Read autoconnect ID out of configuration file, save config file

on any change to autoconnect ID.

main.go

@@ -25,12 +25,14 @@ import (
 )
 
 type conf struct {
+	Autoconnect string
 }
 
 var Config conf
+var conffile string
 
 func main() {
-	conffile := path.Join(confDir, "config.yml")
+	conffile = path.Join(confDir, "config.yml")
 	if _, err := os.Stat(conffile); os.IsNotExist(err) {
 		fd, err := os.Create(conffile)
 		if err != nil {
@@ -50,6 +52,14 @@ func main() {
 	app.Main()
 }
 
+func saveConfig() {
+	confbytes, err := yaml.Marshal(&Config)
+	if err != nil {
+		log.Fatal("Cannot encode configuration: ", err)
+	}
+	err = ioutil.WriteFile(conffile, confbytes, 0700)
+}
+
 func hrDecode(x []byte) int {
 	flags := x[0]
 	if flags&0x80 != 0 { // uint16 format
@@ -84,9 +94,6 @@ func eventloop() {
 	periphs := make([]ble.Peripheral, 0)
 	btns := make([]*widget.Button, 0)
 
-	var autoconnectID string // should load from config file
-	//autoconnectID = "93D3A64F-1664-497D-8B01-77951DB8E0F3"
-
 	var page, offpage, scanpage, connpage, hrpage func()
 
 	f := &layout.Flex{Axis: layout.Vertical}
@@ -166,10 +173,10 @@ func eventloop() {
 					page = offpage
 				} else {
 
-					if autoconnectID != "" {
-						b.Connect(ble.Peripheral{Identifier: autoconnectID})
+					if Config.Autoconnect != "" && b.Connect(ble.Peripheral{Identifier: Config.Autoconnect}) {
 						page = connpage
 					} else {
+						periphs = periphs[:0]
 						page = scanpage
 						b.Scan()
 					}
@@ -178,20 +185,24 @@ func eventloop() {
 				fmt.Printf("found %s (%s)\n", e.Peripheral.Name, e.Peripheral.Identifier)
 				periphs = append(periphs, e.Peripheral)
 				btns = append(btns, &widget.Button{})
-				if e.Peripheral.Identifier == autoconnectID {
-					b.Connect(e.Peripheral)
+				if e.Peripheral.Identifier == Config.Autoconnect && b.Connect(e.Peripheral) {
+					page = connpage
 				}
 			case ble.ConnectEvent:
 				fmt.Printf("Connect event\n")
 				state = "connected"
 				periph = e.Peripheral
+				Config.Autoconnect = periph.Identifier
+				saveConfig()
 				e.Peripheral.DiscoverServices()
 				page = hrpage
 			case ble.ConnectTimeoutEvent:
 				fmt.Printf("Connect timeout\n")
 				state = "timeout"
-				autoconnectID = ""
+				periphs = periphs[:0]
 				page = scanpage
+				Config.Autoconnect = ""
+				saveConfig()
 				b.Scan()
 			case ble.DiscoverServiceEvent:
 				fmt.Printf("DiscoverService %s\n", e.Gatt.UUID)