🚧 RSS as a module

modules/RichSiteSummary/Service/Unsubscriber.cs

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+using System;
+using System.Collections.Concurrent;
+using System.Linq;
+using System.Threading.Tasks;
+using BotFramework;
+using Kruzya.TelegramBot.Core.Service;
+using Kruzya.TelegramBot.RichSiteSummary.Data;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+using Telegram.Bot.Types;
+
+namespace Kruzya.TelegramBot.RichSiteSummary.Service
+{
+    public class Unsubscriber : AbstractTimedHostedService
+    {
+        protected readonly ConcurrentQueue<UserUnsubscribe> _queue;
+        protected readonly IServiceScopeFactory _scopeFactory;
+
+        protected override TimeSpan TimerPeriod => TimeSpan.FromSeconds(1);
+
+        public Unsubscriber(ILogger<Unsubscriber> logger, ITelegramBot bot, ConcurrentQueue<UserUnsubscribe> queue, IServiceScopeFactory scopeFactory) : base(logger, bot)
+        {
+            _scopeFactory = scopeFactory;
+            _queue = queue;
+        }
+
+        protected override async Task OnRun()
+        {
+            if (_queue.Count == 0)
+            {
+                return;
+            }
+
+            UserUnsubscribe user;
+            if (!_queue.TryDequeue(out user))
+            {
+                return;
+            }
+
+            await UnsubscribeUser(user.ChatId);
+        }
+
+        private async Task UnsubscribeUser(ChatId chatId)
+        {
+            using var scope = _scopeFactory.CreateScope();
+            var dbContext = scope.ServiceProvider.GetRequiredService<RichSiteSummaryContext>();
+            
+            dbContext.Subscriptions.RemoveRange(dbContext.Subscriptions.Where(s => s.SubscriberId == chatId.Identifier));
+            await dbContext.SaveChangesAsync();
+        }
+    }
+}