Refactor email fetching to use IMailRepository

Introduced a new `IMailRepository` interface to abstract email-fetching logic, replacing the direct dependency on `IImapEmailService` in `ReadEmailQueryHandler`. Updated `ReadEmailQueryHandler` to use `IMailRepository` for querying emails and added `IMapper` for mapping entities to DTOs.

Modified the constructor of `ReadEmailQueryHandler` to inject `IMailRepository`, `IMapper`, and renamed `IRepository<EmailAccount>` to `EmailAccountRepo`. Replaced `IImapEmailService.FetchEmailsAsync` with `IMailRepository.FindAsync` in the handler's `Handle` method.

Wrapped all changes in `#if NET` preprocessor directives to ensure compatibility with specific build configurations. These changes improve modularity, testability, and separation of concerns.

src/core/DigitalData.MessagingService.Application/Common/Interfaces/Repositories/IMailRepository.cs

@@ -0,0 +1,11 @@
+#if NET
+using DigitalData.MessagingService.Application.Common.Dto.MailSearch;
+using DigitalData.MessagingService.Domain.Entities;
+
+namespace DigitalData.MessagingService.Application.Common.Interfaces.Repositories;
+
+public interface IMailRepository : IRepository<ReceivedEmail>
+{
+    public Task<IEnumerable<ReceivedEmail>> FindAsync(MailSearchFilter mailSearchFilter, EmailAccount accountQuery, CancellationToken cancellationToken = default);
+}
+#endif

src/core/DigitalData.MessagingService.Application/EmailReceiving/Queries/ReadEmailQuery.cs

@@ -1,4 +1,5 @@
 #if NET
+using AutoMapper;
 using DigitalData.MessagingService.Application.Common.Dto;
 using DigitalData.MessagingService.Application.Common.Dto.MailSearch;
 using DigitalData.MessagingService.Application.Common.Interfaces;
@@ -27,26 +28,24 @@ public record ReadEmailQuery : IRequest<IEnumerable<ReceivedEmailDto>>
     public MailSearchFilter Mail { get; init; } = new();
 }
 
-public class ReadEmailQueryHandler(IImapEmailService ImapService, ILogger<ReadEmailQueryHandler> Logger, IRepository<EmailAccount> Repo) : IRequestHandler<ReadEmailQuery, IEnumerable<ReceivedEmailDto>>
+public class ReadEmailQueryHandler(IMapper Mapper, ILogger<ReadEmailQueryHandler> Logger, IRepository<EmailAccount> EmailAccountRepo, IMailRepository MailRepo) : IRequestHandler<ReadEmailQuery, IEnumerable<ReceivedEmailDto>>
 {
     public async Task<IEnumerable<ReceivedEmailDto>> Handle(ReadEmailQuery request, CancellationToken cancellationToken)
     {
-        var accounts = await Repo.FindAsync(request.Account.Id is int id ? x => x.Id == id : x => x.Username == request.Account.Username, cancellationToken: cancellationToken);
+        var accounts = await EmailAccountRepo.FindAsync(request.Account.Id is int id ? x => x.Id == id : x => x.Username == request.Account.Username, cancellationToken: cancellationToken);
 
         if (accounts.Count() > 1)
             Logger.LogWarning("Multiple email accounts found for the given criteria ({Criteria}). Returning the first one.", request.Account.Id is not null ? $"Id: {request.Account.Id}" : $"Username: {request.Account.Username}");
 
-        EmailAccount account = accounts.FirstOrDefault()
+        var account = accounts.FirstOrDefault()
             ?? throw new NotFoundException($"No email account found for the given criteria (Id: {request.Account.Id}, Username: {request.Account.Username}).");
 
         if (string.IsNullOrWhiteSpace(account.ImapServer))
             throw new BadRequestException(
                 $"IMAP is not configured for account '{account.Username}' (Id: {account.Id}). Set ImapServer in EmailAccounts configuration.");
 
-        return await ImapService.FetchEmailsAsync(
+        var mails = await MailRepo.FindAsync(request.Mail, account, cancellationToken);
-            account,
+        return Mapper.Map<IEnumerable<ReceivedEmailDto>>(mails);
-            request.Mail,
-            cancellationToken);
     }
 }
 #endif