From a3139051b14005f1e4c96091e8b3c4cd0e320b0d Mon Sep 17 00:00:00 2001
From: DerGrumpf <phil.keier@hotmail.com>
Date: Wed, 24 Jun 2026 19:07:40 +0200
Subject: [PATCH] WIP: Groundwork for impermanence setup for nixos and home

---
 flake.nix               |  1 +
 home/impermanence.nix   | 13 +++++++++++++
 home/neovim/conform.nix | 37 +++++++++++++++++++++++++++++++++++--
 home/neovim/lsp.nix     |  2 ++
 nixos/default.nix       |  1 +
 nixos/impermanence.nix  | 18 ++++++++++++++++++
 6 files changed, 70 insertions(+), 2 deletions(-)
 create mode 100644 home/impermanence.nix
 create mode 100644 nixos/impermanence.nix

diff --git a/flake.nix b/flake.nix
index 2e874be..c7d6c0a 100644
--- a/flake.nix
+++ b/flake.nix
@@ -210,6 +210,7 @@
               [
                 { nixpkgs.hostPlatform = system; }
                 ./nixos
+                inputs.impermanence.nixosModules.impermanence
               ];
 
         in
diff --git a/home/impermanence.nix b/home/impermanence.nix
new file mode 100644
index 0000000..804e3d9
--- /dev/null
+++ b/home/impermanence.nix
@@ -0,0 +1,13 @@
+{ primaryUser, ... }:
+{
+  home.persistence."/persist/home/${primaryUser}" = {
+    hideMounts = true;
+    directories = [
+      ".config/nix"
+      ".local/share/zoxide"
+    ];
+    files = [
+      ".local/share/fish/fish_history"
+    ];
+  };
+}
diff --git a/home/neovim/conform.nix b/home/neovim/conform.nix
index f915b04..aab32dc 100644
--- a/home/neovim/conform.nix
+++ b/home/neovim/conform.nix
@@ -5,7 +5,6 @@
   programs.nixvim = {
     plugins.conform-nvim = {
       enable = true;
-
       settings = {
         formatters_by_ft = {
           lua = [ "stylua" ];
@@ -13,6 +12,40 @@
           python = [ "black" ];
           rust = [ "rustfmt" ];
           rasi = [ "prettierd" ];
+          c = [ "clang_format" ];
+          cpp = [ "clang_format" ];
+        };
+
+        formatters.clang_format = {
+          # If the file has a project .clang-format (walking up from the
+          # file itself, not nvim's cwd), use it - this is how a real
+          # kernel checkout, or any other C/C++ project's own style,
+          # gets respected automatically. Otherwise fall back to an
+          # inline approximation of kernel style instead of plain LLVM,
+          # since that's the sane default for one-off C files.
+          prepend_args = {
+            __raw = ''
+              function(self, ctx)
+                local found = vim.fs.find(
+                  { ".clang-format", "_clang-format" },
+                  { path = ctx.filename, upward = true }
+                )[1]
+                if found then
+                  return { "-style=file" }
+                end
+                return {
+                  "-style={BasedOnStyle: LLVM, IndentWidth: 8, UseTab: Always, "
+                  .. "TabWidth: 8, BreakBeforeBraces: Linux, ColumnLimit: 80, "
+                  .. "IndentCaseLabels: false, PointerAlignment: Right, "
+                  .. "DerivePointerAlignment: false, SpaceBeforeParens: ControlStatements, "
+                  .. "SpacesInParentheses: false, SpaceAfterCStyleCast: false, "
+                  .. "AllowShortIfStatementsOnASingleLine: false, AllowShortBlocksOnASingleLine: false, "
+                  .. "AllowShortFunctionsOnASingleLine: None, AllowShortLoopsOnASingleLine: false, "
+                  .. "ReflowComments: false}"
+                }
+              end
+            '';
+          };
         };
 
         format_on_save = {
@@ -21,7 +54,6 @@
         };
       };
     };
-
     # Install formatters
     extraPackages = with pkgs; [
       stylua
@@ -29,6 +61,7 @@
       black
       rustfmt
       prettierd
+      clang-tools # provides clang-format
     ];
   };
 }
diff --git a/home/neovim/lsp.nix b/home/neovim/lsp.nix
index 678dc15..7e78df7 100644
--- a/home/neovim/lsp.nix
+++ b/home/neovim/lsp.nix
@@ -29,6 +29,7 @@
             installRustc = true;
           };
           pylsp.enable = true; # Python language server
+          clangd.enable = true;
         };
 
         # Keymaps for LSP actions
@@ -85,6 +86,7 @@
       lua-language-server
       nil
       rust-analyzer
+      clang-tools
     ];
   };
 }
diff --git a/nixos/default.nix b/nixos/default.nix
index fcec4c6..43e0e53 100644
--- a/nixos/default.nix
+++ b/nixos/default.nix
@@ -13,6 +13,7 @@
     ./locale.nix
     ./tailscale.nix
     ./ssh.nix
+    ./impermanence.nix
   ]
   ++ lib.optionals (!isServer) [
     ./regreet.nix
diff --git a/nixos/impermanence.nix b/nixos/impermanence.nix
new file mode 100644
index 0000000..5837af4
--- /dev/null
+++ b/nixos/impermanence.nix
@@ -0,0 +1,18 @@
+_: {
+  environment.persistence."/persist" = {
+    hideMounts = true;
+    files = [
+      "/etc/machine-id"
+      "/etc/ssh/ssh_host_ed25519_key"
+      "/etc/ssh/ssh_host_ed25519_key.pub"
+      "/etc/ssh/ssh_host_rsa_key"
+      "/etc/ssh/ssh_host_rsa_key.pub"
+    ];
+    directories = [
+      "/var/lib/nixos"
+      "/var/lib/systemd"
+      "/var/log"
+      "/var/lib/tailscale"
+    ];
+  };
+}