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I'm am a bit confused here. I don't really get what tense I should use after 'has been a long time'.

Are these correct? If not, why? What do they mean?

1. It has been a long time since I called you out.

2. It has been a long time since I have called you out.

3. It has been a long time since I had called you out before that dinner we had..

4. It has been a long time since I had called you out.

Thanks.
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What exactyly do you mean here by "called you out"? It's not a common idiom, at least in AmE, except perhaps to mean "challenged," and I don't think that's what you intend here. Do you mean "It has been a long time since I called to ask you out?"
Comments  
first sentence is correct
 khoff's reply was promoted to an answer.