feat(nix): command completions + flakes support

default.nix

@@ -1,14 +1,38 @@
-{}: let
-  pkgs = import <nixpkgs> {};
-in
-  pkgs.buildGoModule rec {
-    pname = "nao";
-    version = "3.0.0";
-    src = ./.;
-    buildTarget = "./cmd/nao";
-
-    vendorSha256 = "sha256-sDLbIHeY2Jdos8pgRaR6vbjwRPunAukasKz0m7sMIek=";
-
-    doCheck = false;
-    ldflags = ["-X main.version=${version}"];
-  }
+{
+  installShellFiles,
+  buildGoModule,
+  lib,
+}:
+buildGoModule rec {
+  pname = "nao";
+  version = "3.2.2";
+
+  src = builtins.path {
+    name = "nao";
+    path = ./.;
+  };
+
+  vendorSha256 = "sha256-MTVJWksGWva+Xet+T2aIOXzkxB7w9raJVwa/p1bwkOo=";
+  doCheck = false;
+
+  buildTarget = "./cmd/nao";
+  ldflags = ["-X main.version=${version}"];
+
+  nativeBuildInputs = [
+    installShellFiles
+  ];
+
+  postInstall = ''
+    installShellCompletion --cmd nao \
+      --bash <($out/bin/nao --debug completion bash) \
+      --fish <($out/bin/nao --debug completion fish) \
+      --zsh <($out/bin/nao --debug completion zsh)
+  '';
+
+  meta = with lib; {
+    description = "A CLI tool to take notes without worrying about the path where the file is";
+    homepage = "https://github.com/luisnquin/nao";
+    license = licenses.mit;
+    maintainers = with maintainers; [luisnquin];
+  };
+}

flake.nix

@@ -0,0 +1,30 @@
+{
+  description = "A CLI tool to take notes without worrying about the path where the file is";
+
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+    flake-utils.url = "github:numtide/flake-utils";
+  };
+
+  outputs = inputs:
+    with inputs;
+      flake-utils.lib.eachDefaultSystem (
+        system: let
+          pkgs = import nixpkgs {
+            inherit system;
+          };
+
+          defaultPackage = pkgs.callPackage ./default.nix {};
+        in {
+          inherit defaultPackage;
+
+          defaultApp = flake-utils.lib.mkApp {
+            drv = defaultPackage;
+          };
+
+          devShell = pkgs.mkShell {
+            buildInputs = [defaultPackage];
+          };
+        }
+      );
+}