Conditional type 3. Totally impossible.
Verb tense: past perfect with preceding ’ if’ and ‘would have’ for secondary clause
Examples:
If I had studied harder, I would have found a better job.
If this storm had not started, they would have arrived earlier
One common expression is:
‘If I were you’ before giving advice the second clause using ‘I would’ or ‘I would have’. Here exists a possibility of action on the advice but being someone else is impossible. So see type (1) for a.
Examples:
If I were you, I would get a hair cut before the interview ( here expressing a secondary future action)
B. If I were you, (had been) I would have worn a suit and tie for the interview.