Re: i wish ?
I agree with J & K Tutuoring in most contexts.
It's possible that #1 could refer to the present - My daughter is getting married at this very moment. I wish I could be there.
It's also just about possible that #2 could refer to the present - My daughter is getting married at this ver moment. I wish I could have been there. (ie: I wish I had been able to get there.)
As we so often say, context will usually make the meaning clear.
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