Open-source projects for creating AI-Chatbot to follow a specific promt on install

Don't know if this is the right subreddit for this but I'll as my question anyways. Does anyone know of a open-source chatbot that is easy to add to an android app? It needs to follow specific rules directly on startup. And what do I need to learn to create/develop it with this project? My friend and I are planning to make an chatbot app and we want to start developing it ASAP. Can anyone help?