Feat: Add custom exceptions [#19]

Examples/Examples/Chat/ChatFromExistingExample.cs

@@ -1,5 +1,6 @@
 using System.Text.Json;
 using MaIN.Core.Hub;
+using MaIN.Domain.Exceptions;
 
 namespace Examples;
 
@@ -18,8 +19,16 @@ public async Task Start()
         await result.WithMessage("And about physics?")
             .CompleteAsync();
 
-        var chatNewContext = await AIHub.Chat().FromExisting(result.GetChatId());
-        var messages = chatNewContext.GetChatHistory();
-        Console.WriteLine(JsonSerializer.Serialize(messages));
+        try
+        {
+            var chatNewContext = await AIHub.Chat().FromExisting(result.GetChatId());
+            var messages = chatNewContext.GetChatHistory();
+            Console.WriteLine(JsonSerializer.Serialize(messages));
+        }
+        catch (ChatNotFoundException ex)
+        {
+            Console.WriteLine(ex.PublicErrorMessage);
+        }
+
     }
 }

src/MaIN.Core/Hub/Contexts/ChatContext.cs

@@ -1,5 +1,6 @@
 using MaIN.Domain.Configuration;
 using MaIN.Domain.Entities;
+using MaIN.Domain.Exceptions;
 using MaIN.Domain.Models;
 using MaIN.Services;
 using MaIN.Services.Constants;
@@ -169,8 +170,9 @@ public async Task<ChatResult> CompleteAsync(
     {
         if (_chat.Messages.Count == 0)
         {
-            throw new InvalidOperationException("Chat has no messages."); //TODO good candidate for domain exception
+            throw new EmptyChatException(_chat.Id);
         }
+
         _chat.Messages.Last().Files = _files;
         if(_preProcess)
         {
@@ -190,7 +192,9 @@ public async Task<ChatResult> CompleteAsync(
     public async Task<Chat> GetCurrentChat()
     {
         if (_chat.Id == null)
-            throw new InvalidOperationException("Chat has not been created yet. Call CompleteAsync first.");
+        {
+            throw new ChatNotInitializedException();
+        }
 
         return await _chatService.GetById(_chat.Id);
     }
@@ -203,8 +207,10 @@ public async Task<List<Chat>> GetAllChats()
     public async Task DeleteChat()
     {
         if (_chat.Id == null)
-            throw new InvalidOperationException("Chat has not been created yet.");
-
+        {
+            throw new ChatNotInitializedException();
+        }
+
         await _chatService.Delete(_chat.Id);
     }
 
@@ -227,7 +233,7 @@ public async Task<ChatContext> FromExisting(string chatId)
         var existingChat = await _chatService.GetById(chatId);
         if (existingChat == null)
         {
-            throw new Exception("Chat not found");
+            throw new ChatNotFoundException(chatId);
         }
         return new ChatContext(_chatService, existingChat);
     }

src/MaIN.Domain/Exceptions/AgentContextNotFoundException.cs

@@ -0,0 +1,9 @@
+using System.Net;
+
+namespace MaIN.Domain.Exceptions;
+
+public class AgentContextNotFoundException(string agentId) : MaINCustomException($"Context of agent with id: '{agentId}' not found.")
+{
+    public override string PublicErrorMessage => "Agent context not found.";
+    public override HttpStatusCode HttpStatusCode => HttpStatusCode.NotFound;
+}

src/MaIN.Domain/Exceptions/AgentFlowNotFoundException.cs

@@ -0,0 +1,9 @@
+using System.Net;
+
+namespace MaIN.Domain.Exceptions;
+
+public class AgentFlowNotFoundException(string flowId) : MaINCustomException($"Agent flow with id: '{flowId}' not found.")
+{
+    public override string PublicErrorMessage => "Agent flow not found.";
+    public override HttpStatusCode HttpStatusCode => HttpStatusCode.NotFound;
+}

src/MaIN.Domain/Exceptions/AgentNotFoundException.cs

@@ -0,0 +1,10 @@
+using System.Net;
+
+namespace MaIN.Domain.Exceptions;
+
+public class AgentNotFoundException(string agentId) 
+    : MaINCustomException($"Agent with id: '{agentId}' not found.")
+{
+    public override string PublicErrorMessage => "Agent not found.";
+    public override HttpStatusCode HttpStatusCode => HttpStatusCode.NotFound;
+}

src/MaIN.Domain/Exceptions/ApiRequestFailedException.cs

@@ -0,0 +1,10 @@
+using System.Net;
+
+namespace MaIN.Domain.Exceptions;
+
+public class ApiRequestFailedException(HttpStatusCode statusCode, string requestUrl, string httpMethod) 
+    : MaINCustomException($"API request failed with status code: {statusCode}. Request url: {requestUrl}. Http method: {httpMethod}.")
+{
+    public override string PublicErrorMessage => "An error occurred while processing an external API request";
+    public override HttpStatusCode HttpStatusCode => HttpStatusCode.InternalServerError;
+}

src/MaIN.Domain/Exceptions/ChatNotFoundException.cs

@@ -0,0 +1,10 @@
+using System.Net;
+
+namespace MaIN.Domain.Exceptions;
+
+public class ChatNotFoundException(string chatId) 
+    : MaINCustomException($"Chat with id: '{chatId}' not found.")
+{
+    public override string PublicErrorMessage => "Chat not found.";
+    public override HttpStatusCode HttpStatusCode => HttpStatusCode.NotFound;
+}

src/MaIN.Domain/Exceptions/ChatNotInitializedException.cs

@@ -0,0 +1,9 @@
+using System.Net;
+
+namespace MaIN.Domain.Exceptions;
+
+public class ChatNotInitializedException() : MaINCustomException("Chat has not been created yet. Call 'CompleteAsync' operation first.")
+{
+    public override string PublicErrorMessage => Message;
+    public override HttpStatusCode HttpStatusCode => HttpStatusCode.Conflict;
+}

src/MaIN.Domain/Exceptions/CommandFailedException.cs

@@ -0,0 +1,10 @@
+using System.Net;
+
+namespace MaIN.Domain.Exceptions;
+
+public class CommandFailedException(string commandName) 
+    : MaINCustomException($"{commandName} command execution failed.")
+{
+    public override string PublicErrorMessage => Message;
+    public override HttpStatusCode HttpStatusCode => HttpStatusCode.InternalServerError;
+}

src/MaIN.Domain/Exceptions/EmptyChatException.cs

@@ -0,0 +1,9 @@
+using System.Net;
+
+namespace MaIN.Domain.Exceptions;
+
+public class EmptyChatException(string chatId) : MaINCustomException($"Chat with id: '{chatId}' is empty. Complete operation is impossible.")
+{
+    public override string PublicErrorMessage => "Complete operation is impossible, because chat has no message.";
+    public override HttpStatusCode HttpStatusCode => HttpStatusCode.Conflict;
+}

src/MaIN.Domain/Exceptions/MaINCustomException.cs

@@ -0,0 +1,20 @@
+using System.Net;
+using System.Text.RegularExpressions;
+
+namespace MaIN.Domain.Exceptions;
+
+public abstract class MaINCustomException(string message) : Exception(message)
+{
+    public string ErrorCode => GenerateErrorCode();
+    public string LogMessage { get; private set; } = message;
+    public abstract string PublicErrorMessage { get; }
+    public abstract HttpStatusCode HttpStatusCode { get; }
+
+    private string GenerateErrorCode()
+    {
+        var typeName = GetType().Name;
+        var snakeCaseTypeName = Regex.Replace(typeName, "(?<!^)([A-Z])", "_$1").ToLower();
+
+        return snakeCaseTypeName.Replace("_exception", string.Empty);
+    }
+}

src/MaIN.Domain/Exceptions/ModelNotDownloadedException.cs

@@ -0,0 +1,10 @@
+using System.Net;
+
+namespace MaIN.Domain.Exceptions;
+
+public class ModelNotDownloadedException(string? modelName) 
+    : MaINCustomException($"Given model {modelName ?? string.Empty} is not downloaded.")
+{
+    public override string PublicErrorMessage => Message;
+    public override HttpStatusCode HttpStatusCode => HttpStatusCode.NotFound;
+}

src/MaIN.Domain/Exceptions/ModelNotSupportedException.cs

@@ -0,0 +1,10 @@
+using System.Net;
+
+namespace MaIN.Domain.Exceptions;
+
+public class ModelNotSupportedException(string? modelName) 
+    : MaINCustomException($"Given model {modelName ?? string.Empty} is not supported.")
+{
+    public override string PublicErrorMessage => Message;
+    public override HttpStatusCode HttpStatusCode => HttpStatusCode.BadRequest;
+}

src/MaIN.Domain/Models/SupportedModels.cs

@@ -1,3 +1,5 @@
+using MaIN.Domain.Exceptions;
+
 namespace MaIN.Domain.Models;
 
 public class Model
@@ -207,25 +209,23 @@ public static Model GetModel(string path, string? name)
                                                    StringComparison.InvariantCultureIgnoreCase));
         if (model is null)
         {
-            //todo support domain specific exceptions
-            throw new Exception($"Model {name} is not supported");
+            throw new ModelNotSupportedException(name);
         }
 
         if (File.Exists(Path.Combine(path, model.FileName)))
         {
             return model;
         }
 
-        throw new Exception($"Model {name} is not downloaded");
+        throw new ModelNotDownloadedException(name);
     }
 
     public static Model? GetModelByFileName(string path, string fileName)
     {
         var isPresent = Models.Exists(x => x.FileName == fileName);
         if (!isPresent)
         {
-            //todo support domain specific exceptions
-            Console.WriteLine($"Model {fileName} is not supported");
+            Console.WriteLine($"{new ModelNotSupportedException(fileName).PublicErrorMessage}");
             return null;
         }
 
@@ -234,7 +234,7 @@ public static Model GetModel(string path, string? name)
             return Models.First(x => x.FileName == fileName);
         }
 
-        throw new Exception($"Model {fileName} is not downloaded");
+        throw new ModelNotDownloadedException(fileName);
     }
 
     public static void AddModel(string model, string path, string? mmProject = null)
@@ -257,8 +257,7 @@ public static Model GetModel(string modelName)
                                                    StringComparison.InvariantCultureIgnoreCase));
         if (model is null)
         {
-            //todo support domain specific exceptions
-            throw new NotSupportedException($"Model {modelName} is not supported");
+            throw new ModelNotSupportedException(modelName);
         }
 
         return model;

src/MaIN.Services/Services/AgentFlowService.cs

@@ -1,4 +1,5 @@
 using MaIN.Domain.Entities.Agents.AgentSource;
+using MaIN.Domain.Exceptions;
 using MaIN.Infrastructure.Models;
 using MaIN.Infrastructure.Repositories.Abstract;
 using MaIN.Services.Mappers;
@@ -11,8 +12,10 @@ public class AgentFlowService(IAgentFlowRepository flowRepository, IAgentService
     public async Task<AgentFlow> GetFlowById(string id)
     {
         var flow = await flowRepository.GetFlowById(id);
-        if(flow is null)
-            throw new Exception("Flow not found");
+        if (flow is null)
+        {
+            throw new AgentFlowNotFoundException(id);
+        }
 
         return flow.ToDomain();
     }

src/MaIN.Services/Services/AgentService.cs

@@ -1,6 +1,7 @@
 using MaIN.Domain.Configuration;
 using MaIN.Domain.Entities;
 using MaIN.Domain.Entities.Agents;
+using MaIN.Domain.Exceptions;
 using MaIN.Infrastructure.Repositories.Abstract;
 using MaIN.Services.Constants;
 using MaIN.Services.Mappers;
@@ -28,10 +29,15 @@ public class AgentService(
     public async Task<Chat> Process(Chat chat, string agentId, bool translatePrompt = false)
     {
         var agent = await agentRepository.GetAgentById(agentId);
-        if (agent == null) 
-            throw new ArgumentException("Agent not found."); //TODO candidate for NotFound domain exception
-        if (agent.Context == null) 
-            throw new ArgumentException("Agent context not found.");
+        if (agent == null)
+        {
+            throw new AgentNotFoundException(agentId);
+        } 
+
+        if (agent.Context == null)
+        {
+            throw new AgentContextNotFoundException(agentId);
+        } 
 
         await notificationService.DispatchNotification(
             NotificationMessageBuilder.ProcessingStarted(agentId, agent.CurrentBehaviour), "ReceiveAgentUpdate");
@@ -115,7 +121,9 @@ public async Task<Chat> GetChatByAgent(string agentId)
     {
         var agent = await agentRepository.GetAgentById(agentId);
         if (agent == null)
-            throw new Exception("Agent not found."); //TODO good candidate for custom exception
+        {
+            throw new AgentNotFoundException(agentId);
+        }
 
         var chat = await chatRepository.GetChatById(agent.ChatId);
         return chat!.ToDomain();
@@ -125,7 +133,9 @@ public async Task<Chat> Restart(string agentId)
     {
         var agent = await agentRepository.GetAgentById(agentId);
         if (agent == null)
-            throw new Exception("Agent not found."); //TODO good candidate for custom exception
+        {
+            throw new AgentNotFoundException(agentId);
+        }
 
         var chat = (await chatRepository.GetChatById(agent.ChatId))!.ToDomain();
         var llmService = llmServiceFactory.CreateService(agent.Backend ?? maInSettings.BackendType);

src/MaIN.Services/Services/ChatService.cs

@@ -1,5 +1,6 @@
 using MaIN.Domain.Configuration;
 using MaIN.Domain.Entities;
+using MaIN.Domain.Exceptions;
 using MaIN.Domain.Models;
 using MaIN.Infrastructure.Repositories.Abstract;
 using MaIN.Services.Mappers;
@@ -89,7 +90,11 @@ public async Task Delete(string id)
     public async Task<Chat> GetById(string id)
     {
         var chatDocument = await chatProvider.GetChatById(id);
-        if(chatDocument == null) throw new Exception("Chat not found"); //TODO good candidate for custom exception
+        if (chatDocument == null)
+        {
+            throw new ChatNotFoundException(id);
+        }
+
         return chatDocument.ToDomain();
     }
 

src/MaIN.Services/Services/DataSourceProvider.cs

@@ -2,6 +2,7 @@
 using System.Text;
 using System.Text.Json;
 using MaIN.Domain.Entities.Agents.AgentSource;
+using MaIN.Domain.Exceptions;
 using MaIN.Services.Services.Abstract;
 using MaIN.Services.Utils;
 using MongoDB.Bson;
@@ -76,8 +77,10 @@ public async Task<string> FetchApiData(object? details, string? filter,
         var result = await httpClient.SendAsync(request);
         if (!result.IsSuccessStatusCode)
         {
-            throw new Exception(
-                $"API request failed with status code: {result.StatusCode}"); //TODO candidate for domain exception
+            throw new ApiRequestFailedException(
+                result.StatusCode, 
+                apiDetails?.Url + apiDetails?.Query, 
+                apiDetails?.Method ?? string.Empty);
         }
 
         var data = await result.Content.ReadAsStringAsync();