import React, { useEffect, useRef } from 'react';

interface ModalProps {
  title: string;
  subtitle?: string;
  onClose: () => void;
  children: React.ReactNode;
  footer?: React.ReactNode;
  size?: 'md' | 'lg' | 'xl';
}

const SIZES: Record<NonNullable<ModalProps['size']>, string> = {
  md: 'max-w-md',
  lg: 'max-w-2xl',
  xl: 'max-w-4xl',
};

/**
 * Offene Dialoge in der Reihenfolge ihres Oeffnens. Escape darf nur den
 * obersten schliessen, sonst raeumt ein Tastendruck verschachtelte Dialoge
 * (z. B. "Neuer Kontakt" in einer Opportunity) gleich alle mit weg.
 */
const openModals: symbol[] = [];

/**
 * Schliessen per Escape und per Klick in den Hintergrund. Beides greift in jedem
 * Dialog, weil alle Dialoge im CRM ueber diese Komponente laufen.
 */
function useDismiss(onClose: () => void) {
  // Ueber die Ref bleibt der Escape-Handler an den Dialog gebunden, auch wenn
  // die Elternkomponente bei jedem Rendern ein neues onClose durchgibt - sonst
  // wuerde sich der Dialog beim Neuaufbau des Handlers wieder nach oben
  // sortieren und dem verschachtelten Dialog das Escape wegnehmen.
  const closeRef = useRef(onClose);
  closeRef.current = onClose;

  useEffect(() => {
    const token = Symbol('modal');
    openModals.push(token);

    const onKeyDown = (event: KeyboardEvent) => {
      if (event.key !== 'Escape') return;
      if (openModals[openModals.length - 1] !== token) return;
      closeRef.current();
    };
    window.addEventListener('keydown', onKeyDown);

    return () => {
      window.removeEventListener('keydown', onKeyDown);
      const index = openModals.indexOf(token);
      if (index !== -1) openModals.splice(index, 1);
    };
  }, []);

  // Nur ein Klick, der im Hintergrund beginnt *und* endet, schliesst. So
  // ueberlebt eine Textmarkierung, die im Dialog anfaengt und daneben aufhoert.
  const pressedBackdrop = useRef(false);

  return {
    onMouseDown: (event: React.MouseEvent) => {
      pressedBackdrop.current = event.target === event.currentTarget;
    },
    onClick: (event: React.MouseEvent) => {
      if (pressedBackdrop.current && event.target === event.currentTarget) closeRef.current();
    },
  };
}

export const Modal: React.FC<ModalProps> = ({
  title,
  subtitle,
  onClose,
  children,
  footer,
  size = 'lg',
}) => {
  const dismiss = useDismiss(onClose);

  return (
    <div
      {...dismiss}
      className="fixed inset-0 z-[100] flex items-center justify-center bg-ink-950/50 p-4 backdrop-blur-sm"
    >
      <div
        className={`flex max-h-[92vh] w-full flex-col overflow-hidden rounded-2xl border border-ink-200 bg-surface shadow-lift ${SIZES[size]}`}
        role="dialog"
        aria-modal="true"
        aria-label={title}
      >
        <div className="flex shrink-0 items-start justify-between gap-4 border-b border-ink-100 px-6 py-5">
          <div className="min-w-0">
            <h2 className="truncate text-xl text-ink-900">{title}</h2>
            {subtitle && <p className="mt-0.5 truncate text-xs font-semibold text-ink-400">{subtitle}</p>}
          </div>
          <button
            onClick={onClose}
            className="shrink-0 rounded-lg p-2 text-ink-400 transition hover:bg-ink-100 hover:text-ink-800"
            aria-label="Dialog schließen"
          >
            <svg className="h-5 w-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
              <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M6 18L18 6M6 6l12 12" />
            </svg>
          </button>
        </div>

        <div className="scrollbar-slim flex-1 overflow-y-auto px-6 py-6">{children}</div>

        {footer && (
          <div className="shrink-0 border-t border-ink-100 bg-ink-50/60 px-6 py-4">{footer}</div>
        )}
      </div>
    </div>
  );
};

interface ConfirmDialogProps {
  title: string;
  message: string;
  confirmLabel?: string;
  onConfirm: () => void;
  onCancel: () => void;
}

export const ConfirmDialog: React.FC<ConfirmDialogProps> = ({
  title,
  message,
  confirmLabel = 'Löschen',
  onConfirm,
  onCancel,
}) => {
  const dismiss = useDismiss(onCancel);

  return (
    <div
      {...dismiss}
      className="fixed inset-0 z-[130] flex items-center justify-center bg-ink-950/50 p-4 backdrop-blur-sm"
    >
      <div className="w-full max-w-sm rounded-2xl border border-ink-200 bg-surface p-7 text-center shadow-lift">
        <div className="mx-auto mb-5 flex h-14 w-14 items-center justify-center rounded-full bg-red-50 text-red-600">
          <svg className="h-7 w-7" fill="none" stroke="currentColor" viewBox="0 0 24 24">
            <path
              strokeLinecap="round"
              strokeLinejoin="round"
              strokeWidth={2}
              d="M12 9v2m0 4h.01m-6.938 4h13.856c1.54 0 2.502-1.667 1.732-3L13.732 4c-.77-1.333-2.694-1.333-3.464 0L3.34 16c-.77 1.333.192 3 1.732 3z"
            />
          </svg>
        </div>
        <h3 className="text-lg text-ink-900">{title}</h3>
        <p className="mt-2 text-sm text-ink-500">{message}</p>
        <div className="mt-7 grid grid-cols-2 gap-3">
          <button
            onClick={onCancel}
            className="rounded-xl border border-ink-200 py-3 text-sm font-bold text-ink-600 transition hover:bg-ink-100"
          >
            Abbrechen
          </button>
          <button
            onClick={onConfirm}
            className="rounded-xl bg-red-600 py-3 text-sm font-bold text-white transition hover:bg-red-700"
          >
            {confirmLabel}
          </button>
        </div>
      </div>
    </div>
  );
};