phase/Student_view/chatbot.py

# phase/Student_view/chatbot.py
import streamlit as st
import datetime, os, traceback
from huggingface_hub import InferenceClient

HF_TOKEN = os.getenv("HF_TOKEN")
GEN_MODEL = os.getenv("GEN_MODEL", "TinyLlama/TinyLlama-1.1B-Chat-v1.0")  # <- default TinyLlama

if not HF_TOKEN:
    st.error("⚠️ HF_TOKEN is not set. In your Space, add a Secret named HF_TOKEN.")
else:
    client = InferenceClient(model=GEN_MODEL, token=HF_TOKEN, timeout=60)

TUTOR_PROMPT = (
    "You are a kind Jamaican primary-school finance tutor. "
    "Keep answers short, friendly, and age-appropriate. "
    "Teach step-by-step with tiny examples. Avoid giving personal financial advice."
)

# -------------------------------
# History helpers
# -------------------------------
def _format_history_for_flan(messages: list[dict]) -> str:
    """Format history for text-generation style models."""
    lines = []
    for m in messages:
        txt = (m.get("text") or "").strip()
        if not txt:
            continue
        lines.append(("Tutor" if m.get("sender") == "assistant" else "User") + f": {txt}")
    return "\n".join(lines)

def _history_as_chat_messages(messages: list[dict]) -> list[dict]:
    """Convert history to chat-completion style messages."""
    msgs = [{"role": "system", "content": TUTOR_PROMPT}]
    for m in messages:
        txt = (m.get("text") or "").strip()
        if not txt:
            continue
        role = "assistant" if m.get("sender") == "assistant" else "user"
        msgs.append({"role": role, "content": txt})
    return msgs

def _extract_chat_text(chat_resp) -> str:
    """Extract text from HF chat response."""
    try:
        return chat_resp.choices[0].message["content"] if isinstance(
            chat_resp.choices[0].message, dict
        ) else chat_resp.choices[0].message.content
    except Exception:
        try:
            return chat_resp["choices"][0]["message"]["content"]
        except Exception:
            return str(chat_resp)

# -------------------------------
# Reply logic
# -------------------------------
def _reply_with_hf():
    if "client" not in globals():
        raise RuntimeError("HF client not initialized")

    try:
        # 1) Prefer chat API
        msgs = _history_as_chat_messages(st.session_state.get("messages", []))
        chat = client.chat.completions.create(
            model=GEN_MODEL,
            messages=msgs,
            max_tokens=300,   # give enough room
            temperature=0.2,
            top_p=0.9,
        )
        return _extract_chat_text(chat).strip()

    except ValueError as ve:
        # 2) Fallback to text-generation if chat unsupported
        if "Supported task: text-generation" in str(ve):
            convo = _format_history_for_flan(st.session_state.get("messages", []))
            tg_prompt = f"{TUTOR_PROMPT}\n\n{convo}\n\nTutor:"
            resp = client.text_generation(
                tg_prompt,
                max_new_tokens=300,
                temperature=0.2,
                top_p=0.9,
                repetition_penalty=1.1,
                return_full_text=True,
                stream=False,
            )
            return (resp.get("generated_text") if isinstance(resp, dict) else resp).strip()

        raise  # rethrow anything else

    except Exception as e:
        err_text = ''.join(traceback.format_exception_only(type(e), e)).strip()
        raise RuntimeError(f"Hugging Face API Error: {err_text}")

# -------------------------------
# Session message helper
# -------------------------------
def add_message(text: str, sender: str):
    if "messages" not in st.session_state:
        st.session_state.messages = []
    st.session_state.messages.append(
        {
            "id": str(datetime.datetime.now().timestamp()),
            "text": text,
            "sender": sender,
            "timestamp": datetime.datetime.now()
        }
    )

# -------------------------------
# Streamlit page
# -------------------------------
def show_page():
    st.title("🤖 AI Financial Tutor")
    st.caption("Get personalized help with your financial questions")

    if "messages" not in st.session_state:
        st.session_state.messages = [{
            "id": "1",
            "text": "Hi! I'm your AI Financial Tutor. What would you like to learn today?",
            "sender": "assistant",
            "timestamp": datetime.datetime.now()
        }]
    if "is_typing" not in st.session_state:
        st.session_state.is_typing = False

    chat_container = st.container()
    with chat_container:
        for msg in st.session_state.messages:
            if msg["sender"] == "assistant":
                st.markdown(
                    f"<div style='background-color:#e0e0e0; color:black; padding:10px; border-radius:12px; max-width:70%; margin-bottom:5px;'>{msg['text']}<br><sub>{msg['timestamp'].strftime('%H:%M')}</sub></div>",
                    unsafe_allow_html=True
                )
            else:
                st.markdown(
                    f"<div style='background-color:#4CAF50; color:white; padding:10px; border-radius:12px; max-width:70%; margin-left:auto; margin-bottom:5px;'>{msg['text']}<br><sub>{msg['timestamp'].strftime('%H:%M')}</sub></div>",
                    unsafe_allow_html=True
                )

        if st.session_state.is_typing:
            st.markdown("🤖 _FinanceBot is typing..._")

    if len(st.session_state.messages) == 1:
        st.markdown("Try asking about:")
        cols = st.columns(2)
        quick = [
            "How does compound interest work?",
            "How much should I save for emergencies?",
            "What's a good budgeting strategy?",
            "How do I start investing?"
        ]
        for i, q in enumerate(quick):
            if cols[i % 2].button(q):
                add_message(q, "user")
                st.session_state.is_typing = True
                st.rerun()

    user_input = st.chat_input("Ask me anything about personal finance...")
    if user_input:
        add_message(user_input, "user")
        st.session_state.is_typing = True
        st.rerun()

    if st.session_state.is_typing:
        try:
            with st.spinner("FinanceBot is thinking..."):
                bot_reply = _reply_with_hf()
                add_message(bot_reply, "assistant")
        except Exception as e:
            add_message(f"⚠️ Error: {e}", "assistant")
        finally:
            st.session_state.is_typing = False
            st.rerun()

    if st.button("Back to Dashboard", key="ai_tutor_back_btn"):
        st.session_state.current_page = "Student Dashboard"
        st.rerun()