Enforce ordinary auction bidding deadlines online

components/auction-countdown.tsx

@@ -0,0 +1,44 @@
+'use client';
+
+import { useEffect, useState } from 'react';
+import type { AuctionClockView } from '@/game/auction-clock';
+
+/** Browser time only animates the latest public server frame. It never submits
+ * an auction action or decides that an authoritative deadline has expired. */
+export function AuctionCountdown({ clock, playerName, paused = false }: {
+  clock: AuctionClockView | null;
+  playerName: string;
+  paused?: boolean;
+}) {
+  const [local, setLocal] = useState<{ clock: AuctionClockView; remainingMs: number } | null>(null);
+  const running = !!clock?.event && clock.running && !paused;
+  useEffect(() => {
+    if (!clock || !running || clock.remainingMs <= 0) return;
+    const startedAt = performance.now();
+    const timer = setInterval(() => {
+      const remainingMs = Math.max(0, clock.remainingMs - Math.max(0, performance.now() - startedAt));
+      setLocal({ clock, remainingMs });
+      if (remainingMs === 0) clearInterval(timer);
+    }, 200);
+    return () => clearInterval(timer);
+  }, [clock, running]);
+
+  if (!clock) return null;
+  const remainingMs = running && local?.clock === clock ? local.remainingMs : Math.max(0, clock.remainingMs);
+  const seconds = Math.ceil(remainingMs / 1000);
+  const status = clock.event !== null && seconds === 0
+    ? `${paused ? 'Auction paused. ' : ''}Awaiting server resolution.`
+    : clock.event === null
+      ? `${paused ? 'Auction paused. ' : ''}Clock starts when ordinary bidding is ready.`
+      : paused ? 'Auction paused.'
+        : !clock.running ? 'Bidding clock held while the current game decision finishes.'
+          : `${playerName} may bid or pass.`;
+  return <section className="notice space-y-2" aria-label="Ordinary auction countdown" data-testid="auction-countdown">
+    <output className="block">{status}</output>
+    <p role="timer" aria-live="off" aria-atomic="true" aria-label={`${playerName}’s remaining bidding time`}
+      className="font-semibold tabular-nums">{seconds} {seconds === 1 ? 'second' : 'seconds'} {clock.event === null ? 'available' : 'remaining'}</p>
+    <p className="fine">Ordinary bidding gives each player 10 seconds to bid or pass. The server controls the deadline and resolves expiry.</p>
+    <p className="fine">Online convention: if passing would violate a binding Truthtrance answer, the server submits only the required legal bid.
+      If that bid wins, its normal payment is still owed.</p>
+  </section>;
+}