add pagination for pages

lib/pages/delivery/model/delivery_model.dart

@@ -4,100 +4,61 @@ import 'package:cloud_firestore/cloud_firestore.dart';
 import 'package:fcs/data/services/services.dart';
 import 'package:fcs/domain/constants.dart';
 import 'package:fcs/domain/entities/carton.dart';
-import 'package:fcs/helpers/paginator.dart';
 import 'package:fcs/pages/main/model/base_model.dart';
 import 'package:logging/logging.dart';
 
+import '../../../pagination/paginator_listener.dart';
+
 class DeliveryModel extends BaseModel {
   final log = Logger('DeliveryModel');
-  List<Carton> get cartons => _selectedIndex == 1
-      ? _cartons
-      : List<Carton>.from(_delivered?.values ?? []);
+  PaginatorListener<Carton>? getCartons;
+  int selectedIndex = 1;
 
-  Paginator? _delivered;
-  int _selectedIndex = 1;
-  bool isLoading = false;
-  List<Carton> _cartons = [];
-  StreamSubscription<QuerySnapshot>? listener;
-
-  set selectedIndex(int index) {
-    _selectedIndex = index;
+  onChanged(int index) {
+    selectedIndex = index;
+    loadPaginationCartons(selectedIndex);
     notifyListeners();
   }
 
-  int get selectedIndex => _selectedIndex;
-
-  initData() {
-    _selectedIndex = 1;
-    _loadCartons();
-
-    if (_delivered != null) _delivered!.close();
-    _delivered = _getDelivered();
-    _delivered!.load();
-  }
-
-  Future<void> _loadCartons() async {
+  loadPaginationCartons(int index) {
     if (user == null || !user!.hasDeliveries()) return;
-    String path = "/$cartons_collection/";
-    if (listener != null) listener!.cancel();
-    _cartons = [];
-    try {
-      listener = FirebaseFirestore.instance
-          .collection("$path")
+    String path = "/$cartons_collection";
+
+    Query col = FirebaseFirestore.instance.collection(path);
+    Query pageQuery = FirebaseFirestore.instance.collection(path);
+
+    if (index == 1) {
+      col = col
           .where("status", isEqualTo: carton_shipped_status)
           .where("carton_type", whereIn: [
-            carton_from_packages,
-            carton_from_shipments,
-            carton_small_bag
-          ])
-          .where("is_deleted", isEqualTo: false)
-          .orderBy("carton_number", descending: false)
-          .snapshots()
-          .listen((QuerySnapshot snapshot) {
-            _cartons.clear();
-            _cartons = snapshot.docs.map((documentSnapshot) {
-              var s = Carton.fromMap(
-                  documentSnapshot.data as Map<String, dynamic>,
-                  documentSnapshot.id);
-              return s;
-            }).toList();
-            notifyListeners();
-          });
-    } catch (e) {
-      log.warning("Error!! $e");
+        carton_from_packages,
+        carton_from_shipments,
+        carton_small_bag
+      ]);
+      pageQuery = pageQuery
+          .where("status", isEqualTo: carton_shipped_status)
+          .where("carton_type", whereIn: [
+        carton_from_packages,
+        carton_from_shipments,
+        carton_small_bag
+      ]);
     }
-  }
 
-  Paginator _getDelivered() {
-    if (user == null || !user!.hasDeliveries()) throw "No Privilege";
+    if (index == 2) {
+      col = col
+          .where("is_delivered", isEqualTo: true)
+          .where("status", whereIn: [carton_delivered_status]);
+      pageQuery = pageQuery
+          .where("is_delivered", isEqualTo: true)
+          .where("status", whereIn: [carton_delivered_status]);
+    }
 
-    var pageQuery = FirebaseFirestore.instance
-        .collection("/$cartons_collection")
-        .where("is_delivered", isEqualTo: true)
-        .where("status", whereIn: [carton_delivered_status]).where("is_deleted",
-            isEqualTo: false);
-    var paginator = new Paginator(pageQuery, rowPerLoad: 20, toObj: (data, id) {
-      return Carton.fromMap(data, id);
-    });
-    return paginator;
-  }
+    pageQuery = pageQuery.orderBy("carton_number");
 
-  Future<void> loadMore() async {
-    if (_delivered!.ended || _selectedIndex == 1) return;
-    isLoading = true;
-    notifyListeners();
-    await _delivered!.load(onFinished: () {
-      isLoading = false;
-      notifyListeners();
-    });
-  }
-
-  Future<void> refresh() async {
-    if (_selectedIndex == 1) return;
-
-    await _delivered!.refresh(onFinished: () {
-      notifyListeners();
-    });
+    getCartons?.close();
+    getCartons = PaginatorListener<Carton>(
+        col, pageQuery, (data, id) => Carton.fromMap(data, id),
+        rowPerLoad: 30);
   }
 
   void initUser(user) {
@@ -106,9 +67,7 @@ class DeliveryModel extends BaseModel {
 
   @override
   logout() async {
-    if (listener != null) await listener!.cancel();
-    if (_delivered != null) _delivered!.close();
-    _cartons = [];
+    getCartons?.close();
   }
 
   Future<void> deliver(Carton carton) {