16: Add 'side' to AnchorIdlJupiterPerpsPositionDecoder

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

@@ -1,6 +1,7 @@
 package com.r35157.libs.jupiter.perps.impl.anchoridl;
 
 import com.r35157.libs.jupiter.perps.JupiterPerpsPosition;
+import com.r35157.libs.jupiter.perps.JupiterPerpsPositionDirection;
 import com.r35157.libs.solana.SolanaAccountInfo;
 
 import java.math.BigDecimal;
@@ -22,6 +23,9 @@ class AnchorIdlJupiterPerpsPositionDecoder {
             );
         }
 
+        JupiterPerpsPositionDirection direction =
+                decodeDirection(data[SIDE_OFFSET]);
+
         long rawEntryPrice = ByteBuffer
                 .wrap(data, PRICE_OFFSET, U64_LENGTH)
                 .order(ByteOrder.LITTLE_ENDIAN)
@@ -33,25 +37,44 @@ class AnchorIdlJupiterPerpsPositionDecoder {
 
         JupiterPerpsPosition pos = new JupiterPerpsPosition(
                 positionAccount,
-                entryPrice
+                entryPrice,
+                direction
         );
 
         return pos;
     }
 
+    private JupiterPerpsPositionDirection decodeDirection(
+            byte rawSide
+    ) {
+        // Jupiter Perps position side values are encoded as 1 = LONG, 2 = SHORT.
+        JupiterPerpsPositionDirection direction = switch (rawSide) {
+            case 1 -> JupiterPerpsPositionDirection.LONG;
+            case 2 -> JupiterPerpsPositionDirection.SHORT;
+            default -> throw new IllegalArgumentException(
+                    "Unknown Jupiter Perps position side: " + rawSide
+            );
+        };
+
+        return direction;
+    }
+
     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 U64_LENGTH = 8;
     private static final int SIDE_ENUM_LENGTH = 1;
 
-    private static final int PRICE_OFFSET =
+    private static final int SIDE_OFFSET =
             ANCHOR_DISCRIMINATOR_LENGTH
                     + PUBLIC_KEY_LENGTH // owner
                     + PUBLIC_KEY_LENGTH // pool
                     + PUBLIC_KEY_LENGTH // custody
                     + PUBLIC_KEY_LENGTH // collateralCustody
                     + I64_LENGTH        // openTime
-                    + I64_LENGTH        // updateTime
+                    + I64_LENGTH;       // updateTime
+
+    private static final int PRICE_OFFSET =
+            SIDE_OFFSET
                     + SIDE_ENUM_LENGTH; // side
 }