/**
 * MobileMenu.tsx
 * ---------------------------------------------------------------------------
 * React island that powers the hamburger menu on small screens. Renders the
 * same two-group nav structure as the desktop bar (imported via a data prop so
 * the source of truth stays in site.ts).
 *
 * Accessibility: the button is aria-expanded/aria-controls wired to the panel,
 * Escape closes, clicking a link closes, and focus is returned to the toggle.
 * Animations respect prefers-reduced-motion (Framer Motion reads the media query
 * automatically when we pass the transition).
 */
import { useEffect, useRef, useState } from 'react';
import { AnimatePresence, motion } from 'framer-motion';

export interface MobileNavItem {
  label: string;
  href: string;
  icon: string;
}
export interface MobileNavGroup {
  items: MobileNavItem[];
}

interface Props {
  groups: MobileNavGroup[];
  /** Current path for active link highlighting. */
  currentPath: string;
}

// Small inline mdi-like icons keyed by name (keeps the menu self-contained).
const ICON_PATHS: Record<string, string> = {
  home: 'M10 20v-6h4v6h5v-8h3L12 3 2 12h3v8z',
  account: 'M12 4a4 4 0 1 0 0 8 4 4 0 0 0 0-8zm0 10c-4.4 0-8 2.2-8 5v1h16v-1c0-2.8-3.6-5-8-5z',
  briefcase:
    'M10 16h4a1 1 0 0 0 1-1v-1H7a2 2 0 0 1-2-2V7a2 2 0 0 1 2-2h2V4a2 2 0 0 1 2-2h2a2 2 0 0 1 2 2v1h2a2 2 0 0 1 2 2v8a2 2 0 0 1-2 2h-1v1a3 3 0 0 1-3 3h-4a3 3 0 0 1-3-3v-1z',
  'dice-multiple':
    'M6 3h5v5H6V3zm7 0h5v5h-5V3zM3 11h5v5H3v-5zm7 0h5v5h-5v-5zm7 0h-5v5h5v-5z',
  email:
    'M4 4h16a2 2 0 0 1 2 2v12a2 2 0 0 1-2 2H4a2 2 0 0 1-2-2V6a2 2 0 0 1 2-2zm8 7L4 6v1l8 5 8-5V6l-8 5z',
};

function Icon({ name, className }: { name: string; className?: string }) {
  return (
    <svg className={className} width="20" height="20" viewBox="0 0 24 24" fill="currentColor" aria-hidden="true">
      <path d={ICON_PATHS[name] ?? ''} />
    </svg>
  );
}

function isActive(href: string, path: string): boolean {
  if (href === '/') return path === '/';
  return path === href || path.startsWith(href + '/');
}

export default function MobileMenu({ groups, currentPath }: Props) {
  const [open, setOpen] = useState(false);
  const buttonRef = useRef<HTMLButtonElement>(null);

  // Escape closes the menu; lock body scroll while open.
  useEffect(() => {
    if (!open) return;
    const onKey = (e: KeyboardEvent) => {
      if (e.key === 'Escape') {
        setOpen(false);
        buttonRef.current?.focus();
      }
    };
    document.addEventListener('keydown', onKey);
    document.body.style.overflow = 'hidden';
    return () => {
      document.removeEventListener('keydown', onKey);
      document.body.style.overflow = '';
    };
  }, [open]);

  return (
    <div className="md:hidden">
      <button
        ref={buttonRef}
        type="button"
        onClick={() => setOpen((o) => !o)}
        aria-expanded={open}
        aria-controls="mobile-menu"
        aria-label={open ? 'Close menu' : 'Open menu'}
        className="inline-flex h-10 w-10 items-center justify-center rounded-lg border"
        style={{ color: 'var(--color-text)', borderColor: 'var(--color-border)' }}
      >
        {open ? (
          <svg width="22" height="22" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round">
            <path d="M6 6l12 12M18 6L6 18" />
          </svg>
        ) : (
          <svg width="22" height="22" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round">
            <path d="M4 7h16M4 12h16M4 17h16" />
          </svg>
        )}
      </button>

      <AnimatePresence>
        {open && (
          <>
            {/* Backdrop */}
            <motion.div
              initial={{ opacity: 0 }}
              animate={{ opacity: 1 }}
              exit={{ opacity: 0 }}
              transition={{ duration: 0.2 }}
              onClick={() => setOpen(false)}
              className="fixed inset-0 z-40 bg-black/40 backdrop-blur-sm"
            />
            {/* Panel */}
            <motion.nav
              id="mobile-menu"
              initial={{ x: '100%' }}
              animate={{ x: 0 }}
              exit={{ x: '100%' }}
              transition={{ type: 'tween', duration: 0.28 }}
              className="fixed right-0 top-0 z-50 flex h-[100dvh] w-[min(82vw,22rem)] flex-col gap-6 overflow-y-auto p-6 pt-20 shadow-2xl"
              style={{ backgroundColor: 'var(--color-surface-raised)' }}
            >
              {groups.map((group, gi) => (
                <ul key={gi} className="flex flex-col gap-1">
                  {group.items.map((item) => {
                    const active = isActive(item.href, currentPath);
                    return (
                      <li key={item.href}>
                        <a
                          href={item.href}
                          onClick={() => setOpen(false)}
                          className="flex items-center gap-3 rounded-lg px-3 py-3 text-lg font-medium transition-colors"
                          style={{
                            color: active ? 'var(--color-accent)' : 'var(--color-text)',
                            backgroundColor: active
                              ? 'color-mix(in srgb, var(--color-accent) 14%, transparent)'
                              : 'transparent',
                          }}
                        >
                          <Icon name={item.icon} />
                          {item.label}
                        </a>
                      </li>
                    );
                  })}
                </ul>
              ))}
            </motion.nav>
          </>
        )}
      </AnimatePresence>
    </div>
  );
}