From 1d6ebadcb28d48c2e1fa5110467c1eca87cb5e82 Mon Sep 17 00:00:00 2001
From: surbhi <surbhi.jhavar@gmail.com>
Date: Tue, 4 Nov 2025 13:46:45 -0400
Subject: [PATCH] gas cost estimates for small values

---
 src/components/swap-form.tsx         | 21 ++++++++++++---------
 src/components/swap-review-modal.tsx |  4 +++-
 src/hooks/usePartyPool.ts            |  7 ++++---
 3 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/src/components/swap-form.tsx b/src/components/swap-form.tsx
index 6b010f3..a6ab3ad 100644
--- a/src/components/swap-form.tsx
+++ b/src/components/swap-form.tsx
@@ -111,8 +111,11 @@ export function SwapForm() {
         return;
       }
 
-      // Convert fromAmount to Wei
-      const maxAmountIn = parseUnits(fromAmount, selectedFromToken.decimals);
+      // Calculate maxAmountIn by subtracting fees from user's input
+      // User's input is the total amount they want to spend (including fees)
+      // So we subtract the fee to get the actual amount to swap
+      const userInputInWei = parseUnits(fromAmount, selectedFromToken.decimals);
+      const maxAmountIn = userInputInWei - bestRoute.fee;
 
       // Execute the swap
       await executeSwap(
@@ -339,7 +342,7 @@ export function SwapForm() {
             <div className="flex justify-between text-sm">
               <span className="text-muted-foreground">Estimated Gas Cost:</span>
               <span className="font-medium">
-                {isEstimatingGas ? 'Calculating...' : gasEstimate ? `$${gasEstimate.estimatedCostUsd}` : '-'}
+                {isEstimatingGas ? 'Calculating...' : gasEstimate ? (gasEstimate.estimatedCostUsd.startsWith('<') ? gasEstimate.estimatedCostUsd : `$${gasEstimate.estimatedCostUsd}`) : '-'}
               </span>
             </div>
             <div className="flex justify-between text-sm">
@@ -349,17 +352,17 @@ export function SwapForm() {
             {swapAmounts && swapAmounts.length > 0 && selectedFromToken && fromAmount && (
               <>
                 <div className="flex justify-between text-sm">
-                  <span className="text-muted-foreground">Fee:</span>
+                  <span className="text-muted-foreground">Total Amount In:</span>
                   <span className="font-medium">
-                    {(Number(swapAmounts[0].fee) / Math.pow(10, selectedFromToken.decimals)).toFixed(6)} {selectedFromToken.symbol}
-                    {' '}
-                    ({((Number(swapAmounts[0].fee) / Number(parseUnits(fromAmount, selectedFromToken.decimals))) * 100).toFixed(2)}%)
+                    {formatUnits(swapAmounts[0].amountIn, selectedFromToken.decimals)} {selectedFromToken.symbol}
                   </span>
                 </div>
                 <div className="flex justify-between text-sm">
-                  <span className="text-muted-foreground">Total Amount In:</span>
+                  <span className="text-muted-foreground">Fee:</span>
                   <span className="font-medium">
-                    {((Number(parseUnits(fromAmount, selectedFromToken.decimals)) + Number(swapAmounts[0].fee)) / Math.pow(10, selectedFromToken.decimals)).toFixed(6)} {selectedFromToken.symbol}
+                    {formatUnits(swapAmounts[0].fee, selectedFromToken.decimals)} {selectedFromToken.symbol}
+                    {' '}
+                    ({((Number(swapAmounts[0].fee) / Number(swapAmounts[0].amountIn)) * 100).toFixed(2)}%)
                   </span>
                 </div>
               </>
diff --git a/src/components/swap-review-modal.tsx b/src/components/swap-review-modal.tsx
index 3746bf4..643bcd5 100644
--- a/src/components/swap-review-modal.tsx
+++ b/src/components/swap-review-modal.tsx
@@ -117,7 +117,9 @@ export function SwapReviewModal({
               {gasEstimate && (
                 <div className="flex justify-between text-sm">
                   <span className="text-muted-foreground">Network Fee</span>
-                  <span className="font-medium">${gasEstimate.estimatedCostUsd}</span>
+                  <span className="font-medium">
+                    {gasEstimate.estimatedCostUsd.startsWith('<') ? gasEstimate.estimatedCostUsd : `$${gasEstimate.estimatedCostUsd}`}
+                  </span>
                 </div>
               )}
             </div>
diff --git a/src/hooks/usePartyPool.ts b/src/hooks/usePartyPool.ts
index dacfd6d..d99141b 100644
--- a/src/hooks/usePartyPool.ts
+++ b/src/hooks/usePartyPool.ts
@@ -216,7 +216,8 @@ export function useSwap() {
 
             const totalGas = approvalGas + swapGas;
             const estimatedCostWei = totalGas * gasPrice;
-            const estimatedCostEth = (Number(estimatedCostWei) / 1e18).toFixed(6);
+            // Use more decimal places for testnets with very low gas prices
+            const estimatedCostEth = (Number(estimatedCostWei) / 1e18).toFixed(9);
 
             // Fetch ETH price in USD
             let estimatedCostUsd = '0.00';
@@ -225,7 +226,8 @@ export function useSwap() {
                 const data = await response.json();
                 const ethPriceUsd = data.ethereum?.usd || 0;
                 const costInUsd = parseFloat(estimatedCostEth) * ethPriceUsd;
-                estimatedCostUsd = costInUsd.toFixed(2);
+                // Show "< $0.01" for amounts less than a cent, otherwise show 2 decimal places
+                estimatedCostUsd = costInUsd < 0.01 && costInUsd > 0 ? '< $0.01' : costInUsd.toFixed(2);
             } catch (priceErr) {
                 console.error('Error fetching ETH price:', priceErr);
             }
@@ -238,7 +240,6 @@ export function useSwap() {
             };
 
             setGasEstimate(estimate);
-            console.log('⛽ Gas estimate:', estimate);
             return estimate;
         } catch (err) {
             console.error('Error estimating gas:', err);