Back-in-stock notifications

// src/lists/restock.ts
import { defineList } from "@hogsend/engine";

const restockList = (sku: string, productName: string) =>
  defineList({
    id: `restock-${sku}`,
    name: `Back in stock — ${productName}`,
    description: `One email when ${productName} is available again.`,
    defaultOptIn: false, // opt-in: only people who pressed "notify me"
  });

export const restockLists = [
  restockList("chair-01", "Studio chair"),
  restockList("desk-02", "Standing desk"),
];

// storefront server — the "notify me" button
await hs.events.send({
  name: "product.waitlisted",
  email: shopper.email,
  userId: shopper.id,
  eventProperties: { sku, product_name: product.name },
  lists: { [`restock-${sku}`]: true }, // the event and the opt-in, one call
  idempotencyKey: `waitlist-${shopper.id}-${sku}`,
});

// order placed — buyers stop being waiters
await hs.events.send({
  name: "order.completed",
  userId: shopper.id,
  eventProperties: { order_id: order.id },
  lists: Object.fromEntries(
    order.items.map((item) => [`restock-${item.sku}`, false]),
  ),
});

// src/webhook-sources/inventory.ts
import { defineWebhookSource } from "@hogsend/engine";
import { z } from "zod";
import { Events } from "../journeys/constants/index.js";

const restockSchema = z.object({
  delivery_id: z.string(),
  type: z.string(),
  sku: z.string(),
  product_name: z.string(),
  quantity: z.number(),
});

export const inventorySource = defineWebhookSource({
  meta: {
    id: "inventory",
    name: "Inventory",
    description: "Restock signals from the warehouse system.",
  },
  auth: {
    type: "signature", // fails closed when the secret is unset
    scheme: "hmac-hex",
    envKey: "INVENTORY_WEBHOOK_SECRET",
    header: "x-signature",
  },
  schema: restockSchema,
  async transform(payload) {
    if (payload.type !== "restock" || payload.quantity === 0) return null;

    return {
      event: Events.PRODUCT_RESTOCKED, // "product.restocked" — the routing key
      userEmail: "", // a system event — no user attached
      eventProperties: {
        sku: payload.sku,
        product_name: payload.product_name,
        quantity: payload.quantity,
        source: "inventory",
      },
      idempotencyKey: payload.delivery_id, // a redelivery is a no-op
    };
  },
});

// src/workflows/restock-broadcast.ts
import { hatchet } from "@hogsend/engine";
import { Events, Templates } from "../journeys/constants/index.js";
import { hs } from "../lib/hogsend.js";

export const restockBroadcastTask = hatchet.durableTask({
  name: "restock-broadcast",
  onEvents: [Events.PRODUCT_RESTOCKED],
  retries: 2,
  executionTimeout: "10m",
  fn: async (input: {
    properties: Record<string, string | number | boolean | null>;
  }) => {
    const sku = String(input.properties.sku ?? "");
    const productName = String(input.properties.product_name ?? "");
    if (!sku) return { status: "skipped", reason: "missing_sku" };

    // One campaign per SKU per day, however many times the task retries
    // or the warehouse re-fires.
    const date = new Date().toISOString().slice(0, 10);
    const { campaignId } = await hs.campaigns.send({
      list: `restock-${sku}`,
      template: Templates.ECOMMERCE_BACK_IN_STOCK, // "ecommerce/back-in-stock"
      props: { sku, productName },
      subject: `${productName} is back in stock`,
      idempotencyKey: `restock-${sku}-${date}`,
    });

    return { status: "queued", campaignId, sku };
  },
});

// src/lists/index.ts — spread the restock lists into your lists array
export const lists = [productUpdates, ...restockLists];

// src/webhook-sources/index.ts
export const webhookSources: DefinedWebhookSource[] = [
  posthogSource,
  inventorySource,
];

// src/workflows/index.ts
export const extraWorkflows = [restockBroadcastTask];