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", page_icon="📘", layout="centered")

# --- Inject Custom CSS Styling ---
st.markdown("""
    <style>
    .main {
        background: linear-gradient(135deg, #1e3c72 0%, #2a5298 100%);
        padding: 2rem;
        font-family: 'Segoe UI', sans-serif;
    }
    h1, h2, h3, h4, h5, h6, p, label, .css-10trblm, .css-1v0mbdj, .css-q8sbsg {
        color: #ffffff !important;
        text-align: center;
    }
    .stTextInput > div > div > input {
        background-color: rgba(255, 255, 255, 0.1);
        color: white;
        border: 1px solid rgba(255, 255, 255, 0.5);
        border-radius: 8px;
        padding: 0.5em;
    }
    .stTextInput > div > div > input::placeholder {
        color: rgba(255, 255, 255, 0.6);
    }
    .stButton>button {
        background: rgba(255, 255, 255, 0.15);
        border: 2px solid rgba(255, 255, 255, 0.4);
        color: white;
        font-size: 18px;
        font-weight: bold;
        padding: 0.8em 1.2em;
        border-radius: 10px;
        width: 100%;
        transition: 0.3s ease;
        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.25);
    }
    .stButton>button:hover {
        background: rgba(255, 255, 255, 0.3);
        border-color: white;
        color: white;
    }
    .stSidebar > div:first-child {
        background: #2c3e50;
        padding: 1rem;
        border-radius: 0 15px 15px 0;
    }
    .stSidebar h1, .stSidebar h2, .stSidebar h3, .stSidebar label, .stSidebar p {
        color: white !important;
    }
    hr {
        border: 1px solid rgba(255, 255, 255, 0.3);
        margin: 2em 0;
    }
    </style>
""", unsafe_allow_html=True)

# --- Page Title ---
st.title("🤖 Machine Learning Mentor Chat")
st.markdown("### 📘 Ask anything about ML concepts, tools, or workflows!")

# --- Sidebar: Experience Selector ---
st.sidebar.title("🧑‍🏫 Mentor Preferences")
experience_label = st.sidebar.selectbox(
    "🎓 Choose 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 ML question:", placeholder="e.g. What is overfitting?")
    submit = st.form_submit_button("🚀 Send")

# --- Chat Logic ---
if submit and user_input:
    system_prompt = (
        f"You are a helpful machine learning mentor for a {experience_label.lower()} learner. "
        f"Only answer machine learning-related questions in a concise, friendly tone. "
        f"Keep answers under 150 words. Politely decline off-topic questions."
    )
    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 ---
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("---")