I want some Complex sort of NPC AI for my Unity Game

I want some Complex sort of NPC AI for my Unity Game. GTA AI is the main reference, NPCs should be able to walk around, react to player's Actions(Aiming, Shooting,Fighting),can buy or sell drugs, (I have a working inventory system for that),can drive cars etc. I am using Opsive character controller.This may be a long term Project if done well. More details in the chat.