fix: implement fiat-to-crypto conversion for sweep verification

app/api/crypto-sweep/route.ts

@@ -81,16 +81,45 @@ export async function POST(request: Request) {
         // 5. Initialize Engine and Verify Payment first
         const cryptoEngine = new CryptoEngine(selectedNetwork);
         
+        // 5.1 Convert Fiat amount to Crypto amount for verification
+        let expectedCryptoAmount = transaction.amount.toString();
+        
+        // Always try to fetch price to ensure we are comparing crypto to crypto
+        try {
+            const coinIdMap: Record<string, string> = {
+                'SOL': 'solana',
+                'USDC': 'usd-coin',
+                'USDT': 'tether',
+                'TRX': 'tron',
+                'BTC': 'bitcoin'
+            };
+            const coinId = coinIdMap[selectedToken] || 'solana';
+            const priceUrl = `https://api.coingecko.com/api/v3/simple/price?ids=${coinId}&vs_currencies=usd,try`;
+            const priceRes = await fetch(priceUrl);
+            const priceData = await priceRes.json();
+            const currencyKey = (transaction.currency || 'TRY').toLowerCase();
+            const price = priceData[coinId][currencyKey] || priceData[coinId]['usd'];
+
+            if (price) {
+                // Apply a small tolerance (e.g., 2% for price fluctuations)
+                const rawExpected = parseFloat(transaction.amount) / price;
+                expectedCryptoAmount = (rawExpected * 0.98).toFixed(6);
+                console.log(`[Sweep] Verified Amount: ${transaction.amount} ${transaction.currency} => Expected ~${rawExpected.toFixed(6)} ${selectedToken} (Threshold: ${expectedCryptoAmount})`);
+            }
+        } catch (priceErr) {
+            console.warn("[Sweep] Could not fetch real-time price, using raw amount as fallback:", priceErr);
+        }
+        
         const verification = await cryptoEngine.verifyPayment(
             tempWalletConfig.address, 
-            transaction.amount.toString(), 
+            expectedCryptoAmount, 
             selectedToken
         );
 
         if (!verification.success) {
             return NextResponse.json({ 
                 success: false, 
-                error: "Henüz ödeme algılanmadı (On-chain bakiye yetersiz)",
+                error: `Henüz ödeme algılanmadı. Beklenen: ~${expectedCryptoAmount} ${selectedToken}`,
                 status: 'waiting'
             });
         }