// The host adapter must return a completed receipt only after its rewarded-ad
// success callback. No ad SDK or network service is bundled with this prototype.
export async function requestReward(game, provider, isCurrent = () => true) {
  if (game.rewardPending || game.won || game.deadlocked || !isCurrent()) return { status: 'unavailable' };
  game.rewardPending = true;
  try {
    const receipt = await provider({ levelId: game.level.id, steps: game.level.reward.steps });
    if (!isCurrent()) return { status: 'stale' };
    return { status: game.grantReward(receipt) ? 'granted' : 'cancelled' };
  } catch { return { status: 'failed' }; }
  finally { game.rewardPending = false; }
}