import streamlit as st
import os
from langchain_huggingface import HuggingFaceEndpoint, ChatHuggingFace
from langchain_core.messages import HumanMessage, SystemMessage

# Set environment variables for Hugging Face token
hf = os.getenv('HF_TOKEN')
os.environ['HUGGINGFACEHUB_API_TOKEN'] = hf
os.environ['HF_TOKEN'] = hf

# Page config
st.set_page_config(page_title="Deep Learning Mentor Chat", layout="centered")

# Custom CSS for modern chat UI
st.markdown("""
    <style>
    .main {
        background: linear-gradient(135deg, #2c3e50, #4ca1af);
        color: white;
        font-family: 'Segoe UI', sans-serif;
        padding: 2rem;
    }
    .stButton>button {
        background-color: #1abc9c;
        color: white;
        font-weight: bold;
        padding: 0.6rem 1.2rem;
        border-radius: 10px;
        border: none;
        width: 100%;
        transition: 0.3s ease;
    }
    .stButton>button:hover {
        background-color: #16a085;
        color: #fff;
    }
    h1, h3, p, label, .css-10trblm, .css-1v0mbdj {
        color: white !important;
        text-align: center;
    }
    .chat-container {
        margin-top: 1.5rem;
        display: flex;
        flex-direction: column;
        gap: 1rem;
    }
    .chat-user {
        background-color: #34495e;
        padding: 0.8rem;
        border-radius: 12px;
        align-self: flex-end;
        max-width: 80%;
        font-weight: 500;
        color: white;
    }
    .chat-bot {
        background-color: #2ecc71;
        padding: 0.8rem;
        border-radius: 12px;
        align-self: flex-start;
        max-width: 80%;
        color: white;
    }
    hr {
        border-top: 1px solid #ffffff50;
        margin: 2rem 0;
    }
    </style>
""", unsafe_allow_html=True)

# App title
st.markdown("<h1>🤖 Deep Learning Mentor Chat</h1>", unsafe_allow_html=True)
st.markdown("<p>Learn Deep Learning with personalized AI mentorship</p>", unsafe_allow_html=True)

# Sidebar for experience level
st.sidebar.title("🎓 Select Your Level")
exp = st.sidebar.selectbox("Experience Level", ["Beginner", "Intermediate", "Expert"])

# Load Deep Learning model
mentor_llm = HuggingFaceEndpoint(
    repo_id='Qwen/Qwen3-32B',
    provider='sambanova',
    temperature=0.7,
    max_new_tokens=150,
    task='conversational'
)

deep_mentor = ChatHuggingFace(llm=mentor_llm)

# Session key for conversation
PAGE_KEY = "deep_learning_chat_history"
if PAGE_KEY not in st.session_state:
    st.session_state[PAGE_KEY] = []

# Chat input form
st.markdown("<hr>", unsafe_allow_html=True)
with st.form(key="chat_form"):
    user_input = st.text_input("💬 Ask your deep learning question:")
    submit = st.form_submit_button("Send")

# Handle chat submission
if submit and user_input:
    system_prompt = (
        f"You are a deep learning mentor with {exp.lower()} expertise. "
        f"Only answer deep learning-related questions in a friendly, helpful tone under 150 words. "
        f"If a question is off-topic, politely say it's out of scope."
    )
    messages = [SystemMessage(content=system_prompt), HumanMessage(content=user_input)]
    result = deep_mentor.invoke(messages)
    st.session_state[PAGE_KEY].append((user_input, result.content))

# Chat history display with bubble styling
if st.session_state[PAGE_KEY]:
    st.markdown('<div class="chat-container">', unsafe_allow_html=True)
    for user, bot in st.session_state[PAGE_KEY]:
        st.markdown(f'<div class="chat-user">👤 <strong>You:</strong> {user}</div>', unsafe_allow_html=True)
        st.markdown(f'<div class="chat-bot">🧑‍🏫 <strong>Mentor:</strong> {bot}</div>', unsafe_allow_html=True)
    st.markdown('</div>', unsafe_allow_html=True)