#删除了documents=[]
#将st.session_state的变量全部移动到相应的变量第一次出现位置，而不是在最开始全部声明为None
#将pdf_files = st.file_uploader("Choose your PDF Files and Press OK", type=['pdf'], accept_multiple_files=True)
#修改为if "pdf_files" not in st.session_state:
#    st.session_state.pdf_files = st.file_uploader("Choose your PDF Files and Press OK", type=['pdf'], accept_multiple_files=True)   
#if not st.session_state.pdf_files:
#意思就是如果st.session_state.pdf_files为空，就停止执行程序

import streamlit as st
from llama_index import VectorStoreIndex, SimpleDirectoryReader
from langchain.embeddings.huggingface import HuggingFaceEmbeddings
from llama_index import LangchainEmbedding, ServiceContext
from llama_index import StorageContext, load_index_from_storage
from llama_index import LLMPredictor
#from transformers import HuggingFaceHub
from langchain import HuggingFaceHub
from streamlit.components.v1 import html
from pathlib import Path
from time import sleep
import random
import string

import os
from dotenv import load_dotenv
load_dotenv()

import timeit

st.set_page_config(page_title="Open AI Doc-Chat Assistant", layout="wide")
st.subheader("Open AI Doc-Chat Assistant: Life Enhancing with AI!")

css_file = "main.css"
with open(css_file) as f:
    st.markdown("<style>{}</style>".format(f.read()), unsafe_allow_html=True)
    
HUGGINGFACEHUB_API_TOKEN = os.getenv("HUGGINGFACEHUB_API_TOKEN")

def generate_random_string(length):
    letters = string.ascii_lowercase
    return ''.join(random.choice(letters) for i in range(length))  

#random_string = generate_random_string(20)
#directory_path=random_string

#if "directory_path" not in st.session_state:
#    st.session_state.directory_path = generate_random_string(20)

with st.sidebar:
    st.subheader("Upload your Documents Here: ") 
    pdf_files = st.file_uploader("Choose your PDF Files and Press OK", type=['pdf'], accept_multiple_files=True)
    if "pdf_files" not in st.session_state:
        #st.session_state.pdf_files = st.file_uploader("Choose your PDF Files and Press OK", type=['pdf'], accept_multiple_files=True)   
        st.session_state.pdf_files = pdf_files
        if not st.session_state.pdf_files:   #如果没有上传文件，则程序停止执行，就不会出现documents为空的错误情况、
            st.warning("请上传文档文件")
            st.stop()      
        else:   #如果已经上传文件，则装载文件SimpleDirectoryReader.load_data()
            #st.session_state.pdf_files=pdf_files
            #if not os.path.exists(st.session_state.directory_path):
            if "directory_path" not in st.session_state:
                st.session_state.directory_path = generate_random_string(20)
                os.makedirs(st.session_state.directory_path)
                for pdf_file in st.session_state.pdf_files:
                    #for pdf_file in pdf_files:
                    file_path = os.path.join(st.session_state.directory_path, pdf_file.name)
                    with open(file_path, 'wb') as f:
                        f.write(pdf_file.read())
                    st.success(f"File '{pdf_file.name}' saved successfully.")
                try:
                    start_1 = timeit.default_timer() # Start timer
                    st.write(f"QA文档加载开始：{start_1}")
                    if "documents" not in st.session_state:
                        st.session_state.documents = SimpleDirectoryReader(st.session_state.directory_path).load_data()
                        end_1 = timeit.default_timer() # Start timer
                        st.write(f"QA文档加载结束：{end_1}")
                        st.write(f"QA文档加载耗时：{end_1 - start_1}")
                except Exception as e:
                    print("文档加载出现问题/Waiting for path creation.")  

# Load documents from a directory
#documents = SimpleDirectoryReader('data').load_data()
    
start_2 = timeit.default_timer() # Start timer
st.write(f"向量模型加载开始：{start_2}")
if "embed_model" not in st.session_state:
    st.session_state.embed_model = LangchainEmbedding(HuggingFaceEmbeddings(model_name='sentence-transformers/all-MiniLM-L6-v2'))
end_2 = timeit.default_timer() # Start timer
st.write(f"向量模型加载加载结束：{end_2}")
st.write(f"向量模型加载耗时：{end_2 - start_2}")

if "llm_predictor" not in st.session_state:
    st.session_state.llm_predictor = LLMPredictor(HuggingFaceHub(repo_id="HuggingFaceH4/starchat-beta", model_kwargs={"min_length":100, "max_new_tokens":1024, "do_sample":True, "temperature":0.2,"top_k":50, "top_p":0.95, "eos_token_id":49155}))

if "service_context" not in st.session_state:
    st.session_state.service_context = ServiceContext.from_defaults(llm_predictor=st.session_state.llm_predictor, embed_model=st.session_state.embed_model)

start_3 = timeit.default_timer() # Start timer
st.write(f"向量库构建开始：{start_3}")
if "new_index" not in st.session_state:
    st.session_state.new_index = VectorStoreIndex.from_documents(
    st.session_state.documents,
    service_context=st.session_state.service_context,
)
end_3 = timeit.default_timer() # Start timer
st.write(f"向量库构建结束：{end_3}")
st.write(f"向量库构建耗时：{end_3 - start_3}")

st.session_state.new_index.storage_context.persist("st.session_state.directory_path")

if "storage_context" not in st.session_state:
    st.session_state.storage_context = StorageContext.from_defaults(persist_dir="st.session_state.directory_path")

start_4 = timeit.default_timer() # Start timer
st.write(f"向量库装载开始：{start_4}")
if "loadedindex" not in st.session_state:
    st.session_state.loadedindex = load_index_from_storage(storage_context=st.session_state.storage_context, service_context=st.session_state.service_context)
end_4 = timeit.default_timer() # Start timer
st.write(f"向量库装载结束：{end_4}")
st.write(f"向量库装载耗时：{end_4 - start_4}")

if "query_engine" not in st.session_state:
    st.session_state.query_engine = st.session_state.loadedindex.as_query_engine()
    
if "user_question " not in st.session_state:
    st.session_state.user_question = st.text_input("Enter your query:")
if st.session_state.user_question !="" and not st.session_state.user_question.strip().isspace() and not st.session_state.user_question == "" and not st.session_state.user_question.strip() == "" and not st.session_state.user_question.isspace():
    print("user question: "+st.session_state.user_question)
    with st.spinner("AI Thinking...Please wait a while to Cheers!"):
        start_5 = timeit.default_timer() # Start timer
        st.write(f"Query Engine - AI QA开始：{start_5}") 
        initial_response = st.session_state.query_engine.query(st.session_state.user_question)
        temp_ai_response=str(initial_response)
        final_ai_response=temp_ai_response.partition('<|end|>')[0]
        print("AI Response:\n"+final_ai_response)
        st.write("AI Response:\n\n"+final_ai_response)