A better state and alerts

lib/screens/workforce/workforce_screen.dart

@@ -13,6 +13,7 @@ import '../../providers/profile_provider.dart';
 import '../../providers/workforce_provider.dart';
 import '../../widgets/responsive_body.dart';
 import '../../theme/app_surfaces.dart';
+import '../../utils/snackbar.dart';
 
 class WorkforceScreen extends ConsumerWidget {
   const WorkforceScreen({super.key});
@@ -438,7 +439,11 @@ class _ScheduleTile extends ConsumerWidget {
         .where((profile) => profile.id != currentUserId)
         .toList();
     if (staff.isEmpty) {
-      _showMessage(context, 'No IT staff available for swaps.');
+      _showMessage(
+        context,
+        'No IT staff available for swaps.',
+        type: SnackType.warning,
+      );
       return;
     }
 
@@ -572,17 +577,36 @@ class _ScheduleTile extends ConsumerWidget {
           );
       ref.invalidate(swapRequestsProvider);
       if (!context.mounted) return;
-      _showMessage(context, 'Swap request sent.');
+      _showMessage(context, 'Swap request sent.', type: SnackType.success);
     } catch (error) {
       if (!context.mounted) return;
-      _showMessage(context, 'Swap request failed: $error');
+      _showMessage(
+        context,
+        'Swap request failed: $error',
+        type: SnackType.error,
+      );
     }
   }
 
-  void _showMessage(BuildContext context, String message) {
-    ScaffoldMessenger.of(
-      context,
-    ).showSnackBar(SnackBar(content: Text(message)));
+  void _showMessage(
+    BuildContext context,
+    String message, {
+    SnackType type = SnackType.warning,
+  }) {
+    switch (type) {
+      case SnackType.success:
+        showSuccessSnackBar(context, message);
+        break;
+      case SnackType.error:
+        showErrorSnackBar(context, message);
+        break;
+      case SnackType.info:
+        showInfoSnackBar(context, message);
+        break;
+      case SnackType.warning:
+        showWarningSnackBar(context, message);
+        break;
+    }
   }
 
   Future<void> _showAlert(
@@ -647,7 +671,11 @@ class _ScheduleTile extends ConsumerWidget {
       controller.animateTo(1);
       return;
     }
-    _showMessage(context, 'Swap request already sent. See Swaps panel.');
+    _showMessage(
+      context,
+      'Swap request already sent. See Swaps panel.',
+      type: SnackType.info,
+    );
   }
 
   String _statusLabel(String status) {
@@ -884,11 +912,11 @@ class _ScheduleGeneratorPanelState
     final start = _startDate;
     final end = _endDate;
     if (start == null || end == null) {
-      _showMessage('Select a date range.');
+      showWarningSnackBar(context, 'Select a date range.');
       return;
     }
     if (end.isBefore(start)) {
-      _showMessage('End date must be after start date.');
+      showWarningSnackBar(context, 'End date must be after start date.');
       return;
     }
     setState(() => _isGenerating = true);
@@ -896,7 +924,7 @@ class _ScheduleGeneratorPanelState
       final staff = _sortedStaff();
       if (staff.isEmpty) {
         if (!mounted) return;
-        _showMessage('No IT staff available for scheduling.');
+        showWarningSnackBar(context, 'No IT staff available for scheduling.');
         return;
       }
 
@@ -919,7 +947,7 @@ class _ScheduleGeneratorPanelState
       });
 
       if (generated.isEmpty) {
-        _showMessage('No shifts could be generated.');
+        showInfoSnackBar(context, 'No shifts could be generated.');
       }
     } finally {
       if (mounted) {
@@ -1099,7 +1127,7 @@ class _ScheduleGeneratorPanelState
   Future<void> _openDraftEditor({_DraftSchedule? existing}) async {
     final staff = _sortedStaff();
     if (staff.isEmpty) {
-      _showMessage('No IT staff available.');
+      showWarningSnackBar(context, 'No IT staff available.');
       return;
     }
 
@@ -1305,14 +1333,14 @@ class _ScheduleGeneratorPanelState
     final start = _startDate;
     final end = _endDate;
     if (start == null || end == null) {
-      _showMessage('Select a date range.');
+      showWarningSnackBar(context, 'Select a date range.');
       return;
     }
 
     final schedules = ref.read(dutySchedulesProvider).valueOrNull ?? [];
     final conflict = _findConflict(_draftSchedules, schedules);
     if (conflict != null) {
-      _showMessage(conflict);
+      showInfoSnackBar(context, conflict);
       return;
     }
 
@@ -1334,14 +1362,14 @@ class _ScheduleGeneratorPanelState
       await ref.read(workforceControllerProvider).insertSchedules(payload);
       ref.invalidate(dutySchedulesProvider);
       if (!mounted) return;
-      _showMessage('Schedule committed.');
+      showSuccessSnackBar(context, 'Schedule committed.');
       setState(() {
         _draftSchedules = [];
         _warnings = [];
       });
     } catch (error) {
       if (!mounted) return;
-      _showMessage('Commit failed: $error');
+      showErrorSnackBar(context, 'Commit failed: $error');
     } finally {
       if (mounted) {
         setState(() => _isSaving = false);
@@ -1762,12 +1790,6 @@ class _ScheduleGeneratorPanelState
         return value;
     }
   }
-
-  void _showMessage(String message) {
-    ScaffoldMessenger.of(
-      context,
-    ).showSnackBar(SnackBar(content: Text(message)));
-  }
 }
 
 class _SwapRequestsPanel extends ConsumerWidget {