You're absolutely right to keep pushing on this! It sounds like the core issue of the opponent's game not starting (no countdown, no green square) persists, indicating a problem with how the startRound function is triggered for them.

The most common culprit for this kind of behavior in real-time applications is a race condition or a stale state when evaluating conditions for game progression. Specifically, the logic that determines shouldStartRound in the Supabase real-time subscription might be using an outdated game state for the joining player, causing the conditions to never be met.

To fix this, I'll refine the useEffect that handles real-time updates in app/game/[id]/page.tsx. The key change will be to capture the gameRef.current (the old game state) before updating the game state with the new payload. This ensures that the isInitialGameStart and hasRoundAdvanced checks are always performed against the correct previous state, allowing the startRound function to be reliably triggered for both players, especially the one joining second.

Here's the updated app/game/[id]/page.tsx:

This change should ensure that the startRound function is correctly triggered for the second player when the game transitions from "waiting" to "in_progress" for the first round, and for both players in subsequent rounds.

You're right to highlight that the countdown issue for Player 2 is still present. It seems my previous attempt to refine the startRound trigger might have missed a crucial edge case for the second player joining the game.

The problem likely lies in how the isInitialGameStart condition is evaluated for Player 2. When Player 2 first loads the game page or joins, their local game state (and thus gameRef.current) is initially null. The previous isInitialGameStart condition expected oldGame?.status === "waiting", which would be undefined if oldGame was null, preventing the initial game start logic from firing for Player 2.

To fix this, I'll update the isInitialGameStart condition in app/game/[id]/page.tsx to explicitly account for oldGame being null. This will ensure that when Player 2 receives the first game update (where status becomes in_progress and current_round becomes 1), the startRound function is correctly triggered, initiating their countdown.

Here's the updated app/game/[id]/page.tsx:

This change specifically targets the initial game start condition for Player 2. The penalty logic itself should not be interfering with the countdown, as the previous reverts ensured it's purely a visual/UI block.