frontend/src/components/SignatureOverlay.tsx

import { useEffect, useRef, useState } from 'react';
import { Button } from 'antd';
import SignaturePad, { type SignaturePadHandle } from './SignaturePad';
import './SignatureOverlay.css';

interface SignatureOverlayProps {
  open: boolean;
  onCancel: () => void;
  onConfirm: (dataUrl: string) => void;
}

function SignatureOverlay({ open, onCancel, onConfirm }: SignatureOverlayProps) {
  const padRef = useRef<SignaturePadHandle>(null);
  const [, setData] = useState('');

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

    const prevOverflow = document.body.style.overflow;
    document.body.style.overflow = 'hidden';

    return () => {
      document.body.style.overflow = prevOverflow;
    };
  }, [open]);

  if (!open) return null;

  const handleClear = () => {
    padRef.current?.clear();
    setData('');
  };

  const handleConfirm = () => {
    const pad = padRef.current;
    if (!pad || pad.isEmpty()) return;
    onConfirm(pad.getDataURL());
  };

  return (
    <div className="signature-overlay" role="dialog" aria-modal="true">
      <div className="signature-overlay-stage">
        <div className="signature-overlay-bar">
          <Button type="text" onClick={onCancel}>
            取消
          </Button>
          <span className="signature-overlay-title">请在框内签名</span>
          <Button type="text" onClick={handleClear}>
            清除
          </Button>
        </div>
        <div className="signature-overlay-pad">
          <SignaturePad ref={padRef} onChange={setData} />
        </div>
        <div className="signature-overlay-actions">
          <Button size="large" type="primary" block onClick={handleConfirm}>
            保存签名
          </Button>
        </div>
      </div>
    </div>
  );
}

export default SignatureOverlay;