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

class AdvancedPdfChatbot:
    def __init__(self, openai_api_key):
        os.environ["OPENAI_API_KEY"] = openai_api_key
        self.embeddings = OpenAIEmbeddings()
        self.text_splitter = RecursiveCharacterTextSplitter(chunk_size=1000, chunk_overlap=200)
        self.llm = ChatOpenAI(temperature=0, model_name="gpt-3.5-turbo")
        self.memory = ConversationBufferMemory(memory_key="chat_history", return_messages=True)
        self.qa_chain = None

    def load_and_process_pdf(self, pdf_path):
        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()

    def setup_conversation_chain(self):
        self.qa_chain = ConversationalRetrievalChain.from_llm(
            self.llm,
            retriever=self.db.as_retriever(),
            memory=self.memory
        )

    def chat(self, query):
        if not self.qa_chain:
            return "Please upload a PDF first."
        result = self.qa_chain({"question": query})
        return result['answer']

# 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
    pdf_chatbot.load_and_process_pdf(file_path)
    return "PDF uploaded and processed successfully. You can now start chatting!"

def respond(message, history):
    bot_message = pdf_chatbot.chat(message)
    history.append((message, bot_message))
    return "", history

# 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])

    chatbot_interface = gr.Chatbot()
    msg = gr.Textbox()
    clear = gr.Button("Clear")

    msg.submit(respond, inputs=[msg, chatbot_interface], outputs=[msg, chatbot_interface])
    clear.click(lambda: None, None, chatbot_interface, queue=False)

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