22: Add method decodeCumulativeInterestSnapshot

src/main/tjava/com/r35157/libs/jupiter/perps/impl/anchoridl/AnchorIdlJupiterPerpsPositionDecoder.tjava

@@ -7,6 +7,7 @@ import com.r35157.libs.jupiter.perps.JupiterPerpsPositionDirection;
 import com.r35157.libs.solana.SolanaAccountInfo;
 
 import java.math.BigDecimal;
+import java.math.BigInteger;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 import java.util.Base64;
@@ -56,6 +57,11 @@ class AnchorIdlJupiterPerpsPositionDecoder {
                 .valueOf(rawSizeUsd)
                 .movePointLeft(6);
 
+        BigInteger cumulativeInterestSnapshot = readU128(
+                data,
+                CUMULATIVE_INTEREST_SNAPSHOT_OFFSET
+        );
+
         JupiterPerpsPosition pos = new JupiterPerpsPosition(
                 positionAccount,
                 entryPrice,
@@ -68,6 +74,22 @@ class AnchorIdlJupiterPerpsPositionDecoder {
         return pos;
     }
 
+    BigInteger decodeCumulativeInterestSnapshot(SolanaAccountInfo accountInfo) {
+        byte[] data = Base64.getDecoder().decode(accountInfo.dataBase64());
+
+        if (data.length < CUMULATIVE_INTEREST_SNAPSHOT_OFFSET + U128_LENGTH) {
+            throw new IllegalArgumentException(
+                    "Jupiter Perps position account data is too short: " + data.length
+            );
+        }
+
+        BigInteger value = readU128(
+                data,
+                CUMULATIVE_INTEREST_SNAPSHOT_OFFSET
+        );
+        return value;
+    }
+
     ΩSolanaAddressΩ decodeCustodyAccount(SolanaAccountInfo accountInfo) {
         byte[] data = Base64.getDecoder().decode(accountInfo.dataBase64());
 
@@ -115,11 +137,25 @@ class AnchorIdlJupiterPerpsPositionDecoder {
         return base58.encode(publicKeyBytes);
     }
 
+    private static BigInteger readU128(
+            byte[] data,
+            int offset
+    ) {
+        byte[] bytes = new byte[U128_LENGTH];
+
+        for (int i = 0; i < U128_LENGTH; i++) {
+            bytes[i] = data[offset + U128_LENGTH - 1 - i];
+        }
+
+        return new BigInteger(1, bytes);
+    }
+
     private static final int ANCHOR_DISCRIMINATOR_LENGTH = 8;
     private static final int PUBLIC_KEY_LENGTH = 32;
-    private static final int I64_LENGTH = 8;
     private static final int SIDE_ENUM_LENGTH = 1;
+    private static final int I64_LENGTH = 8;
     private static final int U64_LENGTH = 8;
+    private static final int U128_LENGTH = 16;
 
     private static final int OWNER_OFFSET = ANCHOR_DISCRIMINATOR_LENGTH;
     private static final int POOL_OFFSET = OWNER_OFFSET + PUBLIC_KEY_LENGTH;
@@ -131,6 +167,8 @@ class AnchorIdlJupiterPerpsPositionDecoder {
     private static final int PRICE_OFFSET = SIDE_OFFSET + SIDE_ENUM_LENGTH;
     private static final int SIZE_USD_OFFSET = PRICE_OFFSET + U64_LENGTH;
     private static final int COLLATERAL_USD_OFFSET = SIZE_USD_OFFSET + U64_LENGTH;
+    private static final int REALISED_PNL_USD_OFFSET = COLLATERAL_USD_OFFSET + U64_LENGTH;
+    private static final int CUMULATIVE_INTEREST_SNAPSHOT_OFFSET = REALISED_PNL_USD_OFFSET + I64_LENGTH;
 
     private static final Base58Codec base58 = new Base58CodecImpl();
 }