Vibed it... :(

backend/models/UserSelection.js

@@ -0,0 +1,55 @@
+const mongoose = require('mongoose');
+
+const userSelectionSchema = new mongoose.Schema({
+  userId: {
+    type: mongoose.Schema.Types.ObjectId,
+    ref: 'User',
+    required: true
+  },
+  selectedRecipes: [{
+    recipeId: {
+      type: mongoose.Schema.Types.ObjectId,
+      ref: 'Recipe',
+      required: true
+    },
+    quantity: {
+      type: Number,
+      default: 1,
+      min: 1
+    },
+    addedAt: {
+      type: Date,
+      default: Date.now
+    }
+  }],
+  aggregatedIngredients: [{
+    name: String,
+    totalAmount: Number,
+    unit: String,
+    recipes: [{
+      recipeId: {
+        type: mongoose.Schema.Types.ObjectId,
+        ref: 'Recipe'
+      },
+      recipeTitle: String,
+      amount: Number,
+      quantity: Number // recipe quantity multiplier
+    }]
+  }],
+  createdAt: {
+    type: Date,
+    default: Date.now
+  },
+  updatedAt: {
+    type: Date,
+    default: Date.now
+  }
+});
+
+// Update the updatedAt field before saving
+userSelectionSchema.pre('save', function(next) {
+  this.updatedAt = Date.now();
+  next();
+});
+
+module.exports = mongoose.model('UserSelection', userSelectionSchema);