import { useState, useEffect, useCallback } from 'react';

export interface VolumeAnomaly {
  marketId: string;
  question: string | null;
  category: string | null;
  score: number;       // e.g. 5.0 = 500% of avg
  volume24h: number;
  avgVolume: number;
  liquidity: number;
  detectedAt: string | null;
}

interface AnomaliesMeta {
  minScore: number;
  hours: number;
  count: number;
}

export function useAnomalies(minScore = 3.0, hours = 24, limit = 20) {
  const [anomalies, setAnomalies] = useState<VolumeAnomaly[]>([]);
  const [meta, setMeta] = useState<AnomaliesMeta | null>(null);
  const [loading, setLoading] = useState(true);

  const fetch_ = useCallback(async () => {
    setLoading(true);
    try {
      const res = await fetch(
        `/api/signals/anomalies?min_score=${minScore}&hours=${hours}&limit=${limit}`
      );
      const d = await res.json();
      if (d.success) {
        setAnomalies(d.data ?? []);
        setMeta(d.meta ?? null);
      }
    } catch { /* ignore */ }
    finally { setLoading(false); }
  }, [minScore, hours, limit]);

  useEffect(() => {
    const t = setTimeout(fetch_, 0);
    const interval = setInterval(fetch_, 2 * 60_000);
    return () => { clearTimeout(t); clearInterval(interval); };
  }, [fetch_]);

  return { anomalies, meta, loading, refresh: fetch_ };
}