using System.Collections.Generic;

using System.Net.Http;

using System.Threading.Tasks;

​

namespace Interview

{

    public interface INotificationService

    {

        Task SendEmailAsync(string to, string subject, string body);

    }

​

    public sealed class NotificationService : INotificationService

    {

        public async Task SendEmailAsync(string to, string subject, string body)

        {

            using(var httpClient = new HttpClient())

            {

                var response = await httpClient.PostAsync("https://notification-service.com/api/emails/send", new StringContent(body));

                response.EnsureSuccessStatusCode();

            }

        }

    }

​

    public sealed class User

    {

        public string Id { get; set; }

​

        public string Name { get; set; }

​

        public string Email { get; set; }

    }

​

    public sealed class ReportingService

    {

        private readonly INotificationService _notificationService;

​

        public ReportingService(INotificationService notificationService)

        {

            _notificationService = notificationService;

        }

​

        public async Task SendReportsAsync(List<User> users)

        {

            foreach (var user in users)

            {

                await SendReportAsync(user);

            }

        }

​

        private async Task SendReportAsync(User user)

        {

            await _notificationService.SendEmailAsync(user.Email, "Your report", $"Hi, {user.Name}!");

        }

    }

}

​