Preserve MQTT settings across slot changes

src/helpers/CLICommandUtils.h

@@ -675,6 +675,14 @@ inline bool parseUnsignedIntegerStrict(const char* text, uint32_t& result) {
   return true;
 }
 
+// Zero clears a custom port override; a full broker URI supplies its default.
+inline bool parseMqttPort(const char* text, uint16_t& result) {
+  uint32_t value;
+  if (!parseUnsignedIntegerStrict(text, value) || value > 65535) return false;
+  result = static_cast<uint16_t>(value);
+  return true;
+}
+
 // Copy and split a bounded CLI argument string on runs of spaces/tabs. This
 // provides scanf-like token handling without pulling scanf into firmware. The
 // caller controls the maximum accepted token count through field_capacity.

src/helpers/CommonCLI_Observer.cpp

@@ -574,14 +574,14 @@ bool CommonCLI::handleObserverSetCmd(uint32_t sender_timestamp, const char* conf
       _callbacks->restartBridgeSlot(slot);
       strcpy(reply, "OK");
     } else if (memcmp(subcmd, "port ", 5) == 0) {
-      int port = atoi(&subcmd[5]);
-      if (port > 0 && port <= 65535) {
+      uint16_t port;
+      if (mesh::cli::parseMqttPort(&subcmd[5], port)) {
         _mqtt_prefs.mqtt_slot_port[slot] = port;
         saveObserverPrefs();
         _callbacks->restartBridgeSlot(slot);
         strcpy(reply, "OK");
       } else {
-        strcpy(reply, "Error: port must be between 1 and 65535");
+        strcpy(reply, "Error: port must be 0-65535 (0 uses the URI default)");
       }
     } else if (memcmp(subcmd, "username ", 9) == 0) {
       if (valueTooLong(&subcmd[9], sizeof(_mqtt_prefs.mqtt_slot_username[slot]), reply, "username")) return true;

src/helpers/CompanionMqttSetupPortal.cpp

@@ -612,31 +612,38 @@ bool CompanionMqttSetupPortal::loadStoredConfig(MQTTPrefs& prefs) {
     return false;
   }
 
-  const char* preset = loaded.mqtt_slot_preset[0];
-  const bool custom = strcmp(preset, MQTT_PRESET_CUSTOM) == 0;
-  const MQTTPresetDef* preset_def = custom ? nullptr : findMQTTPreset(preset);
-  if (!preset[0] || (!custom && !preset_def)) return false;
-  if (custom) {
-    const char* host = loaded.mqtt_slot_host[0];
-    if (!host[0]
-        || (loaded.mqtt_slot_port[0] == 0 && strstr(host, "://") == nullptr)
-        || (!loaded.mqtt_slot_topic[0][0] && !isThreeLetterCode(loaded.mqtt_iata))) {
-      return false;
-    }
-  } else {
-    if (preset_def->topic_style == MQTT_TOPIC_MESHCORE
-        && !isThreeLetterCode(loaded.mqtt_iata)) return false;
-    if (preset_def->topic_style == MQTT_TOPIC_MESHRANK
-        && !loaded.mqtt_slot_token[0][0]) return false;
-    if (mqttPresetNeedsSlotCredentials(preset_def)
-        && (!loaded.mqtt_slot_username[0][0] || !loaded.mqtt_slot_password[0][0])) {
-      return false;
-    }
-  }
+  // Incomplete and disabled slots are valid saved settings. Readiness is a
+  // separate decision, so disabling slot 1 or saving a broker in stages cannot
+  // discard all slots and credentials on the next boot.
   prefs = loaded;
   return true;
 }
 
+bool CompanionMqttSetupPortal::hasConfiguredSlot(const MQTTPrefs& prefs) {
+  for (int i = 0; i < RUNTIME_MQTT_SLOTS; ++i) {
+    const char* preset = prefs.mqtt_slot_preset[i];
+    if (!preset[0] || strcmp(preset, MQTT_PRESET_NONE) == 0) continue;
+    if (strcmp(preset, MQTT_PRESET_CUSTOM) == 0) {
+      const char* host = prefs.mqtt_slot_host[i];
+      if (host[0] && (prefs.mqtt_slot_port[i] != 0 || strstr(host, "://"))
+          && (prefs.mqtt_slot_topic[i][0] || isThreeLetterCode(prefs.mqtt_iata))) {
+        return true;
+      }
+      continue;
+    }
+    const MQTTPresetDef* def = findMQTTPreset(preset);
+    if (!def) continue;
+    if (def->topic_style == MQTT_TOPIC_MESHCORE
+        && !isThreeLetterCode(prefs.mqtt_iata)) continue;
+    if (def->topic_style == MQTT_TOPIC_MESHRANK
+        && !prefs.mqtt_slot_token[i][0]) continue;
+    if (mqttPresetNeedsSlotUsername(def) && !prefs.mqtt_slot_username[i][0]) continue;
+    if (mqttPresetNeedsSlotPassword(def) && !prefs.mqtt_slot_password[i][0]) continue;
+    return true;
+  }
+  return false;
+}
+
 bool CompanionMqttSetupPortal::loadEnabled() {
   Preferences nvs;
   if (!nvs.begin(NVS_NAMESPACE, false)) return true;

src/helpers/CompanionMqttSetupPortal.h

@@ -20,6 +20,7 @@ public:
   bool isActive() const { return _active; }
 
   static bool loadStoredConfig(MQTTPrefs& prefs);
+  static bool hasConfiguredSlot(const MQTTPrefs& prefs);
   static bool saveStoredConfig(const MQTTPrefs& prefs);
   static bool loadEnabled();
   static bool saveEnabled(bool enabled);

src/helpers/esp32/WebConfigServer.cpp

@@ -1671,7 +1671,9 @@ void WebConfigServer::handleStatus(AsyncWebServerRequest* req) {
 #ifdef WITH_MQTT_BRIDGE
   doc["runtime_slots"] = has_mqtt ? RUNTIME_MQTT_SLOTS : 0;
   doc["max_slots"] = has_mqtt ? MAX_MQTT_SLOTS : 0;
-  doc["active_slots"] = has_mqtt ? MQTTBridge::getMaxActiveSlots() : 0;
+  const int active_slots = MQTTBridge::getMaxActiveSlots();
+  doc["active_slots"] = has_mqtt
+      ? (active_slots < RUNTIME_MQTT_SLOTS ? active_slots : RUNTIME_MQTT_SLOTS) : 0;
 #else
   doc["runtime_slots"] = 0;
   doc["max_slots"] = 0;