• Constructor:
  protected LambdaServiceWithAppStore() => Init(LoadConfigFromEnvVar);
  -> Suggestion: protected LambdaServiceWithAppStore() : base(LoadConfigFromEnvVar);
• Why do we need to InitAppStore via Activator.CreateInstance -> always creates a new instance (TAppStore : SingletonAppStore)
  -> Suggestion: We can get instance of AppStore by calling SingletonAppStore.Instance or SingletonStore<typeof(TAppStore)>

• IList ParseMessages(SQSEvent sqsEvent)
  return sqsEvent.Records.Select(
  record =>
  {
  // parse the json string to TMessage
  var message = JsonConvert.DeserializeObject(record.Body);

                // validate message schema
                message.Validate();
  
                return message;
            }
        ).ToList();
  

-> Suggestion: Should wrap in try/catch block to log the error during parsing and validating message -> return default message if needed

• UpdateGroupNames

  • foreach (var task in groupTasks)
    {
    await task;
    }
  • foreach (var task in remoteTasks)
    {
    await task;
    }
    -> Suggestion: Consider to use await Task.WhenAll() to run async tasks

• All the calls to svcSalesforce(GetAllPractifiCampaignsAsync, GetAllSalesforceCampaignsAsync...) should be replaced with Proxies, adapter

• Inherit LambdaServiceWithAppStore
• Implement IMessageHandler
• protected IServiceBusClient SvcServiceBus => SingletonStore.Get(()...
• protected ISlackServiceClient SvcSlack = new SlackServiceClient(SlackServiceClientConfig.LoadConfigFromEnvVar());
  -> Suggestion: Should inject in constructor to make this class testable
• public async Task HandleAsync(object reqData, ILambdaContext context)
  -> Suggestion:
  • Should inject ILogTrace in constructor, avoid creating instance of MessageHandlerLogTrace here
  • Keep one try/catch/finally block, remove another one
• AlertErrorToSlack -> Task.WaitAll(SvcSlack.SendWithErrorHandler(slackMsg, logTrace));
  -> Suggestion: Task.Run(() => SvcSlack.SendWithErrorHandler(slackMsg, logTrace)). Just fire and forget, create new task from Thread pool to avoid deadlock, no need to get result

• public abstract class MessageHandler<TMessage, TAppStore> : IMessageHandler<TMessage> where TMessage : IMessage

-> Why do we need AppStore here ?
-> Suggestion:
public abstract class MessageHandler<TMessage> : IMessageHandler<TMessage> where TMessage : IMessage

• public abstract Task<IEnumerable> ProcessAsync(TMessage message, ILogTrace logTrace);
  -> Suggestion: Should inject ILogTrace in Constructor

• Should create a proxy classes (SalesForceContactProxy, SalesForceTopicProxy) to wrap and make some methods testable -> move logic of svcSalesforce, SalesforceUtil -> SalesForceContactProxy/SalesForceTopicProxy:
  public interface ISalesForceContactProxy
  {
  // Contacts
  GetAllContactsAsync
  GetNextPageAsync
  }
  public interface ISalesForceTopicProxy
  {
  // Topics
  GetAllSalesforceObjectsAsync...
  GetAllCampaignInteractionsAsync...
  GetAllCampaignsAsync...
  GetAllTopicsAsync...
  }
  -> Implementation:
  public class SalesForceContactProxy: ISalesForceContactProxy, IDisposable
  {
  ILogTrace _logger;
  AppStore _store;
  IConfig _config;

  ISalesforceServiceClientV2 _salesforceServiceClient;

  SalesForceContactProxy(ILogTrace logTrace, IConfig config)
  {
  _salesforceServiceClient = SalesforceServiceClientV2Factory.Create(...)
  }
  .... // Implement inteface

  protected virtual void Dispose(bool disposing) { _salesforceServiceClient.Dispose....}
  }

• We should consider to create SaleforceTopicServiceAdapter to map object and SalesforceTopicMapping
  public class SalesForceServiceAdapter
  {
  ISalesForceProxy _proxy;
  public SalesForceServiceAdapter(ISalesForceTopicProxy proxy) { _proxy = proxy; }

  protected async Task<IList> GetAllSalesforceCampaignsAsync()
  ....
  }

• This class should:
  • Inherit from LambdaServiceWithAppStore
  • Implement IMessageHandler
• ProcessAsync:
  • Remove do/while -> Replace by while loop -> move logic of GetContacts out of do/while, move logic of GetContactsNextPage to while loop to avoid checking string.IsNullOrWhiteSpace(getContactsData.NextRecordsUrl) twice
• GetContacts
  • Should have try/catch block to catch error when making the call to other methods
  • Consider to lazy initialize getContactsFallbackLevel1Task, getContactsFallbackLevel2Task since if we have the data of the call to GetContactsWithOutOfSyncHandler, we don't need to call getContactsFallbackLevel1Task, getContactsFallbackLevel2Task
• Consider when throwing exception inside GetContactsNextPage and GetContacts since it will stop the flow -> Just need to log the failed contacts and continue to fetch contacts to the end of page
• static readonly object _lock = new object();
  -> Remove unused variable