app.py

import gradio as gr
import pymongo
import certifi
from llama_index.core import VectorStoreIndex
from llama_index.embeddings.huggingface import HuggingFaceEmbedding
from llama_index.llms.gemini import Gemini
from llama_index.vector_stores.mongodb import MongoDBAtlasVectorSearch
from llama_index.core.prompts import PromptTemplate
from dotenv import load_dotenv
import os
import base64
import markdown as md
from datetime import datetime

# Load environment variables
load_dotenv()

# --- Embedding Model ---
embed_model = HuggingFaceEmbedding(model_name="intfloat/multilingual-e5-base")

# --- Prompt Templates ---
ramayana_qa_template = PromptTemplate(
    """You are an expert on the Valmiki Ramayana and a guide who always inspires people with the great Itihasa like the Ramayana.

    Below is text from the epic, including shlokas and their explanations:
    ---------------------
    {context_str}
    ---------------------

    Using only this information, answer the following query.

    Query: {query_str}

    Answer:
     - Intro or general description to ```Query```
     - Related sanskrit shloka(s) followed by its explanation
     - Overview of ```Query```"""
)

gita_qa_template = PromptTemplate(
    """You are an expert on the Bhagavad Gita and a spiritual guide.

    Below is text from the scripture, including verses and their explanations:
    ---------------------
    {context_str}
    ---------------------

    Using only this information, answer the following query.

    Query: {query_str}

    Answer:
     - Intro or context about the topic
     - Relevant sanskrit verse(s) with explanation
     - Conclusion or reflection"""
)

# --- MongoDB Vector Index Loader ---
def get_vector_index(db_name, collection_name, vector_index_name):
    mongo_client = pymongo.MongoClient(
        os.getenv("ATLAS_CONNECTION_STRING"),
        tlsCAFile=certifi.where(),
    )
    mongo_client.server_info()
    print(f"✅ Connected to MongoDB Atlas for collection: {collection_name}")

    vector_store = MongoDBAtlasVectorSearch(
        mongo_client,
        db_name=db_name,
        collection_name=collection_name,
        vector_index_name=vector_index_name,
    )
    return VectorStoreIndex.from_vector_store(vector_store, embed_model=embed_model)

# --- Load Indices Once ---
ramayana_index = get_vector_index("RAG", "ramayana", "ramayana_vector_index")
gita_index = get_vector_index("RAG", "bhagavad_gita", "gita_vector_index")

# --- Gradio Chat Wrapper with Streaming ---
def chat(index, template):
    llm = Gemini(
        model="models/gemini-1.5-flash",
        api_key=os.getenv("GOOGLE_API_KEY"),
        streaming=True
    )
    query_engine = index.as_query_engine(
        llm=llm,
        text_qa_template=template,
        similarity_top_k=5,
        streaming=True,
        verbose=True,
    )

    def fn(message, history):
        streaming_response = query_engine.query(message)

        full_response = ""
        for text in streaming_response.response_gen:
            full_response += text
            yield full_response
        response = query_engine.query(message)
        yield str(response)
        print(f"\n{datetime.now()}:: {message} --> {str(full_response)}\n")
    return fn

# --- Encode Logos ---
def encode_image(image_path):
    with open(image_path, "rb") as image_file:
        return base64.b64encode(image_file.read()).decode("utf-8")

github_logo_encoded = encode_image("Images/github-logo.png")
linkedin_logo_encoded = encode_image("Images/linkedin-logo.png")
website_logo_encoded = encode_image("Images/ai-logo.png")

# --- Gradio UI ---
with gr.Blocks(theme=gr.themes.Soft(font=[gr.themes.GoogleFont("Roboto Mono")]), css="footer {visibility: hidden}") as demo:
    with gr.Tabs():
        with gr.TabItem("Intro"):
            gr.Markdown(md.description)

        def create_tab(tab_title, vector_index, template, intro_md):
            with gr.TabItem(tab_title):
                with gr.Accordion("==========> Overview & Summary <==========", open=False):
                    gr.Markdown(intro_md)
                gr.ChatInterface(
                    fn=chat(vector_index, template),
                    chatbot=gr.Chatbot(height=500),
                    show_progress="full",
                    fill_height=True,
                )

        create_tab("RamayanaGPT🏹", ramayana_index, ramayana_qa_template, md.RamayanaGPT)
        create_tab("GitaGPT🛞", gita_index, gita_qa_template, md.GitaGPT)

        gr.HTML(md.footer.format(github_logo_encoded, linkedin_logo_encoded, website_logo_encoded))

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