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

# Set Hugging Face tokens
hf = os.getenv('Data_science')
os.environ['HUGGINGFACEHUB_API_TOKEN'] = hf
os.environ['HF_TOKEN'] = hf

# --- Page Configuration ---
st.set_page_config(page_title="ML Mentor Chat", layout="centered")

# --- Inject Home Page CSS Styling ---
st.markdown("""
    <style>
    .main {
        background: linear-gradient(135deg, #430089 0%, #82ffa1 100%);
        padding: 2rem;
        font-family: 'Segoe UI', sans-serif;
    }
    .stButton>button {
        background: #ffffff10;
        border: 2px solid #ffffff50;
        color: white;
        font-size: 18px;
        font-weight: 600;
        padding: 0.8em 1.2em;
        border-radius: 12px;
        width: 100%;
        transition: 0.3s ease;
        box-shadow: 0 4px 10px rgba(0, 0, 0, 0.15);
    }
    .stButton>button:hover {
        background: #ffffff30;
        border-color: #fff;
        color: #ffffff;
    }
    h1, h3, p, label {
        color: #ffffff;
        text-align: center;
    }
    hr {
        border: 1px solid #ffffff50;
        margin: 2em 0;
    }
    .css-1aumxhk {
        color: white;  /* Streamlit input text color */
    }
    </style>
""", unsafe_allow_html=True)

# --- Page Title ---
st.title("🤖 Machine Learning Mentor Chat")

# --- Sidebar: Experience Level with same style ---
st.sidebar.title("Mentor Preferences")
experience_label = st.sidebar.selectbox(
    "Select your experience level:", ["Beginner", "Intermediate", "Experienced"]
)

# --- Initialize Chat Model ---
ml_model_skeleton = HuggingFaceEndpoint(
    repo_id='Qwen/Qwen3-14B',
    provider='nebius',
    temperature=0.7,
    max_new_tokens=50,
    task='conversational'
)

ml_mentor = ChatHuggingFace(
    llm=ml_model_skeleton,
    repo_id='Qwen/Qwen3-14B',
    provider='nebius',
    temperature=0.7,
    max_new_tokens=50,
    task='conversational'
)

PAGE_KEY = "ml_chat_history"

# --- Session State Initialization ---
if PAGE_KEY not in st.session_state:
    st.session_state[PAGE_KEY] = []

# --- Chat Input Form ---
with st.form(key="chat_form"):
    user_input = st.text_input("Ask your question:")
    submit = st.form_submit_button("Send")

# --- Chat Logic ---
if submit and user_input:
    system_prompt = (
        f"You are a machine learning mentor with {experience_label.lower()} experience. "
        f"Answer only machine learning questions in a friendly tone and within 150 words. "
        f"Politely inform if the question is out of scope."
    )
    messages = [SystemMessage(content=system_prompt), HumanMessage(content=user_input)]
    result = ml_mentor.invoke(messages)
    st.session_state[PAGE_KEY].append((user_input, result.content))

# --- Chat History Display ---
st.subheader("🗨️ Chat History")
for user, bot in st.session_state[PAGE_KEY]:
    st.markdown(f"**You:** {user}")
    st.markdown(f"**Mentor:** {bot}")
    st.markdown("---")