Extract creation of todos from recurrings todos

lib/todo_from_recurring_todo.rb

@@ -0,0 +1,54 @@
+class TodoFromRecurringTodo
+  attr_reader :user, :recurring_todo, :todo
+  def initialize(user, recurring_todo)
+    @user = user
+    @recurring_todo = recurring_todo
+  end
+
+  def create(time = nil)
+    @todo = build_todo(time)
+    save_todo
+    update_recurring_todo
+    return todo.persisted? ? todo : nil
+  end
+
+  def build_todo(time)
+    user.todos.build(attributes).tap do |todo|
+      todo.recurring_todo_id = recurring_todo.id
+      todo.due = recurring_todo.get_due_date(time)
+      todo.show_from = show_from_date(time)
+    end
+  end
+
+  def update_recurring_todo
+    recurring_todo.inc_occurences
+    recurring_todo.toggle_completion! if recurring_todo.done?(end_date)
+  end
+
+  def end_date
+    todo.due ? todo.due : todo.show_from
+  end
+
+  def attributes
+    {
+      :description => recurring_todo.description,
+      :notes => recurring_todo.notes,
+      :project_id => recurring_todo.project_id,
+      :context_id => recurring_todo.context_id
+    }
+  end
+
+  def save_todo
+    if todo.save
+      todo.tag_with(recurring_todo.tag_list)
+      todo.tags.reload
+    end
+  end
+
+  def show_from_date(time)
+    show_from_date = recurring_todo.get_show_from_date(time)
+    if show_from_date && show_from_date >= Time.zone.now
+      show_from_date
+    end
+  end
+end