Feature/add move node

lib/radiator/outline.ex

@@ -59,6 +59,57 @@ defmodule Radiator.Outline do
     end)
   end
 
+  @doc """
+  Moves a node to another parent.
+
+  ## Examples
+
+      iex> move_node(node_id, new_prev_id, new_parent_id)
+      {:ok, %Node{}}
+  """
+  def move_node(node_id, new_prev_id, new_parent_id) do
+    case NodeRepository.get_node(node_id) do
+      nil ->
+        {:error, :not_found}
+
+      node ->
+        prev_node = get_prev_node(node)
+        parent_node = get_parent_node(node)
+
+        if get_node_id(prev_node) != new_prev_id || get_node_id(parent_node) != new_parent_id do
+          do_move_node(node, new_prev_id, new_parent_id, prev_node, parent_node)
+        else
+          {:ok, node}
+        end
+    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
+    Repo.transaction(fn ->
+      old_next_node =
+        Node
+        |> where_prev_node_equals(node.uuid)
+        |> where_parent_node_equals(get_node_id(parent_node))
+        |> Repo.one()
+
+      new_next_node =
+        Node
+        |> where_prev_node_equals(new_prev_id)
+        |> where_parent_node_equals(new_parent_id)
+        |> Repo.one()
+
+      {:ok, node} = move_node_if(node, new_parent_id, new_prev_id)
+
+      {:ok, _old_next_node} =
+        move_node_if(old_next_node, get_node_id(parent_node), get_node_id(prev_node))
+
+      {:ok, _new_next_node} = move_node_if(new_next_node, new_parent_id, get_node_id(node))
+    end)
+
+    {:ok, node}
+  end
+
   @doc """
   Updates a nodes content.
 
@@ -139,6 +190,26 @@ defmodule Radiator.Outline do
     |> Repo.one()
   end
 
+  @doc """
+  Returns the parent node of a given node in the outline tree.
+  Returns `nil` if parent_id of the node is nil.
+
+  ## Examples
+        iex> get_parent_node(%Node{parent_id: nil})
+        nil
+
+        iex> get_parent_node(%Node{parent_id: 42})
+        %Node{uuid: 42}
+
+  """
+  def get_parent_node(node) when is_nil(node.parent_id), do: nil
+
+  def get_parent_node(node) do
+    Node
+    |> where([n], n.uuid == ^node.parent_id)
+    |> Repo.one()
+  end
+
   @doc """
   Returns all child nodes of a given node.
   ## Examples

test/radiator/outline_test.exs

@@ -247,6 +247,251 @@ defmodule Radiator.OutlineTest do
     end
   end
 
+  describe "move_node/3 - simple context" do
+    setup :simple_node_fixture
+
+    # before 1 2
+    # after  2 1
+    test "move node on same level", %{
+      node_1: node_1,
+      node_2: node_2
+    } do
+      {:ok, _} = Outline.move_node(node_2.uuid, nil, node_2.parent_id)
+
+      # reload nodes
+      node_1 = Repo.reload!(node_1)
+      node_2 = Repo.reload!(node_2)
+
+      assert node_1.prev_id == node_2.uuid
+      assert node_2.prev_id == nil
+    end
+
+    # before 1 2
+    # after  2 1
+    test "move node on same level - move the other node", %{
+      node_1: node_1,
+      node_2: node_2
+    } do
+      {:ok, _} = Outline.move_node(node_1.uuid, node_2.uuid, node_1.parent_id)
+
+      # reload nodes
+      node_1 = Repo.reload!(node_1)
+      node_2 = Repo.reload!(node_2)
+
+      assert node_1.prev_id == node_2.uuid
+      assert node_2.prev_id == nil
+    end
+
+    test "ignore when nothing should change", %{
+      node_1: node_1,
+      node_2: node_2
+    } do
+      {:ok, _} = Outline.move_node(node_2.uuid, node_1.uuid, node_2.parent_id)
+
+      # reload nodes
+      node_1 = Repo.reload!(node_1)
+      node_2 = Repo.reload!(node_2)
+
+      assert node_2.prev_id == node_1.uuid
+      assert node_1.prev_id == nil
+    end
+
+    test "ignore when nothing should change - other way around", %{
+      node_1: node_1,
+      node_2: node_2
+    } do
+      {:ok, _} = Outline.move_node(node_1.uuid, nil, node_2.parent_id)
+
+      # reload nodes
+      node_1 = Repo.reload!(node_1)
+      node_2 = Repo.reload!(node_2)
+
+      assert node_2.prev_id == node_1.uuid
+      assert node_1.prev_id == nil
+    end
+
+    test "move node below other node", %{
+      node_1: node_1,
+      node_2: node_2
+    } do
+      {:ok, _} = Outline.move_node(node_2.uuid, nil, node_1.uuid)
+
+      # reload nodes
+      node_1 = Repo.reload!(node_1)
+      node_2 = Repo.reload!(node_2)
+
+      assert node_1.prev_id == nil
+      assert node_2.prev_id == nil
+
+      assert node_1.parent_id == nil
+      assert node_2.parent_id == node_1.uuid
+    end
+  end
+
+  describe "move_node/3" do
+    setup :complex_node_fixture
+
+    # before 1 2 3 4 5
+    # after  1 2 4 3 5
+    test "move node 4 within list to node 2", %{
+      node_2: node_2,
+      node_3: node_3,
+      node_4: node_4,
+      node_5: node_5
+    } do
+      {:ok, _} = Outline.move_node(node_4.uuid, node_2.uuid, node_4.parent_id)
+
+      # reload nodes
+      node_5 = Repo.reload!(node_5)
+      node_4 = Repo.reload!(node_4)
+      node_3 = Repo.reload!(node_3)
+      node_2 = Repo.reload!(node_2)
+
+      assert node_4.prev_id == node_2.uuid
+      assert node_3.prev_id == node_4.uuid
+      assert node_5.prev_id == node_3.uuid
+    end
+
+    # before 1 2 3 4 5
+    # after  4 1 2 3 5
+    test "move node 4 to the top of the list", %{
+      node_1: node_1,
+      node_2: node_2,
+      node_3: node_3,
+      node_4: node_4,
+      node_5: node_5
+    } do
+      {:ok, _} = Outline.move_node(node_4.uuid, nil, node_4.parent_id)
+
+      # reload nodes
+      node_5 = Repo.reload!(node_5)
+      node_4 = Repo.reload!(node_4)
+      node_3 = Repo.reload!(node_3)
+      node_2 = Repo.reload!(node_2)
+      node_1 = Repo.reload!(node_1)
+
+      assert node_4.prev_id == nil
+      assert node_1.prev_id == node_4.uuid
+      assert node_2.prev_id == node_1.uuid
+      assert node_3.prev_id == node_2.uuid
+      assert node_5.prev_id == node_3.uuid
+    end
+
+    # before 1 2 3 4 5
+    # after  1 3 4 5 2
+    test "move node 2 to the end of the list", %{
+      node_1: node_1,
+      node_2: node_2,
+      node_3: node_3,
+      node_4: node_4,
+      node_5: node_5
+    } do
+      {:ok, _} = Outline.move_node(node_2.uuid, node_5.uuid, node_2.parent_id)
+
+      # reload nodes
+      node_5 = Repo.reload!(node_5)
+      node_4 = Repo.reload!(node_4)
+      node_3 = Repo.reload!(node_3)
+      node_2 = Repo.reload!(node_2)
+      node_1 = Repo.reload!(node_1)
+
+      assert node_3.prev_id == node_1.uuid
+      assert node_4.prev_id == node_3.uuid
+      assert node_5.prev_id == node_4.uuid
+      assert node_2.prev_id == node_5.uuid
+    end
+
+    # before 1 2 3 4 5
+    # after  2 3 4 5 1
+    test "move first node to the end of the list", %{
+      node_1: node_1,
+      node_2: node_2,
+      node_3: node_3,
+      node_4: node_4,
+      node_5: node_5
+    } do
+      {:ok, _} = Outline.move_node(node_1.uuid, node_5.uuid, node_2.parent_id)
+
+      # reload nodes
+      node_5 = Repo.reload!(node_5)
+      node_4 = Repo.reload!(node_4)
+      node_3 = Repo.reload!(node_3)
+      node_2 = Repo.reload!(node_2)
+      node_1 = Repo.reload!(node_1)
+
+      assert node_1.prev_id == node_5.uuid
+      assert node_5.prev_id == node_4.uuid
+      assert node_3.prev_id == node_2.uuid
+      assert node_2.prev_id == nil
+    end
+
+    # before 1 2 3 4 5
+    # after  5 1 2 3 4
+    test "move last node to the top of the list", %{
+      node_1: node_1,
+      node_2: node_2,
+      node_3: node_3,
+      node_4: node_4,
+      node_5: node_5
+    } do
+      {:ok, _} = Outline.move_node(node_5.uuid, nil, node_2.parent_id)
+
+      # reload nodes
+      node_5 = Repo.reload!(node_5)
+      node_4 = Repo.reload!(node_4)
+      node_3 = Repo.reload!(node_3)
+      node_2 = Repo.reload!(node_2)
+      node_1 = Repo.reload!(node_1)
+
+      assert node_5.prev_id == nil
+      assert node_1.prev_id == node_5.uuid
+      assert node_2.prev_id == node_1.uuid
+      assert node_3.prev_id == node_2.uuid
+      assert node_4.prev_id == node_3.uuid
+    end
+
+    test "move nested node to a new parent", %{
+      node_2: node_2,
+      node_3: node_3,
+      nested_node_1: nested_node_1,
+      nested_node_2: nested_node_2
+    } do
+      {:ok, _} = Outline.move_node(nested_node_1.uuid, nil, node_2.uuid)
+
+      # reload nodes
+      nested_node_1 = Repo.reload!(nested_node_1)
+      nested_node_2 = Repo.reload!(nested_node_2)
+
+      assert nested_node_1.parent_id == node_2.uuid
+      assert nested_node_2.parent_id == node_3.uuid
+      assert nested_node_1.prev_id == nil
+      assert nested_node_2.prev_id == nil
+    end
+
+    test "move node with child elements to top", %{
+      parent_node: parent_node,
+      node_3: node_3,
+      nested_node_1: nested_node_1,
+      nested_node_2: nested_node_2
+    } do
+      {:ok, _} = Outline.move_node(node_3.uuid, nil, nil)
+
+      # reload nodes
+      parent_node = Repo.reload!(parent_node)
+      node_3 = Repo.reload!(node_3)
+      nested_node_1 = Repo.reload!(nested_node_1)
+      nested_node_2 = Repo.reload!(nested_node_2)
+
+      assert node_3.prev_id == nil
+      assert node_3.parent_id == nil
+      assert parent_node.prev_id == node_3.uuid
+      assert nested_node_1.parent_id == node_3.uuid
+      assert nested_node_2.parent_id == node_3.uuid
+      assert nested_node_1.prev_id == nil
+      assert nested_node_2.prev_id == nested_node_1.uuid
+    end
+  end
+
   describe "remove_node/1" do
     setup :complex_node_fixture
 
@@ -422,6 +667,36 @@ defmodule Radiator.OutlineTest do
     assert node.level == level
   end
 
+  defp simple_node_fixture(_) do
+    episode = PodcastFixtures.episode_fixture()
+
+    node_1 =
+      node_fixture(
+        episode_id: episode.id,
+        parent_id: nil,
+        prev_id: nil,
+        content: "node_1"
+      )
+
+    node_2 =
+      node_fixture(
+        episode_id: episode.id,
+        parent_id: nil,
+        prev_id: node_1.uuid,
+        content: "node_2"
+      )
+
+    assert node_2.prev_id == node_1.uuid
+    assert node_1.prev_id == nil
+    assert node_1.parent_id == nil
+    assert node_2.parent_id == nil
+
+    %{
+      node_1: node_1,
+      node_2: node_2
+    }
+  end
+
   defp complex_node_fixture(_) do
     episode = PodcastFixtures.episode_fixture()
 
@@ -497,6 +772,17 @@ defmodule Radiator.OutlineTest do
         content: "nested_node_2"
       )
 
+    assert node_5.prev_id == node_4.uuid
+    assert node_4.prev_id == node_3.uuid
+    assert node_3.prev_id == node_2.uuid
+    assert node_2.prev_id == node_1.uuid
+    assert node_1.prev_id == nil
+
+    assert nested_node_1.parent_id == node_3.uuid
+    assert nested_node_2.parent_id == node_3.uuid
+    assert nested_node_1.prev_id == nil
+    assert nested_node_2.prev_id == nested_node_1.uuid
+
     %{
       node_1: node_1,
       node_2: node_2,