app.py

import os
import time
import fitz  # PyMuPDF
import faiss
import google.generativeai as genai
from tenacity import retry, stop_after_attempt, wait_fixed
from sentence_transformers import SentenceTransformer
import os
# from google.colab import userdata
from google.genai import types
from google import genai
import gradio as gr
import json
api_key =os.getenv("GEMINI_API_KEY")

# Gemini client
client = genai.Client(api_key=api_key)

print("Gemini client ready")


embed_model = SentenceTransformer("all-MiniLM-L6-v2")
print("Embedding model loaded")


faiss_index = faiss.read_index("faiss.index")
with open("chunks.json","r",encoding="utf-8") as f:
    chunks = json.load(f)

def call_llm(context, user_question):

    prompt = f"""
Use only the provided context to answer.
Context:
{context}
Question:
{user_question}
"""

    response = client.models.generate_content(
        model="gemini-3-flash-preview",
        contents=prompt,
        config=types.GenerateContentConfig(
            system_instruction="""
You are a helpful RAG assistant.
Answer clearly using only the context.
If answer not found, say not found in document.
""",
            max_output_tokens=1024
        )
    )

    return response.text


def search_faiss(question, top_k=3):

    q_embed = embed_model.encode([question])

    distances, indices = faiss_index.search(q_embed, top_k)

    results = []
    for idx in indices[0]:
        results.append(chunks[idx])

    context = "\n".join(results)

    answer = call_llm(context, question)

    return answer


def ask_question(question):
    answer = search_faiss(question)
    return answer

iface = gr.Interface(
    fn=ask_question,
    inputs=gr.Textbox(lines=2, placeholder="Ask something..."),
    outputs=gr.Textbox(lines=2, placeholder="Ask something..."),
    title="Nexon EV Bot"
)

iface.launch()