First place a garden hose / running water with low volume on top of your sunroof while sunroof is open to see what is happening then check if the carpet is wet. Do not clean debris yet till you verify so you know you found the problem.
Second, place hose by the outside front cowl vent area by the hood to see if it is leaking from there then check carpet if wet.
Lastly, place the hose while moving it around the front passenger door window glass area while closed and also while open and try to hear / see if it is coming from there. Believe it or not, we found out my buddys leak was coming from the front passenger window seal, FZJ80.
It would also be easier if you start lifting the carpet under the front dash / passenger side area to see where it is coming from.