[Scripting Question] How to make code check the type of the foe who poisoned a Pokemon, when a Pokemon is poisoned?

[SuperSpyroDragon64]

# POISON TOXIC CHECK
when :POISON
if !(opponent.hasType?(:POISON))
@effects[PBEffects::Toxic] = 0
@effects[PBEffects::Poisoned] = 1
end
# POISON TOXIC CHECK
when :POISON
if (opponent.hasType?(:POISON))
@effects[PBEffects::Poisoned] = 0
@effects[PBEffects::Toxic] = 1
end

That's basically what I want to program, but I don't speak this coding language.

When a Pokemon is Poisoned or Badly Poisoned, I want the code to check who used the poisoning move. If it is a Poison-type Pokemon, regular poison should be lifted and Toxic Poison should be applied. Otherwise, Toxic Poison should be removed and regular Poison should be applied.

This change should promote the use of Poison-type Pokemon by making Toxic Poison into something only they can apply, be it with extra move effects or Poisonpowder or Toxic.