import { useEffect, useRef, useState } from 'react';
import { createPortal } from 'react-dom';
import { ChevronDown, Search } from 'lucide-react';

// Combo con buscador (regla del grupo: nunca el <select> nativo para listas >= 10 items).
// El panel desplegable se porta a document.body y se posiciona con `position: fixed` calculado
// desde el trigger (igual tecnica que Flyout) — evita que un ancestro con overflow:hidden/auto
// (Expander, DetailPopup, cualquier tarjeta con scroll propio) recorte la lista desplegada.
// options: [{ value, label }]
export function ComboBox({ options, value, onChange, placeholder = '', searchThreshold = 10 }) {
  const [open, setOpen] = useState(false);
  const [query, setQuery] = useState('');
  const [pos, setPos] = useState(null);
  const triggerRef = useRef(null);
  const panelRef = useRef(null);

  function openPanel() {
    const rect = triggerRef.current.getBoundingClientRect();
    setPos({ top: rect.bottom + 4, left: rect.left, width: rect.width });
    setOpen(true);
  }

  useEffect(() => {
    if (!open) return;
    function onDocMouseDown(e) {
      if (triggerRef.current?.contains(e.target)) return;
      if (panelRef.current?.contains(e.target)) return;
      setOpen(false);
    }
    // capture:true para detectar scroll en CUALQUIER ancestro (los eventos de scroll no burbujean).
    function onScroll() { setOpen(false); }
    document.addEventListener('mousedown', onDocMouseDown);
    window.addEventListener('scroll', onScroll, true);
    window.addEventListener('resize', onScroll);
    return () => {
      document.removeEventListener('mousedown', onDocMouseDown);
      window.removeEventListener('scroll', onScroll, true);
      window.removeEventListener('resize', onScroll);
    };
  }, [open]);

  const selected = options.find((o) => String(o.value) === String(value));
  const filtered = query
    ? options.filter((o) => o.label.toLowerCase().includes(query.toLowerCase()))
    : options;

  return (
    <div className="combobox">
      <button
        type="button"
        ref={triggerRef}
        className="input"
        style={{ display: 'flex', alignItems: 'center', justifyContent: 'space-between', cursor: 'pointer' }}
        onClick={() => (open ? setOpen(false) : openPanel())}
      >
        <span style={{ overflow: 'hidden', textOverflow: 'ellipsis', whiteSpace: 'nowrap' }}>{selected ? selected.label : (placeholder || '—')}</span>
        <ChevronDown size={14} />
      </button>
      {open && pos && createPortal(
        <div ref={panelRef} className="combobox-panel" style={{ top: pos.top, left: pos.left, width: pos.width }}>
          {options.length >= searchThreshold && (
            <div className="combobox-search" style={{ position: 'relative' }}>
              <Search size={13} style={{ position: 'absolute', left: 8, top: 9, opacity: .6 }} />
              <input
                autoFocus
                className="input"
                style={{ paddingLeft: 26 }}
                value={query}
                onChange={(e) => setQuery(e.target.value)}
                placeholder="Buscar..."
              />
            </div>
          )}
          {filtered.length === 0 && <div className="combobox-empty">Sin resultados</div>}
          {filtered.map((o) => (
            <div
              key={o.value}
              className={`combobox-option ${String(o.value) === String(value) ? 'active' : ''}`}
              onClick={() => { onChange(o.value); setOpen(false); setQuery(''); }}
            >
              {o.label}
            </div>
          ))}
        </div>,
        document.body
      )}
    </div>
  );
}