Update

src/BackOffice.BFF.Application/Common/Exceptions/DuplicateException.cs

@@ -0,0 +1,29 @@
+namespace BackOffice.BFF.Application.Common.Exceptions;
+
+public class DuplicateException : Exception
+{
+    public DuplicateException()
+        : base()
+    {
+    }
+
+    public DuplicateException(string message)
+        : base(message)
+    {
+    }
+
+    public DuplicateException(string message, Exception innerException)
+        : base(message, innerException)
+    {
+    }
+
+    public DuplicateException(string name, object key)
+        : base($"Entity \"{name}\" ({key}) already exists.")
+    {
+    }
+
+    public DuplicateException(string name, string field, object? key)
+        : base($"Entity \"{name}\" field \"{field}\" ({key}) already exists.")
+    {
+    }
+}

src/BackOffice.BFF.Application/Common/Exceptions/ForbiddenAccessException.cs

@@ -0,0 +1,8 @@
+namespace BackOffice.BFF.Application.Common.Exceptions;
+
+public class ForbiddenAccessException : Exception
+{
+    public ForbiddenAccessException() : base()
+    {
+    }
+}

src/BackOffice.BFF.Application/Common/Exceptions/NotFoundException.cs

@@ -0,0 +1,24 @@
+namespace BackOffice.BFF.Application.Common.Exceptions;
+
+public class NotFoundException : Exception
+{
+    public NotFoundException()
+        : base()
+    {
+    }
+
+    public NotFoundException(string message)
+        : base(message)
+    {
+    }
+
+    public NotFoundException(string message, Exception innerException)
+        : base(message, innerException)
+    {
+    }
+
+    public NotFoundException(string name, object key)
+        : base($"Entity \"{name}\" ({key}) was not found.")
+    {
+    }
+}

src/BackOffice.BFF.Application/Common/Exceptions/ValidationException.cs

@@ -0,0 +1,22 @@
+using FluentValidation.Results;
+
+namespace BackOffice.BFF.Application.Common.Exceptions;
+
+public class ValidationException : Exception
+{
+    public ValidationException()
+        : base("One or more validation failures have occurred.")
+    {
+        Errors = new Dictionary<string, string[]>();
+    }
+
+    public ValidationException(IEnumerable<ValidationFailure> failures)
+        : this()
+    {
+        Errors = failures
+            .GroupBy(e => e.PropertyName, e => e.ErrorMessage)
+            .ToDictionary(failureGroup => failureGroup.Key, failureGroup => failureGroup.ToArray());
+    }
+
+    public IDictionary<string, string[]> Errors { get; }
+}