Refactor with Start() and Stop()

This reduces the lines of code of the main() function significantly and
groups all start and stop actions.

1 files changed, 32 insertions, 16 deletions

diff --git a/main.go b/main.go
index 91f65ba..67af965 100644
--- a/main.go
+++ b/main.go
@@ -24,24 +24,11 @@ func main() {
 	log.Println("+++ Started Sia server +++")
 	defer log.Println("--- Stopped Sia server ---")
 
-	req := homematic.NewRequester(OPENCCU)
-	log.Printf("Created Homematic requester (%s).", OPENCCU)
-
-	inventory, err := req.ListDevices()
+	req, inventory, client, err := Start()
+	defer Stop(client)
 	if err != nil {
-		log.Fatalf("Failed to retrieve device list: %v", err)
+		log.Fatalf("Failed startup process: %v", err)
 	}
-	log.Printf("Retrieved Homematic inventory with %d devices.", len(inventory))
-
-	client, err := ConnectMQTT(BROKER, CLIENT_ID)
-	if err != nil {
-		log.Fatalf("Could not connect to MQTT broker: %v", err)
-	}
-	defer func () {
-		client.Disconnect(MQTT_DISCONNECT_TIMEOUT_US)
-		log.Println("Disconnected from MQTT broker.")
-	}()
-	log.Printf("Connected to MQTT broker (%s).", BROKER)
 
 	for _, device := range inventory {
 		if device.Type == `SHUTTER_CONTACT` {
@@ -79,3 +66,32 @@ func ConnectMQTT(broker string, id string) (mqtt.Client, error) {
 
 	return client, nil
 }
+
+func Start() (homematic.Requester, homematic.Devices, mqtt.Client, error) {
+	var req homematic.Requester
+	var inventory homematic.Devices
+	var client mqtt.Client
+	var err error
+
+	req = homematic.NewRequester(OPENCCU)
+	log.Printf("Created Homematic requester (%s).", OPENCCU)
+
+	inventory, err = req.ListDevices()
+	if err != nil {
+		return req, inventory, client, fmt.Errorf("Failed getting initial device list: %w", err)
+	}
+	log.Printf("Retrieved Homematic inventory with %d devices.", len(inventory))
+
+	client, err = ConnectMQTT(BROKER, CLIENT_ID)
+	if err != nil {
+		return req, inventory, client, fmt.Errorf("Failed connecting to MQTT broker: %w", err)
+	}
+	log.Printf("Connected to MQTT broker (%s).", BROKER)
+
+	return req, inventory, client, nil
+}
+
+func Stop(c mqtt.Client) {
+	c.Disconnect(MQTT_DISCONNECT_TIMEOUT_US)
+	log.Println("Disconnected from MQTT broker.")
+}