Delivered status records delivery date/time

Without a deliveredAt timestamp, any query for fulfillment metrics — average time from ship to delivery, on-time delivery rate, SLA compliance — becomes impossible or relies on updatedAt, which gets overwritten by post-delivery events like refund requests. If the customer contacts support asking when their package arrived, the platform has no answer beyond 'the carrier said so'. Capturing delivery time at the moment the status transitions is a one-line write that prevents a permanent data gap — a gap that can never be filled after the fact.

Add a nullable deliveredAt column to your order model in prisma/schema.prisma and populate it in lib/orders/state-machine.ts alongside other lifecycle timestamps.

// prisma/schema.prisma addition:
// deliveredAt DateTime?

// In transitionOrder (lib/orders/state-machine.ts):
const timestampFields: Record<string, Date> = {}
if (newStatus === 'delivered') timestampFields.deliveredAt = new Date()
if (newStatus === 'shipped')   timestampFields.shippedAt   = new Date()
if (newStatus === 'confirmed') timestampFields.confirmedAt = new Date()
if (newStatus === 'cancelled') timestampFields.cancelledAt = new Date()

await db.orders.update({ where: { id: orderId }, data: { status: newStatus, ...timestampFields } })