1 files changed, 52 insertions, 0 deletions
diff --git a/modules/nixos/nix.nix b/modules/nixos/nix.nix
new file mode 100644
index 0000000..24b5012
--- /dev/null
+++ b/modules/nixos/nix.nix
@@ -0,0 +1,52 @@
+{ config, lib, ... }:
+
+let cfg = config.personal.nix;
+in {
+  options.personal.nix = {
+    enable = lib.mkEnableOption "nix configuration";
+    autoUpgrade = lib.mkEnableOption "automatic system and nixpkgs upgrade";
+    flake = lib.mkOption {
+      type = with lib.types; nullOr str;
+      default = null;
+    };
+    gc.enable = lib.mkEnableOption "garbage collection";
+  };
+
+  config = lib.mkIf cfg.enable {
+    nixpkgs.config = { allowUnfree = true; };
+    nix = {
+      settings = {
+        auto-optimise-store = true;
+        experimental-features = [ "nix-command" "flakes" ];
+      };
+      gc = lib.mkIf cfg.gc.enable {
+        automatic = true;
+        dates = "daily";
+        options = "--delete-old";
+      };
+    };
+    system.autoUpgrade = lib.mkIf cfg.autoUpgrade {
+      enable = true;
+      flake = cfg.flake;
+      flags = if (cfg.flake == null) then
+        [ "--upgrade-all" ]
+      else [
+        "--update-input"
+        "nixpkgs"
+        "--commit-lock-file"
+      ];
+    };
+    systemd.services = {
+      nix-gc.after =
+        lib.optional (cfg.autoUpgrade && cfg.gc.enable) "nixos-upgrade.service";
+      nix-gc-remove-dead-roots = {
+        enable = cfg.gc.enable;
+        description = "Remove dead symlinks in /nix/var/nix/gcroots";
+        serviceConfig.Type = "oneshot";
+        script = "find /nix/var/nix/gcroots -xtype l -delete";
+        before = lib.mkIf config.nix.gc.automatic [ "nix-gc.service" ];
+        wantedBy = lib.mkIf config.nix.gc.automatic [ "nix-gc.service" ];
+      };
+    };
+  };
+}