From 1864468818955edeada607b0be0cc0fdcdbcd649 Mon Sep 17 00:00:00 2001
From: CalDescent <caldescent@protonmail.com>
Date: Fri, 18 Feb 2022 13:41:29 +0000
Subject: [PATCH] Prefer the route with the least number of hops when relaying.

---
 .../arbitrary/ArbitraryDataFileManager.java   | 29 ++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/src/main/java/org/qortal/controller/arbitrary/ArbitraryDataFileManager.java b/src/main/java/org/qortal/controller/arbitrary/ArbitraryDataFileManager.java
index 9b437e2b..e60e32a9 100644
--- a/src/main/java/org/qortal/controller/arbitrary/ArbitraryDataFileManager.java
+++ b/src/main/java/org/qortal/controller/arbitrary/ArbitraryDataFileManager.java
@@ -392,6 +392,33 @@ public class ArbitraryDataFileManager extends Thread {
         }
     }
 
+    private ArbitraryRelayInfo getOptimalRelayInfoEntryForHash(String hash58) {
+        LOGGER.trace("Fetching relay info for hash: {}", hash58);
+        List<ArbitraryRelayInfo> relayInfoList = this.getRelayInfoListForHash(hash58);
+        if (relayInfoList != null && !relayInfoList.isEmpty()) {
+
+            // Remove any with null requestHops
+            relayInfoList.removeIf(r -> r.getRequestHops() == null);
+
+            // If list is now empty, then just return one at random
+            if (relayInfoList.isEmpty()) {
+                return this.getRandomRelayInfoEntryForHash(hash58);
+            }
+
+            // Sort by number of hops (lowest first)
+            relayInfoList.sort(Comparator.comparingInt(ArbitraryRelayInfo::getRequestHops));
+
+            // FUTURE: secondary sort by requestTime?
+
+            ArbitraryRelayInfo relayInfo = relayInfoList.get(0);
+
+            LOGGER.trace("Returning optimal relay info for hash: {} (requestHops {})", hash58, relayInfo.getRequestHops());
+            return relayInfo;
+        }
+        LOGGER.trace("No relay info exists for hash: {}", hash58);
+        return null;
+    }
+
     private ArbitraryRelayInfo getRandomRelayInfoEntryForHash(String hash58) {
         LOGGER.trace("Fetching random relay info for hash: {}", hash58);
         List<ArbitraryRelayInfo> relayInfoList = this.getRelayInfoListForHash(hash58);
@@ -442,7 +469,7 @@ public class ArbitraryDataFileManager extends Thread {
 
         try {
             ArbitraryDataFile arbitraryDataFile = ArbitraryDataFile.fromHash(hash, signature);
-            ArbitraryRelayInfo relayInfo = this.getRandomRelayInfoEntryForHash(hash58);
+            ArbitraryRelayInfo relayInfo = this.getOptimalRelayInfoEntryForHash(hash58);
 
             if (arbitraryDataFile.exists()) {
                 LOGGER.trace("Hash {} exists", hash58);