Create cart → Add items → Update quantity → Apply discount code → Create order

const cart = await client.from('carts').create({
  customer: customerId,  // omit for guest
  status: 'active'
})

await client.from('cart-items').create({
  cart: cartId,
  product: productId,
  variant: variantId,
  option: optionId,
  quantity: 2,
  unitPrice: 39000
})

// Cart items
const { docs: items } = await client.from('cart-items').find({
  where: { cart: { equals: cartId } },
  depth: 1  // includes product, variant, option info
})

// Cart totals
const cart = await client.from('carts').findById(cartId)
// cart.itemsTotal     → items subtotal (auto-calculated)
// cart.shippingFee    → shipping fee
// cart.discountAmount → discount amount
// cart.totalAmount    → final amount (auto-calculated)

// Update quantity
await client.from('cart-items').update(itemId, {
  quantity: 3
})

// Remove item
await client.from('cart-items').delete(itemId)

// 1. Validate code
const { docs } = await client.from('discounts').find({
  where: {
    code: { equals: 'WELCOME10' },
    isActive: { equals: true },
    endsAt: { greater_than: new Date().toISOString() }
  }
})

if (docs.length === 0) {
  // Invalid code
}

// 2. Apply to cart
await client.from('carts').update(cartId, {
  discountCode: 'WELCOME10'
})

// 3. Check discounted amount
const updated = await client.from('carts').findById(cartId)
// updated.discountAmount → discount amount
// updated.totalAmount    → final amount after discount

// 1. Complete cart
await client.from('carts').update(cartId, {
  status: 'completed'
})

// 2. Create order from cart
const order = await client.from('orders').create({
  customer: customerId,
  cart: cartId,
  shippingAddress: {
    recipientName: 'John Doe',
    phone: '010-1234-5678',
    postalCode: '06123',
    address1: '123 Main St',
    address2: 'Apt 4B'
  }
})