Fixed electrum logic (settings).

- Fixed empty arrays to fall back to default servers.
- Fixed RPC/Electrum settings logic.
- Added option set electrum servers before switch RPC -> Electrum mode.
- Fixed "No servers discovered", some servers don't support peer discovery.

basicswap/static/js/pages/settings-page.js

@@ -72,6 +72,39 @@
       connectionTypeSelects.forEach(select => {
         const originalValue = select.dataset.originalValue || select.value;
         this.originalConnectionTypes[select.name] = originalValue;
+
+        select.addEventListener('change', (e) => {
+          const coinName = select.name.replace('connection_type_', '');
+          const electrumSection = document.getElementById(`electrum-section-${coinName}`);
+          const fundTransferSection = document.getElementById(`fund-transfer-section-${coinName}`);
+          const originalValue = this.originalConnectionTypes[select.name];
+
+          if (e.target.value === 'electrum') {
+            if (electrumSection) {
+              electrumSection.classList.remove('hidden');
+
+              const clearnetTextarea = document.getElementById(`electrum_clearnet_${coinName}`);
+              const onionTextarea = document.getElementById(`electrum_onion_${coinName}`);
+
+              if (clearnetTextarea && !clearnetTextarea.value.trim()) {
+                clearnetTextarea.value = electrumSection.dataset.defaultClearnet || '';
+              }
+              if (onionTextarea && !onionTextarea.value.trim()) {
+                onionTextarea.value = electrumSection.dataset.defaultOnion || '';
+              }
+            }
+            if (fundTransferSection) {
+              fundTransferSection.classList.add('hidden');
+            }
+          } else {
+            if (electrumSection) {
+              electrumSection.classList.add('hidden');
+            }
+            if (fundTransferSection && originalValue === 'electrum') {
+              fundTransferSection.classList.remove('hidden');
+            }
+          }
+        });
       });
 
       this.setupWalletModeModal();
@@ -561,7 +594,8 @@
         }
 
         if (!data.clearnet_servers?.length && !data.onion_servers?.length) {
-          html = '<div class="text-sm text-gray-500 dark:text-gray-400 py-4 text-center">No servers discovered. The connected server may not support peer discovery.</div>';
+          const serverName = data.current_server ? `${data.current_server.host}:${data.current_server.port}` : 'The connected server';
+          html = `<div class="text-sm text-gray-500 dark:text-gray-400 py-4 text-center">No servers discovered. <span class="font-mono">${serverName}</span> does not return peer lists.</div>`;
         } else {
           html += `<div class="text-xs text-gray-500 dark:text-gray-400 pt-3 border-t border-gray-200 dark:border-gray-600">Click a server to add it to your list</div>`;
         }

basicswap/templates/settings.html

@@ -204,8 +204,10 @@
          </div>
         </div>
 
-        {% if c.connection_type == 'electrum' %}
-        <div class="mb-6">
+        {% if c.supports_electrum %}
+        <div id="electrum-section-{{ c.name }}" class="mb-6 {% if c.connection_type != 'electrum' %}hidden{% endif %}"
+             data-default-clearnet="{{ c.clearnet_servers_text }}"
+             data-default-onion="{{ c.onion_servers_text }}">
          <h4 class="text-sm font-medium text-gray-900 dark:text-white mb-4">
           Electrum Servers
          </h4>
@@ -213,7 +215,7 @@
          <div class="mb-6">
           <h5 class="text-xs font-medium text-gray-600 dark:text-gray-400 mb-3">Clearnet</h5>
           <div class="bg-gray-50 dark:bg-gray-700 rounded-lg p-4">
-           <textarea class="hover:border-blue-500 bg-gray-50 text-gray-900 appearance-none dark:bg-gray-700 dark:text-white border border-gray-300 dark:border-gray-600 dark:placeholder-gray-400 text-sm rounded-lg outline-none focus:ring-blue-500 focus:border-blue-500 block w-full p-2.5 focus:ring-1 focus:outline-none font-mono" name="electrum_clearnet_{{ c.name }}" id="electrum_clearnet_{{ c.name }}" rows="3" placeholder="electrum.blockstream.info:50002&#10;electrum.emzy.de:50002">{{ c.clearnet_servers_text }}</textarea>
+           <textarea class="hover:border-blue-500 bg-gray-50 text-gray-900 appearance-none dark:bg-gray-700 dark:text-white border border-gray-300 dark:border-gray-600 dark:placeholder-gray-400 text-sm rounded-lg outline-none focus:ring-blue-500 focus:border-blue-500 block w-full p-2.5 focus:ring-1 focus:outline-none font-mono" name="electrum_clearnet_{{ c.name }}" id="electrum_clearnet_{{ c.name }}" rows="3" placeholder="electrum.blockstream.info:50002&#10;electrum.emzy.de:50002">{% if c.connection_type == 'electrum' %}{{ c.clearnet_servers_text }}{% endif %}</textarea>
            <p class="text-xs text-gray-500 dark:text-gray-400 mt-1">One per line. Format: host:port (50002=SSL, 50001=non-SSL)</p>
           </div>
          </div>
@@ -221,7 +223,7 @@
          <div class="mb-4 pt-2">
           <h5 class="text-xs font-medium text-gray-600 dark:text-gray-400 mb-3">TOR (.onion)</h5>
           <div class="bg-gray-50 dark:bg-gray-700 rounded-lg p-4">
-           <textarea class="hover:border-blue-500 bg-gray-50 text-gray-900 appearance-none dark:bg-gray-700 dark:text-white border border-gray-300 dark:border-gray-600 dark:placeholder-gray-400 text-sm rounded-lg outline-none focus:ring-blue-500 focus:border-blue-500 block w-full p-2.5 focus:ring-1 focus:outline-none font-mono text-xs" name="electrum_onion_{{ c.name }}" id="electrum_onion_{{ c.name }}" rows="3" placeholder="explorerzyd...onion:110&#10;lksvbmwwi2b...onion:50001">{{ c.onion_servers_text }}</textarea>
+           <textarea class="hover:border-blue-500 bg-gray-50 text-gray-900 appearance-none dark:bg-gray-700 dark:text-white border border-gray-300 dark:border-gray-600 dark:placeholder-gray-400 text-sm rounded-lg outline-none focus:ring-blue-500 focus:border-blue-500 block w-full p-2.5 focus:ring-1 focus:outline-none font-mono text-xs" name="electrum_onion_{{ c.name }}" id="electrum_onion_{{ c.name }}" rows="3" placeholder="explorerzyd...onion:110&#10;lksvbmwwi2b...onion:50001">{% if c.connection_type == 'electrum' %}{{ c.onion_servers_text }}{% endif %}</textarea>
            <p class="text-xs text-gray-500 dark:text-gray-400 mt-1">One per line. Used when TOR is enabled.</p>
           </div>
          </div>
@@ -253,8 +255,10 @@
            </div>
           </div>
          </div>
+
         </div>
-        <div class="mb-6">
+
+        <div id="fund-transfer-section-{{ c.name }}" class="mb-6 hidden">
          <h4 class="text-sm font-medium text-gray-900 dark:text-white mb-4">
           Fund Transfer
          </h4>

basicswap/ui/page_settings.py

@@ -266,10 +266,10 @@ def page_settings(self, url_split, post_string):
         clearnet_servers = c.get("electrum_clearnet_servers", None)
         onion_servers = c.get("electrum_onion_servers", None)
 
-        if clearnet_servers is None:
+        if not clearnet_servers:
             default_clearnet = DEFAULT_ELECTRUM_SERVERS.get(name, [])
             clearnet_servers = [f"{s['host']}:{s['port']}" for s in default_clearnet]
-        if onion_servers is None:
+        if not onion_servers:
             default_onion = DEFAULT_ONION_SERVERS.get(name, [])
             onion_servers = [f"{s['host']}:{s['port']}" for s in default_onion]