add nix/nixos development enviroment and automation for easy maintenance

.envrc

@@ -0,0 +1 @@
+use flake

.github/workflows/nix-check.yml

@@ -0,0 +1,24 @@
+name: Run nix checks on prs
+
+on:
+  pull_request:
+    branches: [ "master", "rewrite/v3" ]
+
+defaults:
+  run:
+    shell: bash
+
+jobs:
+  check:
+    name: Check Nix
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout codebase
+        uses: actions/checkout@v4
+      - name: Install nix
+        uses: cachix/install-nix-action@v27
+        with: 
+          nix_path: nixpkgs=channel:nixos-unstable
+          extra_nix_config: "extra-experimental-features = nix-command flakes"
+      - name: Run flake check
+        run: nix flake check

.github/workflows/update-nix.yml

@@ -0,0 +1,22 @@
+name: update-flake-lock
+on:
+  workflow_dispatch: # allows manual triggering
+  schedule:
+    - cron: '0 0 * * 0' # runs weekly on Sunday at 00:00
+
+permissions:
+  contents: write
+  pull-requests: write
+
+jobs:
+  lockfile:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+      - name: Install Nix
+        uses: DeterminateSystems/nix-installer-action@main
+      - name: Update flake.lock
+        uses: DeterminateSystems/update-flake-lock@main
+        with:
+          pr-title: "Update flake.lock"

.gitignore

@@ -12,3 +12,7 @@ config.toml
 .etc/blocks.json
 
 flame.svg
+
+.direnv
+result
+result-*

flake.nix

@@ -0,0 +1,75 @@
+{
+  inputs = {
+    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
+    flake-parts.url = "github:hercules-ci/flake-parts";
+    flake-compat = {
+      url = "github:edolstra/flake-compat";
+      flake = false;
+    };
+    rust-overlay = {
+      url = "github:oxalica/rust-overlay";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+  };
+
+  outputs =
+    inputs@{
+      flake-parts,
+      nixpkgs,
+      rust-overlay,
+      ...
+    }:
+    flake-parts.lib.mkFlake { inherit inputs; } {
+      systems = nixpkgs.lib.systems.flakeExposed;
+
+      perSystem =
+        {
+          pkgs,
+          system,
+          ...
+        }:
+        {
+					formatter = nixpkgs.legacyPackages.${system}.nixfmt-rfc-style;
+          _module.args.pkgs = import inputs.nixpkgs {
+            inherit system;
+            overlays = [
+							rust-overlay.overlays.default
+          		(self: super: {
+            		rustToolchain = let rust = super.rust-bin;
+            		in if builtins.pathExists ./rust-toolchain.toml then
+              		rust.fromRustupToolchainFile ./rust-toolchain.toml
+            		else if builtins.pathExists ./rust-toolchain then
+              		rust.fromRustupToolchainFile ./rust-toolchain
+            		else
+              		rust.nightly.latest.default;
+          })
+            ];
+            config = { };
+          };
+
+          # Used to check formatting for nix specificly
+          checks.fmt-check =
+            pkgs.runCommand "format-check"
+              {
+                src = ./.;
+                doCheck = true;
+                nativeBuildInputs = [
+                  pkgs.nixfmt-rfc-style
+                ];
+              }
+              ''
+                					nixfmt --check .
+                					touch $out
+                				'';
+
+          devShells.default = pkgs.mkShell {
+            packages = with pkgs; [
+              rustToolchain
+              pkg-config
+              openssl
+            ];
+          };
+
+        };
+    };
+}

shell.nix

@@ -0,0 +1,12 @@
+(import (
+  let
+    lock = builtins.fromJSON (builtins.readFile ./flake.lock);
+    nodeName = lock.nodes.root.inputs.flake-compat;
+  in
+  fetchTarball {
+    url =
+      lock.nodes.${nodeName}.locked.url
+        or "https://github.com/edolstra/flake-compat/archive/${lock.nodes.${nodeName}.locked.rev}.tar.gz";
+    sha256 = lock.nodes.${nodeName}.locked.narHash;
+  }
+) { src = ./.; }).shellNix