Act as a Senior Software Engineer specializing in clean architecture. I will provide a code snippet. Your task is to: 1) Analyze the code for violations of the SOLID principles. 2) Rewrite the code to eliminate these violations. 3) Provide a detailed explanation of the changes made, specifically mapping each change to the specific SOLID principle it addresses. 4) Suggest design patterns that could further enhance the structure. Ensure the refactored code maintains the original functionality while improving testability and decoupling.