app.py

# 🚀 DigiTwin Streamlit App – Cleaned and Fixed for Fully Merged Models
import streamlit as st
import torch
import os
import time
from threading import Thread
from transformers import AutoTokenizer, AutoModelForCausalLM, TextIteratorStreamer

# --- Hugging Face Token from Secrets ---
HF_TOKEN = st.secrets["HF_TOKEN"]

# --- Streamlit Page Configuration ---
st.set_page_config(
    page_title="DigiTwin - ValLabs",
    page_icon="🚀",
    layout="centered"
)

# --- Logo and App Title ---
#st.image("assets/valonylabz_logo.png", width=150)  # Replace with your logo
st.title("🚀 DigiTwin - ValLabs 🚀")

# --- Model Options (All Fully Merged Models) ---
MODEL_OPTIONS = {
    "GM Qwen (merged)": "amiguel/GM_Qwen1.8B_Finetune",
    "GM Mistral (merged)": "amiguel/GM_finetune"
}

# --- Sidebar: Model Selection ---
with st.sidebar:
    st.header("🧠 Choose Model")
    selected_model_name = st.selectbox("Select model", list(MODEL_OPTIONS.keys()), index=0)
    selected_model = MODEL_OPTIONS[selected_model_name]

# --- Session State for Messages & Reload ---
if "messages" not in st.session_state:
    st.session_state.messages = []
if "model_name" not in st.session_state or st.session_state.model_name != selected_model_name:
    st.session_state.model = None
    st.session_state.model_name = selected_model_name

# --- DigiTwin System Prompt ---
SYSTEM_PROMPT = (
    "You are DigiTwin, the digital twin of Ataliba, an inspection engineer with over 17 years of "
    "experience in mechanical integrity, reliability, piping, and asset management. "
    "Be precise, practical, and technical. Provide advice aligned with industry best practices."
)

# --- Load Fully Merged Model ---
@st.cache_resource
def load_model(model_path):
    tokenizer = AutoTokenizer.from_pretrained(model_path, trust_remote_code=True, token=HF_TOKEN)
    model = AutoModelForCausalLM.from_pretrained(
        model_path,
        device_map="auto",
        torch_dtype=torch.bfloat16,
        trust_remote_code=True,
        token=HF_TOKEN
    )
    return model, tokenizer

# --- Load Model on Selection ---
if st.session_state.model is None:
    with st.spinner(f"Loading model: {selected_model_name}..."):
        st.session_state.model, st.session_state.tokenizer = load_model(selected_model)

model = st.session_state.model
tokenizer = st.session_state.tokenizer

# --- Build Prompt with ChatML Format ---
def build_prompt(messages):
    full_prompt = f"<|im_start|>system\n{SYSTEM_PROMPT}<|im_end|>\n"
    for msg in messages:
        role = msg["role"]
        full_prompt += f"<|im_start|>{role}\n{msg['content']}<|im_end|>\n"
    full_prompt += "<|im_start|>assistant\n"
    return full_prompt

# --- Generate Assistant Response (Streaming) ---
def generate_response(prompt_text, model, tokenizer):
    streamer = TextIteratorStreamer(
        tokenizer,
        skip_prompt=True,
        skip_special_tokens=True
    )
    inputs = tokenizer(prompt_text, return_tensors="pt").to(model.device)

    generation_kwargs = {
        "input_ids": inputs["input_ids"],
        "attention_mask": inputs["attention_mask"],
        "max_new_tokens": 1024,
        "temperature": 0.7,
        "top_p": 0.9,
        "repetition_penalty": 1.1,
        "do_sample": True,
        "streamer": streamer
    }

    thread = Thread(target=model.generate, kwargs=generation_kwargs)
    thread.start()
    return streamer

# --- Avatars ---
USER_AVATAR = "https://raw.githubusercontent.com/achilela/vila_fofoka_analysis/9904d9a0d445ab0488cf7395cb863cce7621d897/USER_AVATAR.png"
BOT_AVATAR = "https://raw.githubusercontent.com/achilela/vila_fofoka_analysis/991f4c6e4e1dc7a8e24876ca5aae5228bcdb4dba/Ataliba_Avatar.jpg"

# --- Display Chat History ---
for message in st.session_state.messages:
    avatar = USER_AVATAR if message["role"] == "user" else BOT_AVATAR
    with st.chat_message(message["role"], avatar=avatar):
        st.markdown(message["content"])

# --- Chat Input Handling ---
if prompt := st.chat_input("Ask your inspection or reliability question..."):

    with st.chat_message("user", avatar=USER_AVATAR):
        st.markdown(prompt)
    st.session_state.messages.append({"role": "user", "content": prompt})

    full_prompt = build_prompt(st.session_state.messages)

    with st.chat_message("assistant", avatar=BOT_AVATAR):
        start_time = time.time()
        streamer = generate_response(full_prompt, model, tokenizer)

        response_container = st.empty()
        full_response = ""

        for chunk in streamer:
            full_response += chunk
            response_container.markdown(full_response + "▌", unsafe_allow_html=True)

        end_time = time.time()
        input_tokens = len(tokenizer(full_prompt)["input_ids"])
        output_tokens = len(tokenizer(full_response)["input_ids"])
        speed = output_tokens / (end_time - start_time)

        st.caption(
            f"🔑 Input Tokens: {input_tokens} | Output Tokens: {output_tokens} | "
            f"🕒 Speed: {speed:.1f} tokens/sec"
        )

        response_container.markdown(full_response)
        st.session_state.messages.append({"role": "assistant", "content": full_response})