Function checkRateLimit

packages/billing/src/subscription.ts:454–547

(params: {
  userId: string
  subscription: SubscriptionRow
  logger: Logger
  conn?: DbConn
})

 * - **Weekly**: billing-aligned weekly cap
 */
export async function checkRateLimit(params: {
  userId: string
  subscription: SubscriptionRow
  logger: Logger
  conn?: DbConn
}): Promise<RateLimitStatus> {
  const { userId, subscription, logger, conn = db } = params
  const now = new Date()

  const limits = await getSubscriptionLimits({
    userId,
    logger,
    conn,
    tier: subscription.tier,
  })

  const weekly = await getWeeklyUsage({
    userId,
    billingPeriodStart: subscription.billing_period_start,
    weeklyCreditsLimit: limits.weeklyCreditsLimit,
    logger,
    conn,
  })

  // Weekly limit takes precedence
  if (weekly.used >= weekly.limit) {
    return {
      limited: true,
      reason: 'weekly_limit',
      canStartNewBlock: false,
      weeklyUsed: weekly.used,
      weeklyLimit: weekly.limit,
      weeklyResetsAt: weekly.resetsAt,
      weeklyPercentUsed: weekly.percentUsed,
    }
  }

  // Find most recent active subscription block grant for this user
  const blocks = await conn
    .select()
    .from(schema.creditLedger)
    .where(
      and(
        eq(schema.creditLedger.user_id, userId),
        eq(schema.creditLedger.type, 'subscription'),
        gt(schema.creditLedger.expires_at, now),
      ),
    )
    .orderBy(desc(schema.creditLedger.created_at))
    .limit(1)

  const currentBlock = blocks[0]

  // No active block → can start a new one
  if (!currentBlock) {
    return {
      limited: false,
      canStartNewBlock: true,