app.py

import os
import gradio as gr
import logging
from langchain.document_loaders import PyPDFLoader
from langchain.text_splitter import RecursiveCharacterTextSplitter
from langchain.embeddings import OpenAIEmbeddings
from langchain.vectorstores import FAISS
from langchain.chat_models import ChatOpenAI
from langchain.chains import ConversationalRetrievalChain, LLMChain
from langchain.memory import ConversationBufferMemory
from langchain.prompts import PromptTemplate
from PyPDF2 import PdfReader

logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

class ResponseStructureSelector:
    def __init__(self, llm):
        self.llm = llm
        self.structure_prompt = PromptTemplate(
            input_variables=['context', 'query'],
            template="""Analyze the context and query to determine the most appropriate response structure:
Context: {context}
Query: {query}

Select the optimal response format:
1. Markdown with bullet points and headlines
2. Concise paragraph with key insights
3. Numbered list with detailed explanations
4. Technical breakdown with subheadings
5. Quick summary with critical points

Choose the number (1-5) of the most suitable format:"""
        )
        self.structure_chain = LLMChain(llm=self.llm, prompt=self.structure_prompt)

    def select_structure(self, context, query):
        try:
            structure_choice = self.structure_chain.run({'context': context, 'query': query})
            return int(structure_choice.strip())
        except:
            return 1  # Default to Markdown structure

class QueryRefiner:
    def __init__(self, llm):
        self.refinement_llm = llm
        self.refinement_prompt = PromptTemplate(
            input_variables=['query', 'context'],
            template="""Refine query for clarity and precision:
Original Query: {query}
Document Context: {context}
Refined, Focused Query:"""
        )
        self.refinement_chain = LLMChain(llm=self.refinement_llm, prompt=self.refinement_prompt)

    def refine_query(self, original_query, context_hints=''):
        try:
            return self.refinement_chain.run({
                'query': original_query, 
                'context': context_hints or "General document"
            }).strip()
        except Exception as e:
            logger.error(f"Query refinement error: {e}")
            return original_query

class AdvancedPdfChatbot:
    def __init__(self, openai_api_key):
        os.environ["OPENAI_API_KEY"] = openai_api_key
        self.llm = ChatOpenAI(temperature=0, model_name='gpt-4o', max_tokens=1000)
        
        self.embeddings = OpenAIEmbeddings()
        self.text_splitter = RecursiveCharacterTextSplitter(chunk_size=800, chunk_overlap=100)
        
        self.memory = ConversationBufferMemory(memory_key="chat_history", return_messages=True)
        self.query_refiner = QueryRefiner(self.llm)
        self.response_selector = ResponseStructureSelector(self.llm)
        
        self.db = None
        self.chain = None
        self.document_metadata = {}

    def _create_response_prompt(self, structure_choice):
        structure_templates = {
            1: """Markdown Response with Structured Insights:
## {title}
### Key Highlights
{content}
### Conclusion
{conclusion}""",
            2: """{title}: {content}. Key Takeaway: {conclusion}""",
            3: """Structured Breakdown:
1. {title}
   - Main Point: {content}
2. Implications
   - {conclusion}""",
            4: """Technical Analysis
## {title}
### Core Concept
{content}
### Technical Implications
{conclusion}""",
            5: """Concise Summary: {title}. Key Points: {content}. Conclusion: {conclusion}."""
        }
        return PromptTemplate(
            template=structure_templates.get(structure_choice, structure_templates[1]),
            input_variables=["title", "content", "conclusion"]
        )

    def load_and_process_pdf(self, pdf_path):
        try:
            # Extract PDF metadata
            reader = PdfReader(pdf_path)
            self.document_metadata = {
                "title": reader.metadata.get("/Title", "Untitled Document"),
                "author": reader.metadata.get("/Author", "Unknown")
            }

            # Load and process PDF
            loader = PyPDFLoader(pdf_path)
            documents = loader.load()
            texts = self.text_splitter.split_documents(documents)
            
            # Create vector store with fewer documents to improve performance
            self.db = FAISS.from_documents(texts[:30], self.embeddings)
            
            # Setup conversational chain
            self.chain = ConversationalRetrievalChain.from_llm(
                llm=self.llm,
                retriever=self.db.as_retriever(search_kwargs={"k": 3}),
                memory=self.memory
            )
            
            return True
        except Exception as e:
            logger.error(f"PDF processing error: {e}")
            return False

    def chat(self, query):
        if not self.chain:
            return "Upload a PDF first."
        
        # Refine query
        context = f"Document: {self.document_metadata.get('title', 'Unknown')}"
        refined_query = self.query_refiner.refine_query(query, context)
        
        # Select response structure
        structure_choice = self.response_selector.select_structure(context, refined_query)
        
        # Perform retrieval and answer generation
        result = self.chain({"question": refined_query})
        
        return result['answer']

# Gradio Interface (remains mostly the same)
pdf_chatbot = AdvancedPdfChatbot(os.environ.get("OPENAI_API_KEY"))

def upload_pdf(pdf_file):
    if not pdf_file:
        return "Upload a PDF file."
    file_path = pdf_file.name if hasattr(pdf_file, 'name') else pdf_file
    return "PDF processed successfully" if pdf_chatbot.load_and_process_pdf(file_path) else "Processing failed"

def respond(message, history):
    try:
        bot_message = pdf_chatbot.chat(message)
        history.append((message, bot_message))
        return "", history
    except Exception as e:
        return f"Error: {e}", history


# Gradio Interface
pdf_chatbot = AdvancedPdfChatbot(os.environ.get("OPENAI_API_KEY"))

def upload_pdf(pdf_file):
    if pdf_file is None:
        return "Please upload a PDF file."
    file_path = pdf_file.name if hasattr(pdf_file, 'name') else pdf_file
    try:
        pdf_chatbot.load_and_process_pdf(file_path)
        return f"PDF processed successfully: {file_path}"
    except Exception as e:
        logger.error(f"PDF processing error: {e}")
        return f"Error processing PDF: {str(e)}"

def respond(message, history):
    if not message:
        return "", history
    try:
        bot_message = pdf_chatbot.chat(message)
        history.append((message, bot_message))
        return "", history
    except Exception as e:
        logger.error(f"Chat response error: {e}")
        return f"Error: {str(e)}", history

def clear_chatbot():
    pdf_chatbot.clear_memory()
    return []

# Gradio UI
with gr.Blocks() as demo:
    gr.Markdown("# Advanced PDF Chatbot")
    with gr.Row():
        pdf_upload = gr.File(label="Upload PDF", file_types=[".pdf"])
        upload_button = gr.Button("Process PDF")

    upload_status = gr.Textbox(label="Upload Status")
    upload_button.click(upload_pdf, inputs=[pdf_upload], outputs=[upload_status])
    chatbot_interface = gr.Chatbot()
    msg = gr.Textbox(placeholder="Enter your query...")
    msg.submit(respond, inputs=[msg, chatbot_interface], outputs=[msg, chatbot_interface])
    clear_button = gr.Button("Clear Conversation")
    clear_button.click(clear_chatbot, outputs=[chatbot_interface])

if __name__ == "__main__":
    demo.launch()