Conditional Compilation Implementation Summary

✅ Successfully Implemented

The Brother Printer functionality now supports conditional compilation, allowing the app to run on iOS Simulator while maintaining full functionality on physical devices.

Architecture

File Structure

lib/utils/
├── brother_printer_util.dart          # Main entry point with export control
├── brother_printer_util_device.dart   # Full implementation with another_brother SDK
└── brother_printer_util_stub.dart     # Stub implementation for unsupported platforms

Implementation Strategy

1. Conditional Export (`brother_printer_util.dart`)

Controls which implementation is used
When another_brother is disabled: exports stub for ALL platforms
When another_brother is enabled: exports device implementation

2. Device Implementation (`brother_printer_util_device.dart`)

Original full-featured implementation
Requires another_brother package
Imports Brother SDK classes (Printer, PrinterInfo, Model, etc.)
Provides real label printing functionality

3. Stub Implementation (`brother_printer_util_stub.dart`)

Lightweight replacement when Brother SDK unavailable
Matches the same public API as device implementation
Returns error messages: “Brother printer is only supported on physical iOS/Android devices”
Shows user-friendly snack bars in UI methods

Usage

For iOS Simulator Testing

# 1. Disable Brother printer
./toggle_brother_printer.sh disable

# 2. Clean and rebuild
flutter clean && flutter pub get && cd ios && pod install

# 3. Run on simulator
flutter run --flavor dev -d "iPhone Air"

Result: App runs successfully on simulator with printer features gracefully disabled.

For Physical Device Testing

# 1. Re-enable Brother printer
./toggle_brother_printer.sh enable

# 2. Clean and rebuild  
flutter clean && flutter pub get && cd ios && pod install

# 3. Run on device
./run.sh dev ios 00008112-001C20911E68A01E

Result: App runs with full Brother printer functionality.

Benefits

✅ Simulator Testing: Can test all other features without printer hardware ✅ Clean Separation: Device and stub implementations completely isolated ✅ Type Safety: Both implementations export identical public API ✅ User Experience: Graceful fallbacks with informative messages ✅ No Runtime Overhead: Conditional compilation happens at build time ✅ Easy Toggle: Simple script to switch between modes

Testing Checklist

✅ Simulator Build (Verified)

App compiles without Brother SDK
App launches on iOS Simulator
Printer UI shows appropriate messages
Other features work normally (calendar, check-in, etc.)

🔲 Device Build (To Test)

App compiles with Brother SDK
App launches on physical iOS device
Brother printer discovery works
Label printing functionality works
All Brother printer features operational

Technical Notes

Why Toggle Script Is Needed

The another_brother plugin has hard dependencies on Brother SDK native frameworks in its podspec:

s.dependency 'BRLMPrinterKit_AB'
s.dependency 'BROTHERSDK'

These frameworks are device-only (no simulator support). Even with conditional Dart imports, CocoaPods will still try to link the frameworks, causing build failures.

Solution: Temporarily comment out the dependency in pubspec.yaml for simulator builds.

Future Improvements

If Brother releases simulator-compatible frameworks:

Remove the toggle script requirement
Update brother_printer_util.dart to use conditional exports
Use runtime platform detection instead of build-time toggling

Alternative Considered

Weak Linking: Attempted to make frameworks optional via Podfile, but CocoaPods doesn’t support partial weak linking of plugin dependencies.

Files Modified

✅ lib/utils/brother_printer_util.dart - Conditional export logic
✅ lib/utils/brother_printer_util_device.dart - Renamed from original
✅ lib/utils/brother_printer_util_stub.dart - New stub implementation
✅ toggle_brother_printer.sh - Helper script to toggle dependency
✅ docs/BROTHER_PRINTER_SIMULATOR.md - Documentation
✅ docs/CONDITIONAL_COMPILATION_SUMMARY.md - This file