Build a Rewards Experience

const SNAPPY = "https://api.snappy.com/public-api";

const headers = {
  "X-Api-Key": process.env.SNAPPY_API_KEY,
  "Content-Type": "application/json",
  // Optional but appreciated — tells us how the call was made.
  "Request-Source": "api_native",
};

async function fetchCollection(collectionId, { location = "US" } = {}) {
  const products = [];
  let cursor = null;

  do {
    const url = new URL(`${SNAPPY}/v3/collections/${collectionId}/products`);
    url.searchParams.set("location", location);      // ISO 3166-1 alpha-2
    url.searchParams.set("include", "brand,tags");   // hydrate brand + tags
    url.searchParams.set("fields", "priceRange,variantsCount");
    url.searchParams.set("page[size]", "100");       // 1–300, default 100
    if (cursor) url.searchParams.set("page[cursor]", cursor);

    const res = await fetch(url, { headers });
    if (!res.ok) throw new Error(`Snappy ${res.status}`);
    const body = await res.json();

    products.push(...body.data);
    cursor = body.links?.next
      ? new URL(body.links.next).searchParams.get("page[cursor]")
      : null;
  } while (cursor);

  return products;
}

// You own this number. 100 points = $1 is easy to reason about.
const POINTS_PER_DOLLAR = 100;

const toPoints = (usd) => Math.round(usd * POINTS_PER_DOLLAR);
const toDollars = (points) => points / POINTS_PER_DOLLAR;

// Show every product's cost in points:
const pointsCost = toPoints(product.priceRange.min.amount);

const balancePoints = user.pointsBalance;          // e.g. 12,450
const maxBudgetUsd = toDollars(balancePoints);      // 124.50

const url = new URL(`${SNAPPY}/v3/collections/${collectionId}/products`);
url.searchParams.set("filter[price][lte]", maxBudgetUsd.toFixed(2));
// Optionally hide the truly tiny stuff so the page feels aspirational:
url.searchParams.set("filter[price][gte]", "15");

async function fetchTags(search) {
  const url = new URL(`${SNAPPY}/v2/products/tags`);
  if (search) url.searchParams.set("title", search); // min 3 chars
  url.searchParams.set("limit", "100");
  const res = await fetch(url, { headers });
  const { results } = await res.json();
  return results; // [{ id, name }, ...]
}

// Your own mapping from a friendly interest to Snappy tag names.
const INTERESTS = {
  "Wellness & Self-Care": ["Wellness", "Beauty", "Fitness"],
  "Travel & Adventure":   ["Travel", "Outdoors"],
  "Food & Dining":        ["Food", "Drinkware", "Kitchen"],
  "Home & Living":        ["Home & Kitchen", "Decor"],
};

async function buildRail(collectionId, interest, maxBudgetUsd) {
  const url = new URL(`${SNAPPY}/v3/collections/${collectionId}/products`);
  url.searchParams.set("include", "brand,tags");
  url.searchParams.set("filter[price][lte]", maxBudgetUsd.toFixed(2));
  url.searchParams.set("page[size]", "12");
  const res = await fetch(url, { headers });
  const { data } = await res.json();

  // Keep products whose tags intersect the interest's tag names.
  const wanted = new Set(INTERESTS[interest]);
  return data.filter((p) => (p.tags ?? []).some((t) => wanted.has(t.name)));
}

async function searchCatalog(collectionId, { query, type, sort, cursor } = {}) {
  const url = new URL(`${SNAPPY}/v3/collections/${collectionId}/products`);
  url.searchParams.set("include", "brand,tags");
  url.searchParams.set("page[size]", "48");
  if (query)  url.searchParams.set("filter[title]", query);
  if (type)   url.searchParams.set("filter[types]", type);   // e.g. "physical"
  if (sort)   url.searchParams.set("sort", sort);            // e.g. "minPrice"
  if (cursor) url.searchParams.set("page[cursor]", cursor);

  const res = await fetch(url, { headers });
  const body = await res.json();
  return {
    items: body.data,
    nextCursor: body.links?.next
      ? new URL(body.links.next).searchParams.get("page[cursor]")
      : null,
  };
}

async function fetchProduct(productId) {
  const url = new URL(`${SNAPPY}/v3/products/${productId}`);
  url.searchParams.set("include", "brand,tags");
  url.searchParams.set("fields", "full"); // expand media + variants
  const res = await fetch(url, { headers });
  return res.json();
}

// Given the user's picks ({ Color: "Black", Size: "L" }), find the variant.
function resolveVariant(product, selection) {
  return product.variants.find((v) =>
    Object.entries(selection).every(([level, value]) => v.options[level] === value)
  );
}

const variant = resolveVariant(product, { Color: "Black", Size: "L" });
// variant.id is what you'll send to checkout.
// Disable option combinations where availability !== "available".

// Debounce on the client; call this from your backend.
async function autocompleteAddress(partial, country = "US") {
  const url = new URL(`${SNAPPY}/v2/orders/addresses/autocomplete`);
  url.searchParams.set("address", partial);  // 4–128 chars
  url.searchParams.set("country", country);
  const res = await fetch(url, { headers });
  const { results } = await res.json();
  return results; // [{ addressLine1, addressLine2?, city, state, zipcode }, ...]
}

async function placeOrder({ variantId, recipient, idempotencyKey }) {
  const res = await fetch(`${SNAPPY}/v2/orders`, {
    method: "POST",
    headers,
    body: JSON.stringify({
      accountId: process.env.SNAPPY_ACCOUNT_ID,
      fundingSourceId: process.env.SNAPPY_FUNDING_SOURCE_ID,
      variantId,
      tags: ["rewards-store"],          // optional: for your reporting
      recipient: {
        firstname: recipient.firstName,
        lastname: recipient.lastName,
        email: recipient.email,
        key: idempotencyKey,            // permanent idempotency key — see below
        shippingAddress: {
          line1: recipient.line1,
          line2: recipient.line2,       // optional
          city: recipient.city,
          state: recipient.state,
          zip: recipient.zip,
          country: recipient.country,   // ISO 3166-1 alpha-2
        },
      },
    }),
  });

  if (!res.ok) return handleOrderError(res);   // see error handling below
  const { result } = await res.json();
  return result; // { orderId, status: "processing", trackingLink }
}

// Express handler for Snappy order webhooks.
app.post("/webhooks/snappy", (req, res) => {
  const { event, data } = req.body;
  if (event.startsWith("order-")) {
    updateOrderStatus(data.orderId, data.status);     // your DB
    if (data.status === "shipped") {
      notifyUser(data.orderId, data.trackingLink);    // your email/push
    }
  }
  res.sendStatus(200); // acknowledge fast
});