feat: create scavenger and handle kind 9735

src/utils/scavenger.ts

@@ -0,0 +1,48 @@
+import { NostrEvent, NSchema as n } from '@nostrify/nostrify';
+import { Kysely } from 'kysely';
+import { z } from 'zod';
+
+import { DittoTables } from '@/db/DittoTables.ts';
+import { getAmount } from '@/utils/bolt11.ts';
+
+interface ScavengerEventOpts {
+  savedEvent: Promise<NostrEvent | undefined>;
+  kysely: Kysely<DittoTables>;
+}
+
+/** Consumes the event already stored in the database and uses it to insert into a new custom table, if eligible.
+ * Scavenger is organism that eats dead or rotting biomass, such as animal flesh or plant material. */
+async function scavengerEvent({ savedEvent, kysely }: ScavengerEventOpts): Promise<void> {
+  const event = await savedEvent;
+  if (!event) return;
+
+  switch (event.kind) {
+    case 9735:
+      await handleEvent9735(kysely, event);
+      break;
+  }
+}
+
+async function handleEvent9735(kysely: Kysely<DittoTables>, event: NostrEvent) {
+  const zapRequestString = event?.tags?.find(([name]) => name === 'description')?.[1];
+  if (!zapRequestString) return;
+  const zapRequest = n.json().pipe(n.event()).optional().catch(undefined).parse(zapRequestString);
+  if (!zapRequest) return;
+
+  const amountSchema = z.coerce.number().int().nonnegative().catch(0);
+  const amount_millisats = amountSchema.parse(getAmount(event?.tags.find(([name]) => name === 'bolt11')?.[1]));
+  if (!amount_millisats || amount_millisats < 1) return;
+
+  const zappedEventId = zapRequest.tags.find(([name]) => name === 'e')?.[1];
+  if (!zappedEventId) return;
+
+  await kysely.insertInto('event_zaps').values({
+    receipt_id: event.id,
+    target_event_id: zappedEventId,
+    sender_pubkey: zapRequest.pubkey,
+    amount_millisats,
+    comment: zapRequest.content,
+  }).execute();
+}
+
+export { scavengerEvent };