app.py

from gevent import monkey
monkey.patch_all()

import os
from dotenv import load_dotenv
import asyncio
from flask import Flask, request, render_template
from flask_cors import CORS
from flask_socketio import SocketIO, emit, join_room, leave_room
from langchain.chains import create_history_aware_retriever, create_retrieval_chain
from langchain.chains.combine_documents import create_stuff_documents_chain
from langchain_community.chat_message_histories import ChatMessageHistory
from langchain_core.chat_history import BaseChatMessageHistory
from langchain_core.prompts import ChatPromptTemplate, MessagesPlaceholder
from langchain_core.runnables.history import RunnableWithMessageHistory
from pinecone import Pinecone
from pinecone_text.sparse import BM25Encoder
from langchain_huggingface import HuggingFaceEmbeddings
from langchain_community.retrievers import PineconeHybridSearchRetriever
from langchain_groq import ChatGroq
from langchain.retrievers import ContextualCompressionRetriever
from langchain.retrievers.document_compressors import FlashrankRerank
from langchain_community.chat_models import ChatPerplexity

# Load environment variables
load_dotenv(".env")
USER_AGENT = os.getenv("USER_AGENT")
GROQ_API_KEY = os.getenv("GROQ_API_KEY")
SECRET_KEY = os.getenv("SECRET_KEY")
PINECONE_API_KEY = os.getenv("PINECONE_API_KEY")
SESSION_ID_DEFAULT = "abc123"

# Set environment variables
os.environ['USER_AGENT'] = USER_AGENT
os.environ["GROQ_API_KEY"] = GROQ_API_KEY
os.environ["TOKENIZERS_PARALLELISM"] = 'true'

# Initialize Flask app and SocketIO with CORS
app = Flask(__name__)
CORS(app)
socketio = SocketIO(app, async_mode='gevent', cors_allowed_origins="*")
app.config['SESSION_COOKIE_SECURE'] = True  # Use HTTPS
app.config['SESSION_COOKIE_HTTPONLY'] = True
app.config['SESSION_COOKIE_SAMESITE'] = 'Lax'
app.config['SECRET_KEY'] = SECRET_KEY

# Function to initialize Pinecone connection
def initialize_pinecone(index_name: str):
    try:
        pc = Pinecone(api_key=PINECONE_API_KEY)
        return pc.Index(index_name)
    except Exception as e:
        print(f"Error initializing Pinecone: {e}")
        raise


##################################################
##          Change down here
##################################################

# Initialize Pinecone index and BM25 encoder
pinecone_index = initialize_pinecone("updated-mbzuai-policies")
bm25 = BM25Encoder().load("./new_mbzuai-policies.json")

##################################################
##################################################

# old_embed_model = HuggingFaceEmbeddings(model_name="sentence-transformers/gte-multilingual-base")

# Initialize models and retriever
embed_model = HuggingFaceEmbeddings(model_name="GameScribes/stella_en_400M_v5", model_kwargs={"trust_remote_code":True})
retriever = PineconeHybridSearchRetriever(
    embeddings=embed_model, 
    sparse_encoder=bm25, 
    index=pinecone_index, 
    top_k=20, 
    alpha=0.5
)

# Initialize LLM
# llm = ChatGroq(model="llama-3.1-70b-versatile", temperature=0, max_tokens=1024, max_retries=2)
llm = ChatPerplexity(temperature=0, pplx_api_key=GROQ_API_KEY, model="llama-3.1-sonar-large-128k-online", max_tokens=1024, max_retries=2)


# Initialize Reranker
compressor = FlashrankRerank()
compression_retriever = ContextualCompressionRetriever(
    base_compressor=compressor, base_retriever=retriever
)

# Contextualization prompt and retriever
contextualize_q_system_prompt = """Given a chat history and the latest user question \
which might reference context in the chat history, formulate a standalone question \
which can be understood without the chat history. Do NOT answer the question, \
just reformulate it if needed and otherwise return it as is.
"""
contextualize_q_prompt = ChatPromptTemplate.from_messages(
    [
        ("system", contextualize_q_system_prompt),
        MessagesPlaceholder("chat_history"),
        ("human", "{input}")
    ]
)
history_aware_retriever = create_history_aware_retriever(llm, compression_retriever, contextualize_q_prompt)

# QA system prompt and chain
qa_system_prompt = """You are a highly skilled information retrieval assistant. Use the following context to answer questions effectively. \
If you don't know the answer, simply state that you don't know. \
Your answer should be in {language} language. \
Provide answers in proper HTML format and keep them concise. \

When responding to queries, follow these guidelines: \

    1. Provide Clear Answers: \
        - Based on the language of the question, you have to answer in that language. E.g. if the question is in English language then answer in the English language or if the question is in Arabic language then you should answer in Arabic language. /
        - Ensure the response directly addresses the query with accurate and relevant information.\

    2. Include Detailed References: \
        - Links to Sources: Include URLs to credible sources where users can verify information or explore further. \
        - Reference Sites: Mention specific websites or platforms that offer additional information. \
        - Downloadable Materials: Provide links to any relevant downloadable resources if applicable. \
    
    3. Formatting for Readability: \
        - The answer should be in a proper HTML format with appropriate tags. \
        - For arabic language response align the text to right and convert numbers also.
        - Double check if the language of answer is correct or not.
        - Use bullet points or numbered lists where applicable to present information clearly. \
        - Highlight key details using bold or italics. \
        - Provide proper and meaningful abbreviations for urls. Do not include naked urls. \
    
    4. Organize Content Logically: \
        - Structure the content in a logical order, ensuring easy navigation and understanding for the user. \
        
{context}
"""
qa_prompt = ChatPromptTemplate.from_messages(
    [
        ("system", qa_system_prompt),
        MessagesPlaceholder("chat_history"),
        ("human", "{input}")
    ]
)
question_answer_chain = create_stuff_documents_chain(llm, qa_prompt)

# Retrieval and Generative (RAG) Chain
rag_chain = create_retrieval_chain(history_aware_retriever, question_answer_chain)

# Chat message history storage
store = {}

def clean_temporary_data():
    store.clear()

def get_session_history(session_id: str) -> BaseChatMessageHistory:
    if session_id not in store:
        store[session_id] = ChatMessageHistory()
    return store[session_id]

# Conversational RAG chain with message history
conversational_rag_chain = RunnableWithMessageHistory(
    rag_chain,
    get_session_history,
    input_messages_key="input",
    history_messages_key="chat_history",
    language_message_key="language",
    output_messages_key="answer",
)

# Function to handle WebSocket connection
@socketio.on('connect')
def handle_connect():
    print(f"Client connected: {request.sid}")
    emit('connection_response', {'message': 'Connected successfully.'})

# Function to handle WebSocket disconnection
@socketio.on('disconnect')
def handle_disconnect():
    print(f"Client disconnected: {request.sid}")
    clean_temporary_data()

# Function to handle WebSocket messages
@socketio.on('message')
def handle_message(data):
    question = data.get('question')
    language = data.get('language')
    if "en" in language:
        language = "English"
    else:
        language = "Arabic"
    session_id = data.get('session_id', SESSION_ID_DEFAULT)
    chain = conversational_rag_chain.pick("answer")

    try:
        for chunk in chain.stream(
                {"input": question, 'language': language},
                config={"configurable": {"session_id": session_id}},
            ):
            emit('response', chunk, room=request.sid)
    except Exception as e:
        print(f"Error during message handling: {e}")
        emit('response', "An error occurred while processing your request." + str(e), room=request.sid)


# Home route
@app.route("/")
def index_view():
    return render_template('chat.html') 

# Main function to run the app
if __name__ == '__main__': 
    socketio.run(app, debug=True)