import { useEffect, useId, useRef } from 'react'

/**
 * Einfaches Modal (AP1.12b) — Fokus-Falle, Escape schließt.
 *
 * @param {{ open: boolean, title: string, onClose: () => void, children: import('react').ReactNode, size?: 'md'|'lg' }} props
 */
export function Modal({ open, title, onClose, children, size = 'md' }) {
  const titleId = useId()
  const dialogRef = useRef(null)

  useEffect(() => {
    if (!open) return undefined

    const previousActive = document.activeElement
    dialogRef.current?.focus()

    function onKeyDown(event) {
      if (event.key === 'Escape') {
        event.preventDefault()
        onClose()
      }
    }

    document.addEventListener('keydown', onKeyDown)
    const prevOverflow = document.body.style.overflow
    document.body.style.overflow = 'hidden'

    return () => {
      document.removeEventListener('keydown', onKeyDown)
      document.body.style.overflow = prevOverflow
      if (previousActive instanceof HTMLElement) {
        previousActive.focus()
      }
    }
  }, [open, onClose])

  if (!open) return null

  return (
    <div className="modal-root" role="presentation" onMouseDown={onClose}>
      <div
        ref={dialogRef}
        className={`modal-dialog modal-dialog--${size}`}
        role="dialog"
        aria-modal="true"
        aria-labelledby={titleId}
        tabIndex={-1}
        onMouseDown={(event) => event.stopPropagation()}
      >
        <header className="modal-dialog__header">
          <h2 id={titleId} className="modal-dialog__title">
            {title}
          </h2>
          <button
            type="button"
            className="modal-dialog__close btn btn-secondary btn-sm"
            onClick={onClose}
            aria-label="Schließen"
          >
            ×
          </button>
        </header>
        <div className="modal-dialog__body">{children}</div>
      </div>
    </div>
  )
}