app.py

import os
import gradio as gr
from transformers import AutoModelForCausalLM, AutoProcessor
import torch
from PIL import Image

# Read token from secret
hf_token = os.environ.get("HF_TOKEN")

# Load model and processor with auth token
model_id = "google/medgemma-4b-it"

processor = AutoProcessor.from_pretrained(model_id, token=hf_token)
model = AutoModelForCausalLM.from_pretrained(
    model_id,
    torch_dtype=torch.float16,
    device_map="auto",
    token=hf_token
)

# Prediction function
def diagnose(image, query):
    inputs = processor(text=query, images=image, return_tensors="pt").to(model.device)
    outputs = model.generate(**inputs, max_new_tokens=256)
    response = processor.batch_decode(outputs, skip_special_tokens=True)[0]
    return response

# Gradio interface
demo = gr.Interface(
    fn=diagnose,
    inputs=[
        gr.Image(type="pil", label="Upload Skin Image"),
        gr.Textbox(lines=2, label="Your Query (e.g., What is the disease?)")
    ],
    outputs=gr.Textbox(label="Diagnosis & Advice"),
    title="🩺 DermaScan with MedGemma",
    description="Upload a skin image and ask a medical question. Powered by Google MedGemma 4B."
)

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