fixed errors and finish endpoints

BookHive/Endpoints/Books/DeleteBookEndpoint.cs

@@ -1,6 +1,7 @@
 using BookHive.Models;
 using BookHive.Repositories;
 using BookHive.Specifications.Books;
+using BookHive.Specifications.Loans;
 using FastEndpoints;
 
 namespace BookHive.Endpoints.Books;
@@ -10,14 +11,14 @@ public class DeleteBookRequest
     public int Id { get; set; }
 }
 
-public class DeleteBookEndpoint(BookRepository bookRepository) : Endpoint<DeleteBookRequest>
+public class DeleteBookEndpoint(BookRepository bookRepository, LoanRepository loanRepository) : Endpoint<DeleteBookRequest>
 {
     public override void Configure()
     {
         Delete("/books/{@Id}", x => new { x.Id });
         AllowAnonymous();
     }
-    
+
     public override async Task HandleAsync(DeleteBookRequest req, CancellationToken ct)
     {
         Book? book = await bookRepository.SingleOrDefaultAsync(new GetBookByIdSpec(req.Id), ct);
@@ -27,7 +28,14 @@ public class DeleteBookEndpoint(BookRepository bookRepository) : Endpoint<Delete
             await Send.NotFoundAsync(ct);
             return;
         }
-        
+
+        Loan? loan = await loanRepository.FirstOrDefaultAsync(new GetAvailableBookByIdSpec(req.Id), ct);
+        if (loan is not null)
+        {
+            await Send.StringAsync("Le livre est encore emprunté", 409, cancellation: ct);
+            return;
+        }
+
         await bookRepository.DeleteAsync(book, ct);
         await Send.OkAsync(cancellation: ct);
     }