How does the action economy for a hasted Fighter using action surge work in DND 5e?


My player’s fighter has just reached 11th level, He duel wields Scimitars. On his normal attack action, he gets 3 attacks plus one additional attack for his bonus action.

If he then decides to use Action surge, on the same turn he is then receiving three additional attacks. As I understand it; action surge does not grant a second bonus action is that correct?

SO if he also happens to be hasted does he get 3 more additional attacks or just 1 additional attack? Haste states that he gets another "action" and as the multi-attack class feature applies would I be correct in my interpretation that he would indeed get 10 attacks that round in 6 seconds?