Merge branch 'discovery'

This allows the client to discover the existence of Shelly and TP-Link
devices.

6 files changed, 42 insertions, 7 deletions

diff --git a/README.md b/README.md
index cb3be93..e0555a0 100644
--- a/README.md
+++ b/README.md
@@ -118,9 +118,21 @@ For all terms not explained here see the [MQTT version 3.1.1 documentation][9].
     - `open`: contact is open
     - `closed`: contact is closed
 
+### `/cover/<id>`
+
+- description: Discovery of Shelly 2PM Gen3 covers
+- direction: Sia server to client
+- Quality of Service: QoS 1 (at least once)
+- retained: yes
+- receives will message: no
+- topic parameters:
+    - `id`: ID of the Shelly 2PM Gen3 cover
+- payloads:
+    - `exists`: a device with the given ID exists
+
 ### `/cover/<id>/movement`
 
-- description: Allows control of Shelly 2PM Gen3 covers
+- description: Control of Shelly 2PM Gen3 covers
 - direction: client to Sia server
 - Quality of Service: QoS 2 (exactly once)
 - retained: no
@@ -132,9 +144,21 @@ For all terms not explained here see the [MQTT version 3.1.1 documentation][9].
     - `retract`: cover decreases the covering surface
     - `stop`: cover stops current motion if given
 
+### `/plug/<id>`
+
+- description: Discovery of TP-Link HS100 Wi-Fi plugs
+- direction: Sia server to client
+- Quality of Service: QoS 1 (at least once)
+- retained: yes
+- receives will message: no
+- topic parameters:
+    - `id`: ID of the TP-Link HS100 Wi-Fi plug
+- payloads:
+    - `exists`: a device with the given ID exists
+
 ### `/plug/<id>/action`
 
-- description: Implements control of tp-link HS100 Wi-Fi plugs
+- description: Control of TP-Link HS100 Wi-Fi plugs
 - direction: client to Sia server
 - Quality of Service: QoS 2 (exactly once)
 - retained: no
diff --git a/cache.go b/cache.go
index 4e0eddc..18ce0c9 100644
--- a/cache.go
+++ b/cache.go
@@ -43,6 +43,7 @@ func (c *Cache) Update(states States) {
 			c.Tx <- MQTTMessage{
 				Topic: topic,
 				Payload: payload,
+				Retain: true,
 			}
 		}
 		c.States[id] = state
diff --git a/main.go b/main.go
index 3194359..ef59574 100644
--- a/main.go
+++ b/main.go
@@ -24,8 +24,8 @@ func main() {
 
 	go MQTTRun(config.MQTT, tx, coverMovement, plugAction)
 	go HomematicRun(config.Homematic, tx)
-	go ShellyRun(config.Shelly, coverMovement)
-	go TPLinkRun(config.TPLink, plugAction)
+	go ShellyRun(config.Shelly, tx, coverMovement)
+	go TPLinkRun(config.TPLink, tx, plugAction)
 
 	Await(syscall.SIGTERM, syscall.SIGINT)
 }
diff --git a/mqtt.go b/mqtt.go
index fd1cba1..acd0108 100644
--- a/mqtt.go
+++ b/mqtt.go
@@ -27,6 +27,7 @@ var (
 type MQTTMessage struct {
 	Topic   string
 	Payload []byte
+	Retain  bool
 }
 
 type Route struct {
@@ -60,6 +61,7 @@ func MQTTRun(config MQTTConfig, tx chan MQTTMessage, routes ...Route) {
 				message := MQTTMessage{
 					Topic: strings.TrimPrefix(msg.Topic(), config.TopicPrefix + "/"),
 					Payload: msg.Payload(),
+					Retain: msg.Retained(),
 				}
 				route.Destination <- message
 			})
@@ -88,7 +90,7 @@ func MQTTRun(config MQTTConfig, tx chan MQTTMessage, routes ...Route) {
 
 	for message := range tx {
 		topic := fmt.Sprintf("%s/%s", config.TopicPrefix, message.Topic)
-		client.Publish(topic, QoS1, RETAINED, message.Payload)
+		client.Publish(topic, QoS1, message.Retain, message.Payload)
 	}
 }
 
diff --git a/shelly.go b/shelly.go
index 508b393..2fa2fa6 100644
--- a/shelly.go
+++ b/shelly.go
@@ -9,7 +9,11 @@ import (
 	"github.com/gorilla/websocket"
 )
 
-func ShellyRun(config ShellyConfigs, route Route) {
+func ShellyRun(config ShellyConfigs, tx chan MQTTMessage, route Route) {
+	for _, shelly := range config {
+		tx <- MQTTMessage{fmt.Sprintf("cover/%s", shelly.ID), []byte("exists"), true}
+	}
+
 	for message := range route.Destination {
 		ip, command, err := parseMessage(config, message)
 		if err != nil {
diff --git a/tplink.go b/tplink.go
index 11d8ab1..a256e71 100644
--- a/tplink.go
+++ b/tplink.go
@@ -16,7 +16,11 @@ const (
 	TPLink_HS100_OFF = false
 )
 
-func TPLinkRun(config TPLinkConfigs, route Route) {
+func TPLinkRun(config TPLinkConfigs, tx chan MQTTMessage, route Route) {
+	for _, tplink := range config {
+		tx <- MQTTMessage{fmt.Sprintf("plug/%s", tplink.ID), []byte("exists"), true}
+	}
+
 	for message := range route.Destination {
 		ip, action, err := tplinkParseMessage(config, message)
 		if err != nil {