public ActionResult <OperationViewModel> Get(string op, int first, int second)
{
// [SW] we're creating a new instance of the service for calculation.
// The method in the controller should do input parsing and orchestration,
// but it's a bad practice to use it for the processing work
var calculator = new Calculator();
// [SW] If we can can check whether the input is correct, we should do that
// instead of relying on exception handling. Exceptions should be exceptional,
// bad input from the user is NOT exceptional, and should be expected
if (!calculator.CanMapToOperator(op))
{
// [SW] If the input is not up to par, we should return early, with a specific message
return(UnprocessableEntity($"Cannot map {op} to a valid operation"));
}
// [SW] We're creating an input model from the input, once we know that the input is viable.
// We can be sure that the `MapStringToOperator` call will not fail
var operation = new Operation
{
Operator = calculator.MapStringToOperator(op),
FirstArgument = first,
SecondArgument = second
};
// [SW] Execute the operation and get the result model back
var model = calculator.ExecuteOperation(operation);
// [SW] Map the model to a view-model and then return the view-model
return(OperationViewModel.FromModel(model));
}
