const fs = require("fs");

function shipOrder(filePath, orderId, destinationCountry) {
  const raw = fs.readFileSync(filePath, "utf8");
  const state = JSON.parse(raw);
  const order = state.orders.find((item) => item.id === orderId);

  if (!order) {
    throw new Error("Order not found");
  }

  if (order.status === "shipped") {
    return { message: "Already shipped", trackingNumber: order.trackingNumber };
  }

  let shippingCost = 5;

  if (destinationCountry !== "US") {
    shippingCost = shippingCost + 15;
  }

  if (order.weightKg > 10) {
    shippingCost = shippingCost + 20;
  }

  order.status = "shipped";
  order.shippingCost = shippingCost;
  order.trackingNumber = "trk-" + Math.floor(Math.random() * 100000);
  order.shippedAt = new Date().toISOString();

  fs.writeFileSync(filePath, JSON.stringify(state, null, 2));
  console.log("Order shipped", orderId);

  return { message: "Shipped", trackingNumber: order.trackingNumber, shippingCost };
}

module.exports = { shipOrder };