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

# Load HuggingFace token from environment variable
hf = os.getenv('Data_science')
if hf is None:
    raise ValueError("Hugging Face token not found. Please set the 'Data_science' environment variable.")
os.environ['HUGGINGFACEHUB_API_TOKEN'] = hf
os.environ['HF_TOKEN'] = hf

# Page config
st.set_page_config(page_title="🐍 Python Mentor Chat", page_icon="💬", layout="centered")

# Inject custom CSS
st.markdown("""
    <style>
    .main {
        background: linear-gradient(135deg, #1f1c2c 0%, #928dab 100%);
        padding: 2rem;
        font-family: 'Segoe UI', sans-serif;
    }
    h1, h2, h3, h4, p, label, .css-10trblm, .css-q8sbsg {
        color: #ffffff !important;
        text-align: center;
    }
    .stTextInput>div>div>input {
        background-color: #ffffff10;
        color: #ffffff;
        border: 1px solid #ffffff50;
        border-radius: 8px;
        padding: 0.6em;
    }
    .stTextInput>div>div>input::placeholder {
        color: #ffffff90;
    }
    .stButton>button {
        background: rgba(255, 255, 255, 0.1);
        border: 2px solid rgba(255, 255, 255, 0.3);
        color: white;
        font-size: 18px;
        font-weight: bold;
        padding: 0.8em 1.2em;
        border-radius: 12px;
        width: 100%;
        transition: all 0.3s ease;
        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
    }
    .stButton>button:hover {
        background: rgba(255, 255, 255, 0.3);
        color: white;
        border-color: white;
    }
    .stSidebar > div:first-child {
        background: #2c3e50;
        color: white;
        border-radius: 0 20px 20px 0;
    }
    .stSidebar h1, .stSidebar h2, .stSidebar h3, .stSidebar h4, .stSidebar label, .stSidebar p {
        color: white !important;
    }
    hr {
        border: 1px solid #ffffff50;
        margin: 1.5em 0;
    }
    </style>
""", unsafe_allow_html=True)

# Title
st.title("🐍 Python Mentor Chat")
st.markdown("### 💬 Your personal Python guide for Data Science and beyond!")

# Sidebar configuration
st.sidebar.title("🧑‍🏫 Mentor Preferences")
experience_label = st.sidebar.selectbox(
    "📈 Select your experience level:", ["Beginner", "Intermediate", "Experienced"]
)

# Load the model
deep_seek_skeleton = HuggingFaceEndpoint(
    repo_id='mistralai/Mistral-7B-Instruct-v0.3',
    provider='novita',
    temperature=0.7,
    max_new_tokens=50,
    task='conversational'
)

deep_seek = ChatHuggingFace(
    llm=deep_seek_skeleton,
    repo_id='mistralai/Mistral-7B-Instruct-v0.3',
    provider='novita',
    temperature=0.7,
    max_new_tokens=50,
    task='conversational'
)

# Chat session history key
PAGE_KEY = "python_chat_history"
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:", placeholder="e.g. What is a Python decorator?")
    submit = st.form_submit_button("🚀 Send")

# Chat logic
if submit and user_input:
    system_prompt = (
        f"Act as a Python mentor for a {experience_label.lower()} learner. "
        f"Answer in a helpful, friendly, and concise manner. Max 150 words. "
        f"If the question is not Python-related, say it's out of scope politely."
    )
    messages = [SystemMessage(content=system_prompt), HumanMessage(content=user_input)]
    result = deep_seek.invoke(messages)
    st.session_state[PAGE_KEY].append((user_input, result.content))

# Display 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("---")