from __future__ import annotations

import unicodedata

from ddgs import DDGS

from config import CONFIG

# Topic stems for a turn that needs current, public facts. Prefix-matched, so
# inflections hit (resultado/resultados). Excludes chitchat (hoy, ahora, cuando)
# to avoid false positives that add a slow search mid-conversation.
_SEARCH_STEMS = (
    "clima", "tiempo", "temperatura", "lluvia", "pronostic",
    "notici", "actualidad", "precio", "cuesta", "dolar",
    "partido", "marcador", "result", "horario", "campeonat", "torneo",
    "eleccion", "elecc", "candidat", "ganador", "president",
    "voto", "vota", "balota", "congres", "alcald", "gobern",
)
# Cues that mark a follow-up riding on the previous turn's topic.
_FOLLOWUP_CUES = {
    "mas", "ese", "esa", "eso", "esos", "esas", "quien", "quienes",
    "cual", "cuales", "detalle", "detalles", "cuenta", "cuentame", "dime",
}


def _norm(text: str) -> str:
    """Lowercase and strip accents so 'mañana' matches 'manana'."""
    decomposed = unicodedata.normalize("NFD", text.lower())
    return "".join(c for c in decomposed if unicodedata.category(c) != "Mn")


def _tokens(text: str) -> list[str]:
    """Normalize text and split it into words."""
    return _norm(text).replace("¿", " ").replace("?", " ").split()


def _has_topic(text: str) -> bool:
    """True when a word starts with one of the current-events stems."""
    return any(w.startswith(stem) for w in _tokens(text) for stem in _SEARCH_STEMS)


def needs_search(text: str, history: list[dict] | None = None) -> bool:
    """True when the turn looks like it needs current public facts.

    Fires on a topic word, or on a follow-up question inside a thread whose
    previous turn was already about a current-events topic -- so "cuéntame más
    sobre los candidatos" keeps searching even with no topic word of its own.
    """
    if not CONFIG.search_enabled:
        return False
    if _has_topic(text):
        return True
    if history:
        prev_user = next(
            (m["content"] for m in reversed(history)
             if m.get("role") == "user" and m.get("content")), "",
        )
        if prev_user and _has_topic(prev_user):
            if "?" in text or (set(_tokens(text)) & _FOLLOWUP_CUES):
                return True
    return False


def search_web(query: str) -> str:
    """Return a short, LLM-friendly digest of top results."""
    if not query:
        return "Sin consulta."
    try:
        with DDGS() as ddgs:
            results = list(
                ddgs.text(query, max_results=CONFIG.search_max_results)
            )
    except Exception as exc:  # noqa: BLE001 - degrade gracefully for the elder
        return f"No pude buscar en internet ahora mismo ({exc})."

    if not results:
        return "No encontre resultados."

    lines = []
    for r in results:
        title = r.get("title", "")
        body = r.get("body", "")
        lines.append(f"- {title}: {body}")
    return "\n".join(lines)