import os
import re
from langchain.chains import RetrievalQA
from langchain.llms import OpenAI as LangchainOpenAI
from langchain.document_loaders import PyPDFLoader
from langchain.text_splitter import CharacterTextSplitter
from langchain.embeddings import OpenAIEmbeddings
from langchain.vectorstores import Chroma
import panel as pn
from panel.template import VanillaTemplate

CSS = """
#header {
    height: 0;
    padding: 0;
}

.pn-busy-container {
    visibility: hidden;
}
"""

pn.extension(raw_css=[CSS])

# Custom CSS to use Lato font
lato_font_style = """
.bk, .bk-root {
    font-family: 'Lato', sans-serif !important;
}
"""

# Create a custom template
template = VanillaTemplate(
    raw_css=[lato_font_style],
    css_files=['https://fonts.googleapis.com/css2?family=Lato:wght@400;700&display=swap']
)

# Set global sizing mode
pn.config.sizing_mode = 'stretch_width'

# Panel extension
pn.extension()

class LangchainConversation:
    def __init__(self):
        self.file_input = pn.widgets.FileInput(height=45)
        self.openaikey = pn.widgets.PasswordInput(value="", placeholder="Enter your OpenAI API Key here...", height=45)
        self.chatbox = pn.widgets.ChatBox(height=300, primary_name="User")
        self.chatbox.param.watch(self._chat, 'value')
        self.chat_history = []  # Chat history to store previous queries and responses

    def _chat(self, event):
        user_message = event.new[-1]
        input = user_message.get("User")
        if input is None:
            return
        os.environ["OPENAI_API_KEY"] = self.openaikey.value
        if self.file_input.value is not None:
            file_path = "/.cache/temp.pdf"
            self.file_input.save(file_path)
            # Check if the uploaded file is a PDF
            if self.file_input.filename.lower().endswith('.pdf'):
                prompt_text = self.remove_empty_lines(input)
                if prompt_text:
                    result = self.qa(file=file_path, query=prompt_text)
                    self.chatbox.append({"AI": result})
            else:
                # Delete the non-PDF file from cache
                os.remove(file_path)
                # Display an error message in the chatbox
                self.chatbox.append({"AI": "Error: Only PDF files are allowed. Please upload a valid PDF file."})

    @staticmethod
    def remove_empty_lines(text):
        lines = re.split(r'\\r\\n|\\r|\\n', text)
        return '\\n'.join([line.strip() for line in lines if line.strip()])

    def qa(self, file, query):
        # Consider chat history when processing new queries
        chat_history_str = "\\n".join([f"User: {q}\\nAI: {a}" for q, a in self.chat_history])

        # Load, split, and analyze the document using the default text splitter
        loader = PyPDFLoader(file)
        documents = loader.load()
        text_splitter = CharacterTextSplitter(chunk_size=1000, chunk_overlap=0)  # Default text splitting
        texts = text_splitter.split_documents(documents)
        embeddings = OpenAIEmbeddings()
        db = Chroma.from_documents(texts, embeddings)
        retriever = db.as_retriever(search_type="similarity", search_kwargs={"k": 3})
        qa = RetrievalQA.from_chain_type(llm=LangchainOpenAI(), chain_type="stuff", retriever=retriever, return_source_documents=True)
        result = qa({"query": query + "\\n" + chat_history_str})

        # Update chat history
        self.chat_history.append((query, result['result']))

        return result['result']


    def view(self):
        custom_link_style = {
            'color': '#1b9aaa',
            'font-weight': 'bold'
        }

        layout = pn.Column(
            pn.pane.Markdown(""" 
            Built by <a href="https://www.mckenzielloydsmith.com/home?utm_source=HuggingFace&utm_medium=PDF+Analyzer" target="_blank">McKenzie</a>.
            """),  # Closing parenthesis for pn.pane.Markdown
            pn.Row(self.file_input, self.openaikey), self.chatbox
        )

        # Add layout to the template
        template.main.append(layout)

        # Serve the template
        return template.servable()

langchain_conversation = LangchainConversation()
langchain_conversation.view()