feat: one-click shopping list from meal plan, fix ingredient merge bug

- Meal-plan page now has a direct "Add to shopping list" action for the
  currently-viewed week, instead of requiring a trip to Shopping Lists and
  manually typing the week's Monday date.
- Fixed a real under-shopping bug in shopping-lists/route.ts: when
  generating from a meal-plan week, ingredients appearing in more than one
  recipe were merged by keeping only the FIRST occurrence's quantity and
  silently dropping the rest. New mergeIngredients() (pantry-shopping-match.ts)
  groups by ingredientId (or normalized name+unit) and sums quantities
  across every recipe in the week; incompatible/unparseable units are kept
  as separate line items rather than guessed at.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

apps/web/app/(app)/meal-plan/page.tsx

@@ -7,6 +7,7 @@ import { db, mealPlans, mealPlanMembers, recipes, userNutritionGoals, eq, and, d
 import { buttonVariants } from "@/components/ui/button";
 import { MealPlanner } from "@/components/meal-plan/meal-planner";
 import { ShareMealPlanButton } from "@/components/meal-plan/share-meal-plan-button";
+import { NewShoppingListButton } from "@/components/meal-plan/new-shopping-list-button";
 import { WeeklyNutritionBar } from "@/components/nutrition/weekly-nutrition-bar";
 import { cn } from "@/lib/utils";
 import { ExportMarkdownButton } from "@/components/shared/export-markdown-button";
@@ -100,6 +101,10 @@ export default async function MealPlanPage({
         </div>
         <div className="flex flex-wrap items-center gap-2">
           <ShareMealPlanButton weekStart={weekStart} />
+          <NewShoppingListButton
+            defaultWeekStart={weekStart}
+            defaultName={formatMessage(msgs.mealPlan.shoppingListWeekName, { week: label })}
+          />
           <Link href="/shopping-lists" className={cn(buttonVariants({ variant: "outline", size: "sm" }))}>
             <ShoppingCart className="h-4 w-4" />
             {msgs.mealPlan.shoppingLists}

apps/web/app/api/v1/shopping-lists/route.ts

@@ -2,7 +2,7 @@ import { NextRequest, NextResponse } from "next/server";
 import { z } from "zod";
 import { db, shoppingLists, shoppingListItems, mealPlans, mealPlanEntries, recipeIngredients, pantryItems, eq, and, desc, inArray } from "@epicure/db";
 import { requireSession } from "@/lib/api-auth";
-import { applyPantryToItems } from "@/lib/pantry-shopping-match";
+import { applyPantryToItems, mergeIngredients } from "@/lib/pantry-shopping-match";
 
 const CreateSchema = z.object({
   name: z.string().min(1).max(100),
@@ -54,20 +54,10 @@ export async function POST(req: NextRequest) {
           where: inArray(recipeIngredients.recipeId, recipeIds),
         });
 
-        // Simple merge by rawName (case-insensitive)
-        const merged = new Map<string, { rawName: string; quantity?: string; unit?: string; ingredientId: string | null }>();
-        for (const ing of ings) {
-          const key = ing.rawName.toLowerCase();
-          if (!merged.has(key)) {
-            merged.set(key, {
-              rawName: ing.rawName,
-              quantity: ing.quantity ?? undefined,
-              unit: ing.unit ?? undefined,
-              ingredientId: ing.ingredientId,
-            });
-          }
-        }
-        const mergedItems = Array.from(merged.values());
+        // Merge same ingredient across all of the week's recipes, summing quantities
+        // (grouped by ingredientId when available, else normalized name+unit) instead
+        // of listing it once per recipe or dropping every occurrence but the first.
+        const mergedItems = mergeIngredients(ings);
 
         // Reduce/flag quantities already covered by the user's pantry. Conservative: never silently
         // drops an item — fully-covered items are still inserted, flagged `inPantry`, so nothing

apps/web/components/meal-plan/new-shopping-list-button.tsx

@@ -10,15 +10,27 @@ import { Dialog, DialogContent, DialogHeader, DialogTitle } from "@/components/u
 import { Input } from "@/components/ui/input";
 import { Label } from "@/components/ui/label";
 
-export function NewShoppingListButton() {
+export function NewShoppingListButton({
+  defaultWeekStart,
+  defaultName,
+}: {
+  /** Pre-fills and locks the source week, e.g. when generating from the currently-viewed meal-plan week. */
+  defaultWeekStart?: string;
+  defaultName?: string;
+}) {
   const t = useTranslations("mealPlan");
   const tCommon = useTranslations("common");
   const router = useRouter();
   const [open, setOpen] = useState(false);
-  const [name, setName] = useState("");
-  const [weekStart, setWeekStart] = useState("");
+  const [name, setName] = useState(defaultName ?? "");
+  const [weekStart, setWeekStart] = useState(defaultWeekStart ?? "");
   const [saving, setSaving] = useState(false);
 
+  function openDialog() {
+    if (defaultWeekStart) { setName(defaultName ?? ""); setWeekStart(defaultWeekStart); }
+    setOpen(true);
+  }
+
   async function create() {
     if (!name.trim()) return;
     setSaving(true);
@@ -44,8 +56,9 @@ export function NewShoppingListButton() {
 
   return (
     <>
-      <Button size="sm" onClick={() => setOpen(true)}>
-        <Plus className="h-4 w-4" /> {t("newList")}
+      <Button size="sm" onClick={openDialog} variant={defaultWeekStart ? "outline" : "default"}>
+        {defaultWeekStart ? <ShoppingCart className="h-4 w-4" /> : <Plus className="h-4 w-4" />}
+        {defaultWeekStart ? t("generateFromThisWeek") : t("newList")}
       </Button>
       <Dialog open={open} onOpenChange={setOpen}>
         <DialogContent className="max-w-md">
@@ -55,11 +68,16 @@ export function NewShoppingListButton() {
               <Label>{t("listNameLabel")}</Label>
               <Input value={name} onChange={(e) => setName(e.target.value)} placeholder={t("listNamePlaceholder")} />
             </div>
-            <div className="space-y-2">
-              <Label>{t("generateFromWeek")}</Label>
-              <Input type="date" value={weekStart} onChange={(e) => setWeekStart(e.target.value)} />
-              <p className="text-xs text-muted-foreground">{t("generateFromWeekHint")}</p>
-            </div>
+            {!defaultWeekStart && (
+              <div className="space-y-2">
+                <Label>{t("generateFromWeek")}</Label>
+                <Input type="date" value={weekStart} onChange={(e) => setWeekStart(e.target.value)} />
+                <p className="text-xs text-muted-foreground">{t("generateFromWeekHint")}</p>
+              </div>
+            )}
+            {defaultWeekStart && (
+              <p className="text-xs text-muted-foreground">{t("generateFromThisWeekHint")}</p>
+            )}
             <div className="flex gap-2 justify-end">
               <Button variant="outline" onClick={() => setOpen(false)}>{tCommon("cancel")}</Button>
               <Button onClick={create} disabled={!name.trim() || saving}>{saving ? t("listCreating") : t("listCreate")}</Button>

apps/web/lib/pantry-shopping-match.ts

@@ -33,17 +33,17 @@ export type PantryAdjustedItem = {
   inPantry: boolean;
 };
 
-function normalizeName(name: string): string {
+export function normalizeName(name: string): string {
   const trimmed = name.toLowerCase().trim().replace(/\s+/g, " ");
   // Simple plural trim — strip a single trailing "s" for words longer than 3 chars.
   return trimmed.length > 3 && trimmed.endsWith("s") ? trimmed.slice(0, -1) : trimmed;
 }
 
-function normalizeUnit(unit: string | null | undefined): string {
+export function normalizeUnit(unit: string | null | undefined): string {
   return (unit ?? "").toLowerCase().trim();
 }
 
-function formatQuantity(n: number): string {
+export function formatQuantity(n: number): string {
   return Number.isInteger(n) ? String(n) : n.toFixed(2).replace(/\.?0+$/, "");
 }
 
@@ -108,3 +108,60 @@ export function applyPantryToItems(
     return { rawName: item.rawName, quantity: item.quantity, unit: item.unit, inPantry: true };
   });
 }
+
+export type MergeSourceIngredient = {
+  rawName: string;
+  quantity: string | null;
+  unit: string | null;
+  ingredientId: string | null;
+};
+
+export type MergedIngredient = {
+  rawName: string;
+  quantity?: string;
+  unit?: string;
+  ingredientId: string | null;
+};
+
+/**
+ * Merges ingredients across recipes (e.g. an entire week's meal plan) so a shopping
+ * list doesn't show the same ingredient once per recipe. Groups by normalized
+ * ingredientId (if present) or normalized name+unit, then SUMS quantities across the
+ * group — the earlier version of this logic kept only the first occurrence and
+ * silently dropped every other recipe's requirement, which under-shopped whenever the
+ * same ingredient appeared in more than one recipe.
+ *
+ * Items with the same name but incompatible/unparseable units are kept as separate
+ * line items rather than guessed at — never invent a converted total.
+ */
+export function mergeIngredients(ingredients: MergeSourceIngredient[]): MergedIngredient[] {
+  const groups = new Map<string, { rawName: string; ingredientId: string | null; unit: string | null; entries: (string | null)[] }>();
+
+  for (const ing of ingredients) {
+    const unitKey = normalizeUnit(ing.unit);
+    const groupKey = ing.ingredientId
+      ? `id:${ing.ingredientId}:${unitKey}`
+      : `name:${normalizeName(ing.rawName)}:${unitKey}`;
+
+    let group = groups.get(groupKey);
+    if (!group) {
+      group = { rawName: ing.rawName, ingredientId: ing.ingredientId, unit: ing.unit, entries: [] };
+      groups.set(groupKey, group);
+    }
+    group.entries.push(ing.quantity);
+  }
+
+  return Array.from(groups.values()).map((group) => {
+    const parsed = group.entries.map((q) => (q ? parseFloat(q) : NaN));
+    const allParseable = parsed.length > 0 && parsed.every((n) => !isNaN(n));
+
+    if (allParseable) {
+      const total = parsed.reduce((sum, n) => sum + n, 0);
+      return { rawName: group.rawName, quantity: formatQuantity(total), unit: group.unit ?? undefined, ingredientId: group.ingredientId };
+    }
+
+    // Unparseable or mixed with/without quantity — can't sum reliably, don't guess.
+    // Fall back to no quantity shown rather than an incorrect total.
+    return { rawName: group.rawName, quantity: undefined, unit: group.unit ?? undefined, ingredientId: group.ingredientId };
+  });
+}

apps/web/messages/en.json

@@ -699,6 +699,9 @@
     "listNamePlaceholder": "Weekly groceries",
     "generateFromWeek": "Generate from meal plan week (optional)",
     "generateFromWeekHint": "Picks Monday of the selected week",
+    "generateFromThisWeek": "Add to shopping list",
+    "generateFromThisWeekHint": "Merges every recipe's ingredients from this week, summing matching ones and flagging what's already in your pantry.",
+    "shoppingListWeekName": "Groceries for {week}",
     "listCreateFailed": "Failed to create",
     "listCreating": "Creating…",
     "listCreate": "Create",

apps/web/messages/fr.json

@@ -687,6 +687,9 @@
     "listNamePlaceholder": "Courses de la semaine",
     "generateFromWeek": "Générer depuis une semaine du planning (facultatif)",
     "generateFromWeekHint": "Sélectionne le lundi de la semaine choisie",
+    "generateFromThisWeek": "Ajouter à la liste de courses",
+    "generateFromThisWeekHint": "Fusionne les ingrédients de toutes les recettes de cette semaine, additionne les quantités identiques et signale ce que vous avez déjà au garde-manger.",
+    "shoppingListWeekName": "Courses pour {week}",
     "listCreateFailed": "Échec de la création",
     "listCreating": "Création…",
     "listCreate": "Créer",