"""Trending Polymarket bets, via their public Gamma REST API
(gamma-api.polymarket.com) — unauthenticated, no key/wallet required, the
same endpoint their own frontend calls (the site itself renders market
data client-side, so there's nothing to scrape from its HTML).

Positions/volumes are high-churn like flights — kept as an in-memory
snapshot rather than persisted history, same pattern as flights.py.
"""

import json
import logging

import httpx

log = logging.getLogger("newsatlas.polymarket")

EVENTS_URL = "https://gamma-api.polymarket.com/events"
_HEADERS = {"User-Agent": "Mozilla/5.0 (NewsAtlas; self-hosted news dashboard)"}

_latest_markets: list[dict] = []


def _leading_outcome(event: dict) -> str:
    """Best-effort one-line summary of where the odds currently sit."""
    markets = event.get("markets") or []
    try:
        if len(markets) == 1:
            outcomes = json.loads(markets[0].get("outcomes") or "[]")
            prices = json.loads(markets[0].get("outcomePrices") or "[]")
            pairs = dict(zip(outcomes, prices))
            if "Yes" in pairs:
                return f"Yes {float(pairs['Yes']) * 100:.0f}%"
        elif len(markets) > 1:
            best_label, best_price = None, -1.0
            for m in markets:
                outcomes = json.loads(m.get("outcomes") or "[]")
                prices = json.loads(m.get("outcomePrices") or "[]")
                pairs = dict(zip(outcomes, prices))
                price = float(pairs.get("Yes", 0) or 0)
                if price > best_price:
                    best_label = m.get("groupItemTitle") or m.get("question") or ""
                    best_price = price
            if best_label is not None:
                return f"{best_label} {best_price * 100:.0f}%"
    except (ValueError, TypeError, KeyError):
        pass
    return ""


def poll_polymarket() -> int:
    global _latest_markets

    params = {
        "order": "volume24hr",
        "ascending": "false",
        "active": "true",
        "closed": "false",
        "limit": "10",
    }
    try:
        resp = httpx.get(EVENTS_URL, params=params, headers=_HEADERS, timeout=15)
        resp.raise_for_status()
        events = resp.json()
    except Exception:
        log.exception("Failed to fetch Polymarket events")
        return 0

    markets = []
    for e in events:
        markets.append(
            {
                "title": e.get("title", ""),
                "slug": e.get("slug", ""),
                "url": f"https://polymarket.com/event/{e.get('slug', '')}",
                "volume_24h": e.get("volume24hr"),
                "leading_outcome": _leading_outcome(e),
            }
        )

    _latest_markets = markets
    log.info("Polymarket poll complete: %d trending markets", len(markets))
    return len(markets)


def get_latest_polymarket() -> list[dict]:
    return _latest_markets