feat: a simple enum implementation

enum/enum.go

@@ -0,0 +1,282 @@
+// Copyright 2025 dudaodong@gmail.com. All rights resulterved.
+// Use of this source code is governed by MIT license
+
+// Package enum provides a simple enum implementation.
+package enum
+
+import (
+	"encoding/json"
+	"fmt"
+	"reflect"
+	"sync"
+)
+
+// Enum defines a common enum interface.
+type Enum[T comparable] interface {
+	Value() T
+	String() string
+	Valid() bool
+}
+
+// Item defines a common enum item struct implement Enum interface.
+type Item[T comparable] struct {
+	value T
+	name  string
+}
+
+func NewItem[T comparable](value T, name string) *Item[T] {
+	return &Item[T]{value: value, name: name}
+}
+
+// NewWithItems creates enum items from value-name pairs.
+// It requires an even number of arguments, where each pair consists of a value of type T and a string name.
+// If the number of arguments is odd or if any argument does not match the expected type, it will panic.
+func NewItems[T comparable](args ...any) []*Item[T] {
+	if len(args) == 0 {
+		return []*Item[T]{}
+	}
+	if len(args)%2 != 0 {
+		panic("New requires even number of arguments (value, name pairs)")
+	}
+
+	items := make([]*Item[T], 0, len(args)/2)
+
+	for i := 0; i < len(args); i += 2 {
+		value, ok := args[i].(T)
+		if !ok {
+			panic(fmt.Sprintf("argument %d is not of type %T", i, value))
+		}
+
+		name, ok := args[i+1].(string)
+		if !ok {
+			panic(fmt.Sprintf("argument %d is not of type string", i+1))
+		}
+
+		items = append(items, &Item[T]{value: value, name: name})
+	}
+
+	return items
+
+}
+
+func (e *Item[T]) Value() T {
+	return e.value
+}
+
+func (e *Item[T]) Name() string {
+	return e.name
+}
+
+// Valid checks if the enum item is valid. If a custom check function is provided, it will be used to validate the value.
+func (e *Item[T]) Valid(check ...func(T) bool) bool {
+	if len(check) > 0 {
+		return check[0](e.value) && e.name != ""
+	}
+	var zero T
+	return e.value != zero && e.name != ""
+}
+
+// MarshalJSON implements the json.Marshaler interface.
+func (e *Item[T]) MarshalJSON() ([]byte, error) {
+	return json.Marshal(map[string]any{
+		"value": e.value,
+		"name":  e.name,
+	})
+}
+
+// UnmarshalJSON implements the json.Unmarshaler interface.
+func (e *Item[T]) UnmarshalJSON(data []byte) error {
+	type alias struct {
+		Value any    `json:"value"`
+		Name  string `json:"name"`
+	}
+	var temp alias
+	if err := json.Unmarshal(data, &temp); err != nil {
+		return err
+	}
+
+	var v T
+	rv := reflect.TypeOf(v)
+	switch rv.Kind() {
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		val, ok := temp.Value.(float64)
+		if !ok {
+			return fmt.Errorf("invalid type for value, want int family")
+		}
+		converted := reflect.ValueOf(int64(val)).Convert(rv)
+		e.value = converted.Interface().(T)
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		val, ok := temp.Value.(float64)
+		if !ok {
+			return fmt.Errorf("invalid type for value, want uint family")
+		}
+		converted := reflect.ValueOf(uint64(val)).Convert(rv)
+		e.value = converted.Interface().(T)
+	case reflect.Float32, reflect.Float64:
+		val, ok := temp.Value.(float64)
+		if !ok {
+			return fmt.Errorf("invalid type for value, want float family")
+		}
+		converted := reflect.ValueOf(val).Convert(rv)
+		e.value = converted.Interface().(T)
+	case reflect.String:
+		val, ok := temp.Value.(string)
+		if !ok {
+			return fmt.Errorf("invalid type for value, want string")
+		}
+		e.value = any(val).(T)
+	case reflect.Bool:
+		val, ok := temp.Value.(bool)
+		if !ok {
+			return fmt.Errorf("invalid type for value, want bool")
+		}
+		e.value = any(val).(T)
+	default:
+		// 枚举类型底层通常是 int，可以尝试 float64->int64->底层类型
+		val, ok := temp.Value.(float64)
+		if ok {
+			converted := reflect.ValueOf(int64(val)).Convert(rv)
+			e.value = converted.Interface().(T)
+		} else {
+			val2, ok2 := temp.Value.(T)
+			if !ok2 {
+				return fmt.Errorf("invalid type for value")
+			}
+			e.value = val2
+		}
+	}
+	e.name = temp.Name
+	return nil
+}
+
+// Registry defines a common enum registry struct.
+type Registry[T comparable] struct {
+	mu     sync.RWMutex
+	values map[T]*Item[T]
+	names  map[string]*Item[T]
+	items  []*Item[T]
+}
+
+func NewRegistry[T comparable](items ...*Item[T]) *Registry[T] {
+	r := &Registry[T]{
+		values: make(map[T]*Item[T]),
+		names:  make(map[string]*Item[T]),
+		items:  make([]*Item[T], 0, len(items)),
+	}
+
+	r.Add(items...)
+
+	return r
+}
+
+// Add adds enum items to the registry.
+func (r *Registry[T]) Add(items ...*Item[T]) {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+
+	for _, item := range items {
+		if _, exists := r.values[item.value]; exists {
+			continue
+		}
+		if _, exists := r.names[item.name]; exists {
+			continue
+		}
+
+		r.values[item.value] = item
+		r.names[item.name] = item
+		r.items = append(r.items, item)
+	}
+}
+
+// Remove removes an enum item from the registry by its value.
+func (r *Registry[T]) Remove(value T) bool {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	item, ok := r.values[value]
+	if !ok {
+		return false
+	}
+	delete(r.values, value)
+	delete(r.names, item.name)
+	for i, it := range r.items {
+		if it.value == value {
+			r.items = append(r.items[:i], r.items[i+1:]...)
+			break
+		}
+	}
+	return true
+}
+
+// Update updates the name of an enum item in the registry by its value.
+func (r *Registry[T]) Update(value T, newName string) bool {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	item, ok := r.values[value]
+	if !ok {
+		return false
+	}
+	delete(r.names, item.name)
+	item.name = newName
+	r.names[newName] = item
+	return true
+}
+
+// GetByValue retrieves an enum item by its value.
+func (r *Registry[T]) GetByValue(value T) (*Item[T], bool) {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+
+	item, ok := r.values[value]
+	return item, ok
+}
+
+// GetByName retrieves an enum item by its name.
+func (r *Registry[T]) GetByName(name string) (*Item[T], bool) {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+
+	item, ok := r.names[name]
+	return item, ok
+}
+
+// Items returns a slice of all enum items in the registry.
+func (r *Registry[T]) Items() []*Item[T] {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+
+	result := make([]*Item[T], len(r.items))
+	copy(result, r.items)
+	return result
+}
+
+// Contains checks if an enum item with the given value exists in the registry.
+func (r *Registry[T]) Contains(value T) bool {
+	_, ok := r.GetByValue(value)
+	return ok
+}
+
+// Validate checks if the given value is a valid enum item in the registry.
+func (r *Registry[T]) Validate(value T) error {
+	if !r.Contains(value) {
+		return fmt.Errorf("invalid enum value: %v", value)
+	}
+	return nil
+}
+
+// ValidateAll checks if all given values are valid enum items in the registry.
+func (r *Registry[T]) ValidateAll(values ...T) error {
+	for _, value := range values {
+		if err := r.Validate(value); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// Size returns the number of enum items in the registry.
+func (r *Registry[T]) Size() int {
+	r.mu.RLock()
+	defer r.mu.RUnlock()
+
+	return len(r.items)
+}

enum/enum_test.go

@@ -0,0 +1,163 @@
+// Copyright 2025 dudaodong@gmail.com. All rights resulterved.
+// Use of this source code is governed by MIT license
+
+package enum
+
+import (
+	"testing"
+
+	"github.com/duke-git/lancet/v2/internal"
+)
+
+type Status int
+
+const (
+	Unknown Status = iota
+	Active
+	Inactive
+)
+
+func TestNewItem(t *testing.T) {
+	t.Parallel()
+	assert := internal.NewAssert(t, "TestNewItem")
+
+	items := NewItems[Status](
+		Active, "Active",
+		Inactive, "Inactive",
+	)
+
+	assert.Equal(2, len(items))
+	assert.Equal(Active, items[0].Value())
+	assert.Equal("Active", items[0].Name())
+	assert.Equal(Inactive, items[1].Value())
+	assert.Equal("Inactive", items[1].Name())
+}
+
+func TestItem_Valid(t *testing.T) {
+	t.Parallel()
+	assert := internal.NewAssert(t, "TestItem_Valid")
+
+	item := NewItem(Active, "Active")
+	assert.Equal(true, item.Valid())
+
+	invalidItem := NewItem(Unknown, "")
+	assert.Equal(false, invalidItem.Valid())
+}
+
+func TestItem_MarshalJSON(t *testing.T) {
+	t.Parallel()
+	assert := internal.NewAssert(t, "TestItem_MarshalJSON")
+
+	item := NewItem(Active, "Active")
+	data, err := item.MarshalJSON()
+	assert.IsNil(err)
+	assert.Equal("{\"name\":\"Active\",\"value\":1}", string(data))
+
+	var unmarshaledItem Item[Status]
+	err = unmarshaledItem.UnmarshalJSON(data)
+	assert.IsNil(err)
+	assert.Equal(item.Value(), unmarshaledItem.Value())
+	assert.Equal(item.Name(), unmarshaledItem.Name())
+}
+
+func TestRegistry_AddAndGet(t *testing.T) {
+	t.Parallel()
+	assert := internal.NewAssert(t, "TestRegistry_AddAndGet")
+
+	registry := NewRegistry[Status]()
+	item1 := NewItem(Active, "Active")
+	item2 := NewItem(Inactive, "Inactive")
+
+	registry.Add(item1, item2)
+
+	assert.Equal(2, registry.Size())
+
+	item, ok := registry.GetByValue(Active)
+	assert.Equal(true, ok)
+	assert.Equal("Active", item.Name())
+
+	item, ok = registry.GetByName("Inactive")
+	assert.Equal(true, ok)
+	assert.Equal(Inactive, item.Value())
+}
+
+func TestRegistry_Remove(t *testing.T) {
+	t.Parallel()
+	assert := internal.NewAssert(t, "TestRegistry_Remove")
+
+	registry := NewRegistry[Status]()
+	item1 := NewItem(Active, "Active")
+	item2 := NewItem(Inactive, "Inactive")
+
+	registry.Add(item1, item2)
+	assert.Equal(2, registry.Size())
+
+	removed := registry.Remove(Active)
+	assert.Equal(true, removed)
+	assert.Equal(1, registry.Size())
+
+	_, ok := registry.GetByValue(Active)
+	assert.Equal(false, ok)
+}
+
+func TestRegistry_Update(t *testing.T) {
+	t.Parallel()
+	assert := internal.NewAssert(t, "TestRegistry_Update")
+
+	registry := NewRegistry[Status]()
+	item1 := NewItem(Active, "Active")
+	registry.Add(item1)
+
+	updated := registry.Update(Active, "Activated")
+	assert.Equal(true, updated)
+
+	item, ok := registry.GetByValue(Active)
+	assert.Equal(true, ok)
+	assert.Equal("Activated", item.Name())
+}
+
+func TestRegistry_Contains(t *testing.T) {
+	t.Parallel()
+	assert := internal.NewAssert(t, "TestRegistry_Contains")
+
+	registry := NewRegistry[Status]()
+	item1 := NewItem(Active, "Active")
+	registry.Add(item1)
+
+	assert.Equal(true, registry.Contains(Active))
+	assert.Equal(false, registry.Contains(Inactive))
+}
+
+func TestRegistry_Validate(t *testing.T) {
+	t.Parallel()
+	assert := internal.NewAssert(t, "TestRegistry_Validate")
+
+	registry := NewRegistry[Status]()
+	item1 := NewItem(Active, "Active")
+	item2 := NewItem(Inactive, "Inactive")
+	registry.Add(item1, item2)
+
+	err := registry.Validate(Active)
+	assert.IsNil(err)
+	err = registry.Validate(Inactive)
+	assert.IsNil(err)
+
+	err = registry.Validate(Unknown)
+	assert.IsNotNil(err)
+}
+
+func TestRegistry_ValidateAll(t *testing.T) {
+	t.Parallel()
+	assert := internal.NewAssert(t, "TestRegistry_ValidateAll")
+
+	registry := NewRegistry[Status]()
+	item1 := NewItem(Active, "Active")
+	item2 := NewItem(Inactive, "Inactive")
+	registry.Add(item1, item2)
+
+	err := registry.ValidateAll(Active, Inactive)
+	assert.IsNil(err)
+
+	err = registry.ValidateAll(Active, Unknown)
+	assert.IsNotNil(err)
+}