import { useState, useEffect, useCallback } from 'react';
import type { Alert } from '../types/market';

export function useAlerts() {
  const [alerts, setAlerts] = useState<Alert[]>([]);
  const [loading, setLoading] = useState(false);

  const fetchAlerts = useCallback(() => {
    setLoading(true);
    fetch('/api/alerts')
      .then(r => r.json())
      .then(d => {
        if (d.success) setAlerts(d.data);
      })
      .catch(() => {})
      .finally(() => setLoading(false));
  }, []);

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

  const createAlert = useCallback(async (
    marketId: string, side: string, direction: string, threshold: number
  ): Promise<boolean> => {
    try {
      const res = await fetch('/api/alerts', {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ market_id: marketId, side, direction, threshold }),
      });
      const d = await res.json();
      if (d.success) {
        fetchAlerts();
        return true;
      }
      return false;
    } catch {
      return false;
    }
  }, [fetchAlerts]);

  const deleteAlert = useCallback(async (id: number): Promise<boolean> => {
    try {
      const res = await fetch(`/api/alerts/${id}`, { method: 'DELETE' });
      const d = await res.json();
      if (d.success) {
        setAlerts(prev => prev.filter(a => a.id !== id));
        return true;
      }
      return false;
    } catch {
      return false;
    }
  }, []);

  const triggeredCount = alerts.filter(a => a.triggered).length;

  return { alerts, loading, triggeredCount, createAlert, deleteAlert, refresh: fetchAlerts };
}