#32 REFACTOR Nix setup (#33)

3 files changed, 134 insertions, 30 deletions

diff --git a/flake.lock b/flake.lock
index 8dc25a3..e3ba5a3 100644
--- a/flake.lock
+++ b/flake.lock
@@ -1,5 +1,23 @@
 {
   "nodes": {
+    "flake-parts": {
+      "inputs": {
+        "nixpkgs-lib": "nixpkgs-lib"
+      },
+      "locked": {
+        "lastModified": 1763759067,
+        "narHash": "sha256-LlLt2Jo/gMNYAwOgdRQBrsRoOz7BPRkzvNaI/fzXi2Q=",
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "rev": "2cccadc7357c0ba201788ae99c4dfa90728ef5e0",
+        "type": "github"
+      },
+      "original": {
+        "owner": "hercules-ci",
+        "repo": "flake-parts",
+        "type": "github"
+      }
+    },
     "nixpkgs": {
       "locked": {
         "lastModified": 1762363567,
@@ -16,9 +34,60 @@
         "type": "github"
       }
     },
+    "nixpkgs-lib": {
+      "locked": {
+        "lastModified": 1761765539,
+        "narHash": "sha256-b0yj6kfvO8ApcSE+QmA6mUfu8IYG6/uU28OFn4PaC8M=",
+        "owner": "nix-community",
+        "repo": "nixpkgs.lib",
+        "rev": "719359f4562934ae99f5443f20aa06c2ffff91fc",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "nixpkgs.lib",
+        "type": "github"
+      }
+    },
+    "nixpkgs_2": {
+      "locked": {
+        "lastModified": 1761236834,
+        "narHash": "sha256-+pthv6hrL5VLW2UqPdISGuLiUZ6SnAXdd2DdUE+fV2Q=",
+        "owner": "nixos",
+        "repo": "nixpkgs",
+        "rev": "d5faa84122bc0a1fd5d378492efce4e289f8eac1",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nixos",
+        "ref": "nixpkgs-unstable",
+        "repo": "nixpkgs",
+        "type": "github"
+      }
+    },
     "root": {
       "inputs": {
-        "nixpkgs": "nixpkgs"
+        "flake-parts": "flake-parts",
+        "nixpkgs": "nixpkgs",
+        "treefmt-nix": "treefmt-nix"
+      }
+    },
+    "treefmt-nix": {
+      "inputs": {
+        "nixpkgs": "nixpkgs_2"
+      },
+      "locked": {
+        "lastModified": 1762938485,
+        "narHash": "sha256-AlEObg0syDl+Spi4LsZIBrjw+snSVU4T8MOeuZJUJjM=",
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "rev": "5b4ee75aeefd1e2d5a1cc43cf6ba65eba75e83e4",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "treefmt-nix",
+        "type": "github"
       }
     }
   },
diff --git a/flake.nix b/flake.nix
index 249b892..f0afc44 100644
--- a/flake.nix
+++ b/flake.nix
@@ -1,36 +1,62 @@
 {
-  description = "A very basic flake";
+  description = "Domino's flakes";
 
   inputs = {
     nixpkgs.url = "github:nixos/nixpkgs?ref=nixos-unstable";
-  };
 
-  outputs = { self, nixpkgs, ... }:
-  let
-    systems = [ "x86_64-linux" "aarch64-linux" "x86_64-darwin" "aarch64-darwin" ];
-    forAllSystems = nixpkgs.lib.genAttrs systems;
-  in {
-    packages = forAllSystems (system:
-      let
-        pkgs = nixpkgs.legacyPackages.${system};
-      in {
-        hello = pkgs.hello;
-        default = pkgs.hello;
-      }
-    );
-
-    devShells = forAllSystems (system:
-      let
-        pkgs = nixpkgs.legacyPackages.${system};
-      in {
-        default = pkgs.mkShell {
-          packages = with pkgs; [
-            erlang_28
-            erlang-language-platform
-            rebar3
-          ];
-        };
-      }
-    );
+    flake-parts = {
+      url = "github:hercules-ci/flake-parts";
+    };
+
+    treefmt-nix.url = "github:numtide/treefmt-nix";
   };
+
+  outputs = 
+    { self, 
+      nixpkgs,
+      flake-parts,
+      treefmt-nix,
+      ... 
+    }@inputs:
+    flake-parts.lib.mkFlake { inherit inputs; } {
+      systems = [ "x86_64-linux" "aarch64-linux" "x86_64-darwin" "aarch64-darwin" ];
+
+      perSystem =
+        { pkgs, system, ... }:
+          let
+            treefmtEval = treefmt-nix.lib.evalModule pkgs ./treefmt.nix;
+          in
+          {
+            # This sets `pkgs` to a nixpkgs with allowUnfree option set.
+            _module.args.pkgs = import nixpkgs {
+              inherit system;
+              config.allowUnfree = true;
+            };
+
+            # nix build
+            packages = {
+              hello = pkgs.hello;
+              default = pkgs.hello;
+            };
+
+            devShells = 
+              {
+                default = pkgs.mkShell {
+                  packages = with pkgs; [
+                    erlang_28
+                    erlang-language-platform
+                    rebar3
+                  ];
+                };
+              };
+
+            # nix fmt
+            formatter = treefmtEval.config.build.wrapper;
+
+            # nix flake check --all-systems
+            checks = {
+              formatting = treefmtEval.config.build.check self;
+            };
+          };
+    };
 }
diff --git a/treefmt.nix b/treefmt.nix
new file mode 100644
index 0000000..4341016
--- /dev/null
+++ b/treefmt.nix
@@ -0,0 +1,9 @@
+# treefmt.nix
+{ pkgs, ... }:
+{
+  # Used to find the project root
+  projectRootFile = "flake.nix";
+  programs = {
+    erlfmt.enable = true;
+  };
+}