fcs/lib/pages/fcs_shipment/model/fcs_shipment_model.dart

import 'dart:async';

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/fcs_shipment.dart';
import 'package:fcs/helpers/paginator.dart';
import 'package:fcs/pages/main/model/base_model.dart';
import 'package:logging/logging.dart';

class FcsShipmentModel extends BaseModel {
  final log = Logger('FcsShipmentModel');

  StreamSubscription<QuerySnapshot> listener;
  List<FcsShipment> _fcsShipments = [];
  List<FcsShipment> get fcsShipments => _selectedIndex == 1
      ? _fcsShipments
      : List<FcsShipment>.from(_delivered.values);

  Paginator _delivered;
  bool isLoading = false;
  int _selectedIndex = 1;
  set selectedIndex(int index) {
    _selectedIndex = index;
    notifyListeners();
  }

  get selectedIndex => _selectedIndex;

  @override
  void privilegeChanged() {
    super.privilegeChanged();
    _loadFcsShipments();

    if (_delivered != null) _delivered.close();
    _delivered = _getDelivered();
  }

  Future<void> _loadFcsShipments() async {
    if (user == null || !user.hasFcsShipments()) return;
    String path = "/$fcs_shipment_collection/";
    if (listener != null) listener.cancel();
    _fcsShipments = [];
    try {
      listener = Firestore.instance
          .collection("$path")
          .orderBy("shipment_number", descending: true)
          .snapshots()
          .listen((QuerySnapshot snapshot) {
        _fcsShipments.clear();
        _fcsShipments = snapshot.documents.map((documentSnapshot) {
          var s = FcsShipment.fromMap(
              documentSnapshot.data, documentSnapshot.documentID);
          return s;
        }).toList();
        notifyListeners();
      });
    } catch (e) {
      log.warning("Error!! $e");
    }
  }

  Paginator _getDelivered() {
    if (user == null || !user.hasFcsShipments()) return null;

    var pageQuery = Firestore.instance
        .collection("/$fcs_shipment_collection")
        .where("is_delivered", isEqualTo: true)
        .where("is_deleted", isEqualTo: false)
        .orderBy("current_status_date", descending: true);
    var paginator = new Paginator(pageQuery, rowPerLoad: 20, toObj: (data, id) {
      return FcsShipment.fromMap(data, id);
    });
    return paginator;
  }

  Future<void> loadMore() async {
    if (_delivered.ended) return;
    isLoading = true;
    notifyListeners();
    await _delivered.load(onFinished: () {
      isLoading = false;
      notifyListeners();
    });
  }

  Future<void> refresh() async {
    await _delivered.refresh(onFinished: () {
      notifyListeners();
    });
  }

  void initUser(user) {
    super.initUser(user);
  }

  @override
  logout() async {
    if (listener != null) await listener.cancel();
    if (_delivered != null) _delivered.close();
    _fcsShipments = [];
  }

  Future<void> create(FcsShipment fcsShipment) {
    return Services.instance.fcsShipmentService.createFcsShipment(fcsShipment);
  }

  Future<void> update(FcsShipment fcsShipment) {
    return Services.instance.fcsShipmentService.updateFcsShipment(fcsShipment);
  }
}