todo_data_model.pas

  ITodo = interface
  end;

  TErrorTodo = class(TInterfacedObject, ITodo)
    public
      [JSONMarshalled(True)][JSONName('error_message')]
      ErrorMessage: string;

      constructor Create(ErrorMessage: string);
      function GetSelf: TObject;

      function ToString: string;
  end;

  TItemTodo = class(TInterfacedObject, ITodo)
    public
      [JSONMarshalled(True)][JSONName('task')]
      Task: string;
      [JSONMarshalled(True)][JSONName('is_completed')]
      IsCompleted: Boolean;

      constructor Create(Task: string; IsCompleted: Boolean);
      function GetSelf: TObject;

      function ToString: string;
  end;

  TListTodo = class(TInterfacedObject, ITodo)
  private
    public
      [JSONMarshalled(True)][JSONName('name')]
      Name: string;
      [JSONMarshalled(True)][JSONName('todos')]
      Todos: TList<TItemTodo>;

      constructor Create();
      destructor Destroy; override;
      function GetSelf: TObject;

      function ToString: string;
  end;