Added Navigation service (#5)

InfiniTime implements a [Navigation Service](https://github.com/InfiniTimeOrg/InfiniTime/blob/develop/doc/NavigationService.md). This pull request will add it to the go library by defining a function
```go
func (i *Device) Navigation(flag string, narrative string, dist string, progress uint8) error {
  ...
}
```
From the InfiniTime manual
 * `flag`: the graphic instruction as provided by [Pure Maps](https://github.com/rinigus/pure-maps/tree/master/qml/icons/navigation). A list of valid instruction icons can be found [here](https://github.com/rinigus/pure-maps/tree/master/qml/icons/navigation)
 * `narrative`: the instruction in words, eg. "At the roundabout take the first exit".
 * `dist`: a short string describing the distance to the upcoming instruction such as "50 m".
 * `progress`: the percent complete in a `uint8`

Adding this to the `itd` daemon is straightforward
```patch
diff --git a/api/types.go b/api/types.go
index 281a85b..14c84de 100644
--- a/api/types.go
+++ b/api/types.go
@@ -22,6 +22,13 @@ type FwUpgradeData struct {
        Files []string
 }

+type NavigationData struct {
+       Flag         string
+       Narrative    string
+       Dist         string
+       Progress     uint8
+}
+
 type NotifyData struct {
        Title string
        Body  string
diff --git a/socket.go b/socket.go
index 6fcba5c..91b37c0 100644
--- a/socket.go
+++ b/socket.go
@@ -204,6 +204,10 @@ func (i *ITD) Address(_ *server.Context) string {
        return i.dev.Address()
 }

+func (i *ITD) Navigation(_ *server.Context, data api.NavigationData) error {
+       return i.dev.Navigation(data.Flag, data.Narrative, data.Dist, data.Progress)
+}
+
 func (i *ITD) Notify(_ *server.Context, data api.NotifyData) error {
        return i.dev.Notify(data.Title, data.Body)
 }
```

Co-authored-by: Yannick Ulrich <yannick.ulrich@durham.ac.uk>
Reviewed-on: https://gitea.arsenm.dev/Arsen6331/infinitime/pulls/5
Co-authored-by: yannickulrich <yannick.ulrich@protonmail.com>
Co-committed-by: yannickulrich <yannick.ulrich@protonmail.com>

README.md

@@ -47,6 +47,7 @@ This library currently supports the following features:
 - Battery level
 - Music control
 - OTA firmware upgrades
+- Navigation
 
 ---
 

infinitime.go

@@ -52,6 +52,10 @@ var charNames = map[string]string{
 	FSTransferChar:  "Filesystem Transfer",
 	FSVersionChar:   "Filesystem Version",
 	WeatherDataChar: "Weather Data",
+	NavFlagsChar:    "Navigation Icon",
+	NavNarrativeChar:"Navigation Instruction",
+	NavManDistChar:  "Navigation Distance to next event",
+	NavProgressChar: "Navigation Progress",
 }
 
 type Device struct {
@@ -67,10 +71,13 @@ type Device struct {
 	fsVersionChar   *gatt.GattCharacteristic1
 	fsTransferChar  *gatt.GattCharacteristic1
 	weatherDataChar *gatt.GattCharacteristic1
+	weatherdataChar *gatt.GattCharacteristic1
 	notifEventCh    chan uint8
 	notifEventDone  bool
 	Music           MusicCtrl
+	Navigation      NavigationCtrl
 	DFU             DFU
+	navigationEv    NavigationEvent
 }
 
 var (
@@ -394,6 +401,14 @@ func (i *Device) resolveChars() error {
 		charResolved := true
 		// Set correct characteristics
 		switch char.Properties.UUID {
+		case NavFlagsChar:
+			i.Navigation.flagsChar = char
+		case NavNarrativeChar:
+			i.Navigation.narrativeChar = char
+		case NavManDistChar:
+			i.Navigation.mandistChar = char
+		case NavProgressChar:
+			i.Navigation.progressChar = char
 		case NewAlertChar:
 			i.newAlertChar = char
 		case NotifEventChar:
@@ -723,6 +738,7 @@ func (i *Device) Notify(title, body string) error {
 	)
 }
 
+
 // These constants represent the possible call statuses selected by the user
 const (
 	CallStatusDeclined uint8 = iota

navigation.go

@@ -0,0 +1,188 @@
+package infinitime
+
+import (
+	"bytes"
+	"encoding/binary"
+	"errors"
+	"github.com/muka/go-bluetooth/bluez/profile/gatt"
+)
+
+const (
+	NavFlagsChar    = "00010001-78fc-48fe-8e23-433b3a1942d0"
+	NavNarrativeChar= "00010002-78fc-48fe-8e23-433b3a1942d0"
+	NavManDistChar  = "00010003-78fc-48fe-8e23-433b3a1942d0"
+	NavProgressChar = "00010004-78fc-48fe-8e23-433b3a1942d0"
+)
+
+type NavigationCtrl struct {
+	flagsChar    *gatt.GattCharacteristic1
+	narrativeChar*gatt.GattCharacteristic1
+	mandistChar  *gatt.GattCharacteristic1
+	progressChar *gatt.GattCharacteristic1
+}
+
+type NavFlag string
+const (
+	NavFlagArrive                  NavFlag = "arrive"
+	NavFlagArriveLeft              NavFlag = "arrive-left"
+	NavFlagArriveRight             NavFlag = "arrive-right"
+	NavFlagArriveStraight          NavFlag = "arrive-straight"
+	NavFlagClose                   NavFlag = "close"
+	NavFlagContinue                NavFlag = "continue"
+	NavFlagContinueLeft            NavFlag = "continue-left"
+	NavFlagContinueRight           NavFlag = "continue-right"
+	NavFlagContinueSlightLeft      NavFlag = "continue-slight-left"
+	NavFlagContinueSlightRight     NavFlag = "continue-slight-right"
+	NavFlagContinueStraight        NavFlag = "continue-straight"
+	NavFlagContinueUturn           NavFlag = "continue-uturn"
+	NavFlagDepart                  NavFlag = "depart"
+	NavFlagDepartLeft              NavFlag = "depart-left"
+	NavFlagDepartRight             NavFlag = "depart-right"
+	NavFlagDepartStraight          NavFlag = "depart-straight"
+	NavFlagEndOfRoadLeft           NavFlag = "end-of-road-left"
+	NavFlagEndOfRoadRight          NavFlag = "end-of-road-right"
+	NavFlagFerry                   NavFlag = "ferry"
+	NavFlagFlag                    NavFlag = "flag"
+	NavFlagFork                    NavFlag = "fork"
+	NavFlagForkLeft                NavFlag = "fork-left"
+	NavFlagForkRight               NavFlag = "fork-right"
+	NavFlagForkSlightLeft          NavFlag = "fork-slight-left"
+	NavFlagForkSlightRight         NavFlag = "fork-slight-right"
+	NavFlagForkStraight            NavFlag = "fork-straight"
+	NavFlagInvalid                 NavFlag = "invalid"
+	NavFlagInvalidLeft             NavFlag = "invalid-left"
+	NavFlagInvalidRight            NavFlag = "invalid-right"
+	NavFlagInvalidSlightLeft       NavFlag = "invalid-slight-left"
+	NavFlagInvalidSlightRight      NavFlag = "invalid-slight-right"
+	NavFlagInvalidStraight         NavFlag = "invalid-straight"
+	NavFlagInvalidUturn            NavFlag = "invalid-uturn"
+	NavFlagMergeLeft               NavFlag = "merge-left"
+	NavFlagMergeRight              NavFlag = "merge-right"
+	NavFlagMergeSlightLeft         NavFlag = "merge-slight-left"
+	NavFlagMergeSlightRight        NavFlag = "merge-slight-right"
+	NavFlagMergeStraight           NavFlag = "merge-straight"
+	NavFlagNewNameLeft             NavFlag = "new-name-left"
+	NavFlagNewNameRight            NavFlag = "new-name-right"
+	NavFlagNewNameSharpLeft        NavFlag = "new-name-sharp-left"
+	NavFlagNewNameSharpRight       NavFlag = "new-name-sharp-right"
+	NavFlagNewNameSlightLeft       NavFlag = "new-name-slight-left"
+	NavFlagNewNameSlightRight      NavFlag = "new-name-slight-right"
+	NavFlagNewNameStraight         NavFlag = "new-name-straight"
+	NavFlagNotificationLeft        NavFlag = "notification-left"
+	NavFlagNotificationRight       NavFlag = "notification-right"
+	NavFlagNotificationSharpLeft   NavFlag = "notification-sharp-left"
+	NavFlagNotificationSharpRight  NavFlag = "notification-sharp-right"
+	NavFlagNotificationSlightLeft  NavFlag = "notification-slight-left"
+	NavFlagNotificationSlightRight NavFlag = "notification-slight-right"
+	NavFlagNotificationStraight    NavFlag = "notification-straight"
+	NavFlagOffRampLeft             NavFlag = "off-ramp-left"
+	NavFlagOffRampRight            NavFlag = "off-ramp-right"
+	NavFlagOffRampSharpLeft        NavFlag = "off-ramp-sharp-left"
+	NavFlagOffRampSharpRight       NavFlag = "off-ramp-sharp-right"
+	NavFlagOffRampSlightLeft       NavFlag = "off-ramp-slight-left"
+	NavFlagOffRampSlightRight      NavFlag = "off-ramp-slight-right"
+	NavFlagOffRampStraight         NavFlag = "off-ramp-straight"
+	NavFlagOnRampLeft              NavFlag = "on-ramp-left"
+	NavFlagOnRampRight             NavFlag = "on-ramp-right"
+	NavFlagOnRampSharpLeft         NavFlag = "on-ramp-sharp-left"
+	NavFlagOnRampSharpRight        NavFlag = "on-ramp-sharp-right"
+	NavFlagOnRampSlightLeft        NavFlag = "on-ramp-slight-left"
+	NavFlagOnRampSlightRight       NavFlag = "on-ramp-slight-right"
+	NavFlagOnRampStraight          NavFlag = "on-ramp-straight"
+	NavFlagRotary                  NavFlag = "rotary"
+	NavFlagRotaryLeft              NavFlag = "rotary-left"
+	NavFlagRotaryRight             NavFlag = "rotary-right"
+	NavFlagRotarySharpLeft         NavFlag = "rotary-sharp-left"
+	NavFlagRotarySharpRight        NavFlag = "rotary-sharp-right"
+	NavFlagRotarySlightLeft        NavFlag = "rotary-slight-left"
+	NavFlagRotarySlightRight       NavFlag = "rotary-slight-right"
+	NavFlagRotaryStraight          NavFlag = "rotary-straight"
+	NavFlagRoundabout              NavFlag = "roundabout"
+	NavFlagRoundaboutLeft          NavFlag = "roundabout-left"
+	NavFlagRoundaboutRight         NavFlag = "roundabout-right"
+	NavFlagRoundaboutSharpLeft     NavFlag = "roundabout-sharp-left"
+	NavFlagRoundaboutSharpRight    NavFlag = "roundabout-sharp-right"
+	NavFlagRoundaboutSlightLeft    NavFlag = "roundabout-slight-left"
+	NavFlagRoundaboutSlightRight   NavFlag = "roundabout-slight-right"
+	NavFlagRoundaboutStraight      NavFlag = "roundabout-straight"
+	NavFlagTurnLeft                NavFlag = "turn-left"
+	NavFlagTurnRight               NavFlag = "turn-right"
+	NavFlagTurnSharpLeft           NavFlag = "turn-sharp-left"
+	NavFlagTurnSharpRight          NavFlag = "turn-sharp-right"
+	NavFlagTurnSlightLeft          NavFlag = "turn-slight-left"
+	NavFlagTurnSlightRight         NavFlag = "turn-slight-right"
+	NavFlagTurnStright             NavFlag = "turn-stright"
+	NavFlagUpdown                  NavFlag = "updown"
+	NavFlagUturn                   NavFlag = "uturn"
+)
+
+type NavigationEvent struct {
+	Flag         NavFlag
+	Narrative    string
+	Dist         string
+	Progress     uint8
+}
+
+var (
+	ErrNavProgress      = errors.New("progress needs to between 0 and 100")
+	ErrNavInvalidFlag   = errors.New("this flag is invalid")
+)
+
+// Navigation sends a NavigationEvent to the watch
+func (i *Device) SetNavigation(ev NavigationEvent) error {
+	if ev.Progress > 100 {
+		return ErrNavProgress
+	}
+
+	if ev.Flag != i.navigationEv.Flag {
+		log.Debug().Str("func", "Navigation").
+		    Msg("Sending flag")
+		if err := i.checkStatus(i.Navigation.flagsChar, NavFlagsChar); err != nil {
+			return err
+		}
+		if err := i.Navigation.flagsChar.WriteValue([]byte(ev.Flag), nil); err != nil {
+			return err
+		}
+		i.navigationEv.Flag = ev.Flag
+	}
+
+	if ev.Narrative != i.navigationEv.Narrative {
+		log.Debug().Str("func", "Navigation").
+		    Msg("Sending narrative")
+		if err := i.checkStatus(i.Navigation.narrativeChar, NavNarrativeChar); err != nil {
+			return err
+		}
+		if err := i.Navigation.narrativeChar.WriteValue([]byte(ev.Narrative), nil); err != nil {
+			return err
+		}
+		i.navigationEv.Narrative = ev.Narrative
+	}
+
+	if ev.Dist != i.navigationEv.Dist {
+		log.Debug().Str("func", "Navigation").
+		    Msg("Sending mandist")
+		if err := i.checkStatus(i.Navigation.mandistChar, NavManDistChar); err != nil {
+			return err
+		}
+		if err := i.Navigation.mandistChar.WriteValue([]byte(ev.Dist), nil); err != nil {
+			return err
+		}
+		i.navigationEv.Dist = ev.Dist
+	}
+
+	if ev.Progress != i.navigationEv.Progress {
+		log.Debug().Str("func", "Navigation").
+		    Msg("Sending progress")
+		if err := i.checkStatus(i.Navigation.progressChar, NavProgressChar); err != nil {
+			return err
+		}
+		buf := &bytes.Buffer{}
+		binary.Write(buf, binary.LittleEndian, ev.Progress)
+		if err := i.Navigation.progressChar.WriteValue(buf.Bytes(), nil); err != nil {
+			return err
+		}
+		i.navigationEv.Progress = ev.Progress
+	}
+
+	return nil
+}