replace todo context implementations with command dispatch

Author: ChristianAlexander

lib/todo_backend/todos.ex

@@ -4,7 +4,11 @@ defmodule TodoBackend.Todos do
   """
 
   import Ecto.Query, warn: false
+  alias TodoBackend.App
   alias TodoBackend.Repo
+  alias TodoBackend.Todos.Commands.CreateTodo
+  alias TodoBackend.Todos.Commands.DeleteTodo
+  alias TodoBackend.Todos.Commands.UpdateTodo
 
   alias TodoBackend.Todos.Projections.Todo
 
@@ -50,9 +54,18 @@ defmodule TodoBackend.Todos do
 
   """
   def create_todo(attrs \\ %{}) do
-    %Todo{}
-    |> Todo.changeset(attrs)
-    |> Repo.insert()
+    uuid = Ecto.UUID.generate()
+
+    command =
+      attrs
+      |> CreateTodo.new()
+      |> CreateTodo.assign_uuid(uuid)
+
+    with :ok <- App.dispatch(command, consistency: :strong) do
+      {:ok, get_todo!(uuid)}
+    else
+      reply -> reply
+    end
   end
 
   @doc """
@@ -67,10 +80,17 @@ defmodule TodoBackend.Todos do
       {:error, %Ecto.Changeset{}}
 
   """
-  def update_todo(%Todo{} = todo, attrs) do
-    todo
-    |> Todo.changeset(attrs)
-    |> Repo.update()
+  def update_todo(%Todo{uuid: uuid}, attrs) do
+    command =
+      attrs
+      |> UpdateTodo.new()
+      |> UpdateTodo.assign_uuid(uuid)
+
+    with :ok <- App.dispatch(command, consistency: :strong) do
+      {:ok, get_todo!(uuid)}
+    else
+      reply -> reply
+    end
   end
 
   @doc """
@@ -85,8 +105,14 @@ defmodule TodoBackend.Todos do
       {:error, %Ecto.Changeset{}}
 
   """
-  def delete_todo(%Todo{} = todo) do
-    Repo.delete(todo)
+  def delete_todo(%Todo{uuid: uuid}) do
+    command = DeleteTodo.new(%{uuid: uuid})
+
+    with :ok <- App.dispatch(command) do
+      :ok
+    else
+      reply -> reply
+    end
   end
 
   @doc """
@@ -101,17 +127,4 @@ defmodule TodoBackend.Todos do
   def delete_all_todos() do
     Repo.delete_all(Todo)
   end
-
-  @doc """
-  Returns an `%Ecto.Changeset{}` for tracking todo changes.
-
-  ## Examples
-
-      iex> change_todo(todo)
-      %Ecto.Changeset{data: %Todo{}}
-
-  """
-  def change_todo(%Todo{} = todo, attrs \\ %{}) do
-    Todo.changeset(todo, attrs)
-  end
 end

lib/todo_backend_web/controllers/todo_controller.ex

@@ -38,7 +38,7 @@ defmodule TodoBackendWeb.TodoController do
   def delete(conn, %{"id" => id}) do
     todo = Todos.get_todo!(id)
 
-    with {:ok, %Todo{}} <- Todos.delete_todo(todo) do
+    with :ok <- Todos.delete_todo(todo) do
       send_resp(conn, :no_content, "")
     end
   end