From 08ba91b9ba83a0194fa0ad36a04d3744f345052a Mon Sep 17 00:00:00 2001
From: MarekWo <mwojtaszek@gmail.com>
Date: Mon, 23 Mar 2026 09:38:29 +0100
Subject: [PATCH] fix(paths): allow non-adjacent duplicate hops for 1-byte
 paths

For 1B hash size, duplicate repeater IDs are valid as long as they
don't appear consecutively (e.g. AA->BB->CC->AA->EE works fine).
For 2B/3B, duplicates remain fully blocked. Applied to all three
input methods: list picker, map picker, and manual entry.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 app/static/js/dm.js | 47 +++++++++++++++++++++++++++++++++++----------
 1 file changed, 37 insertions(+), 10 deletions(-)

diff --git a/app/static/js/dm.js b/app/static/js/dm.js
index 2e3015d..61930af 100644
--- a/app/static/js/dm.js
+++ b/app/static/js/dm.js
@@ -1855,10 +1855,20 @@ function setupPathFormHandlers(pubkey) {
         for (let i = 0; i < pathHex.length; i += chunk) {
             hops.push(pathHex.substring(i, i + chunk).toLowerCase());
         }
-        const dupes = hops.filter((h, i) => hops.indexOf(h) !== i);
-        if (dupes.length > 0) {
-            showNotification(`Duplicate hop(s): ${[...new Set(dupes)].map(d => d.toUpperCase()).join(', ')}`, 'danger');
-            return;
+        if (hashSize === 1) {
+            // 1B: only block adjacent duplicates
+            const adjDupes = hops.filter((h, i) => i > 0 && hops[i - 1] === h);
+            if (adjDupes.length > 0) {
+                showNotification(`Adjacent duplicate hop(s): ${[...new Set(adjDupes)].map(d => d.toUpperCase()).join(', ')}`, 'danger');
+                return;
+            }
+        } else {
+            // 2B/3B: block any duplicate
+            const dupes = hops.filter((h, i) => hops.indexOf(h) !== i);
+            if (dupes.length > 0) {
+                showNotification(`Duplicate hop(s): ${[...new Set(dupes)].map(d => d.toUpperCase()).join(', ')}`, 'danger');
+                return;
+            }
         }
 
         try {
@@ -2007,9 +2017,19 @@ function renderRepeaterList(listEl, repeaters, pubkey) {
         item.addEventListener('click', () => {
             // Check for duplicate hop
             const existingHops = getCurrentPathHops(hashSize);
-            if (existingHops.includes(prefix.toLowerCase())) {
-                showNotification(`${prefix} is already in the path`, 'warning');
-                return;
+            const prefixLc = prefix.toLowerCase();
+            if (hashSize === 1) {
+                // 1B: only block if same as last hop (adjacent duplicate)
+                if (existingHops.length > 0 && existingHops[existingHops.length - 1] === prefixLc) {
+                    showNotification(`${prefix} cannot be adjacent to itself`, 'warning');
+                    return;
+                }
+            } else {
+                // 2B/3B: block any duplicate
+                if (existingHops.includes(prefixLc)) {
+                    showNotification(`${prefix} is already in the path`, 'warning');
+                    return;
+                }
             }
             // Append hop to path hex input
             const current = hexInput.value.replace(/[,\s→]/g, '').trim();
@@ -2136,9 +2156,16 @@ function openRepeaterMapPicker() {
             const prefix = _rptMapSelectedRepeater.public_key.substring(0, hashSize * 2).toLowerCase();
             // Check for duplicate hop
             const existingHops = getCurrentPathHops(hashSize);
-            if (existingHops.includes(prefix)) {
-                showNotification(`${prefix.toUpperCase()} is already in the path`, 'warning');
-                return;
+            if (hashSize === 1) {
+                if (existingHops.length > 0 && existingHops[existingHops.length - 1] === prefix) {
+                    showNotification(`${prefix.toUpperCase()} cannot be adjacent to itself`, 'warning');
+                    return;
+                }
+            } else {
+                if (existingHops.includes(prefix)) {
+                    showNotification(`${prefix.toUpperCase()} is already in the path`, 'warning');
+                    return;
+                }
             }
             const hexInput = document.getElementById('dmPathHexInput');
             if (hexInput) {