fix golint (#8)

Co-authored-by: daniel.w <daniel.w@intteam.net>
Reviewed-on: #8

utils/invited_code/const.go

@@ -0,0 +1,11 @@
+package invited_code
+
+const DefaultCodeLen = 8
+
+var ConvertTable = []string{
+	"O", "D", "W", "X", "Y",
+	"G", "B", "C", "H", "E",
+	"F", "A", "Q", "I", "J",
+	"L", "M", "N", "Z", "K",
+	"P", "V", "R", "S", "T",
+}

utils/invited_code/convert.go

@@ -0,0 +1,80 @@
+package invited_code
+
+import (
+	"fmt"
+	"math"
+	"strings"
+)
+
+type Converter struct {
+	Base         int
+	Length       int
+	ConvertTable []string
+}
+
+func (c *Converter) EncodeFromNum(id int64) (string, error) {
+	code, err := generateCode(id, c.Base, c.Length, c.ConvertTable)
+	if err != nil {
+		return "", err
+	}
+
+	return code, nil
+}
+
+func (c *Converter) DecodeFromCode(code string) (int64, error) {
+	var result int64 = 0
+	length := len(code)
+
+	for i := 0; i < length; i++ {
+		char := string(code[i])
+		index := -1
+		for j, v := range c.ConvertTable {
+			if v == char {
+				index = j
+				break
+			}
+		}
+
+		if index >= 0 {
+			result = result*int64(c.Base) + int64(index)
+		} else {
+			return 0, fmt.Errorf("character not found in convert table")
+		}
+	}
+	return result, nil
+}
+
+// generateCode 從 UID 生成 referralCode
+func generateCode(id int64, base int, length int, convertTable []string) (string, error) {
+	maxReferralUIDBoundary := int64(math.Pow(float64(len(ConvertTable)), float64(DefaultCodeLen)))
+	if id > maxReferralUIDBoundary {
+		return "", fmt.Errorf("encode out of range")
+	}
+
+	encoded := encodeToBase(id, base, length, convertTable)
+
+	return encoded, nil
+}
+
+func encodeToBase(num int64, base int, length int, convertTable []string) string {
+	result := ""
+	for num > 0 {
+		index := num % int64(base)
+		result = convertTable[index] + result
+		num /= int64(base)
+	}
+
+	if len(result) < length {
+		result = strings.Repeat(convertTable[0], length-len(result)) + result
+	}
+
+	return result
+}
+
+func MustConverter(base int, length int, convertTable []string) ConvertUseCase {
+	return &Converter{
+		Base:         base,
+		Length:       length,
+		ConvertTable: convertTable,
+	}
+}

utils/invited_code/convert_test.go

@@ -0,0 +1,123 @@
+package invited_code
+
+import (
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+// 測試 ConvertUseCase 的功能
+func TestConverter(t *testing.T) {
+	tests := []struct {
+		name      string
+		id        int64
+		base      int
+		length    int
+		wantCode  string
+		wantError bool
+	}{
+		{
+			name:      "Test Case 1: Valid ID 1000000",
+			id:        10000000,
+			base:      10,
+			length:    7,
+			wantCode:  "DOOOOOOO",
+			wantError: false,
+		},
+		{
+			name:      "Test Case 2: Valid ID 12345678",
+			id:        12345678,
+			base:      10,
+			length:    8,
+			wantCode:  "DWXYGBCH",
+			wantError: false,
+		},
+		{
+			name:      "Test Case 3: Valid ID 98765432",
+			id:        98765432,
+			base:      10,
+			length:    8,
+			wantCode:  "EHCBGYXW",
+			wantError: false,
+		},
+		{
+			name:      "Test Case 4: ID too large",
+			id:        10000000000000001, // ID 超過界限
+			base:      10,
+			length:    8,
+			wantCode:  "",
+			wantError: true,
+		},
+	}
+
+	converter := MustConverter(10, 8, ConvertTable)
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			code, err := converter.EncodeFromNum(tt.id)
+
+			if tt.wantError {
+				assert.Error(t, err)
+			} else {
+				assert.NoError(t, err)
+				assert.Equal(t, tt.wantCode, code)
+			}
+
+			if !tt.wantError {
+				// 測試解碼
+				decodedID, err := converter.DecodeFromCode(code)
+				assert.NoError(t, err)
+				assert.Equal(t, tt.id, decodedID)
+			}
+		})
+	}
+}
+
+func TestDecodeFromCode(t *testing.T) {
+	converter := MustConverter(10, 8, ConvertTable)
+
+	tests := []struct {
+		name      string
+		code      string
+		wantID    int64
+		wantError bool
+	}{
+		{
+			name:      "Decode valid code 1",
+			code:      "DOOOOOOO", // 對應於 id 10000000
+			wantID:    10000000,
+			wantError: false,
+		},
+		{
+			name:      "Decode valid code 2",
+			code:      "DWXYGBCH", // 對應於 id 12345678
+			wantID:    12345678,
+			wantError: false,
+		},
+		{
+			name:      "Decode valid code 3",
+			code:      "EHCBGYXW", // 對應於 id 98765432
+			wantID:    98765432,
+			wantError: false,
+		},
+		{
+			name:      "Decode invalid code with character not in table",
+			code:      "UWOXZZZ", // 包含 ZZZ，不在轉換表中
+			wantID:    0,
+			wantError: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result, err := converter.DecodeFromCode(tt.code)
+
+			if tt.wantError {
+				assert.Error(t, err)
+				assert.Equal(t, int64(0), result)
+			} else {
+				assert.NoError(t, err)
+				assert.Equal(t, tt.wantID, result)
+			}
+		})
+	}
+}

utils/invited_code/go.mod

@@ -0,0 +1,11 @@
+module code.30cm.net/digimon/library-go/utils/invited_code
+
+go 1.22.3
+
+require github.com/stretchr/testify v1.9.0
+
+require (
+	github.com/davecgh/go-spew v1.1.1 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

utils/invited_code/usecase.go

@@ -0,0 +1,6 @@
+package invited_code
+
+type ConvertUseCase interface {
+	EncodeFromNum(id int64) (string, error)
+	DecodeFromCode(code string) (int64, error)
+}