import { useEffect, useRef, useState } from 'react';
import { createPortal } from 'react-dom';
import styles from './ContextMenu.module.css';

export interface ContextMenuItem {
  label: string;
  onClick: () => void;
  variant?: 'default' | 'danger';
  icon?: React.ReactNode;
}

export interface ContextMenuProps {
  items: ContextMenuItem[];
  /** The trigger element — a button rendered by the component */
  trigger: React.ReactNode;
  align?: 'left' | 'right';
}

export function ContextMenu({ items, trigger, align = 'right' }: ContextMenuProps) {
  const [open, setOpen] = useState(false);
  const [coords, setCoords] = useState({ top: 0, left: 0, right: 0 });
  const triggerRef = useRef<HTMLDivElement>(null);
  const menuRef = useRef<HTMLUListElement>(null);

  useEffect(() => {
    if (!open) return;
    function handleOutside(e: MouseEvent) {
      const target = e.target as Node;
      if (
        triggerRef.current &&
        !triggerRef.current.contains(target) &&
        menuRef.current &&
        !menuRef.current.contains(target)
      ) {
        setOpen(false);
      }
    }
    document.addEventListener('mousedown', handleOutside);
    return () => document.removeEventListener('mousedown', handleOutside);
  }, [open]);

  useEffect(() => {
    if (!open) return;
    function handleKey(e: KeyboardEvent) {
      if (e.key === 'Escape') setOpen(false);
    }
    document.addEventListener('keydown', handleKey);
    return () => document.removeEventListener('keydown', handleKey);
  }, [open]);

  function openMenu() {
    if (!triggerRef.current) return;
    const rect = triggerRef.current.getBoundingClientRect();
    setCoords({
      top: rect.bottom + window.scrollY + 4,
      left: rect.left + window.scrollX,
      right: window.innerWidth - rect.right - window.scrollX,
    });
    setOpen((v) => !v);
  }

  const menuStyle =
    align === 'right'
      ? { top: coords.top, right: coords.right }
      : { top: coords.top, left: coords.left };

  return (
    <div className={styles.root} ref={triggerRef}>
      <div
        className={styles.triggerWrap}
        onClick={(e) => {
          e.stopPropagation();
          openMenu();
        }}
      >
        {trigger}
      </div>
      {open &&
        createPortal(
          <ul
            ref={menuRef}
            className={styles.menu}
            style={{ ...menuStyle, position: 'fixed' }}
            role="menu"
          >
            {items.map((item, i) => (
              <li key={i} role="none">
                <button
                  role="menuitem"
                  className={`${styles.item} ${item.variant === 'danger' ? styles.danger : ''}`}
                  onClick={(e) => {
                    e.stopPropagation();
                    setOpen(false);
                    item.onClick();
                  }}
                >
                  {item.icon && (
                    <span className={styles.icon} aria-hidden="true">
                      {item.icon}
                    </span>
                  )}
                  {item.label}
                </button>
              </li>
            ))}
          </ul>,
          document.body,
        )}
    </div>
  );
}