const prob = h.perf / sumPerf;
        // přidej margin 8%
        const price = 1 / (prob * 0.92);
        h.odds = round(price, 2);
      });

      renderHorseList();
      setupTrack();
      ui.betView.textContent = 0;
    }

    function toOdds(x){ return round(Math.max(1.2, x), 2); }
    function round(n, p){ const m = Math.pow(10,p); return Math.round(n*m)/m; }

    // Render seznamu koní
    function renderHorseList(){
      ui.horses.innerHTML = '';
      horses.forEach((h, i)=>{
        const row = document.createElement('div');
        row.className = 'horse';
        row.innerHTML = `
          <div class="name">${h.name}</div>
          <div class="form">Forma: ${h.perf.toFixed(2)}</div>
          <div class="odds">Kurz: ${h.odds.toFixed(2)}</div>
          <div class="row"><input type="radio" name="horse" value="${i}" /></div>
        `;
        ui.horses.appendChild(row);
      });
      ui.horses.querySelectorAll('input[type="radio"]').forEach(r=>{
        r.addEventListener('change', (e)=>{
          selectedHorse = horses[parseInt(e.target.value,10)];
        });
      });
    }

    // Spustit závod se sázkou
    ui.placeBetBtn.addEventListener('click', placeBet);
    ui.quickBtn.addEventListener('click', quickRace);
    ui.resetBtn.addEventListener('click', ()=>{ bankroll=1000; wins=0; raceId=0; updateStats(); newRace(); });

    document.addEventListener('keydown', (e)=>{
      const k = e.key.toLowerCase();
      if(k==='enter') placeBet();
      if(k==='r') quickRace();
    });

    function placeBet(){
      if(running) return;
      const amt = +ui.betAmount.value;
      if(!selectedHorse){ alert('Vyber koně.'); return; }
      if(!Number.isFinite(amt) || amt<=0){ alert('Zadej platnou částku.'); return; }
      if(amt > bankroll){ alert('Nemáš dostatek prostředků.'); return; }

      bankroll -= amt;
      ui.betView.textContent = amt;
      updateStats();
      runRace(amt, selectedHorse);
    }

    function quickRace(){
      if(running) return;
      // malá sázka 10 na náhodného koně
      selectedHorse = horses[Math.floor(Math.random()*horses.length)];
      ui.betAmount.value = 10;
      placeBet();
    }

    function updateStats(){
      ui.bankroll.textContent = Math.max(0, Math.floor(bankroll));
      ui.racesCount.textContent = raceId;
      ui.winsCount.textContent = wins;
    }

    // Simulace závodu
    function runRace(betAmt, pick){
      running = true;
      // reset pozic
      horses.forEach(h=>{ h.dist = 0; h.node.style.left = '6px'; });

      const start = performance.now();
      const duration = 8000 + Math.random()*2000; // 8–10 s závod
      let finished = false;

      function step(now){
        const dt = (now - start) / 1000;
        horses.forEach(h=>{
          // drobná náhoda v rychlosti v čase
          const jitter = 0.9 + Math.random()*0.2;
          h.dist = Math.min(TRACK_WIDTH, h.speed * dt * 0.7 * jitter);
          h.node.style.left = (6 + h.dist) + 'px';
        });

        // kontrola cíle
        const leaders = horses.filter(h=>h.dist >= TRACK_WIDTH);
        if(leaders.length && !finished){
          finished = true;
          const winner = resolveWinner(leaders);
          settleBet(betAmt, pick, winner);
          running = false;
          newRace();
          return;
        }
        if(!finished) requestAnimationFrame(step);
      }
      requestAnimationFrame(step);
    }

    // Rozhodni vítěze při těsném doběhu
    function resolveWinner(candidates){
      // preferuj toho s vyšší formou, ale přidej náhodu
      candidates.sort((a,b)=> b.perf - a.perf);
      const top = candidates[0];
      if(candidates.length===1) return top;
      return Math.random() < 0.7 ? top : candidates[Math.floor(Math.random()*candidates.length)];
    }

    // Vyhodnocení sázky
    function settleBet(amount, pick, winner){
      raceId++;
      const win = (pick.name === winner.name);
      let payout = 0;
      if(win){
        wins++;
        payout = Math.floor(amount * winner.odds);
        bankroll += payout;
        addHistory(`Závod #${raceId}: Výhra na ${pick.name} • Výplata ${payout}`, 'win');
      } else {
        addHistory(`Závod #${raceId}: Prohra. Vítěz ${winner.name}. Ztráta ${amount}`, 'loss');
      }
      updateStats();
    }

    function addHistory(text, cls){
      const entry = document.createElement('div');
      entry.className = cls === 'win' ? 'win' : 'loss';
      entry.textContent = text;
      ui.history.prepend(entry);
    }

    // Start
    newRace();
    updateStats();
  </script>
</body>