I didn't see you for a long time!

[nelson13]

context: I wait for a friend. A friend not seen a long time. He appears.

For I didn't see you for a long time!, we should not say I haven't seen you for a long time!; is it because at the time of speaking, I have seen him already? If not, what is the reason?

Thank you.

[Odessa Dawn]

***NOT A TEACHER***

I haven't seen you for ages. It is simple present perfect because there is a connection between past and present, IMO

[nelson13]

Does it mean I didn't see you for a long time! is incorrect?

[Odessa Dawn]

***NOT A TEACHER***

I haven't seen you for a long time!

It is fine.


I haven't seen you for ages. It is simple present perfect because there is a connection between past and present, IMO

[Chicken Sandwich]

Does it mean I didn't see you for a long time! is incorrect?

***** NOT A TEACHER *****

It doesn't work in your situation. You can use it in a different context though:

I saw him at your wedding in 1994, and then I didn't see him for a long time.
(The Teacher's Grammar of English - Ron Cowan)

[Odessa Dawn]

Does it mean I didn't see you for a long time! is incorrect?

***NOT A TEACHER***
From my point of view, we use past tense when the action is over. You talk about present that has a relation with past in which we have to use simple present perfect since the action still exists, IMO. In a nutshell, past simple doesn't work in this case.

[Raymott]

context: I wait for a friend. A friend not seen a long time. He appears.

For I didn't see you for a long time!, we should not say I haven't seen you for a long time!; is it because at the time of speaking, I have seen him already? If not, what is the reason?

Thank you.

You're using the simple past. Therefore you are referring to a certain time in the past. So, when was it that you hadn't seen this person for a long time? It's possible if the context is correct.
"When you were in prison [statement of a definite past time], I didn't see you for a long time."
But you are referring to now, not some time in the past, so you must use a present tense, and the present perfect is the right one.

[nelson13]

Thank you very much!