Flutter Order Model for Payment

Below we created an order model for our e-commerce app.

class OrderModel {
  late int id;
  late int userId;
  double? orderAmount;
  String? orderStatus;

  String? paymentStatus;
  double? totalTaxAmount;
  String? orderNote;
  String? createdAt;
  String? updatedAt;
  double? deliveryCharge;
  String? scheduleAt;
  String? otp;
  String? pending;
  String? accepted;
  String? confirmed;
  String? processing;
  String? handover;
  String? pickedUp;
  String? delivered;
  String? canceled;
  String? refundRequested;
  String? refunded;
  int? scheduled;
  String? failed;
  int? detailsCount;

  AddressModel? deliveryAddress;

  OrderModel(
      { required this.id,
        required this.userId,
         this.orderAmount,
         this.paymentStatus,
         this.orderNote,
         this.createdAt,
         this.updatedAt,
         this.deliveryCharge,
         this.scheduleAt,
         this.otp,
         this.orderStatus,
         this.pending,
         this.accepted,
         this.confirmed,
         this.processing,
         this.handover,
         this.pickedUp,
         this.delivered,
         this.canceled,
         this.scheduled,
         this.failed,
         this.detailsCount,
         this.deliveryAddress,
      });

  OrderModel.fromJson(Map<String, dynamic> json) {
    id = json['id'];
    userId = json['user_id'];
    orderAmount = json['order_amount'].toDouble();
    paymentStatus = json['payment_status']??"pending";
    totalTaxAmount =10.0;
    orderNote = json['order_note'];
    createdAt = json['created_at'];
    updatedAt = json['updated_at'];
    orderStatus=json['order_status'];
    deliveryCharge = 10.0;
    scheduleAt = json['schedule_at']??"";
    otp = json['otp'];
    pending = json['pending']??"";
    accepted = json['accepted']??"";
    confirmed = json['confirmed']??"";
    processing = json['processing']??"";
    handover = json['handover']??"";
    pickedUp = json['picked_up']??"";
    delivered = json['delivered']??"";
    canceled = json['canceled']??"";
    scheduled = json['scheduled'];
    failed = json['failed']??"";
    detailsCount = json['details_count'];

    deliveryAddress = (json['delivery_address'] != null
        ? new AddressModel.fromJson(json['delivery_address'])
        : null)!;
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['id'] = this.id;
    data['user_id'] = this.userId;
    data['order_amount'] = this.orderAmount;

    data['payment_status'] = this.paymentStatus;
    data['total_tax_amount'] = this.totalTaxAmount;
    data['order_note'] = this.orderNote;
    data['created_at'] = this.createdAt;
    data['updated_at'] = this.updatedAt;
    data['delivery_charge'] = this.deliveryCharge;
    data['schedule_at'] = this.scheduleAt;
    data['otp'] = this.otp;
    data['pending'] = this.pending;
    data['accepted'] = this.accepted;
    data['confirmed'] = this.confirmed;
    data['processing'] = this.processing;
    data['handover'] = this.handover;
    data['picked_up'] = this.pickedUp;
    data['delivered'] = this.delivered;
    data['canceled'] = this.canceled;
    data['refund_requested'] = this.refundRequested;
    data['refunded'] = this.refunded;
    data['scheduled'] = this.scheduled;
    data['failed'] = this.failed;
    data['details_count'] = this.detailsCount;
    if (this.deliveryAddress != null) {
      data['delivery_address'] = this.deliveryAddress?.toJson();
    }
    return data;
  }
}