feat: apples-to-apples fee comparison (HL-comparable coins only)

src/app/api/fee-compare/route.ts

@@ -188,6 +188,7 @@
   netCostUsdc: number;
   positionSizeUsdc: number;
   avgFeeRateBps: number;
+  gainsExclusiveFeesUsdc?: number; // fees on coins not available on the other venue
   recentTrades: Array<{
     date: string;
     pair: string;
@@ -196,7 +197,8 @@
     tradingFee: number;
     fundingFee: number;
     borrowingFee: number;
-    equivFee?: number;   // equivalent fee on the other venue
+    equivFee?: number;
+    hlComparable?: boolean; // false = coin not listed on HL
     pnl_net: number;
   }>;
 };
@@ -1115,31 +1117,40 @@
   const INCREASE_ACTIONS = new Set(["TradePosSizeIncrease"]);
   const CLOSE_ACTIONS = new Set(["TradeClosedMarket", "TradeClosedTP", "TradeClosedSL", "TradeClosedLIQ"]);
 
-  const byId = new Map<number, { open?: GainsApiTrade; close?: GainsApiTrade }>();
+  const byId = new Map<number, { open?: GainsApiTrade; close?: GainsApiTrade; lastIncrease?: GainsApiTrade }>();
   for (const t of trades) {
     if (!byId.has(t.id)) byId.set(t.id, {});
     const e = byId.get(t.id)!;
     if (OPEN_ACTIONS.has(t.action)) e.open = t;
-    else if (INCREASE_ACTIONS.has(t.action) && e.open) {
-      e.open = { ...e.open, size: t.size, leverage: t.leverage };
+    else if (INCREASE_ACTIONS.has(t.action)) {
+      if (e.open) e.open = { ...e.open, size: t.size, leverage: t.leverage };
+      // Track increases for positions opened before the window (no open event in data)
+      else if (!e.lastIncrease || new Date(t.date).getTime() < new Date(e.lastIncrease.date).getTime()) {
+        e.lastIncrease = t;
+      }
     }
     else if (CLOSE_ACTIONS.has(t.action)) e.close = t;
   }
 
   const now = Date.now();
   const slices: PositionSlice[] = [];
-  for (const { open, close } of byId.values()) {
-    if (!open) continue;
-    const openMs = new Date(open.date).getTime();
-    if (openMs < cutoffMs) continue;
-    // Still-open positions use now as close time (same as reconstructHlPositions)
+  for (const { open, close, lastIncrease } of byId.values()) {
+    // Use open event if available; fall back to earliest increase in the window
+    // for positions opened before the fetch window (open event not in data).
+    const anchor = open ?? lastIncrease;
+    if (!anchor) continue;
+    const rawOpenMs = new Date(anchor.date).getTime();
     const closeMs = close ? new Date(close.date).getTime() : now;
+    // Skip positions that closed before the analysis window
+    if (closeMs < cutoffMs) continue;
+    // Cap openMs to the window start so long-running positions aren't missed
+    const openMs = Math.max(rawOpenMs, cutoffMs);
     slices.push({
-      coin: open.pair.split("/")[0],
-      notionalUsd: open.size * open.leverage,
+      coin: anchor.pair.split("/")[0],
+      notionalUsd: anchor.size * anchor.leverage,
       openMs,
       closeMs,
-      isLong: open.buy !== false,
+      isLong: anchor.buy !== false,
     });
   }
 
@@ -1212,7 +1223,7 @@
 }
 
 // Estimate GMX borrow fees for a set of position slices.
 function estimateGmxBorrowFees(
   positions: PositionSlice[],
   borrowPerSecPerCoin: Record<string, number>
 ): number {
@@ -1342,14 +1353,16 @@
   return "0x" + result;
 }
 
-function walletStats(slug: string, w: AnyWallet): { notional: number; fees: number } | null {
+function walletStats(slug: string, w: AnyWallet, otherSlug?: string): { notional: number; fees: number } | null {
   if (slug === "hyperliquid") {
     const x = w as HlWalletData;
     return x.fills > 0 ? { notional: x.notionalUsd, fees: x.netCostUsd } : null;
   }
   if (slug === "gains") {
     const x = w as GainsWalletData;
-    return x.events > 0 ? { notional: x.positionSizeUsdc, fees: x.netCostUsdc } : null;
+    // When comparing against HL, exclude fees on coins not available on HL
+    const exclusiveFees = otherSlug === "hyperliquid" ? (x.gainsExclusiveFeesUsdc ?? 0) : 0;
+    return x.events > 0 ? { notional: x.positionSizeUsdc, fees: x.netCostUsdc - exclusiveFees } : null;
   }
   if (slug === "gmx-v2") {
     const x = w as GmxWalletData;
@@ -1429,6 +1442,7 @@
     let hlFillsData: HlFill[] = [];
     let hlFundingData: HlFundingEvent[] = [];
     let hlOpenPositions: HlOpenPos[] = [];
+    let hlAvailableCoins = new Set<string>();
     let gainsTradesData: GainsApiTrade[] = [];
     let gmxWalletData: GmxWalletData | null = null;
     let dydxWalletData: DydxWalletData | null = null;
@@ -1456,6 +1470,21 @@
         fetches.push(
           fetchGainsTrades(wallet, cutoffMs).then((d) => { gainsTradesData = d; }).catch(() => {})
         );
+        if (venueA === "hyperliquid" || venueB === "hyperliquid") {
+          fetches.push(
+            fetch(HL_API, {
+              method: "POST",
+              headers: { "Content-Type": "application/json" },
+              body: JSON.stringify({ type: "meta" }),
+              signal: AbortSignal.timeout(5000),
+            })
+              .then((r) => r.json())
+              .then((d: { universe: Array<{ name: string }> }) => {
+                hlAvailableCoins = new Set(d.universe.map((c) => c.name));
+              })
+              .catch(() => {})
+          );
+        }
       }
       if (venueA === "gmx-v2" || venueB === "gmx-v2") {
         fetches.push(
@@ -1480,8 +1509,11 @@
 
     await Promise.all(fetches);
 
-    // Phase 2: fetch HL funding history for Gains positions (Gains→HL carry projection)
+    // Phase 2: fetch HL funding history + extended Gains history for position reconstruction
     let hlFundingHistoryByCoins: Map<string, Array<{ time: number; rate: number }>> = new Map();
+    // Extended Gains history (1 year) used only for HL funding projection reconstruction —
+    // the fee accounting (taker/borrow/funding fees) still uses gainsTradesData (cutoffMs window).
+    let gainsPositionData: GainsApiTrade[] = gainsTradesData;
     if (
       fetchEvmWallet &&
       (venueA === "gains" || venueB === "gains") &&
@@ -1494,7 +1526,13 @@
           .map((t) => t.pair.split("/")[0])
       );
       const coinsToFetch = [...gainsCoinSet].slice(0, 6);
-      hlFundingHistoryByCoins = await fetchHlFundingHistory(coinsToFetch, cutoffMs).catch(() => new Map());
+      const extendedCutoffMs = cutoffMs - 365 * 24 * 60 * 60 * 1000;
+      const [fundingHistory, extendedTrades] = await Promise.all([
+        fetchHlFundingHistory(coinsToFetch, cutoffMs).catch(() => new Map<string, Array<{ time: number; rate: number }>>()),
+        fetchGainsTrades(wallet, extendedCutoffMs).catch(() => gainsTradesData),
+      ]);
+      hlFundingHistoryByCoins = fundingHistory;
+      gainsPositionData = extendedTrades;
     }
 
     function buildVenueResult(slug: string, rate: number, note: string, rateIsLive: boolean): VenueResult {
@@ -1520,13 +1558,15 @@
         }));
       } else if (fetchEvmWallet && slug === "gains") {
         const CLOSE_ACTIONS = new Set(["TradeClosedMarket", "TradeClosedTP", "TradeClosedSL", "TradeClosedLIQ"]);
         const usdcTrades = gainsTradesData.filter((t) => t.collateralIndex === 3);
         const otherSlug = slug === venueA ? venueB : venueA;
         const otherRate = slug === venueA ? rateB : rateA;
         let feesUsdc = 0;
         let fundingFeesUsdc = 0;
         let borrowingFeesUsdc = 0;
         let notionalUsd = 0;
+        let gainsExclusiveFeesUsdc = 0;
+        const checkHlComparable = otherSlug === "hyperliquid" && hlAvailableCoins.size > 0;
         const recentTrades: GainsWalletData["recentTrades"] = [];
 
         for (const t of usdcTrades) {
@@ -1542,11 +1582,19 @@
           borrowingFeesUsdc += borrowingFee;
           const tradeNotional = t.size * t.leverage;
           notionalUsd += tradeNotional;
+          const coin = t.pair.split("/")[0];
+          const hlComparable = checkHlComparable ? hlAvailableCoins.has(coin) : undefined;
+          if (hlComparable === false) {
+            gainsExclusiveFeesUsdc += takerFee + fundingFee + borrowingFee;
+          }
           if (recentTrades.length < 50) {
-            const equivFee = otherSlug === "hyperliquid"
-              ? tradeNotional * (gainsData.perSide[t.pair.split("/")[0]] ?? otherRate)
-              : tradeNotional * otherRate;
-            recentTrades.push({ date: t.date, pair: t.pair, action: t.action, notional: tradeNotional, tradingFee: takerFee, fundingFee, borrowingFee, equivFee, pnl_net: t.pnl_net });
+            // Don't show equivFee for Gains-exclusive coins — the coin doesn't exist on HL
+            const equivFee = hlComparable === false
+              ? undefined
+              : otherSlug === "hyperliquid"
+                ? tradeNotional * (gainsData.perSide[coin] ?? otherRate)
+                : tradeNotional * otherRate;
+            recentTrades.push({ date: t.date, pair: t.pair, action: t.action, notional: tradeNotional, tradingFee: takerFee, fundingFee, borrowingFee, equivFee, hlComparable, pnl_net: t.pnl_net });
           }
         }
 
@@ -1572,6 +1620,7 @@
           netCostUsdc,
           positionSizeUsdc: notionalUsd,
           avgFeeRateBps: notionalUsd > 0 ? (netCostUsdc / notionalUsd) * 10000 : 0,
+          gainsExclusiveFeesUsdc: checkHlComparable ? gainsExclusiveFeesUsdc : undefined,
           recentTrades,
         } satisfies GainsWalletData;
       } else if (fetchEvmWallet && slug === "gmx-v2" && gmxWalletData) {
@@ -1650,7 +1699,7 @@
           }
         }
       } else {
-        const stats = walletStats(venueA, venueAResult.wallet);
+        const stats = walletStats(venueA, venueAResult.wallet, venueB);
         if (stats) {
           let equivFees = stats.notional * rateB;
           let projectedCarry: SimResult["projectedCarry"];
@@ -1663,9 +1712,9 @@
               hlOpenPositions,
               cutoffMs
             );
-          } else if (venueA === "gains" && gainsTradesData.length > 0) {
+          } else if (venueA === "gains" && gainsPositionData.length > 0) {
             positions = reconstructGainsPositions(
-              gainsTradesData.filter((t) => t.collateralIndex === 3),
+              gainsPositionData.filter((t) => t.collateralIndex === 3),
               cutoffMs
             );
           } else if (venueA === "gmx-v2" && gmxWalletData) {
@@ -1790,7 +1839,7 @@
           }
         }
       } else {
-        const stats = walletStats(venueB, venueBResult.wallet);
+        const stats = walletStats(venueB, venueBResult.wallet, venueA);
         if (stats) {
           let equivFees = stats.notional * rateA;
           let projectedCarry: SimResult["projectedCarry"];
@@ -1803,9 +1852,9 @@
               hlOpenPositions,
               cutoffMs
             );
-          } else if (venueB === "gains" && gainsTradesData.length > 0) {
+          } else if (venueB === "gains" && gainsPositionData.length > 0) {
             positions = reconstructGainsPositions(
-              gainsTradesData.filter((t) => t.collateralIndex === 3),
+              gainsPositionData.filter((t) => t.collateralIndex === 3),
               cutoffMs
             );
           } else if (venueB === "gmx-v2" && gmxWalletData) {

src/components/fee-compare-client.tsx

@@ -81,6 +81,7 @@ type GainsWalletData = {
   netCostUsdc: number;
   positionSizeUsdc: number;
   avgFeeRateBps: number;
+  gainsExclusiveFeesUsdc?: number;
   recentTrades: Array<{
     date: string;
     pair: string;
@@ -90,6 +91,7 @@ type GainsWalletData = {
     fundingFee: number;
     borrowingFee: number;
     equivFee?: number;
+    hlComparable?: boolean;
     pnl_net: number;
   }>;
 };
@@ -780,6 +782,11 @@ function WalletSide({
                   {fmtUsd(gW.netCostUsdc)}
                 </p>
               </div>
+              {(gW.gainsExclusiveFeesUsdc ?? 0) > 0.01 && (
+                <p className="text-[10px] text-ink-faint/50 leading-snug pt-0.5">
+                  Incl. {fmtUsd(gW.gainsExclusiveFeesUsdc!)} on pairs not listed on {otherVenue.name} — excluded from comparison.
+                </p>
+              )}
             </div>
           </div>
         );
@@ -1146,6 +1153,7 @@ function GainsTradeTable({
   const PREVIEW = 10;
   const rows = showAll ? trades : trades.slice(0, PREVIEW);
   const hasEquiv = !!otherVenueName && trades.some((t) => t.equivFee !== undefined);
+  const hasComparability = trades.some((t) => t.hlComparable !== undefined);
 
   if (trades.length === 0) return null;
 
@@ -1188,12 +1196,18 @@ function GainsTradeTable({
             {rows.map((t, i) => {
               const netCost = t.tradingFee + t.fundingFee + t.borrowingFee;
               const diff = hasEquiv && t.equivFee !== undefined ? t.equivFee - netCost : undefined;
+              const isExclusive = hasComparability && t.hlComparable === false;
               return (
-              <tr key={i} className="border-b border-ink/5 last:border-0 hover:bg-ink/2 transition-colors">
+              <tr key={i} className={`border-b border-ink/5 last:border-0 transition-colors ${isExclusive ? "opacity-40" : "hover:bg-ink/2"}`}>
                 <td className="px-5 py-3 font-mono text-xs text-ink-faint whitespace-nowrap">
                   {new Date(t.date).toLocaleString("en-US", { month: "short", day: "numeric", hour: "2-digit", minute: "2-digit" })}
                 </td>
-                <td className="px-3 py-3 font-mono text-xs font-bold text-ink">{t.pair.replace("/USD", "")}</td>
+                <td className="px-3 py-3 font-mono text-xs font-bold text-ink">
+                  {t.pair.replace("/USD", "")}
+                  {isExclusive && (
+                    <span className="ml-1.5 text-[9px] font-normal text-ink-faint/60 uppercase tracking-wide">Gains only</span>
+                  )}
+                </td>
                 <td className="px-3 py-3 hidden sm:table-cell">
                   <span className={`inline-flex rounded-md px-2 py-0.5 text-[10px] font-semibold uppercase tracking-[0.06em] ${
                     t.action.includes("Opened") ? "bg-emerald-500/12 text-emerald-500"