Use suffix instead of prefix of serial number for topic / Multiple Inverter Support

hms2mqtt/src/home_assistant.rs

@@ -71,7 +71,12 @@ impl HMSStateResponse {
     }
 
     fn short_dtu_sn(&self) -> String {
-        self.dtu_sn[..8].to_string()
+        let suffix = {
+            let split_pos = self.dtu_sn.char_indices().nth_back(8).unwrap().0;
+            &self.dtu_sn[split_pos..]
+        };
+
+        suffix.to_string()
     }
 
     fn get_total_efficiency(&self) -> f32 {

hms2mqtt/src/mqtt_config.rs

@@ -6,5 +6,6 @@ pub struct MqttConfig {
     pub port: Option<u16>,
     pub username: Option<String>,
     pub password: Option<String>,
+    pub client_id: Option<String>,
     pub tls: Option<bool>,
 }

src/bin/hms-mqtt-publish/rumqttc_wrapper.rs

@@ -63,10 +63,14 @@ impl mqtt_wrapper::MqttWrapper for RumqttcWrapper {
     }
 
     fn new(config: &MqttConfig, suffix: &str) -> Self {
+
         let use_tls = config.tls.is_some_and(|tls| tls);
 
+        let mut client_id = config.client_id.as_deref().unwrap_or("hms-mqtt-publish").to_string();
+        client_id.push_str(suffix);
+
         let mut mqttoptions = MqttOptions::new(
-            "hms800wt2-mqtt-publisher".to_string() + suffix,
+            &client_id, 
             &config.host,
             config.port.unwrap_or_else(|| {
                 if use_tls {