What level of abstraction do you apply to organize interaction between files?

To organize interaction between files in an iOS application, abstraction layers are usually used, which ensure loose coupling and clear separation of responsibilities. Commonly used are:

• Modularity through classes and structures — each file contains a separate class or structure with specific functionality.
• Protocols — to define interaction interfaces between components, allowing implementation changes without modifying the code that uses them.
• Dependency Injection — for passing dependencies between objects without tight coupling.
• Use of managers and services — for example, NetworkManager, DataManager, which encapsulate logic and provide APIs for other parts of the application.

Thus, interaction between files is built through clearly defined interfaces (protocols) and abstractions, rather than direct access to internal class details.