Merge pull request #32 from truvami/downlink-encoder

cmd/http.go

@@ -12,8 +12,8 @@ import (
 	"github.com/google/uuid"
 	"github.com/spf13/cobra"
 	"github.com/truvami/decoder/internal/logger"
+	helpers "github.com/truvami/decoder/pkg/common"
 	"github.com/truvami/decoder/pkg/decoder"
-	"github.com/truvami/decoder/pkg/decoder/helpers"
 	"github.com/truvami/decoder/pkg/decoder/nomadxl/v1"
 	"github.com/truvami/decoder/pkg/decoder/nomadxs/v1"
 	"github.com/truvami/decoder/pkg/decoder/smartlabel/v1"

cmd/nomadxl.go

@@ -6,7 +6,7 @@ import (
 
 	"github.com/spf13/cobra"
 	"github.com/truvami/decoder/internal/logger"
-	"github.com/truvami/decoder/pkg/decoder/helpers"
+	helpers "github.com/truvami/decoder/pkg/common"
 	"github.com/truvami/decoder/pkg/decoder/nomadxl/v1"
 	"go.uber.org/zap"
 )

cmd/nomadxs.go

@@ -6,7 +6,7 @@ import (
 
 	"github.com/spf13/cobra"
 	"github.com/truvami/decoder/internal/logger"
-	"github.com/truvami/decoder/pkg/decoder/helpers"
+	helpers "github.com/truvami/decoder/pkg/common"
 	"github.com/truvami/decoder/pkg/decoder/nomadxs/v1"
 	"go.uber.org/zap"
 )

cmd/smartlabel.go

@@ -6,7 +6,7 @@ import (
 
 	"github.com/spf13/cobra"
 	"github.com/truvami/decoder/internal/logger"
-	"github.com/truvami/decoder/pkg/decoder/helpers"
+	helpers "github.com/truvami/decoder/pkg/common"
 	"github.com/truvami/decoder/pkg/decoder/smartlabel/v1"
 	"github.com/truvami/decoder/pkg/loracloud"
 	"go.uber.org/zap"

cmd/tagsl.go

@@ -6,7 +6,7 @@ import (
 
 	"github.com/spf13/cobra"
 	"github.com/truvami/decoder/internal/logger"
-	"github.com/truvami/decoder/pkg/decoder/helpers"
+	helpers "github.com/truvami/decoder/pkg/common"
 	"github.com/truvami/decoder/pkg/decoder/tagsl/v1"
 	"go.uber.org/zap"
 )

cmd/tagxl.go

@@ -7,7 +7,7 @@ import (
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
 	"github.com/truvami/decoder/internal/logger"
-	"github.com/truvami/decoder/pkg/decoder/helpers"
+	helpers "github.com/truvami/decoder/pkg/common"
 	"github.com/truvami/decoder/pkg/decoder/tagxl/v1"
 	"github.com/truvami/decoder/pkg/loracloud"
 	"go.uber.org/zap"

pkg/common/config.go

@@ -0,0 +1,19 @@
+package common
+
+import "reflect"
+
+type FieldConfig struct {
+	Name      string
+	Start     int
+	Length    int
+	Transform func(interface{}) interface{}
+	Optional  bool
+	Hex       bool
+}
+
+// PayloadConfig defines the overall structure of the payload, including the target struct type
+type PayloadConfig struct {
+	Fields          []FieldConfig
+	TargetType      reflect.Type
+	StatusByteIndex *int // can be nil
+}

pkg/decoder/helpers/helpers.go → pkg/common/helpers.go

@@ -1,7 +1,7 @@
-package helpers
+package common
 
 import (
-	h "encoding/hex"
+	"encoding/hex"
 	"errors"
 	"fmt"
 
@@ -10,11 +10,10 @@ import (
 	"time"
 
 	"github.com/go-playground/validator"
-	"github.com/truvami/decoder/pkg/decoder"
 )
 
 func HexStringToBytes(hexString string) ([]byte, error) {
-	bytes, err := h.DecodeString(hexString)
+	bytes, err := hex.DecodeString(hexString)
 	if err != nil {
 		return nil, err
 	}
@@ -62,7 +61,7 @@ func convertFieldToType(value interface{}, fieldType reflect.Kind) interface{} {
 	}
 }
 
-func extractFieldValue(payloadBytes []byte, start int, length int, optional bool, hex bool) (interface{}, error) {
+func extractFieldValue(payloadBytes []byte, start int, length int, optional bool, hexadecimal bool) (interface{}, error) {
 	if length == -1 {
 		if start >= len(payloadBytes) {
 			return nil, fmt.Errorf("field start out of bounds")
@@ -78,8 +77,8 @@ func extractFieldValue(payloadBytes []byte, start int, length int, optional bool
 
 	// Extract the field value based on its length
 	var value interface{}
-	if hex {
-		value = h.EncodeToString(payloadBytes[start : start+length])
+	if hexadecimal {
+		value = hex.EncodeToString(payloadBytes[start : start+length])
 	} else {
 		value = 0
 		for i := 0; i < length; i++ {
@@ -110,7 +109,7 @@ func UnwrapError(err error) []error {
 }
 
 // DecodeLoRaWANPayload decodes the payload based on the provided configuration and populates the target struct
-func Parse(payloadHex string, config decoder.PayloadConfig) (interface{}, error) {
+func Parse(payloadHex string, config *PayloadConfig) (interface{}, error) {
 	// Convert hex payload to bytes
 	payloadBytes, err := HexStringToBytes(payloadHex)
 	if err != nil {
@@ -189,7 +188,7 @@ func ToIntPointer(value int) *int {
 	return &value
 }
 
-func HexNullPad(payload *string, config *decoder.PayloadConfig) string {
+func HexNullPad(payload *string, config *PayloadConfig) string {
 	var requiredBits = 0
 	for _, field := range config.Fields {
 		if !field.Optional {
@@ -205,7 +204,7 @@ func HexNullPad(payload *string, config *decoder.PayloadConfig) string {
 	return *payload
 }
 
-func ValidateLength(payload *string, config *decoder.PayloadConfig) error {
+func ValidateLength(payload *string, config *PayloadConfig) error {
 	var payloadLength = len(*payload) / 2
 
 	var minLength = 0
@@ -230,3 +229,75 @@ func ValidateLength(payload *string, config *decoder.PayloadConfig) error {
 
 	return nil
 }
+
+func Encode(data interface{}, config PayloadConfig) (string, error) {
+	v := reflect.ValueOf(data)
+
+	// Validate input data is a struct
+	if v.Kind() != reflect.Struct {
+		return "", fmt.Errorf("data must be a struct")
+	}
+
+	// Determine total payload length
+	var length int
+	for _, field := range config.Fields {
+		if field.Start+field.Length > length {
+			length = field.Start + field.Length
+		}
+	}
+	payload := make([]byte, length)
+
+	// Encode fields into the payload
+	for _, field := range config.Fields {
+		fieldValue := v.FieldByName(field.Name)
+
+		// Check if the field exists
+		if !fieldValue.IsValid() {
+			return "", fmt.Errorf("field %s not found in data", field.Name)
+		}
+
+		// Convert the value to bytes
+		var fieldBytes []byte
+		switch fieldValue.Kind() {
+		case reflect.Slice:
+			fieldBytes = fieldValue.Bytes()
+		case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+			fieldBytes = uintToBytes(fieldValue.Uint(), field.Length)
+		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+			fieldBytes = intToBytes(fieldValue.Int(), field.Length)
+		default:
+			return "", fmt.Errorf("unsupported field type: %s", fieldValue.Kind())
+		}
+
+		// Apply the transform function if provided
+		if field.Transform != nil {
+			fieldBytes = field.Transform(fieldBytes).([]byte)
+		}
+
+		// Copy the bytes into the payload at the correct position
+		copy(payload[field.Start:field.Start+field.Length], fieldBytes)
+	}
+
+	// Convert the payload to a hexadecimal string
+	return hex.EncodeToString(payload), nil
+}
+
+// intToBytes converts an integer value to a byte slice
+func intToBytes(value int64, length int) []byte {
+	buf := make([]byte, length)
+	for i := length - 1; i >= 0; i-- {
+		buf[i] = byte(value & 0xFF)
+		value >>= 8
+	}
+	return buf
+}
+
+// uintToBytes converts an unsigned integer value to a byte slice
+func uintToBytes(value uint64, length int) []byte {
+	buf := make([]byte, length)
+	for i := length - 1; i >= 0; i-- {
+		buf[i] = byte(value & 0xFF)
+		value >>= 8
+	}
+	return buf
+}

pkg/decoder/helpers/helpers_test.go → pkg/common/helpers_test.go

@@ -1,11 +1,9 @@
-package helpers
+package common
 
 import (
 	"fmt"
 	"reflect"
 	"testing"
-
-	"github.com/truvami/decoder/pkg/decoder"
 )
 
 func TestInvalidHexString(t *testing.T) {
@@ -37,8 +35,8 @@ type Port1Payload struct {
 }
 
 func TestParse(t *testing.T) {
-	config := decoder.PayloadConfig{
-		Fields: []decoder.FieldConfig{
+	config := PayloadConfig{
+		Fields: []FieldConfig{
 			{Name: "Moving", Start: 0, Length: 1},
 			{Name: "Lat", Start: 1, Length: 4, Transform: func(v interface{}) interface{} {
 				return float64(v.(int)) / 1000000
@@ -59,7 +57,7 @@ func TestParse(t *testing.T) {
 
 	tests := []struct {
 		payload  string
-		config   decoder.PayloadConfig
+		config   PayloadConfig
 		expected interface{}
 	}{
 		{
@@ -82,7 +80,7 @@ func TestParse(t *testing.T) {
 
 	for _, test := range tests {
 		t.Run(test.payload, func(t *testing.T) {
-			decodedData, err := Parse(test.payload, test.config)
+			decodedData, err := Parse(test.payload, &test.config)
 			if err != nil {
 				t.Fatalf("error decoding payload: %v", err)
 			}
@@ -181,8 +179,8 @@ func TestConvertFieldToType(t *testing.T) {
 }
 
 func TestInvalidPayload(t *testing.T) {
-	_, err := Parse("", decoder.PayloadConfig{
-		Fields: []decoder.FieldConfig{
+	_, err := Parse("", &PayloadConfig{
+		Fields: []FieldConfig{
 			{Name: "Moving", Start: 0, Length: 1},
 		},
 		TargetType: reflect.TypeOf(Port1Payload{}),
@@ -191,8 +189,8 @@ func TestInvalidPayload(t *testing.T) {
 		t.Fatal("expected field out of bounds")
 	}
 
-	_, err = Parse("01", decoder.PayloadConfig{
-		Fields: []decoder.FieldConfig{
+	_, err = Parse("01", &PayloadConfig{
+		Fields: []FieldConfig{
 			{Name: "Moving", Start: 0, Length: 2},
 		},
 		TargetType: reflect.TypeOf(Port1Payload{}),
@@ -201,8 +199,8 @@ func TestInvalidPayload(t *testing.T) {
 		t.Fatal("expected field out of bounds")
 	}
 
-	_, err = Parse("01", decoder.PayloadConfig{
-		Fields: []decoder.FieldConfig{
+	_, err = Parse("01", &PayloadConfig{
+		Fields: []FieldConfig{
 			{Name: "Moving", Start: 10, Length: 1},
 		},
 		TargetType: reflect.TypeOf(Port1Payload{}),

pkg/decoder/decoder.go

@@ -1,24 +1,5 @@
 package decoder
 
-import "reflect"
-
-// FieldConfig defines the structure of a single field in the payload
-type FieldConfig struct {
-	Name      string
-	Start     int
-	Length    int
-	Transform func(interface{}) interface{}
-	Optional  bool
-	Hex       bool
-}
-
-// PayloadConfig defines the overall structure of the payload, including the target struct type
-type PayloadConfig struct {
-	Fields          []FieldConfig
-	TargetType      reflect.Type
-	StatusByteIndex *int // can be nil
-}
-
 type Decoder interface {
 	Decode(string, int16, string) (interface{}, interface{}, error)
 }

pkg/decoder/nomadxl/v1/decoder.go

@@ -4,8 +4,8 @@ import (
 	"fmt"
 	"reflect"
 
+	"github.com/truvami/decoder/pkg/common"
 	"github.com/truvami/decoder/pkg/decoder"
-	"github.com/truvami/decoder/pkg/decoder/helpers"
 )
 
 type Option func(*NomadXLv1Decoder)
@@ -38,11 +38,11 @@ func WithSkipValidation(skipValidation bool) Option {
 }
 
 // https://docs.truvami.com/docs/payloads/nomad-XL
-func (t NomadXLv1Decoder) getConfig(port int16) (decoder.PayloadConfig, error) {
+func (t NomadXLv1Decoder) getConfig(port int16) (common.PayloadConfig, error) {
 	switch port {
 	case 101:
-		return decoder.PayloadConfig{
-			Fields: []decoder.FieldConfig{
+		return common.PayloadConfig{
+			Fields: []common.FieldConfig{
 				{Name: "SystemTime", Start: 0, Length: 8},
 				{Name: "UTCDate", Start: 8, Length: 4},
 				{Name: "UTCTime", Start: 12, Length: 4},
@@ -68,8 +68,8 @@ func (t NomadXLv1Decoder) getConfig(port int16) (decoder.PayloadConfig, error) {
 			TargetType: reflect.TypeOf(Port101Payload{}),
 		}, nil
 	case 103:
-		return decoder.PayloadConfig{
-			Fields: []decoder.FieldConfig{
+		return common.PayloadConfig{
+			Fields: []common.FieldConfig{
 
 				{Name: "UTCDate", Start: 0, Length: 4},
 				{Name: "UTCTime", Start: 4, Length: 4},
@@ -88,7 +88,7 @@ func (t NomadXLv1Decoder) getConfig(port int16) (decoder.PayloadConfig, error) {
 		}, nil
 	}
 
-	return decoder.PayloadConfig{}, fmt.Errorf("port %v not supported", port)
+	return common.PayloadConfig{}, fmt.Errorf("port %v not supported", port)
 }
 
 func (t NomadXLv1Decoder) Decode(data string, port int16, devEui string) (interface{}, interface{}, error) {
@@ -98,16 +98,16 @@ func (t NomadXLv1Decoder) Decode(data string, port int16, devEui string) (interf
 	}
 
 	if t.autoPadding {
-		data = helpers.HexNullPad(&data, &config)
+		data = common.HexNullPad(&data, &config)
 	}
 
 	if !t.skipValidation {
-		err := helpers.ValidateLength(&data, &config)
+		err := common.ValidateLength(&data, &config)
 		if err != nil {
 			return nil, nil, err
 		}
 	}
 
-	decodedData, err := helpers.Parse(data, config)
+	decodedData, err := common.Parse(data, &config)
 	return decodedData, nil, err
 }

pkg/decoder/nomadxl/v1/decoder_test.go

@@ -94,7 +94,7 @@ func TestDecode(t *testing.T) {
 func TestInvalidPort(t *testing.T) {
 	decoder := NewNomadXLv1Decoder()
 	_, _, err := decoder.Decode("00", 0, "")
-	if err == nil {
+	if err == nil || err.Error() != "port 0 not supported" {
 		t.Fatal("expected port not supported")
 	}
 }