refactor: move parsing of FindMy data into lib/findmy package

Signed-off-by: deadprogram <[email protected]>

Author: deadprogram

lib/findmy/parse.go

@@ -0,0 +1,62 @@
+package findmy
+
+import (
+	"errors"
+
+	"tinygo.org/x/bluetooth"
+)
+
+const (
+	// Apple, Inc.
+	AppleCompanyID = 0x004C
+
+	// Offline Finding type
+	FindMyPayloadType = 0x12
+
+	// Length of the payload
+	FindMyPayloadLength = 0x19
+
+	// Hint byte
+	FindMyHint = 0x00
+)
+
+var (
+	ErrorDataTooShort         = errors.New("data is too short")
+	ErrorInvalidPayloadType   = errors.New("invalid payload type")
+	ErrorInvalidPayloadLength = errors.New("invalid payload length")
+	ErrorInvalidHint          = errors.New("invalid hint")
+)
+
+// ParseData parses the data from a FindMy device.
+// It returns the status byte, the advertising key, and an error if any.
+func ParseData(address bluetooth.Address, data []byte) (byte, []byte, error) {
+	if len(data) < 27 {
+		return 0, nil, ErrorDataTooShort
+	}
+
+	if data[0] != FindMyPayloadType {
+		return 0, nil, ErrorInvalidPayloadType
+	}
+
+	if data[1] != FindMyPayloadLength {
+		return 0, nil, ErrorInvalidPayloadLength
+	}
+
+	if data[26] != FindMyHint {
+		return 0, nil, ErrorInvalidHint
+	}
+
+	findMyStatus := data[2]
+	var key [28]byte
+	copy(key[6:], data[3:25])
+
+	// turn address into key bytes
+	key[0] = address.MAC[5]
+	key[1] = address.MAC[4]
+	key[2] = address.MAC[3]
+	key[3] = address.MAC[2]
+	key[4] = address.MAC[1]
+	key[5] = address.MAC[0]
+
+	return findMyStatus, key[:], nil
+}

scan.go

@@ -3,25 +3,10 @@ package main
 import (
 	"encoding/hex"
 
-	"errors"
-
+	"github.com/hybridgroup/go-haystack/lib/findmy"
 	"tinygo.org/x/bluetooth"
 )
 
-const (
-	// Apple, Inc.
-	appleCompanyID = 0x004C
-
-	// Offline Finding type
-	findMyPayloadType = 0x12
-
-	// Length of the payload
-	findMyPayloadLength = 0x19
-
-	// Hint byte
-	findMyHint = 0x00
-)
-
 func scanDevices(verboseFlag *bool) error {
 	bluetooth.DefaultAdapter.Enable()
 
@@ -30,8 +15,8 @@ func scanDevices(verboseFlag *bool) error {
 			println("found device:", device.Address.String(), device.RSSI, device.LocalName())
 		}
 
-		if device.ManufacturerData() != nil && device.ManufacturerData()[0].CompanyID == appleCompanyID {
-			status, key, err := parseData(device.Address, device.ManufacturerData()[0].Data)
+		if device.ManufacturerData() != nil && device.ManufacturerData()[0].CompanyID == findmy.AppleCompanyID {
+			status, key, err := findmy.ParseData(device.Address, device.ManufacturerData()[0].Data)
 			if err != nil {
 				println("failed to parse data:", err)
 				return
@@ -40,35 +25,3 @@ func scanDevices(verboseFlag *bool) error {
 		}
 	})
 }
-
-func parseData(address bluetooth.Address, data []byte) (byte, []byte, error) {
-	if len(data) < 27 {
-		return 0, nil, errors.New("data is too short")
-	}
-
-	if data[0] != findMyPayloadType {
-		return 0, nil, errors.New("invalid payload type")
-	}
-
-	if data[1] != findMyPayloadLength {
-		return 0, nil, errors.New("invalid payload length")
-	}
-
-	if data[26] != findMyHint {
-		return 0, nil, errors.New("invalid hint")
-	}
-
-	findMyStatus := data[2]
-	var key [28]byte
-	copy(key[6:], data[3:25])
-
-	// turn address into key bytes
-	key[0] = address.MAC[5]
-	key[1] = address.MAC[4]
-	key[2] = address.MAC[3]
-	key[3] = address.MAC[2]
-	key[4] = address.MAC[1]
-	key[5] = address.MAC[0]
-
-	return findMyStatus, key[:], nil
-}