/* global React */
const { useState, useEffect, useRef, useMemo, useCallback } = React;

// ── App state: route + language ──────────────────────────────────
const LANGS = ['pt-BR', 'en'];
function detectLang() {
  try {
    const saved = localStorage.getItem('axiom0.lang');
    if (saved && LANGS.includes(saved)) return saved;
    const nav = (navigator.language || 'pt-BR').toLowerCase();
    if (nav.startsWith('en')) return 'en';
  } catch (e) {}
  return 'pt-BR';
}

function parseHash() {
  const h = (window.location.hash || '#/').replace(/^#/, '');
  const parts = h.split('/').filter(Boolean);
  return { page: parts[0] || 'home', slug: parts[1] || null };
}

function useRouter() {
  const [route, setRoute] = useState(parseHash());
  useEffect(() => {
    const onHash = () => setRoute(parseHash());
    window.addEventListener('hashchange', onHash);
    return () => window.removeEventListener('hashchange', onHash);
  }, []);
  const navigate = useCallback((page, slug) => {
    const h = slug ? `#/${page}/${slug}` : `#/${page}`;
    window.location.hash = h;
    window.scrollTo({ top: 0, behavior: 'instant' });
  }, []);
  return { route, navigate };
}

function useLang() {
  const [lang, setLang] = useState(detectLang());
  useEffect(() => {
    try { localStorage.setItem('axiom0.lang', lang); } catch (e) {}
    document.documentElement.lang = lang === 'pt-BR' ? 'pt-BR' : 'en';
  }, [lang]);
  return [lang, setLang];
}

// ── IntersectionObserver-based reveal helper ─────────────────────
function useReveal() {
  useEffect(() => {
    document.documentElement.classList.add('js-reveal');
    const markAll = () => {
      document.querySelectorAll('.reveal:not(.in)').forEach((el) => {
        const r = el.getBoundingClientRect();
        if (r.top < window.innerHeight + 40) el.classList.add('in');
      });
    };
    // Initial reveal
    const t1 = setTimeout(markAll, 60);
    const t2 = setTimeout(markAll, 400);
    const onScroll = () => markAll();
    window.addEventListener('scroll', onScroll, { passive: true });
    const mo = new MutationObserver(() => setTimeout(markAll, 30));
    mo.observe(document.body, { childList: true, subtree: true });
    return () => { clearTimeout(t1); clearTimeout(t2); window.removeEventListener('scroll', onScroll); mo.disconnect(); };
  }, []);
}

// Expose to all babel script scopes
Object.assign(window, { useRouter, useLang, useReveal, LANGS });