app.py

import streamlit as st
from streamlit_chat import message as st_message
import numpy as np

from transformers import AutoModelForCausalLM , AutoTokenizer
import torch

tokenizer = AutoTokenizer.from_pretrained("microsoft/DialoGPT-medium")
model = AutoModelForCausalLM.from_pretrained("microsoft/DialoGPT-medium")

def run(user_text , chat_history_ids):
    input_ids = tokenizer.encode(user_text + tokenizer.eos_token , return_tensors = "pt")
    if chat_history_ids is None:
        bot_input_ids = input_ids
    else:
        bot_input_ids = torch.cat([chat_history_ids , input_ids] , dim = -1)
    chat_history_ids = model.generate(bot_input_ids , max_length = 1000 ,
                                      pad_token_id = tokenizer.eos_token_id)
    resp = tokenizer.decode(chat_history_ids[: , bot_input_ids.shape[-1]:][0] ,
                            skip_special_tokens = True)
    return resp , chat_history_ids

if "chat_history_ids" not in st.session_state:
    st.session_state["chat_history_ids"] = None
if "book" not in st.session_state:
    st.session_state["book"] = []

txt = st.text_input("Type Here")

if txt:
    resp , hist = run(txt , st.session_state["chat_history_ids"])
    st.session_state["chat_history_ids"] = hist

    st.session_state["book"].append({"message" : txt ,
                                     "is_user" : True})
    st.session_state["book"].append({"message" : resp ,
                                     "is_user" : False})

for i , chat in enumerate(st.session_state["book"]):
    st_message(**chat , key = str(i))