# phase/Student_view/chatbot.py
import os
import datetime
import traceback
import streamlit as st

# --- use our backend client (utils/api.py) ---
try:
    from utils import api as backend
except ModuleNotFoundError:
    # fallback if running from a different CWD
    import sys, pathlib
    ROOT = pathlib.Path(__file__).resolve().parents[2]
    if str(ROOT) not in sys.path:
        sys.path.insert(0, str(ROOT))
    from utils import api as backend

TUTOR_WELCOME = "Hi! I'm your AI Financial Tutor. What would you like to learn today?"

# -------------------------------
# History helpers
# -------------------------------
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 or "").strip(),
            "sender": sender,
            "timestamp": datetime.datetime.now(),
        }
    )

def _coerce_ts(ts):
    if isinstance(ts, datetime.datetime):
        return ts
    if isinstance(ts, (int, float)):
        try:
            return datetime.datetime.fromtimestamp(ts)
        except Exception:
            return None
    if isinstance(ts, str):
        for parser in (datetime.datetime.fromisoformat, lambda s: datetime.datetime.fromtimestamp(float(s))):
            try:
                return parser(ts)
            except Exception:
                pass
    return None

def _normalize_messages():
    msgs = st.session_state.get("messages", [])
    normed = []
    now = datetime.datetime.now()
    for m in msgs:
        text = (m.get("text") or "").strip()
        sender = m.get("sender") or "user"
        ts = _coerce_ts(m.get("timestamp")) or now
        normed.append({**m, "text": text, "sender": sender, "timestamp": ts})
    st.session_state.messages = normed

def _history_for_backend():
    """Convert our local history into [{role, content}] for the backend."""
    hist = []
    for m in st.session_state.get("messages", []):
        text = (m.get("text") or "").strip()
        if not text:
            continue
        role = "assistant" if (m.get("sender") == "assistant") else "user"
        hist.append({"role": role, "content": text})
    return hist

# -------------------------------
# Reply via backend (/chat)
# -------------------------------
def _reply_via_backend(user_text: str) -> str:
    # Defaults: use selected lesson/level if present
    lesson_id = st.session_state.get("current_lesson_id") or 0
    level_slug = (st.session_state.get("user", {}).get("level") or "beginner").strip().lower()

    try:
        answer = backend.chat_ai(
            query=user_text,
            lesson_id=lesson_id,
            level_slug=level_slug,
            history=_history_for_backend(),
        )
        return (answer or "").strip()
    except Exception as e:
        err_text = "".join(traceback.format_exception_only(type(e), e)).strip()
        return f"⚠️ Chat failed: {err_text}"

# -------------------------------
# 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": TUTOR_WELCOME,
            "sender": "assistant",
            "timestamp": datetime.datetime.now()
        }]
    if "is_typing" not in st.session_state:
        st.session_state.is_typing = False

    _normalize_messages()

    chat_container = st.container()
    with chat_container:
        for msg in st.session_state.messages:
            t = msg["timestamp"].strftime("%H:%M")
            if msg.get("sender") == "assistant":
                bubble = (
                    "<div style='background:#e0e0e0;color:#000;padding:10px;border-radius:12px;"
                    "max-width:70%;margin-bottom:6px;'>"
                    f"{msg.get('text','')}<br><sub>{t}</sub></div>"
                )
            else:
                bubble = (
                    "<div style='background:#4CAF50;color:#fff;padding:10px;border-radius:12px;"
                    "max-width:70%;margin-left:auto;margin-bottom:6px;'>"
                    f"{msg.get('text','')}<br><sub>{t}</sub></div>"
                )
            st.markdown(bubble, unsafe_allow_html=True)

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

    # Quick suggestions when only the welcome is present
    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, key=f"suggest_{i}"):
                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:
        with st.spinner("FinanceBot is thinking..."):
            bot_reply = _reply_via_backend(st.session_state.messages[-1]["text"])
            add_message(bot_reply, "assistant")
        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()