Learn English – Coolest jacket I ever had/ have ever had

None of these options are particularly grammatical.

The most common versions would be to say:

I fasted today.

This is a simple statement of fact.

I was fasting today.

This implies that you were fasting but are not any more.

I had to fast today.

This says that something required that you fast today.

I have had to fast all day.

This says that you've been doing it for a while and can (but does not necessarily) imply that you are no longer doing this action.

I prefer

This is the best performance I have ever seen.

over

This is the best performance I ever saw.

They mean the same thing (namely, that the person saying it witnessed the best performance thus far in their life) unless context implies otherwise.

This is the best performance I will ever see.

The sentence means they will never see a better performance; it's impossible for another performance taking place in the future to be better than this one.