[cm] greet new members & refactor rules

modules/ChatManagement/Handler/Greet.cs

@@ -0,0 +1,52 @@
+using System;
+using System.Linq;
+using System.Threading.Tasks;
+using BotFramework;
+using BotFramework.Attributes;
+using BotFramework.Enums;
+using BotFramework.Utils;
+using Kruzya.TelegramBot.Core.Extensions;
+using Telegram.Bot;
+using Telegram.Bot.Types.Enums;
+using West.TelegramBot.ChatManagement.Service;
+
+namespace West.TelegramBot.ChatManagement.Handler;
+
+public class Greet : BotEventHandler
+{
+    private readonly RulesService _rulesService;
+
+    public Greet(RulesService rulesService)
+    {
+        _rulesService = rulesService;
+    }
+
+    [Message(InChat.Public, MessageFlag.HasNewChatMembers)]
+    public async Task HandleNewChatMembers()
+    {
+        var message = RawUpdate.Message!;
+        var members = message.NewChatMembers!;
+        var reply = new HtmlString();
+        string membersHtml;
+        if (members.Length > 1)
+        {
+            reply.Pre("Приветствуем новых участников!");
+            membersHtml = string.Join(", ", members.Select(u => u.ToHtml()));
+        }
+        else
+        {
+            reply.Pre("Приветствуем нового участника!");
+            membersHtml = members.First().ToHtml();
+        }
+
+        reply.Br().TextBr("{0}");
+
+        if (await _rulesService.HasRulesAsync(Chat))
+        {
+            reply.Text("Пожалуйста, ознакомьтесь с правилами. /rules");
+        }
+
+        await Bot.SendTextMessageAsync(Chat.Id, string.Format(reply.ToString(), membersHtml), 
+            ParseMode.Html, replyToMessageId: message.MessageId);
+    }
+}