app.py

import os
import gradio as gr
from openai import AzureOpenAI
from langchain_community.document_loaders import PyPDFLoader
from langchain_text_splitters import RecursiveCharacterTextSplitter
from langchain_community.vectorstores import Chroma
from langchain_community.embeddings import HuggingFaceEmbeddings

# Load PDF (Tiruvāsagam)
loader = PyPDFLoader("tiru.pdf")
docs = loader.load()

# Split into chunks
splitter = RecursiveCharacterTextSplitter(chunk_size=500, chunk_overlap=50)
chunks = splitter.split_documents(docs)

# Local embedding model (Tamil capable)
embedding_model = HuggingFaceEmbeddings(model_name="sentence-transformers/paraphrase-multilingual-MiniLM-L12-v2")

# Store in Chroma
vectorstore = Chroma.from_documents(chunks, embedding=embedding_model)
retriever = vectorstore.as_retriever(search_type="similarity", search_kwargs={"k":3})

# Azure OpenAI client
client = AzureOpenAI(
    api_key=os.getenv("AZURE_OPENAI_API_KEY").strip(),
    api_version="2025-01-01-preview",
    azure_endpoint=os.getenv("AZURE_OPENAI_ENDPOINT").strip()
)

# Chat function
def chat_fn(message, history):
    docs = retriever.get_relevant_documents(message)
    context = "\n\n".join([d.page_content for d in docs])

    completion = client.chat.completions.create(
        model="gpt-4.1",  # your Azure deployment name
        messages=[
            {
                "role": "system",
                "content": (
                    "You are a helpful assistant answering only from Tiruvāsagam. "
                    "Always reply in Tamil with simple, clear, and correct grammar. "
                    "Be token efficient. "
                    "If the question is not related to Tiruvāsagam, Lord Shiva, or "
                    "Manikkavasagar, just reply: 'எனக்கு தெரியாது'."
                )
            },
            {
                "role": "user",
                "content": f"Context:\n{context}\n\nQuestion: {message}"
            }
        ],
        temperature=0.8,
        max_tokens=500
    )
    return completion.choices[0].message.content

# Gradio UI
chatbot = gr.ChatInterface(
    fn=chat_fn,
    title="திருவாசகம் RAG Chatbot",
    description="திருவாசகத்தை அடிப்படையாகக் கொண்டு கேள்விகளை கேளுங்கள் (Tamil/English supported)."
)

if __name__ == "__main__":
    chatbot.launch(server_name="0.0.0.0", server_port=7860, debug=True)