Can you explain the main idea of the clean architecture principle and its role in software system design?

The main idea of the clean architecture principle is to divide the system into layers with clear dependencies, where inner layers do not depend on outer layers. This makes the code more flexible, testable, and maintainable.

At the center of the architecture are business rules (domain), which do not depend on implementation details such as databases, UI, or external services. External layers can depend on internal ones, but not vice versa.

The role of the principle in design:

• Ensures independence of business logic from technologies and frameworks.
• Simplifies replacing external components without changing the core of the application.
• Improves testability through logic isolation.

Layer examples (from inside out):

• Entities
• Use Cases
• Interface Adapters
• Frameworks & Drivers

This approach helps create systems resilient to changes.