Use backend cache for getting quotes during payment verification

quotes-service.ts

@@ -34,9 +34,8 @@ class QuotesService {
     }
   }
 
-  getLatestQuote(): BN | undefined {
-    console.log({ cachedQuotes: this.cachedQuotes });
-    return this.cachedQuotes[this.cachedQuotes.length - 1];
+  getQuotes(): BN[] {
+    return this.cachedQuotes;
   }
 }
 

src/app/api/flux/route.ts

@@ -4,9 +4,7 @@ import BN from 'bn.js';
 import { fal } from "@fal-ai/client"
 import { FLUX_MODELS } from '../../../services/fluxService'
 import { initializeDataSource } from '../../../data-source'
-
-import { verifyPayment, markSignatureAsUsed } from '../../../utils/verifyPayment'
-import { getUSDCToMTMQuote } from '../../../services/paymentService'
+import { verifyPayment, markSignatureAsUsed } from '../../../utils/verifyPayment';
 
 if (!process.env.FAL_AI_KEY) {
   throw new Error('FAL_AI_KEY is not configured in environment variables')
@@ -49,17 +47,18 @@ export async function POST(req: NextRequest): Promise<NextResponse> {
       )
     }
 
-    const mtmFor1USDC = await getUSDCToMTMQuote();
+    const quotes: BN[] = (global as any).quotesService.getQuotes();
+    const mtmFor1USDC = quotes.reduce((min, quote) => quote.lt(min) ? quote : min, quotes[0]); // Take the least cost in the array
 
     const scale = new BN(100);
     const scaledCost = new BN(model.cost * 100);
 
-    const expectedAmount = scaledCost.mul(mtmFor1USDC).div(scale);
-    const isPaymentVerified = await verifyPayment(transactionSignature, expectedAmount)
+    const lowestQuote = scaledCost.mul(new BN(mtmFor1USDC)).div(scale);
+    const isPaymentVerified = await verifyPayment(transactionSignature, lowestQuote);
 
     if (!isPaymentVerified) {
       return NextResponse.json(
-        { error: 'Payment verification failed or transaction signature has already been used' },
+        { error: 'Payment verification failed or transaction signature has already been used', reload: true },
         { status: 400 }
       )
     }

src/app/api/quotes/route.ts

@@ -1,6 +1,12 @@
+import BN from 'bn.js';
 import { NextRequest, NextResponse } from 'next/server';
 
 export async function GET(req: NextRequest) {
-  const quote = (global as any).quoteService.getLatestQuote();
-  return NextResponse.json(quote);
+  try {
+    const quotes: BN[] = (global as any).quotesService.getQuotes();
+    const quotesAsString = quotes.map(quote => quote.toString());
+    return NextResponse.json(quotesAsString);
+  } catch (error) {
+    return NextResponse.json({ error: 'Failed to fetch quotes' }, { status: 500 });
+  }
 }

src/app/page.tsx

@@ -24,7 +24,10 @@ const Page: React.FC = (): React.ReactElement => {
       try {
         const response = await fetch('/api/quotes');
         const data = await response.json();
-        setMtmFor1USDC(new BN(data.latestQuote)); // Convert the string back to BN
+
+        // Convert the string back to BN
+        const price = new BN(data[data.length - 1]);
+        setMtmFor1USDC(price);
       } catch (error) {
         console.error('Failed to fetch price:', error);
       }

src/services/fluxService.ts

@@ -65,6 +65,8 @@ export async function generateWithFlux(
     }
   } catch (error) {
     console.error('Flux generation error:', error)
+    // Reload the page to get latest prices
+    window.location.reload();
     return {
       error: error instanceof Error ? error.message : 'Generation failed'
     }

src/services/paymentService.ts

@@ -14,13 +14,11 @@ import { WalletType } from './types'
 assert(process.env.NEXT_PUBLIC_SOLANA_RPC_URL, 'SOLANA_RPC_URL is required');
 assert(process.env.NEXT_PUBLIC_MTM_TOKEN_MINT, 'MTM_TOKEN_MINT is required');
 assert(process.env.NEXT_PUBLIC_PAYMENT_RECEIVER_ADDRESS, 'PAYMENT_RECEIVER_ADDRESS is required');
-assert(process.env.NEXT_PUBLIC_USDC_MINT, 'USDC_MINT is required');
 
 const MTM_TOKEN_MINT = process.env.NEXT_PUBLIC_MTM_TOKEN_MINT;
 const PAYMENT_RECEIVER_ADDRESS = process.env.NEXT_PUBLIC_PAYMENT_RECEIVER_ADDRESS;
 const SOLANA_RPC_URL = process.env.NEXT_PUBLIC_SOLANA_RPC_URL;
 const SOLANA_WEBSOCKET_URL = process.env.NEXT_PUBLIC_SOLANA_WEBSOCKET_URL;
-const USDC_MINT = process.env.NEXT_PUBLIC_USDC_MINT;
 
 const connection = new Connection(
   SOLANA_RPC_URL,
@@ -51,22 +49,6 @@ async function findAssociatedTokenAddress(
   )[0]
 }
 
-export async function getUSDCToMTMQuote(): Promise<BN> {
-  const url = `https://api.jup.ag/price/v2?ids=${USDC_MINT}&vsToken=${MTM_TOKEN_MINT}`;
-
-  const response = await fetch(url);
-
-  if (!response.ok) {
-    throw new Error(`Failed to fetch quote: ${response.statusText}`);
-  }
-
-  const quoteResponse = await response.json();
-
-  const priceFromAPI = Number(quoteResponse['data'][USDC_MINT]['price']).toFixed(6);
-  const price = new BN(priceFromAPI.toString().replace('.', ''));
-  return price;
-}
-
 interface WalletAdapter {
   signAndSendTransaction(transaction: Transaction): Promise<{ signature: string }>
 }

src/utils/verifyPayment.ts

@@ -47,7 +47,7 @@ export async function markSignatureAsUsed(transactionSignature: string): Promise
 
 export async function verifyPayment(
   transactionSignature: string,
-  expectedAmount: BN,
+  lowestQuote: BN,
 ): Promise<boolean> {
   try {
     // Check if the signature is already used
@@ -74,17 +74,11 @@ export async function verifyPayment(
 
     const transactionAmount = new BN(amount);
 
-    // Transaction amount should be within 10% of the expected amount
-    const lowerBound = expectedAmount.mul(new BN(9)).div(new BN(10));
-    const upperBound = expectedAmount.mul(new BN(11)).div(new BN(10));
-
-    // transaction within the appropriate range
-    if (transactionAmount.gte(lowerBound) && transactionAmount.lte(upperBound)) {
+    if (transactionAmount.gte(lowestQuote)) {
       console.log('Transaction amount is within the expected range.');
       return true;
     }
     console.log('Transaction amount is not within the expected range.');
-    // TODO: Handle slippage being greater than 10%
     return false;
   } catch (error) {
     console.error('Verification error:', error);