You seem to be confused both about terminology and tenses, so let's try to get this straight:
For present hypotheticals we use a form that is technically referred to as the subjunctive. The subjunctive is identical to the simple past in most forms, but you'll notice that it differs for the first-person singular:
If they were here, I would be happy.
If I were rich, I would be happy. (Not: If I was rich.)
(Just to make things complicated, this form of the subjunctive is disappearing and many people do, in fact, say If I was rich. But for the purposes of illumination, let's treat this as a separate way of inflecting the verb.)
For past hypotheticals we use the past perfect (or pluperfect), not the "present past" that you referred to. (I've never heard the term "present past" before, and in any case I would interpret it as a reference to the present perfect, which is incorrect.) The reason for this is that the simple past is the same in almost all cases as the subjunctive, which is used for the present hypothetical.
If they had been there, I would have been happy.
If I had stayed, I would have met her.
For future hypotheticals we use the simple present. This is not actually surprising, since the simple present is used for near-future events in a variety of contexts in English.
If they come, I'll be happy.
Note, however, that it's actually possible to use both the modal will and other future constructions such as going to in this construction, depending on context.
If they will reduce the price, I'll buy.
Here will retains some of its historical sense of willingness as opposed to indicating mere futurity.
If they are going to leave, then I am, too.
This is a pure future conditional. You can use going to for the future hypothetical in almost any case where you would otherwise use the simple present with no change in meaning.
Your three sentences are examples of what are described in some grammar books for foreign learners of English as the First, Second and Third Conditional. The first suggests that there is a possibility that the speaker will be in Libya, and that, if so, there is a strong probability that the action described in the main clause will occur. The second imagines a situation that is unlikely to occur. The third imagines a situation that might have occurred, but didn’t.
In the circumstances you describe, (1), although grammatical, doesn’t really seem possible. The choice between (2) and (3) depends on timing. (2) would be appropriate when the gift-giving event is more or less concurrent with the time of speaking. (3) would be appropriate after the gift-giving event has taken place. If I was in Libya, I would've done it mixes up (2) and (3) and careful writers will avoid it.
(In (2), were is certainly grammatical, but some speakers may say was instead.)
Best Answer
I'm afraid conditional sentences in English have nothing or next to nothing to do with the sequence of tenses in 'time line'.
a. When you're talking about some possibility in the future, you use present simple in conditional and future simple in main clause.
b. When you're talking about something, happening at the time of speaking, then you use past simple in the conditional and future-in-the-past in main clause. My English language teacher called this kind of conditional "next to impossible" - maybe, just maybe the conditional is fulfilled and the main clause then will take place.
Meaning that he, whoever he is, can amend whatever transgression he made by handing in his report no later than the time I said this phrase.
c. When you're talking about something in the past, then you use past perfect in conditional and future perfect in main clause. By analogy, it's an "impossible" kind of conditional - something already didn't happen, but if it happened when it should have, then...
He didn't hand in his report in time, and lost any chance of being forgiven.