feat: wallet P&L with average cost basis tracking (#156) (#158)

services/ponder/ponder.schema.ts

@@ -259,12 +259,21 @@ export const recenters = onchainTable('recenters', t => ({
   vwapTick: t.integer(), // nullable
 }));
 
-// Holders - track Kraiken token holders
+// Holders - track Kraiken token holders with cost basis for P&L
 export const holders = onchainTable(
   'holders',
   t => ({
     address: t.hex().primaryKey(),
     balance: t.bigint().notNull(),
+    // Cost basis tracking (updated on swaps only, not wallet-to-wallet transfers)
+    totalEthSpent: t
+      .bigint()
+      .notNull()
+      .$default(() => 0n), // cumulative ETH spent buying KRK
+    totalTokensAcquired: t
+      .bigint()
+      .notNull()
+      .$default(() => 0n), // cumulative KRK received from buys
   }),
   table => ({
     addressIdx: index().on(table.address),

services/ponder/src/kraiken.ts

@@ -14,6 +14,10 @@ import { validateContractVersion } from './helpers/version';
 
 const ZERO_ADDRESS = '0x0000000000000000000000000000000000000000' as const;
 
+// Pool address for detecting swaps (buys/sells)
+// Computed deterministically from Uniswap V3 factory + WETH + Kraiken + 1% fee
+const POOL_ADDRESS = (process.env.POOL_ADDRESS || '0x1f69cbfc7d3529a4fb4eadf18ec5644b2603b5ab').toLowerCase() as `0x${string}`;
+
 // Track if version has been validated
 let versionValidated = false;
 
@@ -77,9 +81,25 @@ ponder.on('Kraiken:Transfer', async ({ event, context }) => {
       const oldBalance = toHolder?.balance ?? 0n;
       const newBalance = oldBalance + value;
 
+      // Detect buy: tokens coming FROM the pool = user bought KRK
+      const isBuy = from.toLowerCase() === POOL_ADDRESS;
+      let ethSpentDelta = 0n;
+
+      if (isBuy && value > 0n) {
+        // Approximate ETH cost using current price from stats
+        const currentPrice = statsData.currentPriceWei ?? 0n;
+        if (currentPrice > 0n) {
+          ethSpentDelta = (value * currentPrice) / 10n ** 18n;
+        }
+      }
+
       if (toHolder) {
         await context.db.update(holders, { address: to }).set({
           balance: newBalance,
+          ...(isBuy && {
+            totalEthSpent: (toHolder.totalEthSpent ?? 0n) + ethSpentDelta,
+            totalTokensAcquired: (toHolder.totalTokensAcquired ?? 0n) + value,
+          }),
         });
         // If this was a new holder (balance was 0), increment count
         if (oldBalance === 0n) {
@@ -90,6 +110,8 @@ ponder.on('Kraiken:Transfer', async ({ event, context }) => {
         await context.db.insert(holders).values({
           address: to,
           balance: newBalance,
+          totalEthSpent: ethSpentDelta,
+          totalTokensAcquired: isBuy ? value : 0n,
         });
         holderCountDelta += 1;
       }