import os
# install torch and tf
os.system('pip install transformers SentencePiece')
os.system('pip install torch')

# pip install streamlit-chat 
os.system('pip install streamlit-chat')

from transformers import T5Tokenizer, T5ForConditionalGeneration, AutoTokenizer
import torch

import streamlit as st
from streamlit_chat import message

# 下载模型
tokenizer = T5Tokenizer.from_pretrained("ClueAI/ChatYuan-large-v1")
model = T5ForConditionalGeneration.from_pretrained("ClueAI/ChatYuan-large-v1")
# 修改colab笔记本设置为gpu，推理更快
device = torch.device('cpu')
model.to(device)
print('Model Load done!')

def preprocess(text):
    text = text.replace("\n", "\\n").replace("\t", "\\t")
    return text

def postprocess(text):
    return text.replace("\\n", "\n").replace("\\t", "\t")

def answer(history, sample=True, top_p=1, temperature=0.7):
    '''sample：是否抽样。生成任务，可以设置为True;
    top_p：0-1之间，生成的内容越多样
    max_new_tokens=512 lost...'''

    preprocess_history = []

    for i in range(len(history)):
        preprocess_history[i] = preprocess(text)
    
    #text = preprocess(text)
    #print('用户: '+text)
    encoding = tokenizer(text=preprocess_history, truncation=True, padding=True, max_length=768, return_tensors="pt").to(device) 
    if not sample:
        out = model.generate(**encoding, return_dict_in_generate=True, output_scores=False, max_new_tokens=512, num_beams=1, length_penalty=0.6)
    else:
        out = model.generate(**encoding, return_dict_in_generate=True, output_scores=False, max_new_tokens=512, do_sample=True, top_p=top_p, temperature=temperature, no_repeat_ngram_size=3)
    out_text = tokenizer.batch_decode(out["sequences"], skip_special_tokens=True)
    print('小元: '+postprocess(out_text[0]))
    return postprocess(out_text[0])

st.set_page_config(
    page_title="Chinese ChatBot - Demo",
    page_icon=":robot:"
)

st.header("Chinese ChatBot - Demo")
st.markdown("[Github](https://github.com/scutcyr)")

if 'generated' not in st.session_state:
    st.session_state['generated'] = []

if 'past' not in st.session_state:
    st.session_state['past'] = []

def query(history):
    inputs = tokenizer.dialogue_encode(
        history, add_start_token_as_response=True, return_tensors=True, is_split_into_words=False
    )
    inputs["input_ids"] = inputs["input_ids"].astype("int64")
    ids, scores = model.generate(
        input_ids=inputs["input_ids"],
        token_type_ids=inputs["token_type_ids"],
        position_ids=inputs["position_ids"],
        attention_mask=inputs["attention_mask"],
        max_length=64,
        min_length=1,
        decode_strategy="sampling",
        temperature=1.0,
        top_k=5,
        top_p=1.0,
        num_beams=0,
        length_penalty=1.0,
        early_stopping=False,
        num_return_sequences=20,
    )
    max_dec_len = 64
    num_return_sequences = 20
    bot_response = select_response(
        ids, scores, tokenizer, max_dec_len, num_return_sequences, keep_space=False
    )[0]
    return bot_response

def get_text():
    input_text = st.text_input("用户: ","你好！", key="input")
    return input_text  

history = []
user_input = get_text()
history.append(user_input)

if user_input:
    output = answer(history)
    st.session_state.past.append(user_input)
    st.session_state.generated.append(output)
    history.append(output)

if st.session_state['generated']:

    for i in range(len(st.session_state['generated'])-1, -1, -1):
        message(st.session_state["generated"][i], key=str(i))
        message(st.session_state['past'][i], is_user=True, key=str(i) + '_user')