feat: add a custom made treewide formatter (#7992)

nix/formatter.nix

@@ -0,0 +1,64 @@
+{
+  writeShellApplication,
+  deadnix,
+  statix,
+  alejandra,
+  llvmPackages_19,
+  fd,
+}:
+writeShellApplication {
+  name = "hyprland-treewide-formatter";
+  runtimeInputs = [
+    deadnix
+    statix
+    alejandra
+    llvmPackages_19.clang-tools
+    fd
+  ];
+  text = ''
+    # shellcheck disable=SC2148
+
+    # common excludes
+    excludes="subprojects"
+
+    nix_format() {
+      if [ "$*" = 0 ]; then
+        fd '.*\.nix' . -E "$excludes" -x statix fix -- {} \;
+        fd '.*\.nix' . -E "$excludes" -X deadnix -e -- {} \; -X alejandra {} \;
+      elif [ -d "$1" ]; then
+        fd '.*\.nix' "$1" -E "$excludes" -i -x statix fix -- {} \;
+        fd '.*\.nix' "$1" -E "$excludes" -i -X deadnix -e -- {} \; -X alejandra {} \;
+      else
+        statix fix -- "$1"
+        deadnix -e "$1"
+        alejandra "$1"
+      fi
+    }
+
+    cpp_format() {
+      if [ "$*" = 0 ] || [ "$1" = "." ]; then
+        fd '.*\.cpp' . -E "$excludes"  | xargs clang-format --verbose -i
+      elif [ -d "$1" ]; then
+        fd '.*\.cpp' "$1" -E "$excludes" | xargs clang-format --verbose -i
+      else
+        clang-format --verbose -i "$1"
+      fi
+    }
+
+    for i in "$@"; do
+      case ''${i##*.} in
+        "nix")
+          nix_format "$i"
+          ;;
+        "cpp")
+          cpp_format "$i"
+          ;;
+        *)
+          nix_format "$i"
+          cpp_format "$i"
+          ;;
+      esac
+
+    done
+  '';
+}