From 470802003ab42eefc91c3028c5c1a0732a718cde Mon Sep 17 00:00:00 2001
From: James Hillyerd <james@hillyerd.com>
Date: Fri, 3 Mar 2023 13:42:06 -0800
Subject: [PATCH] flake: Add module to configure daemon

---
 flake.nix  | 17 ++++++++++++-----
 module.nix | 28 ++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+), 5 deletions(-)
 create mode 100644 module.nix

diff --git a/flake.nix b/flake.nix
index 7f458a0..f81aade 100644
--- a/flake.nix
+++ b/flake.nix
@@ -14,6 +14,9 @@
 
   outputs = { self, nixpkgs, flake-utils, rust-overlay, crane }:
     let
+      inherit (nixpkgs) lib;
+      inherit (flake-utils.lib) eachSystem system;
+
       overlays = [
         (import rust-overlay)
         # Build Rust toolchain with helpers from rust-overlay
@@ -22,7 +25,11 @@
         })
       ];
     in
-    flake-utils.lib.eachDefaultSystem
+    {
+      nixosModules.hw-gauge-daemon = import ./module.nix self;
+      nixosModules.default = self.nixosModules.hw-gauge-daemon;
+    } //
+    eachSystem [ system.x86_64-linux ]
       (system:
         let
           pkgs = import nixpkgs { inherit overlays system; };
@@ -32,6 +39,10 @@
           scripts = import ./scripts.nix { inherit pkgs; };
         in
         {
+          packages = {
+            daemon = code.daemon;
+          };
+
           devShells.default = pkgs.mkShell {
             buildInputs = with pkgs; [
               flip-link
@@ -47,9 +58,5 @@
               scripts.daemon.linux.ci
             ];
           };
-
-          packages = {
-            daemon = code.daemon;
-          };
         });
 }
diff --git a/module.nix b/module.nix
new file mode 100644
index 0000000..15686ea
--- /dev/null
+++ b/module.nix
@@ -0,0 +1,28 @@
+flake: { config, lib, pkgs, self, ... }:
+with lib; let
+  cfg = config.services.hw-gauge-daemon;
+in
+{
+  options.services.hw-gauge-daemon = {
+    enable = mkEnableOption "Enable the hw-gauge daemon to display HW info";
+
+    package = mkOption {
+      type = types.package;
+      default = flake.packages.${pkgs.system}.daemon;
+    };
+  };
+
+  config = mkIf cfg.enable {
+    systemd.services.hw-gauge-daemon = {
+      wantedBy = [ "multi-user.target" ];
+
+      serviceConfig = {
+        ExecStart = "${cfg.package}/bin/hw-gauge-daemon";
+        DynamicUser = "yes";
+        Group = "dialout";
+        Restart = "on-failure";
+      };
+    };
+  };
+}
+