D1-18: HomeItemProtection — Home menu item cannot be moved, reordered, or deleted

lib/bds/desktop/shell_live/menu_editor/tree_ops.ex

@@ -180,6 +180,8 @@ defmodule BDS.Desktop.ShellLive.MenuEditor.TreeOps do
   end
 
   @spec move_selected(term(), term()) :: term()
+  def move_selected(%{selected_id: @home_item_id} = state, _direction), do: state
+
   def move_selected(%{selected_id: selected_id} = state, direction)
       when direction in [:up, :down] do
     case find_path(state.items, selected_id) do
@@ -209,6 +211,8 @@ defmodule BDS.Desktop.ShellLive.MenuEditor.TreeOps do
   end
 
   @spec indent_selected(term()) :: term()
+  def indent_selected(%{selected_id: @home_item_id} = state), do: state
+
   def indent_selected(%{selected_id: selected_id} = state) do
     case find_path(state.items, selected_id) do
       nil ->
@@ -249,6 +253,8 @@ defmodule BDS.Desktop.ShellLive.MenuEditor.TreeOps do
   end
 
   @spec unindent_selected(term()) :: term()
+  def unindent_selected(%{selected_id: @home_item_id} = state), do: state
+
   def unindent_selected(%{selected_id: selected_id} = state) do
     case find_path(state.items, selected_id) do
       nil ->
@@ -295,6 +301,8 @@ defmodule BDS.Desktop.ShellLive.MenuEditor.TreeOps do
       when drag_item_id == target_item_id,
       do: state
 
+  def drop_selected(state, @home_item_id, _target_item_id, _position), do: state
+
   @spec drop_selected(term(), term(), term(), term()) :: term()
   def drop_selected(state, drag_item_id, target_item_id, position) do
     drag_path = find_path(state.items, drag_item_id)

lib/bds/desktop/shell_live/menu_editor/tree_predicates.ex

@@ -5,57 +5,73 @@ defmodule BDS.Desktop.ShellLive.MenuEditor.TreePredicates do
 
   @spec can_move_up?(term(), term()) :: term()
   def can_move_up?(items, selected_id) do
-    case TreeOps.find_path(items, selected_id) do
-      [_parent, index] -> index > 0
-      [index] -> index > 0
-      path when is_list(path) -> List.last(path) > 0
-      _other -> false
+    if selected_id == TreeOps.home_item_id() do
+      false
+    else
+      case TreeOps.find_path(items, selected_id) do
+        [_parent, index] -> index > 0
+        [index] -> index > 0
+        path when is_list(path) -> List.last(path) > 0
+        _other -> false
+      end
     end
   end
 
   @spec can_move_down?(term(), term()) :: term()
   def can_move_down?(items, selected_id) do
-    case TreeOps.find_path(items, selected_id) do
-      nil ->
-        false
+    if selected_id == TreeOps.home_item_id() do
+      false
+    else
+      case TreeOps.find_path(items, selected_id) do
+        nil ->
+          false
 
-      path ->
-        parent_path = Enum.drop(path, -1)
-        index = List.last(path)
-        index < length(TreeOps.items_at_path(items, parent_path)) - 1
+        path ->
+          parent_path = Enum.drop(path, -1)
+          index = List.last(path)
+          index < length(TreeOps.items_at_path(items, parent_path)) - 1
+      end
     end
   end
 
   @spec can_indent?(term(), term()) :: term()
   def can_indent?(items, selected_id) do
-    case TreeOps.find_path(items, selected_id) do
-      nil ->
-        false
+    if selected_id == TreeOps.home_item_id() do
+      false
+    else
+      case TreeOps.find_path(items, selected_id) do
+        nil ->
+          false
 
-      [] ->
-        false
+        [] ->
+          false
 
-      [_index] = path ->
-        index = List.last(path)
-        index > 0 and match?(%{kind: :submenu}, TreeOps.item_at_path(items, [index - 1]))
+        [_index] = path ->
+          index = List.last(path)
+          index > 0 and match?(%{kind: :submenu}, TreeOps.item_at_path(items, [index - 1]))
 
-      path ->
-        index = List.last(path)
+        path ->
+          index = List.last(path)
 
-        index > 0 and
-          match?(
-            %{kind: :submenu},
-            TreeOps.item_at_path(items, Enum.drop(path, -1) ++ [index - 1])
-          )
+          index > 0 and
+            match?(
+              %{kind: :submenu},
+              TreeOps.item_at_path(items, Enum.drop(path, -1) ++ [index - 1])
+            )
+      end
     end
   end
 
   @spec can_unindent?(term(), term()) :: term()
   def can_unindent?(items, selected_id) do
-    case TreeOps.find_path(items, selected_id) do
-      [_index] -> false
-      path when is_list(path) -> length(path) > 1
-      _other -> false
+    if selected_id == TreeOps.home_item_id() do
+      false
+    else
+      case TreeOps.find_path(items, selected_id) do
+        [_index] -> false
+        path when is_list(path) -> length(path) > 1
+        _other -> false
+      end
     end
   end