feat: added a custom slot provider option for user to select the slot no and rearrange the order

lib/providers/badge_slot_provider..dart

@@ -1,27 +1,95 @@
 import 'package:flutter/material.dart';
 
+extension FirstOrNullExtension<E> on Iterable<E> {
+  E? get firstOrNull => isEmpty ? null : first;
+}
+
 class BadgeSlotProvider with ChangeNotifier {
-  final Set<String> _selectedBadges = {};
+  // Maps selected badge key -> assigned slot number (1..8)
+  final Map<String, int> _badgeKeyToSlot = {};
+
+  // Available slot numbers pool
+  final Set<int> _availableSlots = {1, 2, 3, 4, 5, 6, 7, 8};
+
   static const int maxSelectedBadges = 8;
 
-  Set<String> get selectedBadges => _selectedBadges;
+  Set<String> get selectedBadges => _badgeKeyToSlot.keys.toSet();
 
-  bool isSelected(String badgeKey) => _selectedBadges.contains(badgeKey);
+  bool isSelected(String badgeKey) => _badgeKeyToSlot.containsKey(badgeKey);
 
-  bool get canSelectMore => _selectedBadges.length < maxSelectedBadges;
+  bool get canSelectMore =>
+      _badgeKeyToSlot.length < maxSelectedBadges && _availableSlots.isNotEmpty;
+
+  int? getSlotForBadge(String badgeKey) => _badgeKeyToSlot[badgeKey];
+
+  List<String> getSelectionsOrderedBySlot() {
+    final entries = _badgeKeyToSlot.entries.toList()
+      ..sort((a, b) => a.value.compareTo(b.value));
+    return entries.map((e) => e.key).toList();
+  }
+
+  /// ✅ Updated reorderSlots to perform push-down insertion
+  void reorderSlots(String fromBadgeKey, String toBadgeKey) {
+    if (!_badgeKeyToSlot.containsKey(fromBadgeKey) ||
+        !_badgeKeyToSlot.containsKey(toBadgeKey)) return;
+
+    final orderedKeys = getSelectionsOrderedBySlot();
+    orderedKeys.remove(fromBadgeKey);
+    final toIndex = orderedKeys.indexOf(toBadgeKey);
+
+    orderedKeys.insert(toIndex, fromBadgeKey);
+
+    _badgeKeyToSlot.clear();
+    _availableSlots
+      ..clear()
+      ..addAll({1, 2, 3, 4, 5, 6, 7, 8});
+
+    for (int i = 0; i < orderedKeys.length; i++) {
+      final slot = i + 1;
+      _badgeKeyToSlot[orderedKeys[i]] = slot;
+      _availableSlots.remove(slot);
+    }
+
+    notifyListeners();
+  }
 
   void toggleSelection(String badgeKey) {
-    if (_selectedBadges.contains(badgeKey)) {
-      _selectedBadges.remove(badgeKey);
-      notifyListeners();
-    } else if (_selectedBadges.length < maxSelectedBadges) {
-      _selectedBadges.add(badgeKey);
+    if (_badgeKeyToSlot.containsKey(badgeKey)) {
+      // Unselect: free its slot
+      final freedSlot = _badgeKeyToSlot.remove(badgeKey);
+      if (freedSlot != null) {
+        _availableSlots.add(freedSlot);
+      }
       notifyListeners();
+      return;
+    }
+
+    if (_badgeKeyToSlot.length >= maxSelectedBadges ||
+        _availableSlots.isEmpty) {
+      return; // Cannot select more
     }
+
+    // Assign smallest available slot
+    final smallest = _availableSlots.reduce((a, b) => a < b ? a : b);
+    _availableSlots.remove(smallest);
+    _badgeKeyToSlot[badgeKey] = smallest;
+    notifyListeners();
   }
 
   void clearSelections() {
-    _selectedBadges.clear();
+    _badgeKeyToSlot.clear();
+    _availableSlots
+      ..clear()
+      ..addAll({1, 2, 3, 4, 5, 6, 7, 8});
     notifyListeners();
   }
+
+  bool canTransfer(String badgeKey) {
+    final slot = _badgeKeyToSlot[badgeKey];
+    return slot != null && slot <= 8;
+  }
+
+  List<String> getTransferableBadges() {
+    return getSelectionsOrderedBySlot().take(8).toList();
+  }
 }

lib/view/save_badge_screen.dart

@@ -216,8 +216,9 @@ class _SaveBadgeScreenState extends State<SaveBadgeScreen> {
                               onPressed: selectionProvider
                                       .selectedBadges.isNotEmpty
                                   ? () async {
-                                      final selectedBadges =
-                                          selectionProvider.selectedBadges;
+                                      // Use transferable badges (first 8 slots only)
+                                      final selectedBadges = selectionProvider
+                                          .getTransferableBadges();
                                       List<Message> badgeDataList = [];
 
                                       for (var badgeKey in selectedBadges) {