build(nix): add nix flake so NixOS users can use the CLI

Author: JasmineLowen

.gitignore

@@ -162,3 +162,6 @@ cython_debug/
 
 # VS Code settings
 .vscode/launch.json
+
+# nix related
+result*

flake.lock

@@ -0,0 +1,69 @@
+{
+  description = "The CLI tool for ZMK";
+
+  inputs = {
+    flake-parts.url = "github:hercules-ci/flake-parts";
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+  };
+
+  outputs =
+    inputs@{ flake-parts, ... }:
+    flake-parts.lib.mkFlake { inherit inputs; } {
+      systems = [
+        "x86_64-linux"
+        "aarch64-linux"
+        "aarch64-darwin"
+        "x86_64-darwin"
+      ];
+      perSystem =
+        {
+          self',
+          pkgs,
+          ...
+        }:
+        let
+          python = pkgs.python3Packages;
+        in
+        {
+          packages.default = self'.packages.zmk-cli;
+          packages.zmk-cli = python.buildPythonPackage (finalAttrs: {
+            pname = "zmk";
+            version = "0.4.0";
+            src = ./.;
+
+            pyproject = true;
+
+            # basically required for all python packages
+            build-system = [
+              python.setuptools
+              python.setuptools-scm
+            ];
+
+            # This is required since some deps in the nixpkgs python
+            # distribution are slightly too old. But this should be resolved
+            # fairly soon
+            #
+            # At the time of writing this we have
+            #
+            # > Checking runtime dependencies for zmk-0.4.0-py3-none-any.whl
+            # >   - dacite<2.0.0,>=1.9.2 not satisfied by version 1.9.1
+            # >   - mako<2.0.0,>=1.3.10 not satisfied by version 1.3.10.dev0
+            # >   - ruamel-yaml<0.19.0,>=0.18.17 not satisfied by version 0.18.16
+            pythonRelaxDeps = true;
+
+            # those were infered by just building the package, the check phase
+            # will inform you about missing deps if any new ones should pop up
+            dependencies = [
+              python.dacite
+              python.giturlparse
+              python.mako
+              python.rich
+              python.ruamel-yaml
+              python.shellingham
+              python.typer
+              python.west
+            ];
+          });
+        };
+    };
+}