utils/orderUtils.js

const Product = require('../models/productModel');

/**
 * Restore stock for a group of items (usually from a cancelled order)
 * @param {Array} items - Array of order items with product and quantity
 */
const restoreOrderStock = async (items) => {
  const bulkOps = items
    .filter((item) => item.product)
    .map((item) => {
      const productId = item.product._id || item.product;
      return {
        updateOne: {
          filter: { _id: productId },
          update: { $inc: { stock: item.quantity } },
        },
      };
    });

  if (bulkOps.length > 0) {
    await Product.bulkWrite(bulkOps);
  }
};

/**
 * Deduct stock for a group of items (usually for a new order)
 * @param {Array} items - Array of order items with product and quantity
 */
const deductOrderStock = async (items) => {
  const bulkOps = items
    .filter((item) => item.product)
    .map((item) => {
      const productId = item.product._id || item.product;
      return {
        updateOne: {
          filter: { _id: productId },
          update: { $inc: { stock: -item.quantity } },
        },
      };
    });

  if (bulkOps.length > 0) {
    await Product.bulkWrite(bulkOps);
  }
};

module.exports = {
  restoreOrderStock,
  deductOrderStock,
};