farmcontrol-api/src/database/tax.js

/**
 * Tax calculation helpers mirroring farmcontrol-ui model value functions.
 */

export function isPopulatedTaxRate(taxRate) {
  return taxRate != null && taxRate.rateType != null;
}

export async function resolveTaxRate(taxRateRef, getObject, taxRateModel) {
  if (!taxRateRef) {
    return null;
  }
  if (isPopulatedTaxRate(taxRateRef)) {
    return taxRateRef;
  }
  const id = taxRateRef._id ?? taxRateRef;
  if (!id) {
    return null;
  }
  if (
    typeof taxRateRef === 'object' &&
    taxRateRef._id &&
    Object.keys(taxRateRef).length === 1
  ) {
    return await getObject({ model: taxRateModel, id, cached: true });
  }
  return await getObject({ model: taxRateModel, id, cached: true });
}

export function amountWithTax(amount, taxRate) {
  const base = Number.parseFloat(amount) || 0;
  if (!base) {
    return 0;
  }
  if (!taxRate) {
    return Number.parseFloat(base.toFixed(2));
  }

  const rate = Number.parseFloat(taxRate.rate) || 0;
  if (taxRate.rateType === 'percentage') {
    return Number.parseFloat((base * (1 + rate / 100)).toFixed(2));
  }
  if (taxRate.rateType === 'amount' || taxRate.rateType === 'fixed') {
    return Number.parseFloat((base + rate).toFixed(2));
  }
  return Number.parseFloat(base.toFixed(2));
}

export function effectiveMarginPrice({ priceMode, price, cost, margin }) {
  if (priceMode === 'margin' && margin != null && cost != null) {
    return cost * (1 + margin / 100);
  }
  return price;
}