WIP refactor

common/boot/default.nix

@@ -0,0 +1,35 @@
+{ config, lib, ... }:
+let
+  ccfg = import ../config.nix;
+  cfg = config.${ccfg.custom_config_key}.boot;
+in
+{
+  imports = [
+    ./grub.nix
+    ./systemd.nix
+  ];
+  config = {
+    assertions = [
+      (
+        let
+          enabledBootloaders = lib.filter (x: x.enabled) [
+            {
+              name = "systemd";
+              enabled = cfg.systemd.enable;
+            }
+            {
+              name = "grub";
+              enabled = cfg.grub.enable;
+            }
+          ];
+        in
+        {
+          assertion = lib.length enabledBootloaders <= 1;
+          message =
+            "Only one bootloader can be enabled at a time. Enabled: "
+            + lib.concatStringsSep ", " (map (x: x.name) enabledBootloaders);
+        }
+      )
+    ];
+  };
+}

common/boot/grub.nix

@@ -5,20 +5,27 @@
 }:
 let
   ccfg = import ../config.nix;
-  cfg_path = "${ccfg.custom_config_key}".boot.grub;
-  cfg = config.${cfg_path};
+  cfg_path = [
+    ccfg.custom_config_key
+    "boot"
+    "grub"
+  ];
+  cfg = lib.attrsets.getAttrFromPath cfg_path config;
 in
 {
-  options.${ccfg.custom_config_key}.boot.grub = {
-    enable = lib.mkEnableOption "Grub bootloader";
-    device = lib.mkOption {
-      type = lib.types.str;
-      default = "/dev/sda";
-      description = ''
-        The device to install GRUB on.
-      '';
+  options =
+    { }
+    // lib.attrsets.setAttrByPath cfg_path {
+      enable = lib.mkEnableOption "Grub bootloader";
+      device = lib.mkOption {
+        type = lib.types.str;
+        default = "/dev/sda";
+        description = ''
+          The device to install GRUB on.
+        '';
+      };
     };
-  };
+
   config = lib.mkIf cfg.enable {
     boot.loader.grub = {
       enable = true;

common/boot/systemd.nix

@@ -5,13 +5,19 @@
 }:
 let
   ccfg = import ../config.nix;
-  cfg_path = "${ccfg.custom_config_key}".boot.systemd;
-  cfg = config.${cfg_path};
+  cfg_path = [
+    ccfg.custom_config_key
+    "boot"
+    "systemd"
+  ];
+  cfg = lib.attrsets.getAttrFromPath cfg_path config;
 in
 {
-  options.${cfg_path} = {
-    enable = lib.mkEnableOption "Systemd bootloader";
-  };
+  options =
+    { }
+    // lib.attrsets.setAttrByPath cfg_path {
+      enable = lib.mkEnableOption "Systemd bootloader";
+    };
   config = lib.mkIf cfg.enable {
     boot.loader = {
       systemd-boot = {