From 75d9f34be6dbe96c3bbbaaf7190513c28aaba71b Mon Sep 17 00:00:00 2001
From: qubeck <qubeck@qubeck.de>
Date: Mon, 15 Jan 2018 13:56:00 +0100
Subject: [PATCH 1/2] Introduced alexa device separation via explicit mapping
 to prevent a race condition on fast changes (e.g. on alexa group state
 change)

---
 code/espurna/alexa.ino | 28 +++++++++++++++-------------
 1 file changed, 15 insertions(+), 13 deletions(-)

diff --git a/code/espurna/alexa.ino b/code/espurna/alexa.ino
index 35b1ba88..15accce0 100644
--- a/code/espurna/alexa.ino
+++ b/code/espurna/alexa.ino
@@ -9,16 +9,17 @@ Copyright (C) 2016-2018 by Xose Pérez <xose dot perez at gmail dot com>
 #if ALEXA_SUPPORT
 
 #include <fauxmoESP.h>
-
+#include <map>
 fauxmoESP alexa;
 
 // -----------------------------------------------------------------------------
 // ALEXA
 // -----------------------------------------------------------------------------
-
-bool _alexa_change = false;
-unsigned int _alexa_device_id = 0;
-bool _alexa_state = false;
+struct alexa_dev {
+  bool _alexa_change = false;
+  bool _alexa_state = false;
+};
+std::map<unsigned char, alexa_dev> alexa_devices;
 
 void _alexaWebSocketOnSend(JsonObject& root) {
     root["alexaVisible"] = 1;
@@ -57,10 +58,9 @@ void alexaSetup() {
         }
     }
 
-    alexa.onSetState([relays](unsigned char device_id, const char * name, bool state) {
-        _alexa_change = true;
-        _alexa_device_id = device_id;
-        _alexa_state = state;
+    alexa.onSetState([&](unsigned char device_id, const char * name, bool state) {
+        alexa_devices[device_id]._alexa_change = true;
+        alexa_devices[device_id]._alexa_state = state;
     });
 
     alexa.onGetState([relays](unsigned char device_id, const char * name) {
@@ -73,10 +73,12 @@ void alexaLoop() {
 
     alexa.handle();
 
-    if (_alexa_change) {
-        DEBUG_MSG_P(PSTR("[ALEXA] Device #%d state: %s\n"), _alexa_device_id, _alexa_state ? "ON" : "OFF");
-        _alexa_change = false;
-        relayStatus(_alexa_device_id, _alexa_state);
+    for (std::map<unsigned char, alexa_dev>::iterator it=alexa_devices.begin(); it!=alexa_devices.end(); ++it) {
+      if (it->second._alexa_change) {
+          DEBUG_MSG_P(PSTR("[ALEXA] Device #%d state: %s\n"), it->first, it->second._alexa_state ? "ON" : "OFF");
+          it->second._alexa_change = false;
+          relayStatus(it->first, it->second._alexa_state);
+      }
     }
 
 }

From 0f948e0498a74e51b80905b4e047bce52060467f Mon Sep 17 00:00:00 2001
From: qubeck <qubeck@qubeck.de>
Date: Mon, 15 Jan 2018 16:09:30 +0100
Subject: [PATCH 2/2] changed alexa change propagation to a queue based impl.
 to be more efficient

---
 code/espurna/alexa.ino | 27 +++++++++++++--------------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/code/espurna/alexa.ino b/code/espurna/alexa.ino
index 15accce0..a7991bac 100644
--- a/code/espurna/alexa.ino
+++ b/code/espurna/alexa.ino
@@ -9,17 +9,18 @@ Copyright (C) 2016-2018 by Xose Pérez <xose dot perez at gmail dot com>
 #if ALEXA_SUPPORT
 
 #include <fauxmoESP.h>
-#include <map>
+#include <queue>
 fauxmoESP alexa;
 
 // -----------------------------------------------------------------------------
 // ALEXA
 // -----------------------------------------------------------------------------
-struct alexa_dev {
-  bool _alexa_change = false;
-  bool _alexa_state = false;
+struct AlexaDevChange {
+  AlexaDevChange(unsigned char device_id, bool state) : device_id(device_id), state(state) {};
+  unsigned char device_id = 0;
+  bool state = false;
 };
-std::map<unsigned char, alexa_dev> alexa_devices;
+static std::queue<AlexaDevChange> _alexa_dev_changes;
 
 void _alexaWebSocketOnSend(JsonObject& root) {
     root["alexaVisible"] = 1;
@@ -59,8 +60,8 @@ void alexaSetup() {
     }
 
     alexa.onSetState([&](unsigned char device_id, const char * name, bool state) {
-        alexa_devices[device_id]._alexa_change = true;
-        alexa_devices[device_id]._alexa_state = state;
+        AlexaDevChange change(device_id, state);
+        _alexa_dev_changes.push(change);
     });
 
     alexa.onGetState([relays](unsigned char device_id, const char * name) {
@@ -73,14 +74,12 @@ void alexaLoop() {
 
     alexa.handle();
 
-    for (std::map<unsigned char, alexa_dev>::iterator it=alexa_devices.begin(); it!=alexa_devices.end(); ++it) {
-      if (it->second._alexa_change) {
-          DEBUG_MSG_P(PSTR("[ALEXA] Device #%d state: %s\n"), it->first, it->second._alexa_state ? "ON" : "OFF");
-          it->second._alexa_change = false;
-          relayStatus(it->first, it->second._alexa_state);
-      }
+    while (!_alexa_dev_changes.empty()) {
+      AlexaDevChange& change = _alexa_dev_changes.front();
+      DEBUG_MSG_P(PSTR("[ALEXA] Device #%d state: %s\n"), change.device_id, change.state ? "ON" : "OFF");
+      relayStatus(change.device_id, change.state);
+      _alexa_dev_changes.pop();
     }
-
 }
 
 #endif