Refactor large classes exceeding 300 lines

[callebtc]

Description:
Several classes exceed the recommended 300-line limit, making them harder to maintain and test.

Large Classes Identified:

• ModernPOSActivity.kt: 381 lines
• PaymentRequestActivity.kt: 852 lines
• TopUpActivity.kt: 562 lines
• Other activities likely affected

Issues:

1. Violates Single Responsibility Principle
2. Harder to test individual components
3. Increased complexity for maintenance

Fix Instructions:
Break down large classes using these patterns:

1. Extract Helper Classes:

// Extract complex logic to separate classes
class PaymentFlowManager(private val activity: PaymentRequestActivity) {
    fun handlePaymentFlow() { /* logic */ }
}

2. Use Fragments for UI Components:

// Split large activities into fragments
class PaymentOptionsFragment : Fragment()
class PaymentStatusFragment : Fragment()  

3. Extract Business Logic:

// Move business logic to separate classes
class PaymentProcessor
class ValidationManager

Refactoring Priority:

1. PaymentRequestActivity.kt (852 lines) - highest priority
2. TopUpActivity.kt (562 lines)
3. ModernPOSActivity.kt (381 lines)

Target: Keep classes under 300 lines, methods under 50 lines