43: Prevent Position Decrease from reducing a position below a configured size reserve

conf/alarmaction_JupiterPerpsPositionDecreaseAlarmAction.conf.example

@@ -1,8 +1,8 @@
 # Wallet and signer used for position-decrease transactions
 ################################################################
-WALLET_ID        {{JUPITER_PERPS_WALLET}}
-SIGNER_KEY_NAME  <SIGNER>
-
+WALLET_ID                         {{JUPITER_PERPS_WALLET}}
+SIGNER_KEY_NAME                   <SIGNER>
+RESERVE_POSITION_SIZE_USD_LIMIT   10
 
 # Id   Asset   Direction   ReceiveToken   SizeDeltaUSD   MaxSlippageBPS
 ########################################################################

src/main/tjava/com/r35157/jupiterperpsalarm/impl/ref/JupiterPerpsPositionDecreaseAlarmAction.tjava

@@ -9,6 +9,7 @@ import com.r35157.libs.solana.SolanaSignedTransaction;
 import com.r35157.libs.solana.SolanaUnsignedTransaction;
 
 import java.io.IOException;
+import java.math.BigDecimal;
 import java.nio.file.Path;
 import java.util.Objects;
 
@@ -68,6 +69,10 @@ public final class JupiterPerpsPositionDecreaseAlarmAction
             JupiterPerpsPosition position =
                     findOpenPosition(positionDecrease);
 
+            if (!isPositionSizeOk(position, positionDecrease)) {
+                return;
+            }
+
             SolanaUnsignedTransaction utrans =
                     jupiter.buildPositionDecreaseTransaction(
                             position.positionAccount(),
@@ -76,8 +81,10 @@ public final class JupiterPerpsPositionDecreaseAlarmAction
                             positionDecrease.sizeUsdDelta(),
                             positionDecrease.maxSlippageBps()
                     );
+
             SolanaSignedTransaction strans =
                     wallet.signTransaction(utrans);
+
             ΩSolanaTransactionSignatureΩ signature =
                     jupiter.executePositionDecreaseTransaction(strans);
 
@@ -135,6 +142,39 @@ public final class JupiterPerpsPositionDecreaseAlarmAction
         return matchingPosition;
     }
 
+    private boolean isPositionSizeOk(
+            JupiterPerpsPosition position,
+            JupiterPerpsPositionDecreaseAlarmActionConfiguration
+                    .ResolvedPositionDecrease positionDecrease
+    ) {
+        ΩUSDCAmountΩ currentPositionSize = position.positionSize();
+        ΩUSDCAmountΩ decreaseSizeUsd = positionDecrease.sizeUsdDelta();
+        ΩUSDCAmountΩ reservePositionSizeUsdLimit =
+                configuration.reservePositionSizeUsdLimit();
+
+        ΩUSDCAmountΩ remainingPositionSize =
+                currentPositionSize.subtract(decreaseSizeUsd);
+
+        if (remainingPositionSize.compareTo(
+                reservePositionSizeUsdLimit
+        ) < 0) {
+            System.err.println(
+                    "Position Decrease of "
+                            + decreaseSizeUsd
+                            + " USD skipped: Position size is "
+                            + currentPositionSize
+                            + " USD and would become "
+                            + remainingPositionSize
+                            + " USD, which is below the "
+                            + reservePositionSizeUsdLimit
+                            + " USD reserve."
+            );
+            return false;
+        }
+
+        return true;
+    }
+
     private final JupiterPerpsPositionDecreaseAlarmActionConfiguration
             configuration;
     private final SolanaWallet wallet;

src/main/tjava/com/r35157/jupiterperpsalarm/impl/ref/JupiterPerpsPositionDecreaseAlarmActionConfiguration.tjava

@@ -10,11 +10,21 @@ import java.util.Objects;
 public record JupiterPerpsPositionDecreaseAlarmActionConfiguration(
         ΩSolanaWalletIdΩ walletId,
         String signerKeyName,
+        ΩUSDCAmountΩ reservePositionSizeUsdLimit,
         Map<Integer, PositionDecrease> positionDecreases
 ) {
     public JupiterPerpsPositionDecreaseAlarmActionConfiguration {
         Objects.requireNonNull(walletId, "walletId");
         Objects.requireNonNull(signerKeyName, "signerKeyName");
+        Objects.requireNonNull(reservePositionSizeUsdLimit, "reservePositionSizeUsdLimit");
+
+        if (reservePositionSizeUsdLimit.signum() < 0) {
+            throw new IllegalArgumentException(
+                    "Position size USD reserve limit cannot be negative: "
+                            + reservePositionSizeUsdLimit
+            );
+        }
+
         positionDecreases = Map.copyOf(positionDecreases);
 
         if (walletId.isBlank()) {

src/main/tjava/com/r35157/jupiterperpsalarm/impl/ref/JupiterPerpsPositionDecreaseAlarmActionConfigurationParser.tjava

@@ -1,6 +1,7 @@
 package com.r35157.jupiterperpsalarm.impl.ref;
 
 import java.io.IOException;
+import java.math.BigDecimal;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.LinkedHashMap;
@@ -20,6 +21,7 @@ public final class JupiterPerpsPositionDecreaseAlarmActionConfigurationParser {
                 positionDecreases = new LinkedHashMap<>();
         ΩSolanaWalletIdΩ walletId = null;
         String signerKeyName = null;
+        ΩUSDCAmountΩ reservePositionSizeUsdLimit = null;
 
         for (int lineNumber = 1; lineNumber <= lines.size(); lineNumber++) {
             String line = removeComment(lines.get(lineNumber - 1)).trim();
@@ -51,6 +53,20 @@ public final class JupiterPerpsPositionDecreaseAlarmActionConfigurationParser {
                         );
                     }
                     signerKeyName = variableResolver.resolve(columns[1]);
+                } else if (firstColumn.equals("RESERVE_POSITION_SIZE_USD_LIMIT")) {
+                    requireColumnCount(
+                            columns,
+                            2,
+                            "RESERVE_POSITION_SIZE_USD_LIMIT value"
+                    );
+                    if (reservePositionSizeUsdLimit != null) {
+                        throw new IllegalArgumentException(
+                                "Duplicate RESERVE_POSITION_SIZE_USD_LIMIT"
+                        );
+                    }
+                    reservePositionSizeUsdLimit = new ΩUSDCAmountΩ(
+                            variableResolver.resolve(columns[1])
+                    );
                 } else {
                     parsePositionDecrease(
                             columns,
@@ -78,9 +94,16 @@ public final class JupiterPerpsPositionDecreaseAlarmActionConfigurationParser {
             );
         }
 
+        if (reservePositionSizeUsdLimit == null) {
+            throw new IllegalArgumentException(
+                    "Missing RESERVE_POSITION_SIZE_USD_LIMIT in " + path
+            );
+        }
+
         return new JupiterPerpsPositionDecreaseAlarmActionConfiguration(
                 walletId,
                 signerKeyName,
+                reservePositionSizeUsdLimit,
                 positionDecreases
         );
     }