From a09f1dec878ec44a433047fa61117e75984743fe Mon Sep 17 00:00:00 2001
From: "Adrian A. Baumann" <ade@adebaumann.com>
Date: Sat, 27 Jun 2026 01:34:57 +0200
Subject: [PATCH] Clear retained HA discovery for removed meters

---
 src/main.cpp | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/main.cpp b/src/main.cpp
index 5a8700b..f71d842 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -272,6 +272,16 @@ static void mqttPublishDiscovery() {
     bool pubOk = mqttClient.publish(topic, payload, true);
     Serial.printf("[MQTT] discovery %s -> %s (ok=%d)\n", topic, payload, pubOk);
   }
+
+  // Clear retained discovery for slots no longer in use (meters removed) so
+  // Home Assistant drops the stale entities instead of keeping them forever.
+  for (int i = meterCount; i < MAX_METERS; i++) {
+    String objId = String(devId) + "_meter_" + String(i) + "_current";
+    char topic[128];
+    snprintf(topic, sizeof(topic), "homeassistant/number/%s/config", objId.c_str());
+    mqttClient.publish(topic, "", true);
+    Serial.printf("[MQTT] discovery clear %s\n", topic);
+  }
 }
 
 static void mqttSubscribe() {