components/handlers/whatsapp_handlers.py

# handlers/whatsapp_handlers.py
import logging
import re
from typing import Optional, Dict

from fastapi.responses import JSONResponse

from components.gateways.headlines_to_wa import fetch_cached_headlines, send_to_whatsapp
from components.indexers.news_indexer import load_news_index  # should return a LlamaIndex VectorStoreIndex
from components.LLMs.Mistral import MistralTogetherClient, build_messages

# ------------------------------------------------------------
# Utilities
# ------------------------------------------------------------

def _safe_send(text: str, to: str) -> dict:
    """Wrap send_to_whatsapp with logging & safe error handling."""
    try:
        res = send_to_whatsapp(text, destination_number=to)
        if res.get("status") == "success":
            logging.info(f"Sent message to {to}")
        else:
            logging.error(f"Failed to send message to {to}: {res}")
        return res
    except Exception as e:
        logging.exception(f"Exception while sending WhatsApp message to {to}: {e}")
        return {"status": "error", "error": str(e)}


# ------------------------------------------------------------
# Headlines
# ------------------------------------------------------------

def handle_headlines(from_number: str) -> JSONResponse:
    full_message_text = fetch_cached_headlines()

    if full_message_text.startswith("❌") or full_message_text.startswith("⚠️"):
        logging.error(f"Failed to fetch digest for {from_number}: {full_message_text}")
        _safe_send(f"Sorry, I couldn't fetch the news digest today. {full_message_text}", to=from_number)
        return JSONResponse(status_code=500, content={"status": "error", "message": "Failed to fetch digest"})

    result = _safe_send(full_message_text, to=from_number)
    if result.get("status") == "success":
        return JSONResponse(status_code=200, content={"status": "success", "message": "Digest sent"})
    else:
        _safe_send(
            f"Sorry, I couldn't send the news digest to you. Error: {result.get('error', 'unknown')}",
            to=from_number,
        )
        return JSONResponse(status_code=500, content={"status": "error", "message": "Failed to send digest"})


# ------------------------------------------------------------
# Preferences / Greeting / Help / Unsubscribe / Small Talk
# ------------------------------------------------------------

def handle_preferences(from_number: str) -> JSONResponse:
    msg = (
        "Let’s tune your feed. Reply with topics you like:\n"
        "• world • india • finance • sports • entertainment\n\n"
        "You can send multiple, e.g.: india, finance"
    )
    _safe_send(msg, to=from_number)
    return JSONResponse(status_code=200, content={"status": "success", "message": "Preferences prompt sent"})


def handle_greeting(from_number: str) -> JSONResponse:
    msg = (
        "Hey! 👋 I’m NuseAI.\n"
        "• Type *headlines* to get today’s digest.\n"
        "• Type *preferences* to set your topics.\n"
        "• Type *help* to see what I can do."
    )
    _safe_send(msg, to=from_number)
    return JSONResponse(status_code=200, content={"status": "success", "message": "Greeting sent"})


def handle_help(from_number: str) -> JSONResponse:
    msg = (
        "Here’s how I can help:\n"
        "• *Headlines* — today’s 🗞️ Daily Digest 🟡\n"
        "• *Preferences* — choose topics/regions\n"
        "• *Unsubscribe* — stop messages\n"
        "Ask me a question anytime (e.g., “What’s India’s CPI outlook?”)."
    )
    _safe_send(msg, to=from_number)
    return JSONResponse(status_code=200, content={"status": "success", "message": "Help sent"})


def handle_unsubscribe(from_number: str) -> JSONResponse:
    _safe_send("You’re unsubscribed. If you change your mind, just say *hi*.", to=from_number)
    return JSONResponse(status_code=200, content={"status": "success", "message": "Unsubscribed"})


def handle_small_talk(from_number: str) -> JSONResponse:
    _safe_send("🙂 Got it. If you’d like the news, just say *headlines*.", to=from_number)
    return JSONResponse(status_code=200, content={"status": "success", "message": "Small talk"})


# ------------------------------------------------------------
# Chat Question → “Explain by number” flow
# ------------------------------------------------------------

_HEADLINE_LINE_RE = re.compile(r"^\s*(\d+)\.\s+(.*)$")

def _extract_number_ref(text: str) -> Optional[int]:
    """
    Find a referenced headline number in free text, e.g.:
    'explain number 14', 'no. 7 please', '#9', '14', 'explain 14 like I am 5'
    Returns int or None.
    """
    s = (text or "").lower()

    # explicit forms
    m = re.search(r"(?:number|no\.?|num|#)\s*(\d+)", s)
    if m:
        return int(m.group(1))

    # a bare number (avoid picking up years like 2025; cap at 1..200)
    m2 = re.search(r"\b(\d{1,3})\b", s)
    if m2:
        n = int(m2.group(1))
        if 1 <= n <= 200:
            return n

    return None


def _parse_rendered_digest(rendered: str) -> Dict[int, str]:
    """
    Parse the same rendered digest string you send on WhatsApp and build a map:
    { number -> headline_line_text }
    """
    mapping: Dict[int, str] = {}
    for line in (rendered or "").splitlines():
        m = _HEADLINE_LINE_RE.match(line)
        if not m:
            continue
        num = int(m.group(1))
        headline_txt = m.group(2).strip()
        mapping[num] = headline_txt
    return mapping


def _retrieve_context_for_headline(headline_text: str, top_k: int = 5) -> str:
    """
    Use the vector index to pull contextual passages related to the headline.
    Gracefully degrades if index is unavailable.
    """
    try:
        index = load_news_index()
        try:
            qe = index.as_query_engine(similarity_top_k=top_k)
        except Exception:
            # Older LlamaIndex fallback
            from llama_index.core.query_engine import RetrievalQueryEngine
            qe = RetrievalQueryEngine(index=index, similarity_top_k=top_k)

        query = (
            "Retrieve concise, factual context that best explains this headline:\n"
            f"{headline_text}\n"
            "Focus on who/what/when/where/why, include crucial numbers, avoid speculation."
        )
        resp = qe.query(query)
        return str(resp)
    except Exception as e:
        logging.exception(f"Vector retrieval failed: {e}")
        return ""


def _eli5_answer(question: str, context: str) -> str:
    """
    Ask Mistral (via Together) to explain using simple words.
    """
    sys_prompt = (
        "You are a concise explainer for a news assistant. "
        "Answer like the person is 5 years old (ELI5): short sentences, simple words, "
        "and 3–6 bullet points max. Be accurate and neutral. If unsure, say so."
    )
    user_prompt = (
        f"QUESTION:\n{question}\n\n"
        f"CONTEXT (may be partial):\n{context}\n\n"
        "Now give a short ELI5 explanation. Avoid jargon. If numbers matter, include them."
    )

    try:
        llm = MistralTogetherClient()
        msgs = build_messages(user_prompt, sys_prompt)
        out, _usage = llm.chat(msgs, temperature=0.2, max_tokens=350)
        return out.strip()
    except Exception as e:
        logging.exception(f"Mistral ELI5 generation failed: {e}")
        return "I couldn’t generate a simple explanation right now. Please try again."


def handle_chat_question(from_number: str, message_text: str) -> JSONResponse:
    """
    Smart handler:
      - If the user references a headline number (“explain 14 like I’m 5”),
        1) Parse the number
        2) Look up that numbered line from the rendered digest
        3) Retrieve vector context
        4) Generate an ELI5 answer with Mistral (Together.ai)
      - Otherwise, provide a gentle hint (for now).
    """
    logging.info(f"Chat question from {from_number}: {message_text}")

    # 1) Try to find a headline number reference
    number = _extract_number_ref(message_text or "")
    if number is not None:
        # 2) Load rendered digest and map numbers to lines
        rendered = fetch_cached_headlines()
        mapping = _parse_rendered_digest(rendered)
        target_line = mapping.get(number)

        if not target_line:
            _safe_send(
                f"I couldn’t find headline *{number}* in today’s digest. "
                "Try another number or say *headlines* to see today’s list.",
                to=from_number,
            )
            return JSONResponse(status_code=200, content={"status": "success", "message": "Number not found"})

        # 3) Retrieve context from the vector index using the headline line
        ctx = _retrieve_context_for_headline(target_line, top_k=5)

        # 4) Generate ELI5 answer
        question = f"Explain headline #{number}: {target_line}"
        answer = _eli5_answer(question, ctx)

        # 5) Send back
        _safe_send(answer, to=from_number)
        return JSONResponse(status_code=200, content={"status": "success", "message": "ELI5 sent"})

    # No number found → for now, guide the user
    _safe_send(
        "Ask me about a specific headline by number, e.g., *explain 7 like I’m 5*.\n"
        "Or type *headlines* for today’s digest.",
        to=from_number,
    )
    return JSONResponse(status_code=200, content={"status": "success", "message": "Generic reply"})