Comisiones de técnicos

// lib/services/commission.service.ts
import { Decimal } from 'decimal.js'
import { prisma } from '@/lib/prisma'

export async function calculateCommission(
  businessId: string,
  orderId: string
) {
  const order = await prisma.serviceOrder.findFirst({
    where: { id: orderId, businessId },
    include: {
      parts:      { select: { subtotal: true } },
      technician: { select: { commissionRate: true, commissionType: true } },
    },
  })
  if (!order?.technician) return new Decimal(0)

  const revenue   = new Decimal(order.cost.toString())
  const partsCost = order.parts.reduce(
    (s, p) => s.plus(p.subtotal.toString()),
    new Decimal(0)
  )
  const rate = new Decimal(order.technician.commissionRate.toString())

  // Dos esquemas: sobre cobro bruto o sobre margen neto
  if (order.technician.commissionType === 'GROSS') {
    return revenue.times(rate).dividedBy(100)
  } else {
    const margin = revenue.minus(partsCost)
    return margin.times(rate).dividedBy(100)
  }
}