app.py

import gradio as gr
import os
from dotenv import load_dotenv
from langchain_community.document_loaders import PyPDFLoader
from langchain.text_splitter import RecursiveCharacterTextSplitter
from langchain_community.vectorstores import Chroma
from langchain.chains import ConversationalRetrievalChain
from langchain_community.embeddings import HuggingFaceEmbeddings 
from langchain_community.llms import HuggingFacePipeline
from langchain.chains import ConversationChain
from langchain.memory import ConversationBufferMemory
from langchain.llms import HuggingFaceHub
# from doctr.models import ocr_predictor
# from doctr.io import DocumentFile
from pathlib import Path
import chromadb
# Later Packages
from getpass import getpass

import weasyprint
import matplotlib.pyplot as plt
from langchain.document_loaders import PyPDFDirectoryLoader
load_dotenv()
# model = ocr_predictor(pretrained = True)
huggingfacehub_api_token = os.getenv("HUGGINGFACEHUB_API_TOKEN")
openai_key = os.getenv("OPEN_API_KEY")
# default_persist_directory = './chroma_HF/'
list_llm = ["mistralai/Mixtral-8x7B-Instruct-v0.1", "mistralai/Mistral-7B-Instruct-v0.1", \
    "google/gemma-7b-it","google/gemma-2b-it", \
    "HuggingFaceH4/zephyr-7b-beta", \
    "TinyLlama/TinyLlama-1.1B-Chat-v1.0", "tiiuae/falcon-7b-instruct", \
    "google/flan-t5-xxl"
]
list_llm_simple = [os.path.basename(llm) for llm in list_llm]
#Extract text data from doctr reaponse
def extract_value_from_response(response):
    value = ''
    for page in response.pages:
        for block in page.blocks:
            for line in block.lines:
                for word in line.words:
                    value += " "+word.value
    return value

# Craete PDf from URL
def create_pdf_from_url(url):
    pdf = weasyprint.HTML(url).write_pdf()
    output_dir = "pdfDir"
    if not os.path.exists(output_dir):
        os.makedirs(output_dir)
    file_path = os.path.join(output_dir,'url_pdf.pdf')
    with open(file_path,'wb') as f:
        f.write(pdf)
    return file_path
# Load PDF document and create doc splits
def load_doc(list_file_path, chunk_size, chunk_overlap):
    # Processing for one document only
    loaders = [PyPDFLoader(x) for x in list_file_path]
    pages = []
    for loader in loaders:
        pages.extend(loader.load())
    text_splitter = RecursiveCharacterTextSplitter(
        chunk_size = chunk_size, 
        chunk_overlap = chunk_overlap)
    doc_splits = text_splitter.split_documents(pages)
    # if len(doc_splits) == 0:
    #     doc = DocumentFile.from_pdf(list_file_path[0])
    #     result = model(doc)
    #     response = extract_value_from_response(result)
    #     doc_splits = text_splitter.split_documents(response)
    return doc_splits

# Create vector database
def create_db(splits, collection_name):
    embedding = HuggingFaceEmbeddings()
    new_client = chromadb.EphemeralClient()
    vectordb = Chroma.from_documents(
        documents = splits,
        embedding = embedding,
        client = new_client,
        collection_name = collection_name,
        # persist_directory=default_persist_directory
    )
    return vectordb


# Load vector database
def load_db():
    embedding = HuggingFaceEmbeddings()
    vectordb = Chroma( embedding_function = embedding)
    return vectordb


# Initialize langchain LLM chain
def initialize_llmchain(llm_model, temperature, max_tokens, top_k, vector_db, progress=gr.Progress()):
    progress(0.1, desc="Initializing HF tokenizer...")    
    # HuggingFaceHub uses HF inference endpoints
    progress(0.5, desc="Initializing HF Hub...")
    # Use of trust_remote_code as model_kwargs
    # Warning: langchain issue
    # URL: https://github.com/langchain-ai/langchain/issues/6080
    if llm_model == "mistralai/Mixtral-8x7B-Instruct-v0.1":
        llm = HuggingFaceHub(
            repo_id=llm_model, 
            model_kwargs={"temperature": temperature, "max_new_tokens": max_tokens, "top_k": top_k, "load_in_8bit": True}
        )
    elif llm_model == "TinyLlama/TinyLlama-1.1B-Chat-v1.0":
        llm = HuggingFaceHub(
            repo_id=llm_model, 
            model_kwargs={"temperature": temperature, "max_new_tokens": 250, "top_k": top_k}
        )
    else:
        llm = HuggingFaceHub(
            repo_id=llm_model, 
            model_kwargs={"temperature": temperature, "max_new_tokens": max_tokens, "top_k": top_k}
        )
    
    progress(0.75, desc="Defining buffer memory...")
    memory = ConversationBufferMemory(
        memory_key="chat_history",
        output_key='answer',
        return_messages=True
    )
    progress(0.8, desc="Defining retrieval chain...")
    retriever = vector_db.as_retriever()
    qa_chain = ConversationalRetrievalChain.from_llm(
        llm,
        retriever = retriever,
        chain_type = "stuff", 
        memory = memory,
        # combine_docs_chain_kwargs={"prompt": your_prompt})
        return_source_documents=True,
        #return_generated_question=False,
        verbose = False,
    )
    progress(0.9, desc="Done!")
    return qa_chain


# Initialize database
def initialize_database(list_file_obj, chunk_size, chunk_overlap, vector_db, url, progress = gr.Progress()):
    if url != "":
       file_path = create_pdf_from_url(url)
       list_file_obj = []
       list_file_obj.append(file_path)
       list_file_path = list_file_obj
    else:
        # Create list of documents (when valid)
        list_file_path = [x.name for x in list_file_obj if x is not None]
    # Create collection_name for vector database
    progress(0.1, desc="Creating collection name...")
    collection_name = Path(list_file_path[0]).stem
    # Fix potential issues from naming convention
    ## Remove space
    collection_name = collection_name.replace(" ","-") 
    ## Limit lenght to 50 characters
    collection_name = collection_name[:50]
    ## Enforce start and end as alphanumeric character
    if not collection_name[0].isalnum():
        collection_name[0] = 'A'
    if not collection_name[-1].isalnum():
        collection_name[-1] = 'Z'
    # print('list_file_path: ', list_file_path)
    print('Collection name: ', collection_name)
    progress(0.25, desc="Loading document...")
    # Load document and create splits
    doc_splits = load_doc(list_file_path, chunk_size, chunk_overlap)
    # Create or load vector database
    progress(0.7, desc="Generating vector database...")
    # global vector_db
    vector_db = create_db(doc_splits, collection_name)
    return vector_db, collection_name, gr.update(value = ""), "Complete!"


def re_initialize_LLM(llm_option, llm_temperature, max_tokens, top_k, vector_db):
    llm_name = list_llm[llm_option]
    print("llm_name: ",llm_name)
    qa_chain = initialize_llmchain(llm_name, llm_temperature, max_tokens, top_k, vector_db)
    return qa_chain


def format_chat_history(message, chat_history):
    formatted_chat_history = []
    for user_message, bot_message in chat_history:
        formatted_chat_history.append(f"User: {user_message}")
        formatted_chat_history.append(f"Assistant: {bot_message}")
    return formatted_chat_history
    

def conversation(qa_chain, message, history, llm_option):
    formatted_chat_history = format_chat_history(message, history)
    # Generate response using QA chain 
    response = qa_chain({"question": message, "chat_history": formatted_chat_history})
    response_answer = response["answer"]
    if response_answer.find("Helpful Answer:") != -1:
        response_answer = response_answer.split("Helpful Answer:")[-1]
    new_history = history + [(message, response_answer)]
    return qa_chain, gr.update(value = ""), new_history
    

def upload_file(file_obj):
    list_file_path = []
    for idx, file in enumerate(file_obj):
        file_path = file_obj.name
        list_file_path.append(file_path)
    # print(file_path)
    return list_file_path


def demo():
    with gr.Blocks(theme = "base") as demo:
        vector_db = gr.State()
        qa_chain = gr.State()
        collection_name = gr.State()
        gr.Markdown(
        '''
        <div style="text-align:center;">
            <span style="font-size:3em; font-weight:bold;">PDF Document Chatbot</span>
        </div>
        ''')
        with gr.Row():
            with gr.Row():
                with gr.Column():
                    document = gr.Files(file_count="multiple", file_types=[".pdf"], interactive=True, label="Upload your PDF documents (single or multiple)")
                    with gr.Row():
                            gr.Markdown(
                            '''
                            <div style="text-align:center;">
                                <span style="font-size:2em; font-weight:bold;">OR</span>
                            </div>
                            ''')
                    with gr.Row():
                        url = gr.Textbox(placeholder = "Enter your URL Here")
                    with gr.Row():
                        db_btn = gr.Radio(["ChromaDB"], label="Vector database type", value = "ChromaDB", type="index", info="Choose your vector database", visible = False)
                    with gr.Accordion("Advanced options - Document text splitter", open=False, visible = False):
                        with gr.Row():
                            slider_chunk_size = gr.Slider(minimum = 100, maximum = 1000, value=600, step=20, label="Chunk size", info="Chunk size", interactive=True, visible = False)
                        with gr.Row():
                            slider_chunk_overlap = gr.Slider(minimum = 10, maximum = 200, value=40, step=10, label="Chunk overlap", info="Chunk overlap", interactive=True, visible = False)
                    llm_btn = gr.Radio(list_llm_simple, label = "LLM models", type = "index", info = "Choose your LLM model")
                    db_progres = gr.Textbox(label="Vector database initialization", value="None")
                    with gr.Row():
                        submit_file = gr.Button("Submit File")
            with gr.Row():
                with gr.Column():
                    chatbot = gr.Chatbot()
                    msg = gr.Textbox(placeholder = "Type Your Message")
                    with gr.Accordion("Advanced options - LLM model", open = False):
                        with gr.Row():
                            slider_temperature = gr.Slider(minimum = 0.0, maximum = 1.0, value=0.7, step=0.1, label="Temperature", info="Model temperature", interactive=True)
                        with gr.Row():
                            slider_maxtokens = gr.Slider(minimum = 224, maximum = 4096, value=1024, step=32, label="Max Tokens", info="Model max tokens", interactive=True)
                        with gr.Row():
                            slider_topk = gr.Slider(minimum = 1, maximum = 10, value=3, step=1, label="top-k samples", info="Model top-k samples", interactive=True)                  
                    with gr.Row():
                        submit_btn = gr.Button("Submit")
                        # clear_btn = gr.ClearButton([msg2, chatbot])
        # Preprocessing events
        #upload_btn.upload(upload_file, inputs=[upload_btn], outputs=[document])
        submit_file.click(initialize_database, \
            inputs=[document, slider_chunk_size, slider_chunk_overlap, vector_db, url], \
            outputs = [vector_db, collection_name, url, db_progres])
        llm_btn.change(
            re_initialize_LLM, \
            inputs = [llm_btn, slider_temperature, slider_maxtokens, slider_topk, vector_db], \
            outputs = [qa_chain]
        )
        msg.submit(conversation, \
            inputs=[qa_chain, msg, chatbot, llm_btn], \
            outputs=[qa_chain, msg, chatbot], \
            queue=False)
        submit_btn.click(conversation, \
            inputs=[qa_chain, msg, chatbot, llm_btn], \
            outputs=[qa_chain, msg, chatbot], \
            queue=False)
    demo.queue().launch(share = True, debug = True)


if __name__ == "__main__":
    demo()