Design a Simple iOS Application

openai Design a simple iOS application with the following requirements: Users should be able to register and log in. Implement a simple chat interface where users can send and receive messages. The application should support the latest iOS version and be compatible with main devices. Please provide the code structure of the application, descriptions of main functional modules, and required pseudocode. Outline predicted challenges and solutions. Example Input 1.用户注册流程 2.用户登录流程 3.发送消息 4.接收消息并显示 5.不同设备之间的适配