From f0800e60ca4f3ce20d5405a727589144393a678c Mon Sep 17 00:00:00 2001
From: Bernardo Magri <bernardo@bernardomagri.eu>
Date: Mon, 13 Apr 2026 11:33:07 +0100
Subject: [PATCH] fix: enable flakes and nix-command and set NIX_PATH for
 nix-shell

---
 core/system/default.nix             |  1 +
 core/system/nix.nix                 | 26 ++++++++++++++++++++++++++
 core/system/scripts/nomarchy-update |  2 +-
 hosts/installer-iso.nix             |  5 ++++-
 4 files changed, 32 insertions(+), 2 deletions(-)
 create mode 100644 core/system/nix.nix

diff --git a/core/system/default.nix b/core/system/default.nix
index 868694f..679f5ac 100644
--- a/core/system/default.nix
+++ b/core/system/default.nix
@@ -4,6 +4,7 @@
   imports = [
     ./options.nix
     ./state.nix
+    ./nix.nix
     ./systemd.nix
     ./virtualization.nix
     ./fonts.nix
diff --git a/core/system/nix.nix b/core/system/nix.nix
new file mode 100644
index 0000000..3855ba0
--- /dev/null
+++ b/core/system/nix.nix
@@ -0,0 +1,26 @@
+{ inputs, lib, ... }:
+
+{
+  nix = {
+    settings = {
+      # Enable experimental features for modern Nix commands and flakes
+      experimental-features = [ "nix-command" "flakes" ];
+      
+      # Allow users in the wheel group to manage the Nix store
+      trusted-users = [ "root" "@wheel" ];
+      
+      # Optimize storage by hard-linking identical files
+      auto-optimise-store = lib.mkDefault true;
+    };
+
+    # Populates NIX_PATH with the nixpkgs input from the flake.
+    # This is critical for making 'nix-shell -p ...' and other legacy
+    # Nix commands work in a flake-based environment without channels.
+    nixPath = [ "nixpkgs=${inputs.nixpkgs}" ];
+
+    # Map all flake inputs to the system registry.
+    # This ensures 'nix shell nixpkgs#...' uses the exact same version
+    # as the rest of the system and doesn't need to re-download.
+    registry = lib.mapAttrs (_: value: { flake = value; }) inputs;
+  };
+}
diff --git a/core/system/scripts/nomarchy-update b/core/system/scripts/nomarchy-update
index 81e7e55..5fd6074 100755
--- a/core/system/scripts/nomarchy-update
+++ b/core/system/scripts/nomarchy-update
@@ -18,7 +18,7 @@ echo "--- Starting Nomarchy Update ---"
 
 # 1. Update Flake Lock
 echo "Updating flake inputs..."
-sudo nix --extra-experimental-features "nix-command flakes" flake update --flake "$REPO_DIR"
+sudo nix flake update --flake "$REPO_DIR"
 
 # 2. Rebuild System
 echo "Applying system-level updates..."
diff --git a/hosts/installer-iso.nix b/hosts/installer-iso.nix
index a4bad7b..21449e1 100644
--- a/hosts/installer-iso.nix
+++ b/hosts/installer-iso.nix
@@ -5,7 +5,10 @@
 # This creates a minimal, text-only installation environment.
 # No desktop environment - just TTY with gum-based installer.
 
-{
+  imports = [
+    ../core/system/nix.nix
+  ];
+
   # Base installation media configuration is handled by the module imported in flake.nix
 
   # Console configuration for a pleasant TTY experience