Refactor message loading API and add message query support

Reworked message loading endpoints and services to support flexible message querying with 'before' and 'after' parameters via a new MessageQuery contract. Updated controller actions, service interfaces, and implementations to use the new query model, and improved error handling. Added integration tests for ChatLoadController and introduced IUserPresenceService interface. Minor fixes and help text improvements in console client commands.

Govor.Application/Interfaces/IMessagesLoader.cs

@@ -4,6 +4,6 @@ namespace Govor.Application.Interfaces;
 
 public interface IMessagesLoader
 {
-    Task<List<Message>> LoadLastMessagesInUserChat(Guid userId,Guid currentId, Guid? startMessageId, int pageSize = 20);
-    Task<List<Message>> LoadLastMessagesInChatGroup(Guid chatId,Guid currentId, Guid? startMessageId, int pageSize = 20);
+    Task<List<Message>> LoadMessagesInUserChat(Guid userId,Guid currentId, Guid? startMessageId, int before = 20, int after = 2);
+    Task<List<Message>> LoadMessagesInChatGroup(Guid chatId,Guid currentId, Guid? startMessageId, int before = 20, int after = 2);
 }

Govor.Application/Interfaces/IUserPresenceService.cs

@@ -0,0 +1,6 @@
+namespace Govor.Application.Interfaces;
+
+public interface IUserPresenceService
+{
+    DateTime WhenUserWasOnline(Guid userId);
+}

Govor.Application/Services/Messages/MessagesLoader.cs

@@ -1,8 +1,6 @@
 using Govor.Application.Interfaces;
-using Govor.Core.Infrastructure.Extensions;
 using Govor.Core.Models.Messages;
 using Govor.Core.Repositories.Groups;
-using Govor.Core.Repositories.Messages;
 using Govor.Core.Repositories.PrivateChats;
 using Govor.Data;
 using Govor.Data.Repositories.Exceptions;
@@ -26,57 +24,121 @@ public class MessagesLoader : IMessagesLoader
         _dbContext = dbContext;
     }
     
-    public async Task<List<Message>> LoadLastMessagesInUserChat(Guid userId, Guid currentUser, Guid? startMessageId, int pageSize = 20)
+    public async Task<List<Message>> LoadMessagesInUserChat(
+        Guid userId,
+        Guid currentUser,
+        Guid? startMessageId,
+        int before = 20,
+        int after = 2)
     {
-        if(userId == Guid.Empty)
+        if (userId == Guid.Empty)
             throw new ArgumentException("User id cannot be empty");
-        
-        if(!_privateChatsRepository.Exist(userId, currentUser))
+
+        if (!_privateChatsRepository.Exist(userId, currentUser))
             throw new InvalidOperationException("Private chat not found");
-        
-        try
+
+        var chat = await _privateChatsRepository.GetByMembersAsync(userId, currentUser);
+
+        var query = _dbContext.Messages
+            .AsNoTracking()
+            .Include(m => m.MediaAttachments)
+            .ThenInclude(m => m.MediaFile)
+            .Where(m => m.RecipientType == RecipientType.User &&
+                        m.RecipientId == chat.Id);
+
+        if (startMessageId is null)
         {
-            var chat  = await _privateChatsRepository.GetByMembersAsync(userId, currentUser);
-            
-            return await _dbContext.Messages
-                .AsNoTracking()
-                .Include(m => m.MediaAttachments)
-                .ThenInclude(m => m.MediaFile)
-                .AsSplitQuery()
-                .Where(m => m.RecipientType == RecipientType.User &&
-                           m.RecipientId == chat.Id)
-                .Take(pageSize)
-                .ToListOrThrowIfEmpty(new NotFoundException("Messages not found"));
-        }
-        catch (NotFoundException ex)
-        {
-            return new List<Message>();
+            return await query
+                .OrderByDescending(m => m.SentAt)
+                .Take(before)
+                .ToListAsync();
         }
+
+        var startMessage = await _dbContext.Messages.FindAsync(startMessageId.Value);
+        if (startMessage == null)
+            throw new NotFoundException("Start message not found");
+
+        var beforeMessages = await query
+            .Where(m => m.SentAt < startMessage.SentAt)
+            .OrderByDescending(m => m.SentAt)
+            .Take(before)
+            .ToListAsync();
+
+        var afterMessages = await query
+            .Where(m => m.SentAt > startMessage.SentAt)
+            .OrderBy(m => m.SentAt)
+            .Take(after)
+            .ToListAsync();
+
+        // older -> start -> newer
+        var result = beforeMessages
+            .OrderBy(m => m.SentAt)
+            .Concat(new[] { startMessage })
+            .Concat(afterMessages)
+            .ToList();
+
+        return result;
     }
 
-    public async Task<List<Message>> LoadLastMessagesInChatGroup(Guid chatId, Guid currentUser, Guid? startMessageId, int pageSize = 20)
+
+    public async Task<List<Message>> LoadMessagesInChatGroup(
+        Guid chatId,
+        Guid currentUser,
+        Guid? startMessageId,
+        int before = 20,
+        int after = 2)
     {
-        if(chatId == Guid.Empty)
+        if (chatId == Guid.Empty)
             throw new ArgumentException("Chat id cannot be empty");
-        
-        if(!await _groupsRepository.IsUserMemberOfGroupAsync(currentUser, chatId))
-            throw new UnauthorizedAccessException("You are not in a group.");
-        
-        try
+
+        var isMember = await _groupsRepository.IsUserMemberOfGroupAsync(currentUser, chatId);
+        if (!isMember)
+            throw new UnauthorizedAccessException("You are not a member of this group.");
+
+        var baseQuery = _dbContext.Messages
+            .AsNoTracking()
+            .Include(m => m.MediaAttachments)
+            .ThenInclude(m => m.MediaFile)
+            .AsSplitQuery()
+            .Where(m => m.RecipientType == RecipientType.Group && m.RecipientId == chatId);
+
+        if (startMessageId is null)
         {
-            return await _dbContext.Messages
-                .AsNoTracking()
-                .Include(m => m.MediaAttachments)
-                .ThenInclude(m => m.MediaFile)
-                .AsSplitQuery()
-                .Where(m => m.RecipientType == RecipientType.Group &&
-                            m.RecipientId == chatId)
-                .Take(pageSize)
-                .ToListOrThrowIfEmpty(new NotFoundException("Messages not found"));
-        }
-        catch (NotFoundException ex)
-        {
-            return new List<Message>();
+            return await baseQuery
+                .OrderByDescending(m => m.SentAt)
+                .Take(before)
+                .OrderBy(m => m.SentAt)
+                .ToListAsync();
         }
+
+        var startMessage = await _dbContext.Messages
+            .AsNoTracking()
+            .FirstOrDefaultAsync(m => m.Id == startMessageId.Value && 
+                                      m.RecipientType == RecipientType.Group && 
+                                      m.RecipientId == chatId);
+
+        if (startMessage == null)
+            throw new NotFoundException("Start message not found in this group.");
+
+        var beforeMessages = await baseQuery
+            .Where(m => m.SentAt < startMessage.SentAt)
+            .OrderByDescending(m => m.SentAt)
+            .Take(before)
+            .ToListAsync();
+
+        var afterMessages = await baseQuery
+            .Where(m => m.SentAt > startMessage.SentAt)
+            .OrderBy(m => m.SentAt)
+            .Take(after)
+            .ToListAsync();
+
+        var result = beforeMessages
+            .OrderBy(m => m.SentAt)
+            .Concat(new[] { startMessage })
+            .Concat(afterMessages)
+            .ToList();
+
+        return result;
     }
+
 }