Extract a query object for not done todos

app/models/todos/undone_todos_query.rb

@@ -0,0 +1,44 @@
+module Todos
+  class UndoneTodosQuery
+    attr_reader :current_user
+    def initialize(current_user)
+      @current_user = current_user
+    end
+
+    def query(params)
+      if params[:done]
+        not_done_todos = current_user.todos.completed.completed_after(Time.zone.now - params[:done].to_i.days)
+      else
+        not_done_todos = current_user.todos.active.not_hidden
+      end
+
+      not_done_todos = not_done_todos.
+        reorder(Arel.sql("todos.due IS NULL, todos.due ASC, todos.created_at ASC")).
+        includes(Todo::DEFAULT_INCLUDES)
+
+      not_done_todos = not_done_todos.limit(sanitize(params[:limit])) if params[:limit]
+
+      if params[:due]
+        due_within_when = Time.zone.now + params['due'].to_i.days
+        not_done_todos = not_done_todos.where('todos.due <= ?', due_within_when)
+      end
+
+      if params[:tag]
+        tag = Tag.where(:name => params['tag']).first
+        not_done_todos = not_done_todos.where('taggings.tag_id = ?', tag.id)
+      end
+
+      if params[:context_id]
+        context = current_user.contexts.find(params[:context_id])
+        not_done_todos = not_done_todos.where('context_id' => context.id)
+      end
+
+      if params[:project_id]
+        project = current_user.projects.find(params[:project_id])
+        not_done_todos = not_done_todos.where('project_id' => project)
+      end
+
+      return not_done_todos
+    end
+  end
+end