From 83fc1e357ffcd63e095130b8f7b10fb88cb82493 Mon Sep 17 00:00:00 2001
From: Dirk Jahnke <dirk.jahnke@mailbox.org>
Date: Mon, 28 Dec 2020 17:18:19 +0100
Subject: [PATCH] Added MQTT last will and testament

---
 src/main.cpp | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/main.cpp b/src/main.cpp
index 1c2fd43..1d8eefe 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -40,6 +40,12 @@ IPAddress mqttServerIP(192, 168, 89, 95);
 const char *mqttUser = "default";
 const char *mqttPassword = "12345678";
 
+const char *lwtTopic = "doorBellGW/LWT";
+const char *lwtMessage = "Offline";
+const char *onlineMessage = "Online";
+const bool lwtRetain = true;
+const int lwtQos = 2;
+
 const char *doorBellTopic = "doorBellGW/doorbell";
 const char *postboxFlapTopic = "doorBellGW/mailboxFlap";
 const char *postboxDoorTopic = "doorBellGW/mailboxDoor";
@@ -91,6 +97,11 @@ struct {
 };
 #define NUM_OUTPUTS (sizeof(myOutputs) / sizeof(myOutputs[0]))
 
+
+// Forward function declarations:
+void reconnect();
+void sendMqttMessage(const char *topic, const char *message);
+
 uint8_t getOutputIndexByPin(uint8_t pin) {
   for (unsigned int i=0; i<NUM_OUTPUTS; ++i) {
     if (myOutputs[i].pin == pin) {
@@ -193,9 +204,10 @@ void reconnect() {
   while (!mqttClient.connected()) {
     Serial.print(F("Attempting MQTT connection..."));
     // Attempt to connect
-    if (mqttClient.connect("doorBellGateway", mqttUser, mqttPassword)) {
+    if (mqttClient.connect("doorBellGateway", mqttUser, mqttPassword, lwtTopic, lwtQos, lwtRetain, lwtMessage)) {
       Serial.println(F("connected"));
       // Once connected, publish an announcement...
+      mqttClient.publish_P(lwtTopic, onlineMessage, lwtRetain);
       // mqttClient.publish("hello","hello world");
       // ... and resubscribe
       Serial.println(F("MQTT subscribe doorbell"));
@@ -208,7 +220,6 @@ void reconnect() {
           Serial.println(F("ERROR: Failed to subscribe"));
         }
       }
-
     } else {
       Serial.print(F("failed, rc="));
       Serial.print(mqttClient.state());