'use client'

import { useEffect, useRef, useState } from 'react'
import { useLocale } from 'next-intl'
import { useRouter, usePathname } from '@/navigation'
import { routing } from '@/i18n/routing'

const LANGUAGE_LABELS: Record<string, string> = {
  en: 'English',
  fr: 'Français',
  es: 'Español',
  it: 'Italiano',
}

function Flag({ locale, className }: { locale: string; className?: string }) {
  return (
    <img
      src={`/flags/${locale}.svg`}
      alt=""
      className={['w-6 h-4 rounded-sm object-cover shrink-0', className].filter(Boolean).join(' ')}
    />
  )
}

function ChevronIcon() {
  return (
    <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round" aria-hidden>
      <polyline points="6 9 12 15 18 9" />
    </svg>
  )
}

export function LanguageSwitcher() {
  const locale = useLocale()
  const router = useRouter()
  const pathname = usePathname()
  const [open, setOpen] = useState(false)
  const containerRef = useRef<HTMLDivElement>(null)

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

    function handlePointerDown(event: MouseEvent) {
      if (containerRef.current && !containerRef.current.contains(event.target as Node)) {
        setOpen(false)
      }
    }

    function handleKeyDown(event: KeyboardEvent) {
      if (event.key === 'Escape') setOpen(false)
    }

    document.addEventListener('mousedown', handlePointerDown)
    document.addEventListener('keydown', handleKeyDown)
    return () => {
      document.removeEventListener('mousedown', handlePointerDown)
      document.removeEventListener('keydown', handleKeyDown)
    }
  }, [open])

  function selectLocale(loc: string) {
    setOpen(false)
    router.replace(pathname, { locale: loc })
  }

  return (
    <div ref={containerRef} className="relative">
      <button
        type="button"
        onClick={() => setOpen((value) => !value)}
        aria-haspopup="listbox"
        aria-expanded={open}
        className="flex items-center gap-2 rounded-lg py-1.5 pl-2 pr-2.5 text-gray-600 dark:text-gray-400 hover:bg-gray-100 dark:hover:bg-slate-800 transition-colors cursor-pointer"
      >
        <Flag locale={locale} />
        <ChevronIcon />
      </button>

      {open && (
        <ul
          role="listbox"
          className="absolute right-0 top-full mt-2 min-w-[9rem] rounded-lg border border-gray-200 dark:border-slate-800 bg-white dark:bg-slate-900 shadow-lg py-1 z-50"
        >
          {routing.locales.map((loc) => (
            <li key={loc} role="option" aria-selected={loc === locale}>
              <button
                type="button"
                onClick={() => selectLocale(loc)}
                className={[
                  'flex w-full items-center gap-2.5 px-3 py-2 text-sm text-left transition-colors cursor-pointer',
                  loc === locale
                    ? 'bg-violet-50 dark:bg-violet-500/10 text-violet-600 dark:text-violet-400 font-medium'
                    : 'text-gray-700 dark:text-gray-300 hover:bg-gray-100 dark:hover:bg-slate-800',
                ].join(' ')}
              >
                <Flag locale={loc} />
                {LANGUAGE_LABELS[loc]}
              </button>
            </li>
          ))}
        </ul>
      )}
    </div>
  )
}