app.py

import os
import gradio as gr
from langchain.document_loaders import PyPDFLoader
from langchain.text_splitter import RecursiveCharacterTextSplitter
from langchain.embeddings import OpenAIEmbeddings
from langchain.vectorstores import FAISS
from langchain.chains import ConversationalRetrievalChain
from langchain.chat_models import ChatOpenAI
from langchain.memory import ConversationBufferMemory
import shutil
from collections import deque
from langchain.prompts import PromptTemplate



openai_api_key = os.environ.get("OPENAI_API_KEY")

class AdvancedPdfChatbot:
    def __init__(self, openai_api_key):
        self.memory = deque(maxlen=20)
        os.environ["OPENAI_API_KEY"] = openai_api_key
        self.embeddings = OpenAIEmbeddings()
        self.text_splitter = RecursiveCharacterTextSplitter(chunk_size=1000, chunk_overlap=0)
        self.llm =  ChatOpenAI(temperature=0.7,model_name='gpt-4o',max_tokens=2048,top_p = 0.7)
        self.memory = ConversationBufferMemory(memory_key="chat_history", output_key='answer',return_messages=True)
        self.qa_chain = None
        self.pdf_path = None
        self.template = """
You are a file-based knowledge assistant that interacts with users like ChatGPT. Your primary source of knowledge comes from user-uploaded files, such as PDFs. You do not rely on general knowledge or the internet. Instead, you extract, analyze, and synthesize information directly from the content of the provided file(s).  
**1. Personality and Tone**  
- Be polite, clear, and professional.  
- Use formal, academic language when the context requires it.  
- Provide concise, well-structured responses, and maintain a helpful and supportive tone.  
**2. Core Capabilities**  
- Extract and summarize key information from the provided file.  
- Answer user questions based on the content of the file.  
- Provide in-depth analysis, explanations, and references to the file's content.  
- Suggest relevant sections, chapters, or pages where specific information can be found.  
- Offer guidance on how users can interpret and understand the file's contents.  
**3. Knowledge and Scope**  
- Your knowledge is limited to the content found in the uploaded file(s).  
- You should not answer questions unrelated to the file's content unless explicitly requested.  
- If a user asks a question that is not found in the file, inform them that the information is not available.  
**4. Interaction Rules**  
- Respond with specific references to the document's content, including page numbers, sections, or headings, if available.  
- If the user asks for clarification, politely request more details.  
- Provide accurate, detailed, structured, clear explanations for user queries.  
- Never "make up" information. If something is not in the file, clearly state that it cannot be found.  
**5. Context Awareness**  
- Remember the content of the file for the duration of the session.  
- Use file-specific knowledge to provide logical and evidence-backed responses.  
- If multiple files are uploaded, clarify which file is being referenced and specify which file the information is from.  
**6. Technical Details**  
- Summarize content into concise answers and organize information using bullet points, lists, or structured paragraphs.  
- If asked to provide a summary, focus on key points, main arguments, and essential takeaways.  
- When a user asks for a section or heading, search for relevant text within the file.  
- Do not offer answers beyond the scope of the file, and avoid guessing.  
**7. Example Usage**  
User: "Can you summarize the main argument from the introduction of the file?"  
Response: "Sure! The introduction discusses [key points] and highlights the central argument that [main idea]. This can be found on page 2 under the heading 'Introduction'."  
User: "Where can I find the definition of 'symbolic interactionism' in the document?"  
Bot Response: "The definition of 'symbolic interactionism' appears on page 12 under the subheading 'Key Theoretical Concepts'."  
User: "Explain the concept of 'cognitive dissonance' as it is presented in the document."  
Bot Response: "In the document, 'cognitive dissonance' is defined as [definition from the file]. It appears in the context of [brief explanation] and can be found on page 15 under the section 'Theoretical Foundations'."  



** You should also be able to have a casual conversation when users say thank you or hi or hello, you should be an interactive chat bot.
**End of Prompt**
        Context: {context}
        Question: {question}
        Answer:
        """

        self.prompt = PromptTemplate(template=self.template, input_variables=["context", "question"])

    def load_and_process_pdf(self, pdf_path):
        try:
            loader = PyPDFLoader(pdf_path)
            documents = loader.load()
            texts = self.text_splitter.split_documents(documents)
            self.db = FAISS.from_documents(texts, self.embeddings)
            self.setup_conversation_chain()
            self.pdf_path = pdf_path
        except Exception as e:
            return f"An error occurred while processing the PDF: {e}"

    def setup_conversation_chain(self):
        self.qa_chain = ConversationalRetrievalChain.from_llm(
            self.llm,
            retriever=self.db.as_retriever(),
            memory=self.memory,
            return_source_documents=True,
            combine_docs_chain_kwargs={"prompt": self.prompt}
        )

    def chat(self, query):
        if not self.qa_chain:
            return "Please upload a PDF first."
        result = self.qa_chain({"question": query})
        return result  # Return the entire result dictionary

    def get_pdf_path(self):
        
        if self.pdf_path:
            return self.pdf_path
        else:
            return "No PDF uploaded yet."

# Initialize the chatbot
pdf_chatbot = AdvancedPdfChatbot(openai_api_key)



def upload_pdf(pdf_file):
    if pdf_file is None:
        return "Please upload a PDF file."
    file_path = pdf_file.name  # This is the full path, e.g., /tmp/tmp1234.pdf
    pdf_chatbot.memory.clear()  # Clears chat history
    pdf_chatbot.load_and_process_pdf(file_path)
    return file_path




def respond(message, history):
    if not pdf_chatbot.qa_chain:
        return "", history, "", "", "", "", "", ""

    # Generate response using QA chain
    response = pdf_chatbot.chat(message)
    response_answer = response["answer"]
    if response_answer.find("Helpful Answer:") != -1:
        response_answer = response_answer.split("Helpful Answer:")[-1]
    response_sources = response["source_documents"]

    # Extract source documents and page numbers
    response_source1 = response_sources[0].page_content.strip() if len(response_sources) > 0 else ""
    response_source2 = response_sources[1].page_content.strip() if len(response_sources) > 1 else ""
    response_source3 = response_sources[2].page_content.strip() if len(response_sources) > 2 else ""
    response_source1_page = response_sources[0].metadata["page"] + 1 if len(response_sources) > 0 else ""
    response_source2_page = response_sources[1].metadata["page"] + 1 if len(response_sources) > 1 else ""
    response_source3_page = response_sources[2].metadata["page"] + 1 if len(response_sources) > 2 else ""

    # Append user message and response to chat history
    history.append((message, response_answer))

    return "", history, response_source1, response_source1_page, response_source2, response_source2_page, response_source3, response_source3_page
def clear_chatbot():
    pdf_chatbot.memory.clear()
    return []

def get_pdf_path():
    # Call the method to return the current PDF path
    return pdf_chatbot.get_pdf_path()

# Create the Gradio interface
with gr.Blocks() as demo:
    gr.Markdown("# 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])

    path_button = gr.Button("Get PDF Path")
    pdf_path_display = gr.Textbox(label="Current PDF Path")
    
    chatbot_interface = gr.Chatbot()
    msg = gr.Textbox()
    clear = gr.Button("Clear")

    with gr.Accordion("Advanced - Document references", open=False):
        with gr.Row():
            doc_source1 = gr.Textbox(label="Reference 1", lines=2, container=True, scale=20)
            source1_page = gr.Number(label="Page", scale=1)
        with gr.Row():
            doc_source2 = gr.Textbox(label="Reference 2", lines=2, container=True, scale=20)
            source2_page = gr.Number(label="Page", scale=1)
        with gr.Row():
            doc_source3 = gr.Textbox(label="Reference 3", lines=2, container=True, scale=20)
            source3_page = gr.Number(label="Page", scale=1)

    msg.submit(respond, inputs=[msg, chatbot_interface], outputs=[msg, chatbot_interface, doc_source1, source1_page, doc_source2, source2_page, doc_source3, source3_page])
    clear.click(clear_chatbot, outputs=[chatbot_interface])
    path_button.click(get_pdf_path, outputs=[pdf_path_display])

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