extract module: move consistency validations to a new module

lib/radiator/outline.ex

@@ -21,6 +21,7 @@ defmodule Radiator.Outline do
   alias Radiator.Outline.Node
   alias Radiator.Outline.NodeRepoResult
   alias Radiator.Outline.NodeRepository
+  alias Radiator.Outline.Validations, as: NodeValidator
   alias Radiator.Repo
 
   require Logger
@@ -138,7 +139,12 @@ defmodule Radiator.Outline do
       node ->
         parent_node = get_parent_node(node)
 
-        case validate_consistency_for_move(node, new_prev_id, new_parent_id, parent_node) do
+        case NodeValidator.validate_consistency_for_move(
+               node,
+               new_prev_id,
+               new_parent_id,
+               parent_node
+             ) do
           {:error, error} ->
             {:error, error}
 
@@ -149,39 +155,6 @@ defmodule Radiator.Outline do
     end
   end
 
-  defp validate_consistency_for_move(
-         %{prev_id: new_prev_id, parent_id: new_parent_id},
-         new_prev_id,
-         new_parent_id,
-         _parent_node
-       ) do
-    {:error, :noop}
-  end
-
-  # when prev is nil, every parent is allowed
-  defp validate_consistency_for_move(
-         node,
-         nil,
-         _new_parent_id,
-         _parent_node
-       ) do
-    {:ok, node}
-  end
-
-  # when prev is not nil, parent and prev must be consistent
-  defp validate_consistency_for_move(
-         node,
-         new_prev_id,
-         new_parent_id,
-         _parent_node
-       ) do
-    if NodeRepository.get_node(new_prev_id).parent_id == new_parent_id do
-      {:ok, node}
-    else
-      {:error, :parent_and_prev_not_consistent}
-    end
-  end
-
   # low level function to move a node
   defp do_move_node(node, new_prev_id, new_parent_id, prev_node, parent_node) do
     node_repo_result = %NodeRepoResult{node: node}

lib/radiator/outline/validations.ex

@@ -0,0 +1,49 @@
+defmodule Radiator.Outline.Validations do
+  @moduledoc """
+    Collection of consistency validations for the outline tree.
+  """
+
+  alias Radiator.Outline.NodeRepository
+
+  def validate_consistency_for_move(
+        %{prev_id: new_prev_id, parent_id: new_parent_id},
+        new_prev_id,
+        new_parent_id,
+        _parent_node
+      ) do
+    {:error, :noop}
+  end
+
+  # when prev is nil, every parent is allowed
+  def validate_consistency_for_move(
+        node,
+        nil,
+        _new_parent_id,
+        _parent_node
+      ) do
+    {:ok, node}
+  end
+
+  # when prev is not nil, parent and prev must be consistent
+  def validate_consistency_for_move(
+        node,
+        new_prev_id,
+        new_parent_id,
+        _parent_node
+      ) do
+    if NodeRepository.get_node(new_prev_id).parent_id == new_parent_id do
+      {:ok, node}
+    else
+      {:error, :parent_and_prev_not_consistent}
+    end
+  end
+
+  def validate_tree(episode_id) do
+    tree_nodes = get_node_tree
+    all_nodes_by_episode = NodeRepository.list_nodes_by_episode(episode_id)
+    # tree_nodes
+    # every level has 1 node with prev_id nil
+    # all other nodes in level have prev_id set and are connected to the previous node
+    Enum.size(tree_nodes) == Enum.size(all_nodes_by_episode)
+  end
+end