From 9e5fb043146c14d0dab3672d32d19d2ab4de9d89 Mon Sep 17 00:00:00 2001
From: Laurent <loleaurc@gmail.com>
Date: Tue, 22 Jan 2019 20:02:34 +0100
Subject: [PATCH] Elapsed time (#909)

* new elapsed attribute giving the elapsed time since the previous msg

* configurable elapsed attribute

* Update deviceReceive.js

* Update deviceReceive.js
---
 docs/configuration/configuration.md |  4 +++-
 lib/extension/deviceReceive.js      | 14 ++++++++++++--
 lib/util/settings.js                |  3 +++
 3 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/docs/configuration/configuration.md b/docs/configuration/configuration.md
index 138b3b50d..9dcd6aab3 100644
--- a/docs/configuration/configuration.md
+++ b/docs/configuration/configuration.md
@@ -58,4 +58,6 @@ advanced:
   # Optional: Add a last_seen attribute to MQTT messages, contains date/time of last Zigbee message
   # possible values are: disable (default), ISO_8601, epoch
   last_seen: 'disable'
-```
\ No newline at end of file
+  # Optional: Add an elapsed attribute to MQTT messages, contains milliseconds since the previous msg
+  elapsed: false
+```
diff --git a/lib/extension/deviceReceive.js b/lib/extension/deviceReceive.js
index 64817aa4b..651fe277c 100644
--- a/lib/extension/deviceReceive.js
+++ b/lib/extension/deviceReceive.js
@@ -13,6 +13,7 @@ class DeviceReceive {
         this.state = state;
         this.publishDeviceState = publishDeviceState;
         this.coordinator = null;
+        this.elapsed = {};
     }
 
     onZigbeeStarted() {
@@ -113,15 +114,24 @@ class DeviceReceive {
             }
 
             // Add last seen timestamp
+            const now = Date.now();
             switch (settings.get().advanced.last_seen) {
             case 'ISO_8601':
-                payload.last_seen = new Date().toISOString();
+                payload.last_seen = new Date(now).toISOString();
                 break;
             case 'epoch':
-                payload.last_seen = Date.now();
+                payload.last_seen = now;
                 break;
             }
 
+            if (settings.get().advanced.elapsed) {
+                if (this.elapsed[device.ieeeAddr]) {
+                    payload.elapsed = now - this.elapsed[device.ieeeAddr];
+                }
+ 
+                this.elapsed[device.ieeeAddr] = now;
+            }
+
             this.publishDeviceState(device, payload, cache);
         };
 
diff --git a/lib/util/settings.js b/lib/util/settings.js
index 052dbb9cb..90f1c93ab 100644
--- a/lib/util/settings.js
+++ b/lib/util/settings.js
@@ -39,6 +39,9 @@ const defaults = {
          */
         last_seen: 'disable',
 
+        // Optional: Add an elapsed attribute to MQTT messages, contains milliseconds since the previous msg
+        elapsed: false,
+
         /**
          * https://github.com/Koenkk/zigbee2mqtt/issues/685#issuecomment-449112250
          *