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

# --- Load Environment Token ---
hf = os.getenv('Data_science')
os.environ['HUGGINGFACEHUB_API_TOKEN'] = hf
os.environ['HF_TOKEN'] = hf

# --- Streamlit Page Configuration ---
st.set_page_config(page_title="🗃️ SQL Mentor Chat", page_icon="🗃️", layout="centered")

# --- Custom CSS Styling ---
st.markdown("""
    <style>
    .main {
        background: linear-gradient(135deg, #430089 0%, #82ffa1 100%);
        padding: 2rem;
        font-family: 'Segoe UI', sans-serif;
    }
    h1, h2, h3, h4, h5, h6, p, label, .css-10trblm, .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: 0.6em;
    }
    .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: 12px;
        width: 100%;
        transition: all 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)

# --- Title ---
st.title("🗃️ SQL Mentor Chat")
st.markdown("### 💬 Ask your SQL queries below. Learn by doing!")

# --- Sidebar for Experience ---
st.sidebar.title("🎓 Mentor Preferences")
exp = st.sidebar.selectbox("📚 Select your experience level:", ["Beginner", "Intermediate", "Expert"])

# --- Model Initialization ---
sql_model_skeleton = HuggingFaceEndpoint(
    repo_id='HuggingFaceH4/zephyr-7b-beta',
    provider='hf-inference',
    temperature=0.7,
    max_new_tokens=110,
    task='conversational'
)

sql_mentor = ChatHuggingFace(
    llm=sql_model_skeleton,
    repo_id='HuggingFaceH4/zephyr-7b-beta',
    provider='hf-inference',
    temperature=0.7,
    max_new_tokens=110,
    task='conversational'
)

# --- Session History Key ---
PAGE_KEY = "chat_history_sql"
if PAGE_KEY not in st.session_state:
    st.session_state[PAGE_KEY] = []

# --- Chat Form ---
with st.form(key="chat_form"):
    user_input = st.text_input("📌 Ask your SQL question:", placeholder="e.g. What does GROUP BY do in SQL?")
    submit = st.form_submit_button("📤 Send")

# --- Process Query ---
if submit and user_input:
    system_prompt = (
        f"Act as a SQL mentor with {exp.lower()} expertise. "
        f"Respond in a clear and friendly tone. "
        f"Only answer SQL-related questions and keep responses under 150 words. "
        f"If a question is outside SQL, politely say it's out of scope."
    )
    messages = [SystemMessage(content=system_prompt), HumanMessage(content=user_input)]
    result = sql_mentor.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("---")