
+                inherit (config.pre-commit.settings) enabledPackages package;
+              in
+              pkgs.mkShell {
+                packages = enabledPackages ++ [ package ];
+                shellHook = ''
+                  echo "Running Pre-commit checks"
+                  echo "========================="
+                '';
+              };
+
+            # impl: https://github.com/cachix/git-hooks.nix/blob/master/flake-module.nix
+            pre-commit = {
+              # Disable `checks` flake output
+              check.enable = false;
+
+              # Enable commonly used formatters
+              settings.hooks = {
+                # Basic whitespace formatting
+                editorconfig-checker.enable = true;
+
+                # *.nix formatting
+                nixfmt-rfc-style.enable = true;
+
+                # *.rs formatting
+                rustfmt.enable = true;
+
+                # *.{js,jsx,ts,tsx,css,html,md,json} formatting
+                prettier = {
+                  enable = true;
+                  args = [
+                    "--check"
+                    "--list-different=false"
+                    "--log-level=warn"
+                    "--ignore-unknown"
+                    "--write"
+                  ];
+                };
+              };
+            };
+          };
+      };
+    };
+}

shells/default.nix

@@ -1,9 +1,16 @@
-{ ... }:
+{ inputs, ... }:
 {
+  imports = [
+    (import ../checks/pre-commit.nix {
+      inherit inputs;
+    }).flake.flakeModules.git-hooks
+  ];
+
   perSystem =
     {
       pkgs,
       inputs',
+      config,
       ...
     }:
     {
@@ -36,10 +43,12 @@
               inputs'.dlang-nix.packages.dmd
             ];
 
-          shellHook = ''
-            export REPO_ROOT="$PWD"
-            figlet -t "Metacraft Nixos Modules"
-          '';
+          shellHook =
+            ''
+              export REPO_ROOT="$PWD"
+              figlet -t "Metacraft Nixos Modules"
+            ''
+            + config.pre-commit.installationScript;
         };
     };
 }