Refactor to flake-utils.

Reduce boilerplate and add `apps` and `devShells`.

flake.lock

@@ -1,24 +1,58 @@
 {
   "nodes": {
+    "flake-utils": {
+      "inputs": {
+        "systems": "systems"
+      },
+      "locked": {
+        "lastModified": 1701680307,
+        "narHash": "sha256-kAuep2h5ajznlPMD9rnQyffWG8EM/C73lejGofXvdM8=",
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "rev": "4022d587cbbfd70fe950c1e2083a02621806a725",
+        "type": "github"
+      },
+      "original": {
+        "owner": "numtide",
+        "repo": "flake-utils",
+        "type": "github"
+      }
+    },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1702645756,
-        "narHash": "sha256-qKI6OR3TYJYQB3Q8mAZ+DG4o/BR9ptcv9UnRV2hzljc=",
+        "lastModified": 1702846620,
+        "narHash": "sha256-45K8VhHgE8cSPUgm5ixOTtmplWGXJN4ozNvjmEVSYGc=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "40c3c94c241286dd2243ea34d3aef8a488f9e4d0",
+        "rev": "50b80afb13c6bcf8cc4be7e1fbd7719a85c487cb",
         "type": "github"
       },
       "original": {
         "id": "nixpkgs",
-        "ref": "nixos-23.11",
+        "ref": "release-23.11",
         "type": "indirect"
       }
     },
     "root": {
       "inputs": {
+        "flake-utils": "flake-utils",
         "nixpkgs": "nixpkgs"
       }
+    },
+    "systems": {
+      "locked": {
+        "lastModified": 1681028828,
+        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
+        "owner": "nix-systems",
+        "repo": "default",
+        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-systems",
+        "repo": "default",
+        "type": "github"
+      }
     }
   },
   "root": "root",

flake.nix

@@ -2,30 +2,24 @@
   description = "Super Nintendo Interface";
 
   # Nixpkgs / NixOS version to use.
-  inputs.nixpkgs.url = "nixpkgs/nixos-23.11";
+  inputs.nixpkgs.url = "nixpkgs/release-23.11";
+  inputs.flake-utils.url = "github:numtide/flake-utils";
 
   outputs = {
     self,
     nixpkgs,
+    flake-utils,
   }: let
     # to work with older version of flakes
     lastModifiedDate = self.lastModifiedDate or self.lastModified or "19700101";
 
     version = "0.0.95";
-
-    # System types to support.
-    supportedSystems = ["x86_64-linux" "x86_64-darwin" "aarch64-linux" "aarch64-darwin"];
-
-    # Helper function to generate an attrset '{ x86_64-linux = f "x86_64-linux"; ... }'.
-    forAllSystems = nixpkgs.lib.genAttrs supportedSystems;
-
-    # Nixpkgs instantiated for supported system types.
-    nixpkgsFor = forAllSystems (system: import nixpkgs {inherit system;});
+  in
+    flake-utils.lib.eachDefaultSystem (system: let
+      pkgs = nixpkgs.legacyPackages.${system};
     in {
       # Provide some binary packages for selected system types.
-    packages = forAllSystems (system: let
-      pkgs = nixpkgsFor.${system};
-    in rec {
+      packages = rec {
         default = sni;
 
         sni = pkgs.buildGoModule {
@@ -66,6 +60,25 @@
             maintainers = with maintainers; [island_usurper];
           };
         };
-    });
+
+        apps = rec {
+          sni = {
+            type = "app";
+            program = "${self.packages.${system}.sni}/bin/sni";
           };
+          default = sni;
+        };
+
+        devShells = {
+          default = pkgs.mkShell {
+            buildInputs = with pkgs; [
+              go
+              gtk3.dev
+              libayatana-appindicator.dev
+              pkg-config
+            ];
+          };
+        };
+      };
+    });
 }