MQTT: add HA auto-discovery, meter metadata, drop maxduty

- Add name/unit/range fields per meter (saved to config, shown in web form)
- Publish Home Assistant MQTT discovery configs for each meter (number entity)
- Add MQTT_MANUFACTURER constant at top of file
- Increase PubSubClient buffer to 1024 bytes for discovery payloads
- Remove maxduty from MQTT subscription and HA discovery
- Publish current state on MQTT connect and on MQTT-set changes

src/main.cpp

@@ -11,11 +11,15 @@
 #define MAX_METERS 10
 #define PWM_FREQ 5000
 #define PWM_RES 10
+#define MQTT_MANUFACTURER "Baumann Enkataleiptics"
 
 struct MeterConfig {
   int pin;
   float maxDuty;
   float currentValue;
+  char name[32] = "";
+  char unit[16] = "";
+  float range = 100.0;
 };
 
 struct MqttConfig {
@@ -72,6 +76,9 @@ static void loadConfig() {
     meters[i].pin          = m["pin"]     | 0;
     meters[i].maxDuty      = m["maxD"]    | 0.0f;
     meters[i].currentValue = m["current"] | 0.0f;
+    strlcpy(meters[i].name, m["name"] | "", sizeof(meters[i].name));
+    strlcpy(meters[i].unit, m["unit"] | "", sizeof(meters[i].unit));
+    meters[i].range        = m["range"]   | 100.0f;
   }
   Serial.printf("[CFG] loaded hostname=%s meters=%d mqtt_en=%d\n", hostname, meterCount, mqttCfg.enabled);
 }
@@ -94,6 +101,9 @@ static void saveConfig() {
     m["pin"]     = meters[i].pin;
     m["maxD"]    = meters[i].maxDuty;
     m["current"] = meters[i].currentValue;
+    m["name"]    = meters[i].name;
+    m["unit"]    = meters[i].unit;
+    m["range"]   = meters[i].range;
   }
 
   File f = LittleFS.open("/config.json", "w");
@@ -134,6 +144,8 @@ static void applyMeters() {
 // MQTT
 // ---------------------------------------------------------------------------
 
+static void mqttPublishCurrent(int idx);
+
 static void mqttCallback(char* topic, byte* payload, unsigned int len) {
   String valStr;
   for (unsigned i = 0; i < len; i++) valStr += (char)payload[i];
@@ -161,12 +173,7 @@ static void mqttCallback(char* topic, byte* payload, unsigned int len) {
       ledcWrite(idx, constrain((int)(pct * 1023), 0, 1023));
     }
     saveConfig();
-  } else if (suffix == "/maxduty/set") {
+    mqttPublishCurrent(idx);
-    Serial.printf("[MQTT] set meter%d maxduty=%.1f\n", idx, val);
-    meters[idx].maxDuty = constrain(val, 0, 100);
-    attachMeters();
-    applyMeters();
-    saveConfig();
   }
 }
 
@@ -179,6 +186,45 @@ static void mqttPublishCurrent(int idx) {
   Serial.printf("[MQTT] publish topic=%s val=%s ok=%d\n", topic, val, ok);
 }
 
+static void mqttPublishDiscovery() {
+  if (!mqttCfg.enabled || !mqttClient.connected()) return;
+
+  uint8_t mac[6];
+  WiFi.macAddress(mac);
+  char devId[32];
+  snprintf(devId, sizeof(devId), "m1730_%02x%02x%02x", mac[3], mac[4], mac[5]);
+
+  for (int i = 0; i < meterCount; i++) {
+    String objId = String(devId) + "_meter_" + String(i) + "_current";
+    String stat  = String(mqttCfg.prefix) + "/meter/" + String(i) + "/current";
+    String name  = strlen(meters[i].name) > 0
+      ? String(meters[i].name)
+      : "Meter " + String(i);
+
+    JsonDocument doc;
+    doc["unique_id"]         = objId;
+    doc["name"]              = name;
+    doc["state_topic"]       = stat;
+    doc["command_topic"]     = stat + "/set";
+    doc["min"]               = 0;
+    doc["max"]               = 100;
+    doc["step"]              = 0.1;
+    if (strlen(meters[i].unit) > 0)
+      doc["unit_of_measurement"] = meters[i].unit;
+    doc["device"]["identifiers"][0] = devId;
+    doc["device"]["name"]    = hostname;
+    doc["device"]["manufacturer"] = MQTT_MANUFACTURER;
+    doc["device"]["model"]   = "ESP32";
+
+    char topic[128];
+    snprintf(topic, sizeof(topic), "homeassistant/number/%s/config", objId.c_str());
+    char payload[512];
+    serializeJson(doc, payload, sizeof(payload));
+    bool pubOk = mqttClient.publish(topic, payload, true);
+    Serial.printf("[MQTT] discovery %s -> %s (ok=%d)\n", topic, payload, pubOk);
+  }
+}
+
 static void mqttSubscribe() {
   if (!mqttCfg.enabled) return;
   for (int i = 0; i < meterCount; i++) {
@@ -186,9 +232,6 @@ static void mqttSubscribe() {
     snprintf(t, sizeof(t), "%s/meter/%d/current/set", mqttCfg.prefix, i);
     mqttClient.subscribe(t);
     Serial.printf("[MQTT] subscribed %s\n", t);
-    snprintf(t, sizeof(t), "%s/meter/%d/maxduty/set", mqttCfg.prefix, i);
-    mqttClient.subscribe(t);
-    Serial.printf("[MQTT] subscribed %s\n", t);
   }
 }
 
@@ -211,6 +254,7 @@ static bool mqttConnect() {
 
   mqttClient.setServer(mqttCfg.host, mqttCfg.port);
   mqttClient.setCallback(mqttCallback);
+  mqttClient.setBufferSize(1024);
 
   Serial.printf("[MQTT] connecting to %s:%d as %s\n", mqttCfg.host, mqttCfg.port, clientId);
   bool ok = mqttClient.connect(clientId, mqttCfg.user, mqttCfg.pass,
@@ -220,6 +264,9 @@ static bool mqttConnect() {
     Serial.printf("[MQTT] connected to %s:%d\n", mqttCfg.host, mqttCfg.port);
     mqttClient.publish(statusTopic, "online: true", true);
     mqttSubscribe();
+    mqttPublishDiscovery();
+    for (int i = 0; i < meterCount; i++)
+      mqttPublishCurrent(i);
   } else {
     Serial.printf("[MQTT] failed rc=%d\n", mqttClient.state());
   }
@@ -294,11 +341,19 @@ static void handleRoot() {
     dtostrf(meters[i].maxDuty, 1, 1, maxStr);
     dtostrf(meters[i].currentValue, 1, 1, curStr);
 
+    String nameVal = escHtml(meters[i].name);
+    String unitVal = escHtml(meters[i].unit);
+    char rangeStr[8];
+    dtostrf(meters[i].range, 1, 1, rangeStr);
+
     meterRows += "<fieldset><legend>Meter " + String(i) + "</legend>";
     meterRows += "<div class=row><label>Pin</label><input name=m" + String(i) + "_pin type=number min=0 max=99 value=" + String(meters[i].pin) + "></div>";
-    meterRows += "<div class=row><label>Max Duty %</label><input name=m" + String(i) + "_maxD type=number step=any min=0 max=100 value=" + String(maxStr) + "></div>";
+    meterRows += "<div class=row><label>Name</label><input name=m" + String(i) + "_name value='" + nameVal + "'></div>";
+    meterRows += "<div class=row><label>Unit</label><input name=m" + String(i) + "_unit value='" + unitVal + "'></div>";
+    meterRows += "<div class=row><label>Range</label><input name=m" + String(i) + "_range type=number step=any min=0 value=" + String(rangeStr) + "></div>";
+    meterRows += "<div class=row><label>Max Duty</label><input name=m" + String(i) + "_maxD type=number step=any min=0 max=100 value=" + String(maxStr) + "></div>";
     meterRows += "<div class=slider-row>";
-    meterRows += "<label>Output %</label>";
+    meterRows += "<label>Output</label>";
     meterRows += "<input name=m" + String(i) + "_cur type=range min=0 max=100 step=0.1 value=" + String(curStr) + ">";
     meterRows += "<span class=val id=m" + String(i) + ">" + String(curStr) + "%</span>";
     meterRows += "</div></fieldset>";
@@ -430,6 +485,12 @@ static void handleConfig() {
     String pf = "m" + String(i) + "_";
     if (server.hasArg(pf + "pin"))
       newMeters[i].pin = server.arg(pf + "pin").toInt();
+    if (server.hasArg(pf + "name"))
+      strlcpy(newMeters[i].name, server.arg(pf + "name").c_str(), sizeof(newMeters[i].name));
+    if (server.hasArg(pf + "unit"))
+      strlcpy(newMeters[i].unit, server.arg(pf + "unit").c_str(), sizeof(newMeters[i].unit));
+    if (server.hasArg(pf + "range"))
+      newMeters[i].range = server.arg(pf + "range").toFloat();
     if (server.hasArg(pf + "maxD"))
       newMeters[i].maxDuty = server.arg(pf + "maxD").toFloat();
     if (server.hasArg(pf + "cur"))
@@ -439,7 +500,8 @@ static void handleConfig() {
   meterCount = newCount;
   memcpy(meters, newMeters, sizeof(meters));
   for (int i = 0; i < meterCount; i++)
-    Serial.printf("[HTTP] meter%d pin=%d maxD=%.1f cur=%.1f\n", i, meters[i].pin, meters[i].maxDuty, meters[i].currentValue);
+    Serial.printf("[HTTP] meter%d pin=%d name=%s unit=%s range=%.1f maxD=%.1f cur=%.1f\n",
+      i, meters[i].pin, meters[i].name, meters[i].unit, meters[i].range, meters[i].maxDuty, meters[i].currentValue);
 
   saveConfig();
   attachMeters();