feat(batch38): merge consumer-lifecycle

dotnet/src/ZB.MOM.NatsNet.Server/JetStream/NatsStream.Consumers.cs

@@ -310,4 +310,80 @@ internal sealed partial class NatsStream
             return _consumerList.All(c => ReferenceEquals(c, observingConsumer));
         }
     }
+
+    internal (NatsConsumer? Consumer, Exception? Error) AddConsumerWithAction(
+        ConsumerConfig config,
+        string oname,
+        ConsumerAction action,
+        bool pedantic = false) =>
+        AddConsumerWithAssignment(config, oname, null, isRecovering: false, action, pedantic);
+
+    internal (NatsConsumer? Consumer, Exception? Error) AddConsumer(
+        ConsumerConfig config,
+        string oname,
+        bool pedantic = false) =>
+        AddConsumerWithAssignment(config, oname, null, isRecovering: false, ConsumerAction.CreateOrUpdate, pedantic);
+
+    internal (NatsConsumer? Consumer, Exception? Error) AddConsumerWithAssignment(
+        ConsumerConfig config,
+        string oname,
+        ConsumerAssignment? assignment,
+        bool isRecovering,
+        ConsumerAction action,
+        bool pedantic = false)
+    {
+        ArgumentNullException.ThrowIfNull(config);
+
+        _mu.EnterWriteLock();
+        try
+        {
+            if (_closed)
+                return (null, new InvalidOperationException("stream closed"));
+
+            var name = !string.IsNullOrWhiteSpace(oname)
+                ? oname
+                : (!string.IsNullOrWhiteSpace(config.Name) ? config.Name! : (config.Durable ?? string.Empty));
+            if (string.IsNullOrWhiteSpace(name))
+                return (null, new InvalidOperationException("consumer name required"));
+
+            config.Name = name;
+            config.Durable ??= name;
+
+            var defaultsErr = NatsConsumer.SetConsumerConfigDefaults(config, Config, null, pedantic);
+            if (defaultsErr is not null)
+                return (null, new InvalidOperationException(defaultsErr.Description ?? "consumer defaults invalid"));
+
+            var cfgErr = NatsConsumer.CheckConsumerCfg(config, Config, null, isRecovering);
+            if (cfgErr is not null)
+                return (null, new InvalidOperationException(cfgErr.Description ?? "consumer config invalid"));
+
+            if (_consumers.TryGetValue(name, out var existing))
+            {
+                if (action == ConsumerAction.Create)
+                    return (null, new InvalidOperationException(JsApiErrors.NewJSConsumerAlreadyExistsError().Description ?? "consumer exists"));
+
+                existing.UpdateConfig(config);
+                if (assignment is not null)
+                    existing.SetConsumerAssignment(assignment);
+                return (existing, null);
+            }
+
+            if (action == ConsumerAction.Update)
+                return (null, new InvalidOperationException(JsApiErrors.NewJSConsumerDoesNotExistError().Description ?? "consumer does not exist"));
+
+            var consumer = NatsConsumer.Create(this, config, action, assignment);
+            if (consumer is null)
+                return (null, new InvalidOperationException("consumer create failed"));
+
+            consumer.SetConsumerAssignment(assignment);
+            consumer.UpdateInactiveThreshold(config);
+            consumer.UpdatePauseState(config);
+            _consumers[name] = consumer;
+            return (consumer, null);
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
 }