public APIGatewayProxyResponse FunctionHandler()

in Amazon.QLDB.DMVSample.Api/Functions/AddSecondaryOwnerFunction.cs [58:114]
51 lines of code
4 McCabe index (conditional complexity)

        public APIGatewayProxyResponse FunctionHandler(APIGatewayProxyRequest request, ILambdaContext context)
        {
            VehicleRegistration vehicleRegistration = JsonConvert.DeserializeObject<VehicleRegistration>(request.Body);

            return this.qldbDriver.Execute(transactionExecutor =>
            {
                context.Logger.Log($"Checking vehicle registration already exists for VIN {vehicleRegistration.Vin}.");
                if (!CheckIfVinAlreadyExists(transactionExecutor, vehicleRegistration.Vin))
                {
                    context.Logger.Log($"Vehicle registration does not exist for VIN {vehicleRegistration.Vin}, returning not found.");
                    return new APIGatewayProxyResponse 
                    { 
                        StatusCode = (int)HttpStatusCode.NotFound
                    };
                }

                context.Logger.Log($"Vehicle registration already exists, checking what's changed between current value and request.");

                IEnumerable<string> existingSecondaryOwners = GetSecondaryOwners(transactionExecutor, vehicleRegistration.Vin);
                IEnumerable<string> newSecondaryOwnersGovIds = vehicleRegistration.Owners.SecondaryOwners
                                                                .Select(x => x.PersonId)
                                                                .Except(existingSecondaryOwners);
                if (!newSecondaryOwnersGovIds.Any())
                {
                    context.Logger.Log($"Nothing changed, returning not modified.");
                    return new APIGatewayProxyResponse 
                    { 
                        StatusCode = (int)HttpStatusCode.NotModified
                    };
                }

                string secondaryOwnerPersonDocumentId = this.tableMetadataService.GetDocumentId(transactionExecutor, PersonTableName, "GovId", newSecondaryOwnersGovIds.First());
                if (!CheckIfSecondaryOwnerExists(existingSecondaryOwners, secondaryOwnerPersonDocumentId))
                {
                    context.Logger.Log($"Secondary owner does not exists with document ID {secondaryOwnerPersonDocumentId}, adding secondary owner.");
                    IIonValue ionVin = this.valueFactory.NewString(vehicleRegistration.Vin);
                    IIonValue ionSecondaryOwner = ConvertOwnerToIonValue(new Owner { PersonId = secondaryOwnerPersonDocumentId });

                    IResult result = transactionExecutor.Execute($"FROM VehicleRegistration AS v WHERE v.VIN = ? " +
                        "INSERT INTO v.Owners.SecondaryOwners VALUE ?", ionVin, ionSecondaryOwner);
                    
                    context.Logger.Log($"Secondary owner added with document ID {secondaryOwnerPersonDocumentId}, returning OK.");
                    return new APIGatewayProxyResponse 
                    { 
                        StatusCode = (int)HttpStatusCode.OK
                    };
                } 
                else
                {
                    context.Logger.Log($"Secondary owner already exists, returning not modified.");
                    return new APIGatewayProxyResponse 
                    { 
                        StatusCode = (int)HttpStatusCode.NotModified
                    };
                }
            });
        }