Add rewritten infinitime abstraction and integrate it into ITD

2024-04-13 21:20:12 -07:00
parent 2a8013e63e
commit 7e68d5541c
31 changed files with 2758 additions and 474 deletions
--- a/infinitime/chars.go
+++ b/infinitime/chars.go
@@ -0,0 +1,142 @@
+package infinitime
+
+import "tinygo.org/x/bluetooth"
+
+type btChar struct {
+	Name      string
+	ID        bluetooth.UUID
+	ServiceID bluetooth.UUID
+}
+
+var (
+	musicServiceUUID      = mustParse("00000000-78fc-48fe-8e23-433b3a1942d0")
+	navigationServiceUUID = mustParse("00010000-78fc-48fe-8e23-433b3a1942d0")
+	motionServiceUUID     = mustParse("00030000-78fc-48fe-8e23-433b3a1942d0")
+	weatherServiceUUID    = mustParse("00050000-78fc-48fe-8e23-433b3a1942d0")
+)
+
+var (
+	newAlertChar = btChar{
+		"New Alert",
+		bluetooth.CharacteristicUUIDNewAlert,
+		bluetooth.ServiceUUIDAlertNotification,
+	}
+	notifEventChar = btChar{
+		"Notification Event",
+		mustParse("00020001-78fc-48fe-8e23-433b3a1942d0"),
+		bluetooth.ServiceUUIDAlertNotification,
+	}
+	stepCountChar = btChar{
+		"Step Count",
+		mustParse("00030001-78fc-48fe-8e23-433b3a1942d0"),
+		motionServiceUUID,
+	}
+	rawMotionChar = btChar{
+		"Raw Motion",
+		mustParse("00030002-78fc-48fe-8e23-433b3a1942d0"),
+		motionServiceUUID,
+	}
+	firmwareVerChar = btChar{
+		"Firmware Version",
+		bluetooth.CharacteristicUUIDFirmwareRevisionString,
+		bluetooth.ServiceUUIDDeviceInformation,
+	}
+	currentTimeChar = btChar{
+		"Current Time",
+		bluetooth.CharacteristicUUIDCurrentTime,
+		bluetooth.ServiceUUIDCurrentTime,
+	}
+	localTimeChar = btChar{
+		"Local Time",
+		bluetooth.CharacteristicUUIDLocalTimeInformation,
+		bluetooth.ServiceUUIDCurrentTime,
+	}
+	batteryLevelChar = btChar{
+		"Battery Level",
+		bluetooth.CharacteristicUUIDBatteryLevel,
+		bluetooth.ServiceUUIDBattery,
+	}
+	heartRateChar = btChar{
+		"Heart Rate",
+		bluetooth.CharacteristicUUIDHeartRateMeasurement,
+		bluetooth.ServiceUUIDHeartRate,
+	}
+	fsVersionChar = btChar{
+		"Filesystem Version",
+		mustParse("adaf0200-4669-6c65-5472-616e73666572"),
+		bluetooth.ServiceUUIDFileTransferByAdafruit,
+	}
+	fsTransferChar = btChar{
+		"Filesystem Transfer",
+		mustParse("adaf0200-4669-6c65-5472-616e73666572"),
+		bluetooth.ServiceUUIDFileTransferByAdafruit,
+	}
+	dfuCtrlPointChar = btChar{
+		"DFU Control Point",
+		bluetooth.CharacteristicUUIDLegacyDFUControlPoint,
+		bluetooth.ServiceUUIDLegacyDFU,
+	}
+	dfuPacketChar = btChar{
+		"DFU Packet",
+		bluetooth.CharacteristicUUIDLegacyDFUPacket,
+		bluetooth.ServiceUUIDLegacyDFU,
+	}
+	navigationFlagsChar = btChar{
+		"Navigation Flags",
+		mustParse("00010001-78fc-48fe-8e23-433b3a1942d0"),
+		navigationServiceUUID,
+	}
+	navigationNarrativeChar = btChar{
+		"Navigation Narrative",
+		mustParse("00010002-78fc-48fe-8e23-433b3a1942d0"),
+		navigationServiceUUID,
+	}
+	navigationManDist = btChar{
+		"Navigation Man Dist",
+		mustParse("00010003-78fc-48fe-8e23-433b3a1942d0"),
+		navigationServiceUUID,
+	}
+	navigationProgress = btChar{
+		"Navigation Progress",
+		mustParse("00010004-78fc-48fe-8e23-433b3a1942d0"),
+		navigationServiceUUID,
+	}
+	weatherDataChar = btChar{
+		"Weather Data",
+		mustParse("00050001-78fc-48fe-8e23-433b3a1942d0"),
+		weatherServiceUUID,
+	}
+	musicEventChar = btChar{
+		"Music Event",
+		mustParse("00000001-78fc-48fe-8e23-433b3a1942d0"),
+		musicServiceUUID,
+	}
+	musicStatusChar = btChar{
+		"Music Status",
+		mustParse("00000002-78fc-48fe-8e23-433b3a1942d0"),
+		musicServiceUUID,
+	}
+	musicArtistChar = btChar{
+		"Music Artist",
+		mustParse("00000003-78fc-48fe-8e23-433b3a1942d0"),
+		musicServiceUUID,
+	}
+	musicTrackChar = btChar{
+		"Music Track",
+		mustParse("00000004-78fc-48fe-8e23-433b3a1942d0"),
+		musicServiceUUID,
+	}
+	musicAlbumChar = btChar{
+		"Music Album",
+		mustParse("00000005-78fc-48fe-8e23-433b3a1942d0"),
+		musicServiceUUID,
+	}
+)
+
+func mustParse(s string) bluetooth.UUID {
+	uuid, err := bluetooth.ParseUUID(s)
+	if err != nil {
+		panic(err)
+	}
+	return uuid
+}
--- a/infinitime/dfu.go
+++ b/infinitime/dfu.go
@@ -0,0 +1,222 @@
+package infinitime
+
+import (
+	"bytes"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"io"
+	"io/fs"
+
+	"tinygo.org/x/bluetooth"
+)
+
+const (
+	dfuSegmentSize     = 20 // Size of each firmware packet
+	dfuPktRecvInterval = 10 // Amount of packets to send before checking for receipt
+)
+
+var (
+	dfuCmdStart              = []byte{0x01, 0x04}
+	dfuCmdRecvInitPkt        = []byte{0x02, 0x00}
+	dfuCmdInitPktComplete    = []byte{0x02, 0x01}
+	dfuCmdPktReceiptInterval = []byte{0x08}
+	dfuCmdRecvFirmware       = []byte{0x03}
+	dfuCmdValidate           = []byte{0x04}
+	dfuCmdActivateReset      = []byte{0x05}
+
+	dfuResponseStart            = []byte{0x10, 0x01, 0x01}
+	dfuResponseInitParams       = []byte{0x10, 0x02, 0x01}
+	dfuResponseRecvFwImgSuccess = []byte{0x10, 0x03, 0x01}
+	dfuResponseValidate         = []byte{0x10, 0x04, 0x01}
+)
+
+// DFUOptions contains options for [UpgradeFirmware]
+type DFUOptions struct {
+	InitPacket      fs.File
+	FirmwareImage   fs.File
+	ProgressFunc    func(sent, received, total uint32)
+	SegmentSize     int
+	ReceiveInterval uint8
+}
+
+// UpgradeFirmware upgrades the firmware running on the PineTime.
+func (d *Device) UpgradeFirmware(opts DFUOptions) error {
+	if opts.SegmentSize <= 0 {
+		opts.SegmentSize = dfuSegmentSize
+	}
+
+	if opts.ReceiveInterval <= 0 {
+		opts.ReceiveInterval = dfuPktRecvInterval
+	}
+
+	ctrlPoint, err := d.getChar(dfuCtrlPointChar)
+	if err != nil {
+		return err
+	}
+
+	packet, err := d.getChar(dfuPacketChar)
+	if err != nil {
+		return err
+	}
+
+	d.deviceMtx.Lock()
+	defer d.deviceMtx.Unlock()
+
+	d.updating.Store(true)
+	defer d.updating.Store(false)
+
+	_, err = ctrlPoint.WriteWithoutResponse(dfuCmdStart)
+	if err != nil {
+		return err
+	}
+
+	fi, err := opts.FirmwareImage.Stat()
+	if err != nil {
+		return err
+	}
+	size := uint32(fi.Size())
+
+	sizePacket := make([]byte, 8, 12)
+	sizePacket = binary.LittleEndian.AppendUint32(sizePacket, size)
+	_, err = packet.WriteWithoutResponse(sizePacket)
+	if err != nil {
+		return err
+	}
+
+	_, err = awaitDFUResponse(ctrlPoint, dfuResponseStart)
+	if err != nil {
+		return err
+	}
+
+	err = writeDFUInitPacket(ctrlPoint, packet, opts.InitPacket)
+	if err != nil {
+		return err
+	}
+
+	err = setRecvInterval(ctrlPoint, opts.ReceiveInterval)
+	if err != nil {
+		return err
+	}
+
+	err = sendFirmware(ctrlPoint, packet, opts, size)
+	if err != nil {
+		return err
+	}
+
+	return finalize(ctrlPoint)
+}
+
+func finalize(ctrlPoint *bluetooth.DeviceCharacteristic) error {
+	_, err := ctrlPoint.WriteWithoutResponse(dfuCmdValidate)
+	if err != nil {
+		return err
+	}
+
+	_, err = awaitDFUResponse(ctrlPoint, dfuResponseValidate)
+	if err != nil {
+		return err
+	}
+
+	_, _ = ctrlPoint.WriteWithoutResponse(dfuCmdActivateReset)
+	return nil
+}
+
+func sendFirmware(ctrlPoint, packet *bluetooth.DeviceCharacteristic, opts DFUOptions, totalSize uint32) error {
+	_, err := ctrlPoint.WriteWithoutResponse(dfuCmdRecvFirmware)
+	if err != nil {
+		return err
+	}
+
+	var (
+		chunksSinceReceipt uint8
+		bytesSent          uint32
+	)
+
+	chunk := make([]byte, opts.SegmentSize)
+	for {
+		n, err := opts.FirmwareImage.Read(chunk)
+		if err != nil && !errors.Is(err, io.EOF) {
+			return err
+		} else if n == 0 {
+			break
+		}
+
+		bytesSent += uint32(n)
+		_, err = packet.WriteWithoutResponse(chunk[:n])
+		if err != nil {
+			return err
+		}
+
+		if errors.Is(err, io.EOF) {
+			break
+		}
+
+		chunksSinceReceipt += 1
+		if chunksSinceReceipt == opts.ReceiveInterval {
+			sizeData, err := awaitDFUResponse(ctrlPoint, []byte{0x11})
+			if err != nil {
+				return err
+			}
+			size := binary.LittleEndian.Uint32(sizeData)
+			if size != bytesSent {
+				return fmt.Errorf("size mismatch: expected %d, got %d", bytesSent, size)
+			}
+			if opts.ProgressFunc != nil {
+				opts.ProgressFunc(bytesSent, size, totalSize)
+			}
+			chunksSinceReceipt = 0
+		}
+	}
+
+	return nil
+}
+
+func writeDFUInitPacket(ctrlPoint, packet *bluetooth.DeviceCharacteristic, initPkt fs.File) error {
+	_, err := ctrlPoint.WriteWithoutResponse(dfuCmdRecvInitPkt)
+	if err != nil {
+		return err
+	}
+
+	initData, err := io.ReadAll(initPkt)
+	if err != nil {
+		return err
+	}
+
+	_, err = packet.WriteWithoutResponse(initData)
+	if err != nil {
+		return err
+	}
+
+	_, err = ctrlPoint.WriteWithoutResponse(dfuCmdInitPktComplete)
+	if err != nil {
+		return err
+	}
+
+	_, err = awaitDFUResponse(ctrlPoint, dfuResponseInitParams)
+	return err
+}
+
+func setRecvInterval(ctrlPoint *bluetooth.DeviceCharacteristic, interval uint8) error {
+	_, err := ctrlPoint.WriteWithoutResponse(append(dfuCmdPktReceiptInterval, interval))
+	return err
+}
+
+func awaitDFUResponse(ctrlPoint *bluetooth.DeviceCharacteristic, expect []byte) ([]byte, error) {
+	respCh := make(chan []byte, 1)
+	err := ctrlPoint.EnableNotifications(func(buf []byte) {
+		respCh <- buf
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	data := <-respCh
+	ctrlPoint.EnableNotifications(nil)
+
+	if !bytes.HasPrefix(data, expect) {
+		return nil, fmt.Errorf("unexpected dfu response %x (expected %x)", data, expect)
+	}
+
+	return bytes.TrimPrefix(data, expect), nil
+}
--- a/infinitime/fs.go
+++ b/infinitime/fs.go
@@ -0,0 +1,601 @@
+package infinitime
+
+import (
+	"errors"
+	"io"
+	"io/fs"
+	"math"
+	"path"
+	"strings"
+	"sync"
+	"sync/atomic"
+
+	"go.elara.ws/itd/internal/fsproto"
+	"tinygo.org/x/bluetooth"
+)
+
+// FS represents a remote BLE filesystem
+type FS struct {
+	mtx sync.Mutex
+	dev *Device
+}
+
+// Stat gets information about a file at the given path.
+//
+// WARNING: Since there's no stat command in the BLE FS protocol,
+// this function does a ReadDir and then finds the requested file
+// in the results, which makes it pretty slow.
+func (ifs *FS) Stat(p string) (fs.FileInfo, error) {
+	dir := path.Dir(p)
+	entries, err := ifs.ReadDir(dir)
+	if err != nil {
+		return nil, err
+	}
+
+	for _, entry := range entries {
+		if entry.Name() == path.Base(p) {
+			return entry.Info()
+		}
+	}
+
+	return nil, fsproto.ErrFileNotExists
+}
+
+// Remove removes a file or empty directory at the given path.
+//
+// For a function that removes directories recursively, see [FS.RemoveAll]
+func (ifs *FS) Remove(path string) error {
+	ifs.mtx.Lock()
+	defer ifs.mtx.Unlock()
+
+	char, err := ifs.dev.getChar(fsTransferChar)
+	if err != nil {
+		return err
+	}
+
+	return ifs.requestThenAwaitResponse(
+		char,
+		fsproto.DeleteFileOpcode,
+		fsproto.DeleteFileRequest{
+			PathLen: uint16(len(path)),
+			Path:    path,
+		},
+		func(buf []byte) (bool, error) {
+			var mdr fsproto.DeleteFileResponse
+			return true, fsproto.ReadResponse(buf, fsproto.DeleteFileResp, &mdr)
+		},
+	)
+}
+
+// Rename moves a file or directory from an old path to a new path.
+func (ifs *FS) Rename(old, new string) error {
+	ifs.mtx.Lock()
+	defer ifs.mtx.Unlock()
+
+	char, err := ifs.dev.getChar(fsTransferChar)
+	if err != nil {
+		return err
+	}
+
+	return ifs.requestThenAwaitResponse(
+		char,
+		fsproto.MoveFileOpcode,
+		fsproto.MoveFileRequest{
+			OldPathLen: uint16(len(old)),
+			OldPath:    old,
+			NewPathLen: uint16(len(new)),
+			NewPath:    new,
+		},
+		func(buf []byte) (bool, error) {
+			var mfr fsproto.MoveFileResponse
+			return true, fsproto.ReadResponse(buf, fsproto.MoveFileResp, &mfr)
+		},
+	)
+}
+
+// Mkdir creates a new directory at the specified path.
+//
+// For a function that creates necessary parents as well, see [FS.MkdirAll]
+func (ifs *FS) Mkdir(path string) error {
+	ifs.mtx.Lock()
+	defer ifs.mtx.Unlock()
+
+	char, err := ifs.dev.getChar(fsTransferChar)
+	if err != nil {
+		return err
+	}
+
+	return ifs.requestThenAwaitResponse(
+		char,
+		fsproto.MakeDirectoryOpcode,
+		fsproto.MkdirRequest{
+			PathLen: uint16(len(path)),
+			Path:    path,
+		},
+		func(buf []byte) (bool, error) {
+			var mdr fsproto.MkdirResponse
+			return true, fsproto.ReadResponse(buf, fsproto.MakeDirectoryResp, &mdr)
+		},
+	)
+}
+
+// ReadDir reads the directory at the specified path and returns a list of directory entries.
+func (ifs *FS) ReadDir(path string) ([]fs.DirEntry, error) {
+	ifs.mtx.Lock()
+	defer ifs.mtx.Unlock()
+
+	char, err := ifs.dev.getChar(fsTransferChar)
+	if err != nil {
+		return nil, err
+	}
+
+	var out []fs.DirEntry
+	return out, ifs.requestThenAwaitResponse(
+		char,
+		fsproto.ListDirectoryOpcode,
+		fsproto.ListDirRequest{
+			PathLen: uint16(len(path)),
+			Path:    path,
+		},
+		func(buf []byte) (bool, error) {
+			var ldr fsproto.ListDirResponse
+			err := fsproto.ReadResponse(buf, fsproto.ListDirectoryResp, &ldr)
+			if err != nil {
+				return true, err
+			}
+
+			if ldr.EntryNum == ldr.TotalEntries {
+				return true, nil
+			}
+
+			out = append(out, DirEntry{
+				flags:   ldr.Flags,
+				modtime: ldr.ModTime,
+				size:    ldr.FileSize,
+				path:    string(ldr.Path),
+			})
+
+			return false, nil
+		},
+	)
+}
+
+// RemoveAll removes the file at the specified path and any children it contains,
+// similar to the rm -r command.
+func (ifs *FS) RemoveAll(p string) error {
+	if p == "" {
+		return nil
+	}
+
+	if path.Clean(p) == "/" {
+		return fsproto.ErrNoRemoveRoot
+	}
+
+	fi, err := ifs.Stat(p)
+	if err != nil {
+		return nil
+	}
+
+	if fi.IsDir() {
+		return ifs.removeWithChildren(p)
+	} else {
+		err = ifs.Remove(p)
+
+		var code int8
+		if err, ok := err.(fsproto.Error); ok {
+			code = err.Code
+		}
+
+		if err != nil && code != -2 {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// removeWithChildren removes the directory at the given path and its children recursively.
+func (ifs *FS) removeWithChildren(p string) error {
+	list, err := ifs.ReadDir(p)
+	if err != nil {
+		return err
+	}
+
+	for _, entry := range list {
+		name := entry.Name()
+
+		if name == "." || name == ".." {
+			continue
+		}
+		entryPath := path.Join(p, name)
+
+		if entry.IsDir() {
+			err = ifs.removeWithChildren(entryPath)
+		} else {
+			err = ifs.Remove(entryPath)
+		}
+
+		var code int8
+		if err, ok := err.(fsproto.Error); ok {
+			code = err.Code
+		}
+
+		if err != nil && code != -2 {
+			return err
+		}
+	}
+
+	return ifs.Remove(p)
+}
+
+// MkdirAll creates a directory and any necessary parents in the file system,
+// similar to the mkdir -p command.
+func (ifs *FS) MkdirAll(path string) error {
+	if path == "" || path == "/" {
+		return nil
+	}
+
+	splitPath := strings.Split(path, "/")
+	for i := 1; i < len(splitPath); i++ {
+		curPath := strings.Join(splitPath[0:i+1], "/")
+
+		err := ifs.Mkdir(curPath)
+
+		var code int8
+		if err, ok := err.(fsproto.Error); ok {
+			code = err.Code
+		}
+
+		if err != nil && code != -17 {
+			return err
+		}
+	}
+
+	return nil
+}
+
+var _ fs.File = (*File)(nil)
+
+// File represents a remote file on a BLE filesystem.
+//
+// If ProgressFunc is set, it will be called whenever a read or write happens
+// with the amount of bytes transferred and the total size of the file.
+type File struct {
+	fs           *FS
+	path         string
+	offset       uint32
+	size         uint32
+	readOnly     bool
+	ProgressFunc func(transferred, total uint32)
+}
+
+// Open opens an existing file at the specified path.
+// It returns a handle for the file and an error, if any.
+func (ifs *FS) Open(path string) (*File, error) {
+	return &File{
+		fs:       ifs,
+		path:     path,
+		offset:   0,
+		readOnly: true,
+	}, nil
+}
+
+// Create creates a new file with the specified path and size.
+// It returns a handle for the created file and an error, if any.
+func (ifs *FS) Create(path string, size uint32) (*File, error) {
+	return &File{
+		fs:     ifs,
+		path:   path,
+		offset: 0,
+		size:   size,
+	}, nil
+}
+
+// Write writes data from the byte slice b to the file.
+// It returns the number of bytes written and an error, if any.
+func (fl *File) Write(b []byte) (int, error) {
+	if fl.readOnly {
+		return 0, fsproto.ErrFileReadOnly
+	}
+
+	fl.fs.mtx.Lock()
+	defer fl.fs.mtx.Unlock()
+
+	char, err := fl.fs.dev.getChar(fsTransferChar)
+	if err != nil {
+		return 0, err
+	}
+	defer char.EnableNotifications(nil)
+
+	var chunkLen uint32
+
+	dataLen := uint32(len(b))
+	transferred := uint32(0)
+	mtu := uint32(fl.fs.mtu(char))
+
+	// continueCh is used to prevent race conditions. When the
+	// request loop starts, it reads from continueCh, blocking it
+	// until it's "released" by the notification function after
+	// the response is processed.
+	continueCh := make(chan struct{}, 2)
+	var notifErr error
+	err = char.EnableNotifications(func(buf []byte) {
+		var wfr fsproto.WriteFileResponse
+		err = fsproto.ReadResponse(buf, fsproto.WriteFileResp, &wfr)
+		if err != nil {
+			notifErr = err
+			char.EnableNotifications(nil)
+			close(continueCh)
+			return
+		}
+
+		transferred += chunkLen
+		fl.offset += chunkLen
+
+		if wfr.FreeSpace == 0 || transferred == dataLen {
+			char.EnableNotifications(nil)
+			close(continueCh)
+			return
+		}
+
+		if fl.ProgressFunc != nil {
+			fl.ProgressFunc(transferred, fl.size)
+		}
+
+		// Release the request loop
+		continueCh <- struct{}{}
+	})
+
+	err = fsproto.WriteRequest(char, fsproto.WriteFileHeaderOpcode, fsproto.WriteFileHeaderRequest{
+		PathLen:  uint16(len(fl.path)),
+		Offset:   fl.offset,
+		FileSize: fl.size,
+		Path:     fl.path,
+	})
+	if err != nil {
+		return int(transferred), err
+	}
+
+	for range continueCh {
+		if notifErr != nil {
+			return int(transferred), notifErr
+		}
+
+		amountLeft := dataLen - transferred
+		chunkLen = mtu
+		if amountLeft < mtu {
+			chunkLen = amountLeft
+		}
+
+		err = fsproto.WriteRequest(char, fsproto.WriteFileOpcode, fsproto.WriteFileRequest{
+			Status:   0x01,
+			Offset:   fl.offset,
+			ChunkLen: chunkLen,
+			Data:     b[transferred : transferred+chunkLen],
+		})
+		if err != nil {
+			return int(transferred), err
+		}
+	}
+
+	return int(transferred), notifErr
+}
+
+// Read reads data from the file into the byte slice b.
+// It returns the number of bytes read and an error, if any.
+func (fl *File) Read(b []byte) (int, error) {
+	fl.fs.mtx.Lock()
+	defer fl.fs.mtx.Unlock()
+
+	char, err := fl.fs.dev.getChar(fsTransferChar)
+	if err != nil {
+		return 0, err
+	}
+	defer char.EnableNotifications(nil)
+
+	transferred := uint32(0)
+	maxLen := uint32(len(b))
+	mtu := uint32(fl.fs.mtu(char))
+
+	var (
+		notifErr error
+		done     bool
+	)
+
+	// continueCh is used to prevent race conditions. When the
+	// request loop starts, it reads from continueCh, blocking it
+	// until it's "released" by the notification function after
+	// the response is processed.
+	continueCh := make(chan struct{}, 2)
+	err = char.EnableNotifications(func(buf []byte) {
+		var rfr fsproto.ReadFileResponse
+		err = fsproto.ReadResponse(buf, fsproto.ReadFileResp, &rfr)
+		if err != nil {
+			notifErr = err
+			char.EnableNotifications(nil)
+			close(continueCh)
+			return
+		}
+
+		fl.size = rfr.FileSize
+
+		if rfr.Offset == rfr.FileSize || rfr.ChunkLen == 0 {
+			notifErr = io.EOF
+			done = true
+			char.EnableNotifications(nil)
+			close(continueCh)
+			return
+		}
+
+		n := copy(b[transferred:], rfr.Data[:rfr.ChunkLen])
+		fl.offset += uint32(n)
+		transferred += uint32(n)
+
+		if fl.ProgressFunc != nil {
+			fl.ProgressFunc(transferred, rfr.FileSize)
+		}
+
+		// Release the request loop
+		continueCh <- struct{}{}
+	})
+	if err != nil {
+		return 0, err
+	}
+	defer char.EnableNotifications(nil)
+
+	amountLeft := maxLen - transferred
+	chunkLen := mtu
+	if amountLeft < mtu {
+		chunkLen = amountLeft
+	}
+
+	err = fsproto.WriteRequest(char, fsproto.ReadFileHeaderOpcode, fsproto.ReadFileHeaderRequest{
+		PathLen: uint16(len(fl.path)),
+		Offset:  fl.offset,
+		ReadLen: chunkLen,
+		Path:    fl.path,
+	})
+	if err != nil {
+		return 0, err
+	}
+
+	if notifErr != nil {
+		return int(transferred), notifErr
+	}
+
+	for !done {
+		// Wait for the notification function to release the loop
+		<-continueCh
+
+		if notifErr != nil {
+			return int(transferred), notifErr
+		}
+
+		amountLeft = maxLen - transferred
+		chunkLen = mtu
+		if amountLeft < mtu {
+			chunkLen = amountLeft
+		}
+
+		err = fsproto.WriteRequest(char, fsproto.ReadFileOpcode, fsproto.ReadFileRequest{
+			Status:  0x01,
+			Offset:  fl.offset,
+			ReadLen: chunkLen,
+		})
+		if err != nil {
+			return int(transferred), err
+		}
+	}
+
+	return int(transferred), notifErr
+}
+
+// Stat returns information about the file,
+func (fl *File) Stat() (fs.FileInfo, error) {
+	return fl.fs.Stat(fl.path)
+}
+
+// Seek sets the offset for the next Read or Write on the file to the specified offset.
+// The whence parameter specifies the seek reference point:
+//
+//	io.SeekStart: offset is relative to the start of the file.
+//	io.SeekCurrent: offset is relative to the current offset.
+//	io.SeekEnd: offset is relative to the end of the file.
+//
+// Seek returns the new offset and an error, if any.
+func (fl *File) Seek(offset int64, whence int) (int64, error) {
+	if offset > math.MaxUint32 {
+		return 0, fsproto.ErrInvalidOffset
+	}
+	u32Offset := uint32(offset)
+
+	fl.fs.mtx.Lock()
+	defer fl.fs.mtx.Unlock()
+
+	if fl.size == 0 {
+		return 0, errors.New("file size unknown")
+	}
+
+	var newOffset uint32
+	switch whence {
+	case io.SeekStart:
+		newOffset = u32Offset
+	case io.SeekCurrent:
+		newOffset = fl.offset + u32Offset
+	case io.SeekEnd:
+		newOffset = fl.size + u32Offset
+	}
+
+	if newOffset > fl.size || newOffset < 0 {
+		return 0, fsproto.ErrInvalidOffset
+	}
+	fl.offset = newOffset
+
+	return int64(fl.offset), nil
+}
+
+// Close always returns nil
+func (fl *File) Close() error {
+	return nil
+}
+
+// requestThenAwaitResponse executes a BLE FS request and then waits for one or more responses,
+// until fn returns true or an error is encountered.
+func (ifs *FS) requestThenAwaitResponse(char *bluetooth.DeviceCharacteristic, opcode fsproto.FSReqOpcode, req any, fn func(buf []byte) (bool, error)) error {
+	var stopped atomic.Bool
+	errCh := make(chan error, 1)
+	char.EnableNotifications(func(buf []byte) {
+		stop, err := fn(buf)
+		if err != nil && !stopped.Load() {
+			errCh <- err
+			char.EnableNotifications(nil)
+			return
+		} else if !stopped.Load() {
+			errCh <- nil
+		}
+
+		if stop && !stopped.Load() {
+			stopped.Store(true)
+			close(errCh)
+			char.EnableNotifications(nil)
+		}
+	})
+	defer char.EnableNotifications(nil)
+
+	err := fsproto.WriteRequest(char, opcode, req)
+	if err != nil {
+		return err
+	}
+
+	for err := range errCh {
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (ifs *FS) mtu(char *bluetooth.DeviceCharacteristic) uint16 {
+	mtuVal, _ := char.GetMTU()
+	if mtuVal == 0 {
+		mtuVal = 256
+	}
+	return mtuVal - 20
+}
+
+var _ fs.FS = (*GoFS)(nil)
+var _ fs.StatFS = (*GoFS)(nil)
+var _ fs.ReadDirFS = (*GoFS)(nil)
+
+// GoFS implements [io/fs.FS], [io/fs.StatFS], and [io/fs.ReadDirFS]
+// for the InfiniTime filesystem
+type GoFS struct {
+	*FS
+}
+
+// Open opens an existing file at the specified path.
+// It returns a handle for the file and an error, if any.
+func (gfs GoFS) Open(path string) (fs.File, error) {
+	return gfs.FS.Open(path)
+}
--- a/infinitime/fstypes.go
+++ b/infinitime/fstypes.go
@@ -0,0 +1,142 @@
+package infinitime
+
+import (
+	"fmt"
+	"io/fs"
+	"strconv"
+	"time"
+)
+
+// DirEntry represents an entry from a directory listing
+type DirEntry struct {
+	flags   uint32
+	modtime uint64
+	size    uint32
+	path    string
+}
+
+// Name returns the name of the file described by the entry
+func (de DirEntry) Name() string {
+	return de.path
+}
+
+// IsDir reports whether the entry describes a directory.
+func (de DirEntry) IsDir() bool {
+	return de.flags&0b1 == 1
+}
+
+// Type returns the type bits for the entry.
+func (de DirEntry) Type() fs.FileMode {
+	if de.IsDir() {
+		return fs.ModeDir
+	} else {
+		return 0
+	}
+}
+
+// Info returns the FileInfo for the file or subdirectory described by the entry.
+func (de DirEntry) Info() (fs.FileInfo, error) {
+	return FileInfo{
+		name:    de.path,
+		size:    de.size,
+		modtime: de.modtime,
+		mode:    de.Type(),
+		isDir:   de.IsDir(),
+	}, nil
+}
+
+func (de DirEntry) String() string {
+	var isDirChar rune
+	if de.IsDir() {
+		isDirChar = 'd'
+	} else {
+		isDirChar = '-'
+	}
+
+	// Get human-readable value for file size
+	val, unit := bytesHuman(de.size)
+	prec := 0
+	// If value is less than 10, set precision to 1
+	if val < 10 {
+		prec = 1
+	}
+	// Convert float to string
+	valStr := strconv.FormatFloat(val, 'f', prec, 64)
+
+	// Return string formatted like so:
+	// -  10 kB file
+	// or:
+	// d   0 B  .
+	return fmt.Sprintf(
+		"%c %3s %-2s %s",
+		isDirChar,
+		valStr,
+		unit,
+		de.path,
+	)
+}
+
+func bytesHuman(b uint32) (float64, string) {
+	const unit = 1000
+	// Set possible unit prefixes (PineTime flash is 4MB)
+	units := [2]rune{'k', 'M'}
+	// If amount of bytes is less than smallest unit
+	if b < unit {
+		// Return unchanged with unit "B"
+		return float64(b), "B"
+	}
+
+	div, exp := uint32(unit), 0
+	// Get decimal values and unit prefix index
+	for n := b / unit; n >= unit; n /= unit {
+		div *= unit
+		exp++
+	}
+
+	// Create string for full unit
+	unitStr := string([]rune{units[exp], 'B'})
+
+	// Return decimal with unit string
+	return float64(b) / float64(div), unitStr
+}
+
+// FileInfo implements fs.FileInfo
+type FileInfo struct {
+	name    string
+	size    uint32
+	modtime uint64
+	mode    fs.FileMode
+	isDir   bool
+}
+
+// Name returns the base name of the file
+func (fi FileInfo) Name() string {
+	return fi.name
+}
+
+// Size returns the total size of the file
+func (fi FileInfo) Size() int64 {
+	return int64(fi.size)
+}
+
+// Mode returns the mode of the file
+func (fi FileInfo) Mode() fs.FileMode {
+	return fi.mode
+}
+
+// ModTime returns the modification time of the file
+// As of now, this is unimplemented in InfiniTime, and
+// will always return 0.
+func (fi FileInfo) ModTime() time.Time {
+	return time.Unix(0, int64(fi.modtime))
+}
+
+// IsDir returns whether the file is a directory
+func (fi FileInfo) IsDir() bool {
+	return fi.isDir
+}
+
+// Sys is unimplemented and returns nil
+func (fi FileInfo) Sys() any {
+	return nil
+}
--- a/infinitime/infinitime.go
+++ b/infinitime/infinitime.go
@@ -0,0 +1,173 @@
+package infinitime
+
+import (
+	"fmt"
+	"sync"
+	"sync/atomic"
+	"time"
+
+	"tinygo.org/x/bluetooth"
+)
+
+type Options struct {
+	Allowlist    []string
+	Blocklist    []string
+	ScanInterval time.Duration
+
+	OnDisconnect func(dev *Device)
+	OnReconnect  func(dev *Device)
+	OnConnect    func(dev *Device)
+}
+
+func reconnect(opts Options, adapter *bluetooth.Adapter, device *Device, mac string) {
+	if device == nil {
+		return
+	}
+
+	done := false
+	for {
+		adapter.Scan(func(a *bluetooth.Adapter, sr bluetooth.ScanResult) {
+			if sr.Address.String() != mac {
+				return
+			}
+
+			dev, err := a.Connect(sr.Address, bluetooth.ConnectionParams{})
+			if err != nil {
+				return
+			}
+			adapter.StopScan()
+
+			device.deviceMtx.Lock()
+			device.device = dev
+			device.deviceMtx.Unlock()
+
+			device.notifierMtx.Lock()
+			for char, notifier := range device.notifierMap {
+				c, err := device.getChar(char)
+				if err != nil {
+					continue
+				}
+
+				err = c.EnableNotifications(nil)
+				if err != nil {
+					continue
+				}
+
+				err = c.EnableNotifications(notifier.notify)
+				if err != nil {
+					continue
+				}
+			}
+			device.notifierMtx.Unlock()
+
+			done = true
+		})
+
+		if done {
+			return
+		}
+
+		time.Sleep(opts.ScanInterval)
+	}
+}
+
+func Connect(opts Options) (device *Device, err error) {
+	adapter := bluetooth.DefaultAdapter
+
+	if opts.ScanInterval == 0 {
+		opts.ScanInterval = 2 * time.Minute
+	}
+
+	var mac string
+	adapter.SetConnectHandler(func(dev bluetooth.Device, connected bool) {
+		if mac == "" || dev.Address.String() != mac {
+			return
+		}
+
+		if connected {
+			if opts.OnReconnect != nil {
+				opts.OnReconnect(device)
+			}
+		} else {
+			if opts.OnDisconnect != nil {
+				opts.OnDisconnect(device)
+			}
+			go reconnect(opts, adapter, device, mac)
+		}
+	})
+
+	err = adapter.Enable()
+	if err != nil {
+		return nil, err
+	}
+
+	var scanErr error
+	err = adapter.Scan(func(a *bluetooth.Adapter, sr bluetooth.ScanResult) {
+		if sr.LocalName() != "InfiniTime" {
+			return
+		}
+
+		dev, err := a.Connect(sr.Address, bluetooth.ConnectionParams{})
+		if err != nil {
+			scanErr = err
+			adapter.StopScan()
+			return
+		}
+		mac = dev.Address.String()
+
+		device = &Device{adapter: a, device: dev, notifierMap: map[btChar]notifier{}}
+		if opts.OnConnect != nil {
+			opts.OnConnect(device)
+		}
+		adapter.StopScan()
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	if scanErr != nil {
+		return nil, scanErr
+	}
+
+	return device, nil
+}
+
+// Device represents an InfiniTime device
+type Device struct {
+	adapter *bluetooth.Adapter
+
+	deviceMtx sync.Mutex
+	device    bluetooth.Device
+	updating  atomic.Bool
+
+	notifierMtx sync.Mutex
+	notifierMap map[btChar]notifier
+}
+
+// FS returns a handle for InifniTime's filesystem'
+func (d *Device) FS() *FS {
+	return &FS{
+		dev: d,
+	}
+}
+
+func (d *Device) getChar(c btChar) (*bluetooth.DeviceCharacteristic, error) {
+	if d.updating.Load() {
+		return nil, fmt.Errorf("device is currently updating")
+	}
+
+	d.deviceMtx.Lock()
+	defer d.deviceMtx.Unlock()
+
+	services, err := d.device.DiscoverServices([]bluetooth.UUID{c.ServiceID})
+	if err != nil {
+		return nil, fmt.Errorf("characteristic %s (%s) not found", c.ID, c.Name)
+	}
+
+	chars, err := services[0].DiscoverCharacteristics([]bluetooth.UUID{c.ID})
+	if err != nil {
+		return nil, fmt.Errorf("characteristic %s (%s) not found", c.ID, c.Name)
+	}
+
+	return chars[0], err
+}
--- a/infinitime/info.go
+++ b/infinitime/info.go
@@ -0,0 +1,101 @@
+package infinitime
+
+import (
+	"context"
+	"encoding/binary"
+)
+
+// Address returns the MAC address of the connected device.
+func (d *Device) Address() string {
+	return d.device.Address.String()
+}
+
+// Version returns the version of InifniTime that the connected device is running.
+func (d *Device) Version() (string, error) {
+	c, err := d.getChar(firmwareVerChar)
+	if err != nil {
+		return "", err
+	}
+
+	ver := make([]byte, 16)
+	n, err := c.Read(ver)
+	return string(ver[:n]), err
+}
+
+// BatteryLevel returns the current battery level of the connected PineTime.
+func (d *Device) BatteryLevel() (lvl uint8, err error) {
+	c, err := d.getChar(batteryLevelChar)
+	if err != nil {
+		return 0, err
+	}
+
+	err = binary.Read(c, binary.LittleEndian, &lvl)
+	return lvl, err
+}
+
+// WatchBatteryLevel calls fn whenever the battery level changes.
+func (d *Device) WatchBatteryLevel(ctx context.Context, fn func(level uint8, err error)) error {
+	return watchChar(ctx, d, batteryLevelChar, fn)
+}
+
+// StepCount returns the current step count recorded on the watch.
+func (d *Device) StepCount() (sc uint32, err error) {
+	c, err := d.getChar(stepCountChar)
+	if err != nil {
+		return 0, err
+	}
+
+	err = binary.Read(c, binary.LittleEndian, &sc)
+	return sc, err
+}
+
+// WatchStepCount calls fn whenever the step count changes.
+func (d *Device) WatchStepCount(ctx context.Context, fn func(count uint32, err error)) error {
+	return watchChar(ctx, d, stepCountChar, fn)
+}
+
+// HeartRate returns the current heart rate recorded on the watch.
+func (d *Device) HeartRate() (uint8, error) {
+	c, err := d.getChar(heartRateChar)
+	if err != nil {
+		return 0, err
+	}
+
+	data := make([]byte, 2)
+	_, err = c.Read(data)
+	if err != nil {
+		return 0, err
+	}
+
+	return data[1], nil
+}
+
+// WatchHeartRate calls fn whenever the heart rate changes.
+func (d *Device) WatchHeartRate(ctx context.Context, fn func(rate uint8, err error)) error {
+	return watchChar(ctx, d, heartRateChar, func(rate [2]uint8, err error) {
+		fn(rate[1], err)
+	})
+}
+
+// MotionValues represents gyroscope coordinates.
+type MotionValues struct {
+	X int16
+	Y int16
+	Z int16
+}
+
+// Motion returns the current gyroscope coordinates of the PineTime.
+func (d *Device) Motion() (mv MotionValues, err error) {
+	c, err := d.getChar(rawMotionChar)
+	if err != nil {
+		return MotionValues{}, err
+	}
+
+	err = binary.Read(c, binary.LittleEndian, &mv)
+	return mv, err
+}
+
+// WatchMotion calls fn whenever the gyroscope coordinates change.
+func (d *Device) WatchMotion(ctx context.Context, fn func(level MotionValues, err error)) error {
+	return watchChar(ctx, d, rawMotionChar, fn)
+}
--- a/infinitime/music.go
+++ b/infinitime/music.go
@@ -0,0 +1,68 @@
+package infinitime
+
+import "context"
+
+type MusicEvent uint8
+
+const (
+	MusicEventOpen    MusicEvent = 0xe0
+	MusicEventPlay    MusicEvent = 0x00
+	MusicEventPause   MusicEvent = 0x01
+	MusicEventNext    MusicEvent = 0x03
+	MusicEventPrev    MusicEvent = 0x04
+	MusicEventVolUp   MusicEvent = 0x05
+	MusicEventVolDown MusicEvent = 0x06
+)
+
+// SetMusicStatus sets whether the music is playing or paused.
+func (d *Device) SetMusicStatus(playing bool) error {
+	char, err := d.getChar(musicStatusChar)
+	if err != nil {
+		return err
+	}
+
+	if playing {
+		_, err = char.WriteWithoutResponse([]byte{0x1})
+	} else {
+		_, err = char.WriteWithoutResponse([]byte{0x0})
+	}
+	return err
+}
+
+// SetMusicArtist sets the music artist.
+func (d *Device) SetMusicArtist(artist string) error {
+	char, err := d.getChar(musicArtistChar)
+	if err != nil {
+		return err
+	}
+
+	_, err = char.WriteWithoutResponse([]byte(artist))
+	return err
+}
+
+// SetMusicTrack sets the music track name.
+func (d *Device) SetMusicTrack(track string) error {
+	char, err := d.getChar(musicTrackChar)
+	if err != nil {
+		return err
+	}
+
+	_, err = char.WriteWithoutResponse([]byte(track))
+	return err
+}
+
+// SetMusicAlbum sets the music album name.
+func (d *Device) SetMusicAlbum(album string) error {
+	char, err := d.getChar(musicAlbumChar)
+	if err != nil {
+		return err
+	}
+
+	_, err = char.WriteWithoutResponse([]byte(album))
+	return err
+}
+
+// WatchMusicEvents calls fn whenever the InfiniTime music app broadcasts an event.
+func (d *Device) WatchMusicEvents(ctx context.Context, fn func(event MusicEvent, err error)) error {
+	return watchChar(ctx, d, musicEventChar, fn)
+}
--- a/infinitime/navigation.go
+++ b/infinitime/navigation.go
@@ -0,0 +1,137 @@
+package infinitime
+
+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"
+	NavFlagTurnStraight            NavFlag = "turn-straight"
+	NavFlagUpDown                  NavFlag = "updown"
+	NavFlagUTurn                   NavFlag = "uturn"
+)
+
+// SetNavFlag sets the navigation flag icon.
+func (d *Device) SetNavFlag(flag NavFlag) error {
+	char, err := d.getChar(navigationFlagsChar)
+	if err != nil {
+		return err
+	}
+	_, err = char.WriteWithoutResponse([]byte(flag))
+	return err
+}
+
+// SetNavNarrative sets the navigation narrative string.
+func (d *Device) SetNavNarrative(narrative string) error {
+	char, err := d.getChar(navigationNarrativeChar)
+	if err != nil {
+		return err
+	}
+	_, err = char.WriteWithoutResponse([]byte(narrative))
+	return err
+}
+
+// SetNavManeuverDistance sets the navigation maneuver distance.
+func (d *Device) SetNavManeuverDistance(manDist string) error {
+	char, err := d.getChar(navigationManDist)
+	if err != nil {
+		return err
+	}
+	_, err = char.WriteWithoutResponse([]byte(manDist))
+	return err
+}
+
+// SetNavProgress sets the navigation progress.
+func (d *Device) SetNavProgress(progress uint8) error {
+	char, err := d.getChar(navigationProgress)
+	if err != nil {
+		return err
+	}
+	_, err = char.WriteWithoutResponse([]byte{progress})
+	return err
+}
--- a/infinitime/notifs.go
+++ b/infinitime/notifs.go
@@ -0,0 +1,42 @@
+package infinitime
+
+var (
+	regularNotifHeader = []byte{0x00, 0x01, 0x00}
+	callNotifHeader    = []byte{0x03, 0x01, 0x00}
+)
+
+// Notify sends a notification to the PineTime using the Alert Notification Service
+func (d *Device) Notify(title, body string) error {
+	c, err := d.getChar(newAlertChar)
+	if err != nil {
+		return err
+	}
+
+	content := title + "\x00" + body
+	_, err = c.WriteWithoutResponse(append(regularNotifHeader, content...))
+	return err
+}
+
+type CallStatus uint8
+
+const (
+	CallStatusDeclined CallStatus = iota
+	CallStatusAccepted
+	CallStatusMuted
+)
+
+// NotifyCall sends a call to the PineTime using the Alert Notification Service,
+// then executes fn once the user presses a button on the watch.
+func (d *Device) NotifyCall(from string, fn func(CallStatus)) error {
+	c, err := d.getChar(newAlertChar)
+	if err != nil {
+		return err
+	}
+
+	_, err = c.WriteWithoutResponse(append(callNotifHeader, from...))
+	if err != nil {
+		return err
+	}
+
+	return watchCharOnce(d, notifEventChar, fn)
+}
--- a/infinitime/resources.go
+++ b/infinitime/resources.go
@@ -0,0 +1,135 @@
+package infinitime
+
+import (
+	"archive/zip"
+	"encoding/json"
+	"errors"
+	"io"
+	"path/filepath"
+)
+
+type ResourceOperation int
+
+const (
+	// ResourceUpload represents the upload phase
+	// of resource loading
+	ResourceUpload = iota
+	// ResourceRemove represents the obsolete
+	// file removal phase of resource loading
+	ResourceRemove
+)
+
+// resourceManifest is the structure of the resource manifest file
+type resourceManifest struct {
+	Resources []resource         `json:"resources"`
+	Obsolete  []obsoleteResource `json:"obsolete_files"`
+}
+
+// resource represents a resource entry in the manifest
+type resource struct {
+	Name string `json:"filename"`
+	Path string `json:"path"`
+}
+
+// obsoleteResource represents an obsolete file entry in the manifest
+type obsoleteResource struct {
+	Path  string `json:"path"`
+	Since string `json:"since"`
+}
+
+// ResourceLoadProgress contains information on the progress of
+// a resource load
+type ResourceLoadProgress struct {
+	Operation   ResourceOperation
+	Name        string
+	Total       uint32
+	Transferred uint32
+}
+
+// LoadResources accepts the path of an InfiniTime resource archive and loads its contents to the watch's filesystem.
+func LoadResources(archivePath string, fs *FS, progress func(ResourceLoadProgress)) error {
+	r, err := zip.OpenReader(archivePath)
+	if err != nil {
+		return err
+	}
+	defer r.Close()
+
+	manifestFl, err := r.Open("resources.json")
+	if err != nil {
+		return err
+	}
+
+	var manifest resourceManifest
+	err = json.NewDecoder(manifestFl).Decode(&manifest)
+	if err != nil {
+		return err
+	}
+
+	err = manifestFl.Close()
+	if err != nil {
+		return err
+	}
+
+	for _, file := range manifest.Obsolete {
+		err := fs.RemoveAll(file.Path)
+		if err != nil {
+			return err
+		}
+
+		progress(ResourceLoadProgress{
+			Operation: ResourceRemove,
+			Name:      filepath.Base(file.Path),
+		})
+	}
+
+	for _, file := range manifest.Resources {
+		src, err := r.Open(file.Name)
+		if err != nil {
+			return err
+		}
+
+		fi, err := src.Stat()
+		if err != nil {
+			return err
+		}
+
+		err = fs.MkdirAll(filepath.Dir(file.Path))
+		if err != nil {
+			return err
+		}
+
+		dst, err := fs.Create(file.Path, uint32(fi.Size()))
+		if err != nil {
+			return err
+		}
+
+		dst.ProgressFunc = func(transferred, total uint32) {
+			progress(ResourceLoadProgress{
+				Name:        file.Name,
+				Transferred: transferred,
+				Total:       total,
+			})
+		}
+
+		_, err = io.Copy(dst, src)
+		if err != nil {
+			return errors.Join(
+				err,
+				src.Close(),
+				dst.Close(),
+			)
+		}
+
+		err = src.Close()
+		if err != nil {
+			return err
+		}
+
+		err = dst.Close()
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
--- a/infinitime/time.go
+++ b/infinitime/time.go
@@ -0,0 +1,58 @@
+package infinitime
+
+import (
+	"bytes"
+	"encoding/binary"
+	"time"
+)
+
+// SetTime sets the current time, and then sets the timezone data,
+// if the local time characteristic is available.
+func (d *Device) SetTime(t time.Time) error {
+	c, err := d.getChar(currentTimeChar)
+	if err != nil {
+		return err
+	}
+
+	buf := &bytes.Buffer{}
+	binary.Write(buf, binary.LittleEndian, uint16(t.Year()))
+	binary.Write(buf, binary.LittleEndian, uint8(t.Month()))
+	binary.Write(buf, binary.LittleEndian, uint8(t.Day()))
+	binary.Write(buf, binary.LittleEndian, uint8(t.Hour()))
+	binary.Write(buf, binary.LittleEndian, uint8(t.Minute()))
+	binary.Write(buf, binary.LittleEndian, uint8(t.Second()))
+	binary.Write(buf, binary.LittleEndian, uint8(t.Weekday()))
+	binary.Write(buf, binary.LittleEndian, uint8((t.Nanosecond()/1000)/1e6*256))
+	binary.Write(buf, binary.LittleEndian, uint8(0b0001))
+
+	_, err = c.WriteWithoutResponse(buf.Bytes())
+	if err != nil {
+		return err
+	}
+
+	ltc, err := d.getChar(localTimeChar)
+	if err != nil {
+		return nil
+	}
+
+	_, offset := t.Zone()
+	dst := 0
+
+	// Local time expects two values: the timezone offset and the dst offset, both
+	// expressed in quarters of an hour.
+	// Timezone offset is to be constant over DST, with dst offset holding the offset != 0
+	// when DST is in effect.
+	// As there is no standard way in go to get the actual dst offset, we assume it to be 1h
+	// when DST is in effect
+	if t.IsDST() {
+		dst = 3600
+		offset -= 3600
+	}
+
+	buf.Reset()
+	binary.Write(buf, binary.LittleEndian, uint8(offset/3600*4))
+	binary.Write(buf, binary.LittleEndian, uint8(dst/3600*4))
+
+	_, err = ltc.WriteWithoutResponse(buf.Bytes())
+	return err
+}
--- a/infinitime/watch.go
+++ b/infinitime/watch.go
@@ -0,0 +1,108 @@
+package infinitime
+
+import (
+	"bytes"
+	"context"
+	"encoding/binary"
+	"sync"
+
+	"tinygo.org/x/bluetooth"
+)
+
+type notifier interface {
+	notify([]byte)
+}
+
+type watcher[T any] struct {
+	mu         sync.Mutex
+	nextFuncID int
+	callbacks  map[int]func(T, error)
+	char       *bluetooth.DeviceCharacteristic
+}
+
+func (w *watcher[T]) addCallback(fn func(T, error)) int {
+	w.mu.Lock()
+	defer w.mu.Unlock()
+	funcID := w.nextFuncID
+	w.callbacks[funcID] = fn
+	w.nextFuncID++
+	return funcID
+}
+
+func (w *watcher[T]) notify(b []byte) {
+	var val T
+	err := binary.Read(bytes.NewReader(b), binary.LittleEndian, &val)
+	w.mu.Lock()
+	for _, fn := range w.callbacks {
+		go fn(val, err)
+	}
+	w.mu.Unlock()
+}
+
+func (w *watcher[T]) cancelFn(d *Device, ch btChar, id int) func() {
+	return func() {
+		w.mu.Lock()
+		delete(w.callbacks, id)
+		w.mu.Unlock()
+
+		if len(w.callbacks) == 0 {
+			d.notifierMtx.Lock()
+			delete(d.notifierMap, ch)
+			d.notifierMtx.Unlock()
+			w.char.EnableNotifications(nil)
+		}
+	}
+}
+
+func watchChar[T any](ctx context.Context, d *Device, ch btChar, fn func(T, error)) error {
+	d.notifierMtx.Lock()
+	defer d.notifierMtx.Unlock()
+
+	if n, ok := d.notifierMap[ch]; ok {
+		w := n.(*watcher[T])
+		funcID := w.addCallback(fn)
+		context.AfterFunc(ctx, w.cancelFn(d, ch, funcID))
+		go func() {
+			<-ctx.Done()
+			w.cancelFn(d, ch, funcID)()
+		}()
+		return nil
+	} else {
+		c, err := d.getChar(ch)
+		if err != nil {
+			return err
+		}
+
+		w := &watcher[T]{callbacks: map[int]func(T, error){}}
+		err = c.EnableNotifications(w.notify)
+		if err != nil {
+			return err
+		}
+		w.char = c
+		funcID := w.addCallback(fn)
+		d.notifierMap[ch] = w
+
+		context.AfterFunc(ctx, w.cancelFn(d, ch, funcID))
+		return nil
+	}
+}
+
+func watchCharOnce[T any](d *Device, ch btChar, fn func(T)) error {
+	ctx, cancel := context.WithCancel(context.Background())
+
+	var watchErr error
+	err := watchChar(ctx, d, ch, func(val T, err error) {
+		defer cancel()
+		if err != nil {
+			watchErr = err
+			return
+		}
+		fn(val)
+	})
+	if err != nil {
+		return err
+	}
+
+	<-ctx.Done()
+	return watchErr
+}
--- a/infinitime/weather.go
+++ b/infinitime/weather.go
@@ -0,0 +1,124 @@
+package infinitime
+
+import (
+	"bytes"
+	"encoding/binary"
+	"errors"
+	"time"
+)
+
+const (
+	weatherVersion = 0
+
+	currentWeatherType  = 0
+	forecastWeatherType = 1
+)
+
+type WeatherIcon uint8
+
+const (
+	WeatherIconClear WeatherIcon = iota
+	WeatherIconFewClouds
+	WeatherIconClouds
+	WeatherIconHeavyClouds
+	WeatherIconCloudsWithRain
+	WeatherIconRain
+	WeatherIconThunderstorm
+	WeatherIconSnow
+	WeatherIconMist
+)
+
+// CurrentWeather represents the current weather
+type CurrentWeather struct {
+	Time        time.Time
+	CurrentTemp float32
+	MinTemp     float32
+	MaxTemp     float32
+	Location    string
+	Icon        WeatherIcon
+}
+
+// Bytes returns the [CurrentWeather] struct encoded using the InfiniTime
+// weather wire protocol.
+func (cw CurrentWeather) Bytes() []byte {
+	buf := &bytes.Buffer{}
+
+	buf.WriteByte(currentWeatherType)
+	buf.WriteByte(weatherVersion)
+
+	_, offset := cw.Time.Zone()
+	binary.Write(buf, binary.LittleEndian, cw.Time.Unix()+int64(offset))
+
+	binary.Write(buf, binary.LittleEndian, int16(cw.CurrentTemp*100))
+	binary.Write(buf, binary.LittleEndian, int16(cw.MinTemp*100))
+	binary.Write(buf, binary.LittleEndian, int16(cw.MaxTemp*100))
+
+	location := make([]byte, 32)
+	copy(location, cw.Location)
+	buf.Write(location)
+
+	buf.WriteByte(byte(cw.Icon))
+
+	return buf.Bytes()
+}
+
+// Forecast represents a weather forecast
+type Forecast struct {
+	Time time.Time
+	Days []ForecastDay
+}
+
+// ForecastDay represents a forecast for a single day
+type ForecastDay struct {
+	MinTemp int16
+	MaxTemp int16
+	Icon    WeatherIcon
+}
+
+// Bytes returns the [Forecast] struct encoded using the InfiniTime
+// weather wire protocol.
+func (f Forecast) Bytes() []byte {
+	buf := &bytes.Buffer{}
+
+	buf.WriteByte(forecastWeatherType)
+	buf.WriteByte(weatherVersion)
+
+	_, offset := f.Time.Zone()
+	binary.Write(buf, binary.LittleEndian, f.Time.Unix()+int64(offset))
+
+	buf.WriteByte(uint8(len(f.Days)))
+
+	for _, day := range f.Days {
+		binary.Write(buf, binary.LittleEndian, day.MinTemp*100)
+		binary.Write(buf, binary.LittleEndian, day.MaxTemp*100)
+		buf.WriteByte(byte(day.Icon))
+	}
+
+	return buf.Bytes()
+}
+
+// SetCurrentWeather updates the current weather data on the PineTime
+func (d *Device) SetCurrentWeather(cw CurrentWeather) error {
+	c, err := d.getChar(weatherDataChar)
+	if err != nil {
+		return err
+	}
+
+	_, err = c.WriteWithoutResponse(cw.Bytes())
+	return err
+}
+
+// SetForecast sets future forecast data on the PineTime
+func (d *Device) SetForecast(f Forecast) error {
+	c, err := d.getChar(weatherDataChar)
+	if err != nil {
+		return err
+	}
+
+	if len(f.Days) > 5 {
+		return errors.New("amount of forecast days exceeds maximum of 5")
+	}
+
+	_, err = c.WriteWithoutResponse(f.Bytes())
+	return err
+}