From 221afa98b05b85924a271c8c1dcb74ac7b19567f Mon Sep 17 00:00:00 2001
From: Florian <1technophile@users.noreply.github.com>
Date: Thu, 18 Mar 2021 15:07:59 -0500
Subject: [PATCH] Change uptime calculation method (#901)

and revert #897
---
 main/ZmqttDiscovery.ino |  2 +-
 main/main.ino           | 18 ++++++++++++++++--
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/main/ZmqttDiscovery.ino b/main/ZmqttDiscovery.ino
index 2ae11d7..80478be 100644
--- a/main/ZmqttDiscovery.ino
+++ b/main/ZmqttDiscovery.ino
@@ -174,7 +174,7 @@ void pubMqttDiscovery() {
   createDiscovery("sensor", //set Type
                   subjectSYStoMQTT, "SYS: Uptime", (char*)getUniqueId("uptime", "").c_str(), //set state_topic,name,uniqueId
                   "", "", "{{ value_json.uptime }}", //set availability_topic,device_class,value_template,
-                  "", "", "min", //set,payload_on,payload_off,unit_of_meas,
+                  "", "", "s", //set,payload_on,payload_off,unit_of_meas,
                   0, //set  off_delay
                   "", "", true, "", //set,payload_avalaible,payload_not avalaible   ,is a gateway entity, command topic
                   "", "", "", "", false // device name, device manufacturer, device model, device mac, retain
diff --git a/main/main.ino b/main/main.ino
index dcb9b82..6b292a5 100644
--- a/main/main.ino
+++ b/main/main.ino
@@ -1318,12 +1318,26 @@ void loop() {
 #endif
 }
 
+/** 
+ * Calculate uptime and take into account the millis() rollover
+ */
+unsigned long uptime() {
+  static unsigned long lastUptime = 0;
+  static unsigned long uptimeAdd = 0;
+  unsigned long uptime = millis() / 1000 + uptimeAdd;
+  if (uptime < lastUptime) {
+    uptime += 4294967;
+    uptimeAdd += 4294967;
+  }
+  lastUptime = uptime;
+  return uptime;
+}
+
 #if defined(ESP8266) || defined(ESP32) || defined(__AVR_ATmega2560__) || defined(__AVR_ATmega1280__)
 void stateMeasures() {
   StaticJsonBuffer<JSON_MSG_BUFFER> jsonBuffer;
   JsonObject& SYSdata = jsonBuffer.createObject();
-  unsigned long uptime = millis() / 60000; //minutes uptime
-  SYSdata["uptime"] = uptime;
+  SYSdata["uptime"] = uptime();
   SYSdata["version"] = OMG_VERSION;
   Log.trace(F("retrieving value of system characteristics Uptime (min):%u" CR), uptime);
 #  if defined(ESP8266) || defined(ESP32)