app/src/admin/ui/Modal.tsx

import { useState, type ReactNode } from "react";
import Dialog from "@mui/material/Dialog";
import DialogTitle from "@mui/material/DialogTitle";
import DialogContent from "@mui/material/DialogContent";
import DialogActions from "@mui/material/DialogActions";
import Typography from "@mui/material/Typography";
import MuiButton from "@mui/material/Button";
import useDialogScrollLock from "./useDialogScrollLock";

export interface ModalProps {
  isOpen: boolean;
  onClose: () => void;
  onSubmit: () => void;
  title: string;
  subtitle?: string;
  children: ReactNode;
  loading?: boolean;
  submitDisabled?: boolean;
  submitText?: string;
  cancelText?: string;
  /** Hide the secondary cancel button (e.g. modals whose only action closes). */
  hideCancel?: boolean;
  maxWidth?: "xs" | "sm" | "md" | "lg";
}

/** Form modal over MUI Dialog. Preserves the legacy FormModal prop shape. */
export default function Modal({
  isOpen,
  onClose,
  onSubmit,
  title,
  subtitle,
  children,
  loading = false,
  submitDisabled = false,
  submitText = "Uložit",
  cancelText = "Zrušit",
  hideCancel = false,
  maxWidth = "sm",
}: ModalProps) {
  useDialogScrollLock(isOpen);
  // Freeze the shown title/subtitle/submitText while closing, so the fade-out
  // never flashes the "create" variant when the caller clears `editingUser` on
  // close (React derive-state-from-props: update only while open).
  // Freeze label-affecting props (incl. `loading`) while open, so neither the
  // title/submitText NOR the loading state flips during the close fade-out
  // (e.g. on save, `loading` goes false a beat before the dialog finishes
  // closing — without this the button would flash back to "Uložit změny").
  const [shown, setShown] = useState({ title, subtitle, submitText, loading });
  if (
    isOpen &&
    (shown.title !== title ||
      shown.subtitle !== subtitle ||
      shown.submitText !== submitText ||
      shown.loading !== loading)
  ) {
    setShown({ title, subtitle, submitText, loading });
  }

  return (
    <Dialog
      open={isOpen}
      onClose={shown.loading ? undefined : onClose}
      fullWidth
      maxWidth={maxWidth}
      disableScrollLock
      slotProps={{ paper: { sx: { borderRadius: 3 } } }}
    >
      <DialogTitle sx={{ pb: shown.subtitle ? 0.5 : 1.5 }}>
        {shown.title}
        {shown.subtitle && (
          <Typography variant="body2" color="text.secondary">
            {shown.subtitle}
          </Typography>
        )}
      </DialogTitle>
      <DialogContent>{children}</DialogContent>
      <DialogActions sx={{ px: 3, pb: 2 }}>
        {!hideCancel && (
          <MuiButton onClick={onClose} color="inherit" disabled={shown.loading}>
            {cancelText}
          </MuiButton>
        )}
        <MuiButton
          onClick={onSubmit}
          variant="contained"
          disabled={shown.loading || submitDisabled}
        >
          {shown.loading ? "Ukládám…" : shown.submitText}
        </MuiButton>
      </DialogActions>
    </Dialog>
  );
}