problem: can't reason about zap reciepts

src/routes/rockets/[ignition]/+page.svelte

@@ -1,7 +1,7 @@
 <script lang="ts">
 	import { page } from '$app/stores';
 	import { ndk } from '@/ndk';
-	import type { NDKEvent } from '@nostr-dev-kit/ndk';
+	import { NDKEvent, type NDKTag } from '@nostr-dev-kit/ndk';
 	import type { ExtendedBaseType, NDKEventStore } from '@nostr-dev-kit/ndk-svelte';
 	import { onDestroy } from 'svelte';
 	import { derived, type Readable } from 'svelte/store';
@@ -19,6 +19,7 @@
 
 	let rocketEvents: NDKEventStore<NDKEvent> | undefined;
 	let latestRocketEvent: Readable<ExtendedBaseType<NDKEvent> | undefined>;
+	let zaps: Readable<ExtendedBaseType<NDKEvent>[]>;
 
 	let candidateProducts: Readable<ExtendedBaseType<NDKEvent>[]>;
 	onDestroy(() => {
@@ -35,8 +36,10 @@
 	if (rName && rPubkey) {
 		//the user wants the latest valid state of this rocket
 		rocketEvents = $ndk.storeSubscribe(
-			[{ '#d': [rName], authors: [rPubkey], kinds: [31108 as number] },
-            { '#a': [`31108:${rPubkey}:${rName}`]}],
+			[
+				{ '#d': [rName], authors: [rPubkey], kinds: [31108 as number] },
+				{ '#a': [`31108:${rPubkey}:${rName}`] }
+			],
 			{ subId: rName }
 		);
 	}
@@ -45,9 +48,9 @@
 		if (rocketEvents) {
 			latestRocketEvent = derived(rocketEvents, ($events) => {
 				if (rocketEvents) {
-                    let sorted = $events.filter(e=>{
-                        return e.kind == 31108;
-                    })
+					let sorted = $events.filter((e) => {
+						return e.kind == 31108;
+					});
 					sorted = sorted.toSorted((a, b) => {
 						return a.created_at - b.created_at;
 					});
@@ -56,18 +59,75 @@
 				return undefined;
 			});
 
-            if ($latestRocketEvent) {
-                candidateProducts = derived(rocketEvents, ($events) =>{
-                    return $events.filter(e=>{
-						for (let p of $latestRocketEvent.getMatchingTags("product")) {
+			if ($latestRocketEvent) {
+				candidateProducts = derived(rocketEvents, ($events) => {
+					return $events.filter((e) => {
+						for (let p of $latestRocketEvent.getMatchingTags('product')) {
 							if (p[1].includes(e.id)) {
-								return false
+								return false;
 							}
 						}
-                        return e.kind == 1908;
-                    })
-                })
-            }
+						return e.kind == 1908;
+					});
+				});
+
+				zaps = derived(rocketEvents, ($events) => {
+					return $events.filter((e) => {
+						return e.kind == 9735;
+					});
+				});
+			}
+		}
+	}
+
+	function getMapOfProducts(rocket: NDKEvent): Map<string, NDKTag> {
+		let productIDs = new Map<string, NDKTag>();
+		for (let product of rocket.getMatchingTags('product')) {
+			if (product.length > 1 && product[1].split(':') && product[1].split(':').length > 0) {
+				productIDs.set(product[1].split(':')[0], product);
+			}
+		}
+		return productIDs
+	}
+
+	//todo: check that this zap is not already included in the payment JSON for the product
+	//todo: list purchases on the rocket page (from product tags, as well as zap receipts that aren't yet included). Deduct total products available if not 0.
+	//todo: make the page flash or something and show each time someone buys the product.
+	//todo: split this out so that we can consume it for the payment page too (so that we know if there are really products left or they're all sold)
+	function getZapData(zap: NDKEvent) {
+		let desc = zap.getMatchingTags('description');
+		if (desc && desc.length == 1) {
+			let request = new NDKEvent($ndk, JSON.parse(desc[0][1]));
+
+			console.log(request.author.pubkey);
+			let eTags = request.getMatchingTags('e');
+			let zappedProductIsLegit = false;
+			let productPrice = 0;
+			if (eTags && eTags.length > 0) {
+				for (let etag of eTags) {
+					if (etag.length > 1) {
+						if ($latestRocketEvent && getMapOfProducts($latestRocketEvent)) {
+							let products = getMapOfProducts($latestRocketEvent)
+							let thisProduct = products.get(etag[1])
+							if (thisProduct) {
+								zappedProductIsLegit = true
+								productPrice = parseInt(thisProduct[1].split(":")[1], 10)
+							}
+						}
+					}
+				}
+			}
+			console.log(zappedProductIsLegit)
+			if (!zappedProductIsLegit) {
+				console.log(request.rawEvent())
+			}
+			let amount = request.getMatchingTags('amount');
+			if (amount && amount.length == 1) {
+				if (amount[0].length == 2) {
+					let amountInt = parseInt(amount[0][1], 10);
+					console.log(amountInt >= productPrice);
+				}
+			}
 		}
 	}
 
@@ -83,12 +143,21 @@
 			'modify relevant data and republish event according to https://github.com/nostrocket/NIPS/blob/main/31108.md and https://github.com/nostrocket/NIPS/blob/main/MSBR334000.md '
 		]}
 	/>
-    {#if candidateProducts && $candidateProducts}
-    <Subheading title="Product Candidates" />
-    <CreateNewProduct rocketEvent={$latestRocketEvent} />
-    {#each $candidateProducts as r}<ProductCard rocket={$latestRocketEvent} product={r} />{/each}
-    {/if}
-	
+	{#if candidateProducts && $candidateProducts}
+		<Subheading title="Product Candidates" />
+		<CreateNewProduct rocketEvent={$latestRocketEvent} />
+		{#each $candidateProducts as r}<ProductCard rocket={$latestRocketEvent} product={r} />{/each}
+	{/if}
+
+	{#if zaps && $zaps}
+		{#each $zaps as z}<p
+				on:click={() => {
+					getZapData(z);
+				}}
+			>
+				{z.id}
+			</p>{/each}
+	{/if}
 {:else}
 	IGNITION: {rIgnitionOrActual} <br />
 	NAME: {rName} <br />