(#421) identity: update query handlers

MiniSpace.Services.Identity/src/MiniSpace.Services.Identity.Infrastructure/Mongo/Queries/Handlers/GetOnlineUsersHandler.cs

@@ -0,0 +1,46 @@
+using System;
+using System.Linq;
+using System.Threading.Tasks;
+using Convey.CQRS.Queries;
+using Convey.Persistence.MongoDB;
+using MiniSpace.Services.Identity.Application.DTO;
+using MiniSpace.Services.Identity.Application.Queries;
+using MiniSpace.Services.Identity.Infrastructure.Mongo.Documents;
+using MongoDB.Driver;
+
+namespace MiniSpace.Services.Identity.Infrastructure.Mongo.Queries.Handlers
+{
+    internal sealed class GetOnlineUsersHandler : IQueryHandler<GetOnlineUsers, PagedResult<UserDto>>
+    {
+        private readonly IMongoRepository<UserDocument, Guid> _userRepository;
+
+        public GetOnlineUsersHandler(IMongoRepository<UserDocument, Guid> userRepository)
+        {
+            _userRepository = userRepository;
+        }
+
+        public async Task<PagedResult<UserDto>> HandleAsync(GetOnlineUsers query)
+        {
+            var filter = Builders<UserDocument>.Filter.Eq(u => u.IsOnline, true);
+
+            var totalResults = await _userRepository.Collection.CountDocumentsAsync(filter);
+
+            var totalPages = (int)Math.Ceiling(totalResults / (double)query.PageSize);
+
+            var onlineUsers = await _userRepository.Collection
+                .Find(filter)
+                .SortByDescending(u => u.LastActive)  
+                .Skip((query.Page - 1) * query.PageSize)
+                .Limit(query.PageSize)  
+                .ToListAsync();  
+
+            return PagedResult<UserDto>.Create(
+                onlineUsers.Select(user => user.AsDto()),  
+                query.Page,
+                query.PageSize,
+                totalPages,
+                totalResults
+            );
+        }
+    }
+}