// Simulation: live ticker of "sold" events + animated number hook + formatters.

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

let _eid = 1;
function makeSaleEvent(now) {
  const kind = pick(GIFT_LIST);
  const listing = makeListing(kind);
  return {
    id: _eid++,
    kind,
    name: listing.name,
    num: listing.num,
    ton: listing.ton,
    rub: listing.rub,
    tier: listing.tier,
    buyer: pick(SELLERS),
    seller: listing.seller,
    when: now || Date.now(),
  };
}

function seedSales(n = 8) {
  const arr = [];
  const now = Date.now();
  for (let i = 0; i < n; i++) arr.push(makeSaleEvent(now - i * 22000 - Math.random() * 8000));
  return arr;
}

function useTicker(enabled = true, intervalMs = 3400) {
  const [events, setEvents] = useState(() => seedSales());
  useEffect(() => {
    if (!enabled) return;
    const id = setInterval(() => {
      setEvents(prev => [makeSaleEvent(), ...prev].slice(0, 30));
    }, intervalMs + Math.random() * 1500);
    return () => clearInterval(id);
  }, [enabled, intervalMs]);
  return events;
}

// Animated counter — eases value toward target over `duration` ms.
function useAnimatedNumber(target, duration = 1200) {
  const [val, setVal] = useState(target);
  const fromRef = useRef(target);
  const startRef = useRef(0);
  const rafRef = useRef(0);
  useEffect(() => {
    fromRef.current = val;
    startRef.current = performance.now();
    cancelAnimationFrame(rafRef.current);
    const tick = (t) => {
      const p = Math.min(1, (t - startRef.current) / duration);
      const ease = 1 - Math.pow(1 - p, 3);
      setVal(fromRef.current + (target - fromRef.current) * ease);
      if (p < 1) rafRef.current = requestAnimationFrame(tick);
    };
    rafRef.current = requestAnimationFrame(tick);
    return () => cancelAnimationFrame(rafRef.current);
  }, [target, duration]);
  return val;
}

// Formatters
function fmtRub(v) { return Math.round(v).toLocaleString('ru-RU') + ' ₽'; }
function fmtRubShort(v) {
  if (v >= 1000000) return (v / 1000000).toFixed(1).replace('.0','') + ' млн ₽';
  if (v >= 1000) return (v / 1000).toFixed(v >= 10000 ? 0 : 1).replace('.0','') + 'k ₽';
  return Math.round(v) + ' ₽';
}
function fmtTon(v) { return (Math.round(v * 100) / 100).toFixed(2) + ' TON'; }
function fmtRel(t) {
  const s = Math.max(1, Math.round((Date.now() - t) / 1000));
  if (s < 60) return s + ' с назад';
  const m = Math.round(s / 60); if (m < 60) return m + ' м назад';
  const h = Math.round(m / 60); if (h < 24) return h + ' ч назад';
  return Math.round(h / 24) + ' д назад';
}

window.useTicker = useTicker;
window.useAnimatedNumber = useAnimatedNumber;
window.makeSaleEvent = makeSaleEvent;
window.fmtRub = fmtRub;
window.fmtRubShort = fmtRubShort;
window.fmtTon = fmtTon;
window.fmtRel = fmtRel;