Repository

using System;
using System.Collections.Generic;
using GeoCoordinatePortable;
using System.Xml.Serialization;
using System.Text;
using System.IO;

namespace ConsoleApp1
{
    public class Repository
    {
        private static List<Order> _orders;
        private static List<Courier> _couriers;
        private static HashSet<Guid> _guids;

        public Repository()
        {
            _orders = new List<Order>();
            _couriers = new List<Courier>();
        }

        public void AddCourier(Courier courier) =>
            _couriers.Add(courier);

        public static void AddOrder(double weight, GeoCoordinate source, GeoCoordinate destination)
        {
            Guid guid = Guid.NewGuid();
            while (_guids.Contains(guid))
                guid = Guid.NewGuid();
            _guids.Add(guid);
            _orders.Add(new Order(weight, source, destination, guid));
        }

        public static bool AssignCourier(Order order)
        {
            double minDist = double.MaxValue;
            foreach (var courier in _couriers)
            {
                if (courier.MaxAccWeightOfParcel >= order.Weight &&
                courier.CurrentPosition.GetDistanceTo(order.StartPoint) < minDist)
                    minDist = courier.CurrentPosition.GetDistanceTo(order.StartPoint);
            }

            foreach (var courier in _couriers)
            {
                if (courier.MaxAccWeightOfParcel >= order.Weight &&
                courier.CurrentPosition.GetDistanceTo(order.StartPoint) == minDist)
                {
                    order.StartTime = DateTime.Now;
                    courier.IsAvailable = false;
                    order.CourierID = courier.ID;
                    return true;
                }
            }
            return false;
        }

        public static void CompleteOrder(Order order)
        {
            order.EndTime = DateTime.Now;
            foreach (var courier in _couriers)
                if (courier.ID == order.CourierID)
                {
                    courier.IsAvailable = true;
                    courier.CurrentPosition = order.EndPoint;
                }
        }

        public static void SaveInfo()
        {
            try
            {
                XmlSerializer xmlFormatter = new XmlSerializer(typeof(List<Order>));

                using (FileStream fs = new FileStream(@"..\..\..\orders.xml", FileMode.OpenOrCreate))
                {
                    xmlFormatter.Serialize(fs, _orders);
                }

                xmlFormatter = new XmlSerializer(typeof(List<Courier>));

                using (FileStream fs = new FileStream(@"..\..\..\couriers.xml", FileMode.OpenOrCreate))
                {
                    xmlFormatter.Serialize(fs, _couriers);
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
        }

        public static void LoadInfo()
        {
            try
            {
                XmlSerializer xmlFormatter = new XmlSerializer(typeof(List<Order>));

                using (FileStream fs = new FileStream(@"..\..\..\orders.xml", FileMode.Open))
                {
                    _orders = (List<Order>)xmlFormatter.Deserialize(fs);
                }

                xmlFormatter = new XmlSerializer(typeof(List<Courier>));

                using (FileStream fs = new FileStream(@"..\..\..\couriers.xml", FileMode.Open))
                {
                    _couriers = (List<Courier>)xmlFormatter.Deserialize(fs);
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.Message);
            }
        }

    }
}