feature(#20): this commit introduces a handler to revoke a client's audience

Author: https-richardy

Applications/Backend/Source/HttpsRichardy.Federation.Application/Handlers/Client/RevokeAudienceFromClientHandler.cs

@@ -0,0 +1,33 @@
+namespace HttpsRichardy.Federation.Application.Handlers.Client;
+
+public sealed class RevokeAudienceFromClientHandler(IClientCollection clientCollection) :
+    IDispatchHandler<RevokeClientAudienceScheme, Result<IReadOnlyCollection<string>>>
+{
+    public async Task<Result<IReadOnlyCollection<string>>> HandleAsync(
+        RevokeClientAudienceScheme parameters, CancellationToken cancellation = default)
+    {
+        var filters = ClientFilters.WithSpecifications()
+            .WithIdentifier(parameters.Id)
+            .Build();
+
+        var clients = await clientCollection.GetClientsAsync(filters, cancellation);
+        var client = clients.FirstOrDefault();
+
+        if (client is null)
+        {
+            return Result<IReadOnlyCollection<string>>.Failure(ClientErrors.ClientDoesNotExist);
+        }
+
+        var audienceToRemove = client.Audiences.FirstOrDefault(current => current.Value == parameters.Audience);
+        if (audienceToRemove is null)
+        {
+            return Result<IReadOnlyCollection<string>>.Failure(ClientErrors.AudienceNotAssigned);
+        }
+
+        client.Audiences.Remove(audienceToRemove);
+
+        await clientCollection.UpdateAsync(client, cancellation);
+
+        return Result<IReadOnlyCollection<string>>.Success([.. client.Audiences.Select(current => current.Value)]);
+    }
+}

Applications/Backend/Source/HttpsRichardy.Federation.Application/Payloads/Client/RevokeClientAudienceScheme.cs

@@ -0,0 +1,11 @@
+namespace HttpsRichardy.Federation.Application.Payloads.Client;
+
+public sealed record RevokeClientAudienceScheme :
+    IDispatchable<Result<IReadOnlyCollection<string>>>
+{
+    [JsonIgnore]
+    public string Id { get; init; } = default!;
+
+    [JsonIgnore]
+    public string Audience { get; init; } = default!;
+}