Add separate base cost and margin pricing formulas

src/app/[locale]/order/item/[id]/form.tsx

@@ -26,7 +26,7 @@ import { Product } from "@/db/schema";
 import { MinusIcon, PlusIcon } from "@heroicons/react/24/solid";
 import { useMemo, useState } from "react";
 import { debounce } from "radash";
-import { calculateItemPrice } from "@/utils/pricing";
+import { calculateItemPricing } from "@/utils/pricing";
 
 const Files = dynamic(() => import("./files/files"), {
   ssr: false,
@@ -83,7 +83,7 @@ const Form = ({ session, initialCart, itemId, product }: Props) => {
       pieces: quantity,
     },
   };
-  const computedPrice = calculateItemPrice(product, previewItem);
+  const computedPrice = calculateItemPricing(product, previewItem).price;
 
   return (
     <>

src/app/[locale]/order/items.tsx

@@ -16,7 +16,7 @@ import {
   Tooltip,
 } from "@radix-ui/themes";
 import { useFormatter, useLocale, useTranslations } from "next-intl";
-import { calculateItemPrice } from "@/utils/pricing";
+import { calculateItemPricing } from "@/utils/pricing";
 
 type Props = {
   cart: ShoppingCart;
@@ -46,7 +46,7 @@ const OrderItems = ({ cart: initialCart, products }: Props) => {
           (product) => product.id === item.productId
         );
         const itemPrice =
-          item.price ?? (product ? calculateItemPrice(product, item) : 0);
+          item.price ?? (product ? calculateItemPricing(product, item).price : 0);
 
         return (
           <Flex

src/db/validation.ts

@@ -121,11 +121,23 @@ export const productSchema = z.object({
 
   pricing: z
     .object({
+      baseCostFormula: z
+        .string()
+        .optional()
+        .describe(
+          "Base cost formula. Supports numbers, variables, +, -, *, /, ^ and parentheses. Example: size.area * 0.02 + files.totalPieces * 0.1 + configTotals.cost",
+        ),
+      marginFormula: z
+        .string()
+        .optional()
+        .describe(
+          "Margin formula. Supports numbers, variables, +, -, *, /, ^ and parentheses. Example: size.area * 0.01 + files.totalPieces * 0.05 + configTotals.margin",
+        ),
       formula: z
         .string()
         .optional()
         .describe(
-          "Pricing formula. Supports numbers, variables, +, -, *, /, ^ and parentheses. Example: size.area * 0.02 + files.totalPieces * 0.1 + configTotals.cost",
+          "Legacy total price formula kept for backward compatibility. Prefer baseCostFormula and marginFormula.",
         ),
     })
     .optional()
@@ -171,8 +183,12 @@ export const orderItemSchema = z.object({
   id: z.string(),
   productId: z.string(),
   price: z.number().optional(),
+  baseCost: z.number().optional(),
+  margin: z.number().optional(),
   pricing: z
     .object({
+      baseCostFormula: z.string().optional(),
+      marginFormula: z.string().optional(),
       formula: z.string().optional(),
     })
     .optional(),

src/hooks/useCart/actions.ts

@@ -9,7 +9,7 @@ import {
   ShoppingCart,
 } from "@/db/validation";
 import { createThumbnail } from "@/utils/thumbnail";
-import { calculateItemPrice } from "@/utils/pricing";
+import { calculateItemPricing } from "@/utils/pricing";
 import { eq } from "drizzle-orm";
 import { DateTime } from "luxon";
 import { cookies } from "next/headers";
@@ -615,6 +615,14 @@ const hydrateItemPricing = async (
     .limit(1);
   if (!product) return;
 
-  item.pricing = { formula: product.pricing?.formula };
-  item.price = calculateItemPrice(product, item);
+  const pricing = calculateItemPricing(product, item);
+
+  item.pricing = {
+    baseCostFormula: product.pricing?.baseCostFormula,
+    marginFormula: product.pricing?.marginFormula,
+    formula: product.pricing?.formula,
+  };
+  item.baseCost = pricing.baseCost;
+  item.margin = pricing.margin;
+  item.price = pricing.price;
 };

src/utils/pricing.ts

@@ -183,14 +183,14 @@ export const evaluatePriceFormula = (formula: string, context: unknown) => {
   return semantics(match).eval(context);
 };
 
-export const calculateItemPrice = (
-  product: Product,
-  item: Partial<OrderItemPayload>
-) => {
-  const formula = product.pricing?.formula;
-  if (!formula) return 0;
+export type ItemPricingBreakdown = {
+  baseCost: number;
+  margin: number;
+  price: number;
+};
 
-  const context = buildPriceContext(product, item);
+const evaluateFormulaSafely = (formula: string | undefined, context: unknown) => {
+  if (!formula) return 0;
 
   try {
     const result = evaluatePriceFormula(formula, context);
@@ -200,3 +200,52 @@ export const calculateItemPrice = (
     return 0;
   }
 };
+
+export const calculateItemPricing = (
+  product: Product,
+  item: Partial<OrderItemPayload>
+): ItemPricingBreakdown => {
+  const baseCostFormula = product.pricing?.baseCostFormula;
+  const marginFormula = product.pricing?.marginFormula;
+  const legacyFormula = product.pricing?.formula;
+
+  const context = buildPriceContext(product, item);
+
+  if (baseCostFormula || marginFormula) {
+    const baseCost = evaluateFormulaSafely(baseCostFormula, context);
+    const margin = evaluateFormulaSafely(marginFormula, {
+      ...context,
+      pricing: { baseCost },
+    });
+
+    return {
+      baseCost,
+      margin,
+      price: baseCost + margin,
+    };
+  }
+
+  if (legacyFormula) {
+    const legacyPrice = evaluateFormulaSafely(legacyFormula, context);
+    return {
+      // Legacy formulas only define total price; we keep margin at 0 to avoid
+      // inventing profit data and treat the total as production cost.
+      baseCost: legacyPrice,
+      margin: 0,
+      price: legacyPrice,
+    };
+  }
+
+  return {
+    baseCost: 0,
+    margin: 0,
+    price: 0,
+  };
+};
+
+export const calculateItemPrice = (
+  product: Product,
+  item: Partial<OrderItemPayload>
+) => {
+  return calculateItemPricing(product, item).price;
+};