haven't seen you in a long time

(I) haven't seen you in a long time.

Fig. an expression of greeting, often said as part of a series. Mary: Hi, Fred! Haven't seen you in a long time. Fred: Yeah. Longtime no see. Tom: Well, John. Is that you? I haven't seen you in a long time. John: Good to see you, Tom!
See also: long, seen, time