nix: add script to clean up my system

hostsModules/laptop/scripts/cleanNix.nix

@@ -0,0 +1,68 @@
+{
+  pkgs,
+  ...
+}:
+pkgs.writeShellApplication {
+  name = "custom-cleanNix";
+
+  runtimeInputs = with pkgs; [
+    git
+    nixos-rebuild
+    matrix-commander-rs
+    libnotify
+    alejandra
+    deadnix
+  ];
+
+  text = ''
+    set -e
+
+    FLAKE_DIR="/home/tomasr/nixos"
+    FLAKE="$FLAKE_DIR#laptop"
+    TIME=$(date -u +"%Y-%m-%dT%H-%M-%SZ")
+
+    ERROR_FILE=$(mktemp)
+
+    # snapshot current state
+    git -C "$FLAKE_DIR" add -A
+    git -C "$FLAKE_DIR" commit --allow-empty -m "snapshot pre-cleanup-$TIME"
+    git -C "$FLAKE_DIR" tag "pre-cleanup-$TIME" HEAD
+
+    # removes dead code
+    deadnix --edit "$FLAKE_DIR" # removes unused code
+    statix fix "$FLAKE_DIR" # check other linting issues
+    alejandra "$FLAKE_DIR" # formats the config
+
+    if sudo /run/current-system/sw/bin/nixos-rebuild switch --flake "$FLAKE" 2> "$ERROR_FILE"; then # use /run/.../bin/ uses the sudoless rule
+    
+      if ! git -C "$FLAKE_DIR" diff --quiet HEAD; then
+        git -C "$FLAKE_DIR" add -A
+        git -C "$FLAKE_DIR" commit -m "Auto: cleanup-$TIME"
+        git -C "$FLAKE_DIR" push
+
+        notify-send "Nix auto cleanup" "Everything OK"
+
+        matrix-commander-rs --verbose -m "Nix auto cleanup. Everything OK.<br><a href=\"https://matrix.to/#/@notificationbot_0000:matrix.org\">@notificationbot_0000</a>" \
+          --html \
+          -r "\!7j-78_02dHROeLj4Ns8F12eo4IiZGv4zNsQ_1-WlyIU"
+        else
+          notify-send "Nix auto cleanup" "No changes"
+          git -C "$FLAKE_DIR" push
+        fi
+
+    else
+      ERROR_MSG=$(cat "$ERROR_FILE")
+
+      notify-send -u critical "Nix auto cleanup" "FAILED"
+
+      matrix-commander-rs --verbose -m "Nix auto cleanup failed.<br>Error: <pre>$ERROR_MSG</pre><br><a href=\"https://matrix.to/#/@notificationbot_0000:matrix.org\">@notificationbot_0000</a>" \
+        --html \
+        -r "\!7j-78_02dHROeLj4Ns8F12eo4IiZGv4zNsQ_1-WlyIU"
+
+      git -C "$FLAKE_DIR" reset --hard "pre-cleanup-$TIME"
+    fi
+    git -C "$FLAKE_DIR" tag -d "pre-cleanup-$TIME" # removes the tag
+    
+    rm -f "$ERROR_FILE"
+  '';
+}

modules/nixos/nixUtils.nix

@@ -1,5 +1,6 @@
 # some options are in ../../hostsModules/laptop/nixos/nixUtils.nix
 {
+  pkgs,
   pkgs-unstable,
   inputs,
   ...
@@ -29,5 +30,7 @@
   alejandra
   vimPluginsUpdater # used for building plugins
   nix-index
+  statix
+  (pkgs.callPackage ../../hostsModules/laptop/scripts/cleanNix.nix {})
   ];
 }