feat: some generators & parser improvements

device/internal/junk-tag/generator.go

@@ -1,14 +1,106 @@
 package junktag
 
+import (
+	crand "crypto/rand"
+	"encoding/hex"
+	"fmt"
+	"strconv"
+	"strings"
+	"time"
+
+	v2 "math/rand/v2"
+)
+
 type Generator interface {
-	Generate() []byte
+	Generate() ([]byte, error)
 }
 
 type newGenerator func(string) (Generator, error)
 
 type BytesGenerator struct {
+	value []byte
 }
 
-func (b *BytesGenerator) Generate() []byte {
-	return nil
+func (bg *BytesGenerator) Generate() ([]byte, error) {
+	return bg.value, nil
+}
+
+func newBytesGenerator(param string) (Generator, error) {
+	isNotHex := !strings.HasPrefix(param, "0x") ||
+		!strings.HasPrefix(param, "0x") && !isHexString(param)
+	if isNotHex {
+		return nil, fmt.Errorf("not correct hex: %s", param)
+	}
+
+	hex, err := hexToBytes(param)
+	if err != nil {
+		return nil, fmt.Errorf("hexToBytes: %w", err)
+	}
+
+	return &BytesGenerator{value: hex}, nil
+}
+
+func isHexString(s string) bool {
+	for _, char := range s {
+		if !((char >= '0' && char <= '9') ||
+			(char >= 'a' && char <= 'f') ||
+			(char >= 'A' && char <= 'F')) {
+			return false
+		}
+	}
+	return len(s) > 0
+}
+
+func hexToBytes(hexStr string) ([]byte, error) {
+	hexStr = strings.TrimPrefix(hexStr, "0x")
+	hexStr = strings.TrimPrefix(hexStr, "0X")
+
+	// Ensure even length (pad with leading zero if needed)
+	if len(hexStr)%2 != 0 {
+		hexStr = "0" + hexStr
+	}
+
+	return hex.DecodeString(hexStr)
+}
+
+type RandomPacketGenerator struct {
+	cha8Rand *v2.ChaCha8
+	size     int
+}
+
+func (rpg *RandomPacketGenerator) Generate() ([]byte, error) {
+	junk := make([]byte, rpg.size)
+	_, err := rpg.cha8Rand.Read(junk)
+	return junk, err
+}
+
+func newRandomPacketGenerator(param string) (Generator, error) {
+	size, err := strconv.Atoi(param)
+	if err != nil {
+		return nil, fmt.Errorf("randome packet parse int: %w", err)
+	}
+	// TODO: add size check
+
+	buf := make([]byte, 32)
+	_, err = crand.Read(buf)
+	if err != nil {
+		return nil, fmt.Errorf("randome packet crand read: %w", err)
+	}
+
+	return &RandomPacketGenerator{cha8Rand: v2.NewChaCha8([32]byte(buf)), size: size}, nil
+}
+
+type TimestampGenerator struct {
+}
+
+func (tg *TimestampGenerator) Generate() ([]byte, error) {
+	return time.Now().MarshalBinary()
+}
+
+func newTimestampGenerator(param string) (Generator, error) {
+	if len(param) != 0 {
+		return nil, fmt.Errorf("timestamp param needs to be empty: %s", param)
+	}
+
+	return &TimestampGenerator{}, nil
 }

device/internal/junk-tag/generator_test.go

@@ -0,0 +1,124 @@
+package junktag
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func Test_newBytesGenerator(t *testing.T) {
+	type args struct {
+		param string
+	}
+	tests := []struct {
+		name    string
+		args    args
+		want    []byte
+		wantErr error
+	}{
+		{
+			name: "empty",
+			args: args{
+				param: "",
+			},
+			wantErr: fmt.Errorf("not correct hex"),
+		},
+		{
+			name: "wrong start",
+			args: args{
+				param: "123456",
+			},
+			wantErr: fmt.Errorf("not correct hex"),
+		},
+		{
+			name: "not only hex value",
+			args: args{
+				param: "0x12345q",
+			},
+			wantErr: fmt.Errorf("not correct hex"),
+		},
+		{
+			name: "valid hex",
+			args: args{
+				param: "0xf6ab3267fa",
+			},
+			want: []byte{0xf6, 0xab, 0x32, 0x67, 0xfa},
+		},
+		{
+			name: "valid hex with odd length",
+			args: args{
+				param: "0xfab3267fa",
+			},
+			want: []byte{0xf, 0xab, 0x32, 0x67, 0xfa},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := newBytesGenerator(tt.args.param)
+
+			if tt.wantErr != nil {
+				require.ErrorAs(t, err, &tt.wantErr)
+				require.Nil(t, got)
+				return
+			}
+
+			require.Nil(t, err)
+			require.NotNil(t, got)
+
+			gotValues, _ := got.Generate()
+			require.Equal(t, tt.want, gotValues)
+		})
+	}
+}
+
+func Test_newRandomPacketGenerator(t *testing.T) {
+	type args struct {
+		param string
+	}
+	tests := []struct {
+		name    string
+		args    args
+		wantErr error
+	}{
+		{
+			name: "empty",
+			args: args{
+				param: "",
+			},
+			wantErr: fmt.Errorf("parse int"),
+		},
+		{
+			name: "not an int",
+			args: args{
+				param: "x",
+			},
+			wantErr: fmt.Errorf("parse int"),
+		},
+		{
+			name: "valid",
+			args: args{
+				param: "12",
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := newRandomPacketGenerator(tt.args.param)
+			if tt.wantErr != nil {
+				require.ErrorAs(t, err, &tt.wantErr)
+				require.Nil(t, got)
+				return
+			}
+
+			require.Nil(t, err)
+			require.NotNil(t, got)
+			first, err := got.Generate()
+			require.Nil(t, err)
+
+			second, err := got.Generate()
+			require.Nil(t, err)
+			require.NotEqual(t, first, second)
+		})
+	}
+}

device/internal/junk-tag/parser.go

@@ -18,10 +18,10 @@ const (
 )
 
 var validEnum = map[Enum]newGenerator{
-	EnumBytes:        func(s string) (Generator, error) { return &BytesGenerator{}, nil },
+	EnumBytes:        newBytesGenerator,
 	EnumCounter:      func(s string) (Generator, error) { return &BytesGenerator{}, nil },
-	EnumTimestamp:    func(s string) (Generator, error) { return &BytesGenerator{}, nil },
-	EnumRandomBytes:  func(s string) (Generator, error) { return &BytesGenerator{}, nil },
+	EnumTimestamp:    newTimestampGenerator,
+	EnumRandomBytes:  newRandomPacketGenerator,
 	EnumWaitTimeout:  func(s string) (Generator, error) { return &BytesGenerator{}, nil },
 	EnumWaitResponse: func(s string) (Generator, error) { return &BytesGenerator{}, nil },
 }
@@ -35,24 +35,19 @@ type Tag struct {
 	Param string
 }
 
-func parseTags(input string) ([]Tag, error) {
+func parseTag(input string) (Tag, error) {
 	// Regular expression to match <tagname optional_param>
 	re := regexp.MustCompile(`([a-zA-Z]+)(?:\s+([^>]+))?>`)
 
-	matches := re.FindAllStringSubmatch(input, -1)
-	tags := make([]Tag, 0, len(matches))
-
-	for _, match := range matches {
-		tag := Tag{
-			Name: Enum(match[1]),
-		}
-		if len(match) > 2 && match[2] != "" {
-			tag.Param = strings.TrimSpace(match[2])
-		}
-		tags = append(tags, tag)
+	match := re.FindStringSubmatch(input)
+	tag := Tag{
+		Name: Enum(match[1]),
+	}
+	if len(match) > 2 && match[2] != "" {
+		tag.Param = strings.TrimSpace(match[2])
 	}
 
-	return tags, nil
+	return tag, nil
 }
 
 func Parse(input string) (Foo, error) {
@@ -62,26 +57,29 @@ func Parse(input string) (Foo, error) {
 		return Foo{}, fmt.Errorf("empty input: %s", input)
 	}
 
-	for _, inputParam := range inputSlice[1:] {
-		if len(inputParam) == 1 {
+	// skip byproduct of split
+	inputSlice = inputSlice[1:]
+	rv := Foo{x: make([]Generator, 0, len(inputSlice))}
+
+	for _, inputParam := range inputSlice {
+		if len(inputParam) <= 1 {
 			return Foo{}, fmt.Errorf("empty tag in input: %s", inputSlice)
 		} else if strings.Count(inputParam, ">") != 1 {
 			return Foo{}, fmt.Errorf("ill formated input: %s", input)
 		}
 
-		tags, _ := parseTags(inputParam)
-		for _, tag := range tags {
-			fmt.Printf("Tag: %s, Param: %s\n", tag.Name, tag.Param)
-			gen, ok := validEnum[tag.Name]
-			if !ok {
-				return Foo{}, fmt.Errorf("invalid tag")
-			}
-			_, err := gen(tag.Param)
-			if err != nil {
-				return Foo{}, fmt.Errorf("")
-			}
+		tag, _ := parseTag(inputParam)
+		fmt.Printf("Tag: %s, Param: %s\n", tag.Name, tag.Param)
+		gen, ok := validEnum[tag.Name]
+		if !ok {
+			return Foo{}, fmt.Errorf("invalid tag: %s", tag.Name)
 		}
+		generator, err := gen(tag.Param)
+		if err != nil {
+			return Foo{}, fmt.Errorf("gen: %w", err)
+		}
+		rv.x = append(rv.x, generator)
 	}
 
-	return Foo{}, nil
+	return rv, nil
 }

device/internal/junk-tag/parser_test.go

@@ -29,7 +29,7 @@ func TestParse(t *testing.T) {
 		{
 			name:    "extra <",
 			args:    args{input: "<<b 0xf6ab3267fa><c>"},
-			wantErr: fmt.Errorf("ill formated input"),
+			wantErr: fmt.Errorf("empty tag in input"),
 		},
 		{
 			name:    "empty <>",
@@ -51,10 +51,11 @@ func TestParse(t *testing.T) {
 			_, err := Parse(tt.args.input)
 
 			// TODO:  ErrorAs doesn't work as you think
-			// if tt.wantErr != nil {
-			require.ErrorAs(t, err, &tt.wantErr)
-			// 	return
-			// }
+			if tt.wantErr != nil {
+				require.ErrorAs(t, err, &tt.wantErr)
+				return
+			}
+			require.Nil(t, err)
 		})
 	}
 }