Mqtt discovery (#320)

* add mqtt discovery (compatibile with home assistant) with omg status binary sensor & bme280 sensor

* added mqtt discovery to Test_config.h for ESP32 (ESP8266 & other boards was not tested)

* include support for ESP8266 & arduino mega

* fix getting MAC for esp8266

* esp8266 fix

* make mqtt discovery functions functions more generic, readable and easy to use & extend

* make mqtt discovery functions functions more generic, readable and easy to use & extend PART 2

* remove the macro for each attribute and supposing that if there is a bme280 we expose all

ZmqttDiscovery.ino

@@ -0,0 +1,166 @@
+/*
+  OpenMQTTGateway Addon  - ESP8266 or Arduino program for home automation
+
+   Act as a wifi or ethernet gateway between your 433mhz/infrared IR signal  and a MQTT broker
+   Send and receiving command by MQTT
+
+   This is the Home Assistant mqtt Discovery addon.
+
+    Copyright: (c) Rafal Herok
+
+    This file is part of OpenMQTTGateway.
+
+    OpenMQTTGateway is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    OpenMQTTGateway is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifdef ZmqttDiscovery
+
+void pubMqttDiscovery()
+{
+#ifdef omgStatus
+  trc(F("omgStatusDiscovery"));
+  createDiscovery("binary_sensor",                                      //set sensorType
+                  will_Topic, DEVICENAME, getUniqueId("omg", "status"), //set state_topic,name,uniqueId
+                  "", "connectivity", "",                               //set availability_topic,device_class,value_template,
+                  Gateway_AnnouncementMsg, will_Message, "",            //set,payload_on,payload_off,unit_of_meas,
+                  true, false, 0);                                      //set optimistic,retain, off_delay
+#endif
+#ifdef discBme280
+  trc(F("bme280Discovery"));
+  createDiscovery("sensor",
+                  BME, "tempc", getUniqueId("bme", "tempc"),
+                  will_Topic, "temperature", "{{ value_json.tempc }}",
+                  "", "", "°C",
+                  true, false, 0);
+  createDiscovery("sensor",
+                  BME, "tempf", getUniqueId("bme", "tempf"),
+                  will_Topic, "temperature", "{{ value_json.tempf }}",
+                  "", "", "°F",
+                  true, false, 0);
+  createDiscovery("sensor",
+                  BME, "pa", getUniqueId("bme", "pa"),
+                  will_Topic, "pressure", "{{ float(value_json.pa) * 0.01 }}",
+                  "", "", "hPa",
+                  true, false, 0);
+  createDiscovery("sensor",
+                  BME, "hum", getUniqueId("bme", "hum"),
+                  will_Topic, "humidity", "{{ value_json.hum }}",
+                  "", "", "%",
+                  true, false, 0);
+  createDiscovery("sensor",
+                  BME, "altim", getUniqueId("bme", "altim"),
+                  will_Topic, "", "{{ value_json.altim }}",
+                  "", "", "m",
+                  true, false, 0);
+  createDiscovery("sensor",
+                  BME, "altift", getUniqueId("bme", "altift"),
+                  will_Topic, "", "{{ value_json.altift }}",
+                  "", "", "ft",
+                  true, false, 0);
+#endif
+}
+
+void createDiscovery(String sensor_type,
+                     String state_topic, String name, String unique_id,
+                     String availability_topic, String device_class, String value_template,
+                     String payload_on, String payload_off, String unit_of_meas,
+                     bool optimistic, bool retain, int off_delay)
+{
+  StaticJsonBuffer<JSON_MSG_BUFFER> jsonBuffer3;
+  JsonObject &sensor = jsonBuffer3.createObject();
+  sensor.set("stat_t", state_topic); //state_topic
+  sensor.set("name", name);          //name
+  sensor.set("uniq_id", unique_id);  //unique_id
+  if (availability_topic != "")
+  {
+    sensor.set("avty_t", availability_topic); //availability_topic
+  }
+  if (device_class != "")
+  {
+    sensor.set("dev_cla", device_class); //device_class
+  }
+  if (value_template != "")
+  {
+    sensor.set("val_tpl", value_template); //value_template
+  }
+  if (payload_on != "")
+  {
+    sensor.set("pl_on", payload_on); // payload_on
+  }
+  if (payload_off != "")
+  {
+    sensor.set("pl_off", payload_off); //payload_off
+  }
+  if (unit_of_meas != "")
+  {
+    sensor.set("unit_of_meas", unit_of_meas); //unit_of_measurement
+  }
+  if (optimistic != true)
+  {
+    sensor.set("opt", optimistic); //optimistic
+  }
+  if (retain != false)
+  {
+    sensor.set("ret", retain); //retain
+  }
+  if (off_delay > 0)
+  {
+    sensor.set("off_delay", off_delay); //off_delay
+  }
+
+  char JSONmessageBuffer[JSON_MSG_BUFFER];
+  StaticJsonBuffer<JSON_MSG_BUFFER> jsonDeviceBuffer;
+  JsonObject &device = jsonDeviceBuffer.createObject();
+  device.set("name", DEVICENAME);
+  device.set("manufacturer", DEVICEMANUFACTURER);
+  device.set("sw_version", OMG_VERSION);
+  JsonArray &identifiers = device.createNestedArray("identifiers");
+  identifiers.add(getMacAddress());
+
+  sensor.set("device", device); //device sensor is connected to
+
+  String topic = (String)discovery_Topic + "/" + sensor_type + "/" + unique_id + "/config";
+  pubDiscovery(topic, sensor);
+}
+
+void pubDiscovery(String topicori, JsonObject &data)
+{
+  char JSONmessageBuffer[JSON_MSG_BUFFER];
+  trc(F("Pub json into:"));
+  trc(topicori);
+  data.printTo(JSONmessageBuffer, sizeof(JSONmessageBuffer));
+  trc(JSONmessageBuffer);
+  client.publish((char *)topicori.c_str(), JSONmessageBuffer, true);
+}
+
+String getMacAddress()
+{
+  uint8_t baseMac[6];
+#ifdef ESP8266
+  WiFi.macAddress(baseMac);
+#else
+  esp_read_mac(baseMac, ESP_MAC_WIFI_STA);
+#endif
+  char baseMacChr[13] = {0};
+  sprintf(baseMacChr, "%02X%02X%02X%02X%02X%02X", baseMac[0], baseMac[1], baseMac[2], baseMac[3], baseMac[4], baseMac[5]);
+  return String(baseMacChr);
+}
+
+String getUniqueId(String name, String sufix)
+{
+  String uniqueId = (String)getMacAddress() + name + sufix;
+  return String(uniqueId);
+}
+
+#endif