What happened during the battle of Ap Bac and Lt Vanns assessment?

I have to answer this question in a short essay: What problems did the battle of Ap Bac reveal? What was Vanns assessment? Why did Diem and ARVN officers claim it was a victory? How and why did Harkins and Krulak downplay or ignore Vanns conclusion? Do you think the war was already lost at this point?