Add app package

packages/app/src/zappers.ts

@@ -0,0 +1,57 @@
+import {writable, derived} from 'svelte/store'
+import {withGetter} from '@welshman/store'
+import type {Zapper} from '@welshman/util'
+import {uniq, bech32ToHex, indexBy, tryCatch, uniqBy, batcher, postJson} from '@welshman/lib'
+import {env} from './core'
+import {collection} from './collection'
+import {profilesByPubkey} from './profiles'
+
+export const zappers = withGetter(writable<Zapper[]>([]))
+
+export const zappersByPubkey = derived([profilesByPubkey, zappers], ([$profilesByPubkey, $zappers]) =>
+  indexBy(
+    $zapper => $zapper.pubkey,
+    $zappers.filter($zapper => $zapper.pubkey && $profilesByPubkey.get($zapper.pubkey)?.lnurl === $zapper.lnurl),
+  ),
+)
+
+export const fetchZappers = (lnurls: string[]) => {
+  const base = env.DUFFLEPUD_URL!
+
+  if (!base) {
+    throw new Error("DUFFLEPUD_URL is required to fetch zapper info")
+  }
+
+  const res: any = postJson(`${base}/zapper/info`, {lnurls: lnurls.map(bech32ToHex)})
+  const zappersByLnurl = new Map<string, Zapper>()
+
+  for (const {lnurl, info} of res?.data || []) {
+    tryCatch(() => zappersByLnurl.set(bech32ToHex(lnurl), info))
+  }
+
+  return zappersByLnurl
+}
+
+export const {
+  indexStore: zappersByLnurl,
+  deriveItem: deriveZapper,
+  loadItem: loadZapper,
+} = collection({
+  name: "zappers",
+  store: zappers,
+  getKey: (zapper: Zapper) => zapper.lnurl,
+  load: batcher(800, async (lnurls: string[]) => {
+    const fresh = await fetchZappers(uniq(lnurls))
+    const stale = zappersByLnurl.get()
+    const items: Zapper[] = lnurls.map(lnurl => {
+      const zapper = fresh.get(lnurl) || stale.get(lnurl) || {}
+
+      return {...zapper, lnurl}
+    })
+
+    zappers.update($zappers => uniqBy($zapper => $zapper.lnurl, [...$zappers, ...items]))
+
+    return items
+  }),
+})
+