feat: Add logger service and improve expense dialog with enhanced receipt management and calculation logic.

lib/blocs/balance/balance_bloc.dart

@@ -19,10 +19,10 @@
 ///   balanceRepository: balanceRepository,
 ///   expenseRepository: expenseRepository,
 /// );
-/// 
+///
 /// // Load balances for a group
 /// balanceBloc.add(LoadGroupBalances('groupId123'));
-/// 
+///
 /// // Mark a settlement as completed
 /// balanceBloc.add(MarkSettlementAsCompleted(
 ///   groupId: 'groupId123',
@@ -32,6 +32,7 @@
 /// ));
 /// ```
 library;
+
 import 'package:flutter_bloc/flutter_bloc.dart';
 import '../../repositories/balance_repository.dart';
 import '../../repositories/expense_repository.dart';
@@ -46,10 +47,10 @@ class BalanceBloc extends Bloc<BalanceEvent, BalanceState> {
   final ErrorService _errorService;
 
   /// Constructor for BalanceBloc.
-  /// 
+  ///
   /// Initializes the bloc with required repositories and optional services.
   /// Sets up event handlers for balance-related operations.
-  /// 
+  ///
   /// Args:
   ///   [balanceRepository]: Repository for balance data operations
   ///   [expenseRepository]: Repository for expense data operations
@@ -61,7 +62,12 @@ class BalanceBloc extends Bloc<BalanceEvent, BalanceState> {
     BalanceService? balanceService,
     ErrorService? errorService,
   }) : _balanceRepository = balanceRepository,
-       _balanceService = balanceService ?? BalanceService(balanceRepository: balanceRepository, expenseRepository: expenseRepository),
+       _balanceService =
+           balanceService ??
+           BalanceService(
+             balanceRepository: balanceRepository,
+             expenseRepository: expenseRepository,
+           ),
        _errorService = errorService ?? ErrorService(),
        super(BalanceInitial()) {
     on<LoadGroupBalances>(_onLoadGroupBalance);
@@ -70,11 +76,11 @@ class BalanceBloc extends Bloc<BalanceEvent, BalanceState> {
   }
 
   /// Handles [LoadGroupBalances] events.
-  /// 
+  ///
   /// Loads and calculates user balances for a specific group along with
   /// optimal settlement recommendations. This provides a complete overview
   /// of who owes money to whom and the most efficient payment strategy.
-  /// 
+  ///
   /// Args:
   ///   [event]: The LoadGroupBalances event containing the group ID
   ///   [emit]: State emitter function
@@ -83,18 +89,22 @@ class BalanceBloc extends Bloc<BalanceEvent, BalanceState> {
     Emitter<BalanceState> emit,
   ) async {
     try {
-      emit(BalanceLoading());
-      
+      // Emit empty state initially to avoid infinite spinner
+      emit(const GroupBalancesLoaded(balances: [], settlements: []));
+
       // Calculate group user balances
-      final userBalances = await _balanceRepository.calculateGroupUserBalances(event.groupId);
-      
+      final userBalances = await _balanceRepository.calculateGroupUserBalances(
+        event.groupId,
+      );
+
       // Calculate optimal settlements
-      final settlements = await _balanceService.calculateOptimalSettlements(event.groupId);
-      
-      emit(GroupBalancesLoaded(
-        balances: userBalances,
-        settlements: settlements,
-      ));
+      final settlements = await _balanceService.calculateOptimalSettlements(
+        event.groupId,
+      );
+
+      emit(
+        GroupBalancesLoaded(balances: userBalances, settlements: settlements),
+      );
     } catch (e) {
       _errorService.logError('BalanceBloc', 'Error loading balance: $e');
       emit(BalanceError(e.toString()));
@@ -102,11 +112,11 @@ class BalanceBloc extends Bloc<BalanceEvent, BalanceState> {
   }
 
   /// Handles [RefreshBalance] events.
-  /// 
+  ///
   /// Refreshes the balance data for a group while trying to maintain the current
   /// state when possible to provide a smoother user experience. Only shows loading
   /// state if there's no existing balance data.
-  /// 
+  ///
   /// Args:
   ///   [event]: The RefreshBalance event containing the group ID
   ///   [emit]: State emitter function
@@ -119,17 +129,20 @@ class BalanceBloc extends Bloc<BalanceEvent, BalanceState> {
       if (state is! GroupBalancesLoaded) {
         emit(BalanceLoading());
       }
-      
+
       // Calculate group user balances
-      final userBalances = await _balanceRepository.calculateGroupUserBalances(event.groupId);
-      
+      final userBalances = await _balanceRepository.calculateGroupUserBalances(
+        event.groupId,
+      );
+
       // Calculate optimal settlements
-      final settlements = await _balanceService.calculateOptimalSettlements(event.groupId);
-      
-      emit(GroupBalancesLoaded(
-        balances: userBalances,
-        settlements: settlements,
-      ));
+      final settlements = await _balanceService.calculateOptimalSettlements(
+        event.groupId,
+      );
+
+      emit(
+        GroupBalancesLoaded(balances: userBalances, settlements: settlements),
+      );
     } catch (e) {
       _errorService.logError('BalanceBloc', 'Error refreshing balance: $e');
       emit(BalanceError(e.toString()));
@@ -137,11 +150,11 @@ class BalanceBloc extends Bloc<BalanceEvent, BalanceState> {
   }
 
   /// Handles [MarkSettlementAsCompleted] events.
-  /// 
+  ///
   /// Records a settlement transaction between two users, marking that
   /// a debt has been paid. This updates the balance calculations and
   /// automatically refreshes the group balance data to reflect the change.
-  /// 
+  ///
   /// Args:
   ///   [event]: The MarkSettlementAsCompleted event containing settlement details
   ///   [emit]: State emitter function
@@ -156,9 +169,9 @@ class BalanceBloc extends Bloc<BalanceEvent, BalanceState> {
         toUserId: event.toUserId,
         amount: event.amount,
       );
-      
+
       emit(const BalanceOperationSuccess('Settlement marked as completed'));
-      
+
       // Reload balance after settlement
       add(RefreshBalance(event.groupId));
     } catch (e) {
@@ -166,4 +179,4 @@ class BalanceBloc extends Bloc<BalanceEvent, BalanceState> {
       emit(BalanceError(e.toString()));
     }
   }
-}
+}