cast/cast.go

package cast

import (
	"bytes"
	"encoding/json"
	"fmt"
	"reflect"
	"slices"
	"sort"
	"strconv"
	"strings"
	"time"
)

// If 泛型三元表达式
func If[T any](condition bool, trueVal, falseVal T) T {
	if condition {
		return trueVal
	}
	return falseVal
}

// In 泛型包含判断
func In[T comparable](arr []T, val T) bool {
	return slices.Contains(arr, val)
}

// As 忽略错误，返回零值 (消除摩擦)
func As[T any](v T, err error) T {
	if err != nil {
		var zero T
		return zero
	}
	return v
}

func RealValue(v reflect.Value) reflect.Value {
	for v.Kind() == reflect.Pointer || v.Kind() == reflect.Interface {
		if v.IsNil() {
			return v
		}
		v = v.Elem()
	}
	return v
}
// --- Core Cast Logic ---

// To 泛型转换 (支持基础类型、Slice、Map 及 JSON 自动转换，零摩擦模式)
func To[T any](v any) T {
	var zero T
	targetType := reflect.TypeOf((*T)(nil)).Elem()

	// 1. 处理 JSON 自动转换 (Input: string/[]byte, Target: struct/map/slice)
	if isJSONText(v) && isComplexType(targetType) {
		return FromJSON[T](v)
	}

	// 2. 处理 JSON 自动转换 (Input: struct/map/slice, Target: string/[]byte)
	if isComplexValue(v) && (targetType.Kind() == reflect.String || (targetType.Kind() == reflect.Slice && targetType.Elem().Kind() == reflect.Uint8)) {
		s := ToJSON(v)
		return any(reflectCast(s, targetType).Interface()).(T)
	}

	// 3. 处理 Slice/Map
	if targetType.Kind() == reflect.Slice && targetType.Elem().Kind() != reflect.Uint8 {
		sv := reflect.MakeSlice(targetType, 0, 0)
		ptr := reflect.New(targetType)
		ptr.Elem().Set(sv)
		fillToSlice(ptr.Elem(), v)
		return ptr.Elem().Interface().(T)
	}
	if targetType.Kind() == reflect.Map {
		mv := reflect.MakeMap(targetType)
		fillToMap(mv, v)
		return mv.Interface().(T)
	}

	// 4. 处理基础类型
	res := reflectCast(v, targetType)
	if !res.IsValid() {
		return zero
	}
	return res.Interface().(T)
}

func reflectCastE(value any, t reflect.Type) (reflect.Value, error) {
	switch t.Kind() {
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		i, err := ToInt64E(value)
		if err != nil {
			return reflect.Value{}, err
		}
		return reflect.ValueOf(i).Convert(t), nil
	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
		i, err := ToUint64E(value)
		if err != nil {
			return reflect.Value{}, err
		}
		return reflect.ValueOf(i).Convert(t), nil
	case reflect.Float32, reflect.Float64:
		f, err := ToFloat64E(value)
		if err != nil {
			return reflect.Value{}, err
		}
		return reflect.ValueOf(f).Convert(t), nil
	case reflect.String:
		return reflect.ValueOf(String(value)).Convert(t), nil
	case reflect.Bool:
		return reflect.ValueOf(Bool(value)).Convert(t), nil
	case reflect.Interface:
		if value == nil {
			return reflect.Zero(t), nil
		}
		return reflect.ValueOf(value), nil
	}

	if t == reflect.TypeOf(time.Duration(0)) {
		return reflect.ValueOf(Duration(value)), nil
	}

	return reflect.Zero(t), fmt.Errorf("unsupported target type: %v", t)
}

func ToInt64E(v any) (int64, error) {
	if i, ok := toInt64(v); ok {
		return i, nil
	}
	s := String(v)
	i, err := strconv.ParseInt(s, 10, 64)
	if err == nil {
		return i, nil
	}
	if f, err := strconv.ParseFloat(s, 64); err == nil {
		return int64(f), nil
	}
	return 0, fmt.Errorf("cannot cast %v to int64", v)
}

func ToUint64E(v any) (uint64, error) {
	switch realValue := v.(type) {
	case int, int8, int16, int32, int64:
		return uint64(Int64(realValue)), nil
	case uint, uint8, uint16, uint32, uint64:
		return Uint64(realValue), nil
	case float32, float64:
		return uint64(Float64(realValue)), nil
	case bool:
		return If(realValue, uint64(1), uint64(0)), nil
	}
	s := String(v)
	i, err := strconv.ParseUint(s, 10, 64)
	if err == nil {
		return i, nil
	}
	if f, err := strconv.ParseFloat(s, 64); err == nil {
		return uint64(f), nil
	}
	return 0, fmt.Errorf("cannot cast %v to uint64", v)
}

func ToFloat64E(v any) (float64, error) {
	switch realValue := v.(type) {
	case int, int8, int16, int32, int64:
		return float64(Int64(realValue)), nil
	case uint, uint8, uint16, uint32, uint64:
		return float64(Uint64(realValue)), nil
	case float32:
		return float64(realValue), nil
	case float64:
		return realValue, nil
	case bool:
		return If(realValue, 1.0, 0.0), nil
	}
	s := String(v)
	f, err := strconv.ParseFloat(s, 64)
	if err != nil {
		return 0, fmt.Errorf("cannot cast %v to float64", v)
	}
	return f, nil
}

func isJSONText(v any) bool {
	switch val := v.(type) {
	case string:
		s := strings.TrimSpace(val)
		return strings.HasPrefix(s, "{") || strings.HasPrefix(s, "[")
	case []byte:
		s := bytes.TrimSpace(val)
		return bytes.HasPrefix(s, []byte("{")) || bytes.HasPrefix(s, []byte("["))
	}
	return false
}

func isComplexType(t reflect.Type) bool {
	kind := t.Kind()
	for kind == reflect.Ptr {
		t = t.Elem()
		kind = t.Kind()
	}
	return kind == reflect.Struct || kind == reflect.Map || (kind == reflect.Slice && t.Elem().Kind() != reflect.Uint8)
}

func isComplexValue(v any) bool {
	if v == nil {
		return true
	}
	rv := RealValue(reflect.ValueOf(v))
	if !rv.IsValid() || rv.Kind() == reflect.Pointer || rv.Kind() == reflect.Interface {
		return true
	}
	kind := rv.Kind()
	return kind == reflect.Struct || kind == reflect.Map || (kind == reflect.Slice && rv.Type().Elem().Kind() != reflect.Uint8)
}

func parseInt(s string) int64 {
	i, err := strconv.ParseInt(s, 10, 64)
	if err == nil {
		return i
	}
	if f, err := strconv.ParseFloat(s, 64); err == nil {
		return int64(f)
	}
	return 0
}

func parseUint(s string) uint64 {
	i, err := strconv.ParseUint(s, 10, 64)
	if err == nil {
		return i
	}
	if f, err := strconv.ParseFloat(s, 64); err == nil {
		return uint64(f)
	}
	return 0
}

func Int(value any) int { return int(Int64(value)) }

// Helper for integer coercion to avoid repetition
func toInt64(value any) (int64, bool) {
	switch v := value.(type) {
	case int: return int64(v), true
	case int8: return int64(v), true
	case int16: return int64(v), true
	case int32: return int64(v), true
	case int64: return v, true
	case uint: return int64(v), true
	case uint8: return int64(v), true
	case uint16: return int64(v), true
	case uint32: return int64(v), true
	case uint64: return int64(v), true
	case float32: return int64(v), true
	case float64: return int64(v), true
	case bool: return If(v, int64(1), int64(0)), true
	}
	return 0, false
}

func Int64(value any) int64 {
	if value == nil { return 0 }
	if i, ok := toInt64(value); ok { return i }
	
	switch realValue := value.(type) {
	case []byte: return parseInt(string(realValue))
	case string: return parseInt(realValue)
	}
	
	rv := reflect.ValueOf(value)
	if rv.Kind() == reflect.Pointer || rv.Kind() == reflect.Interface {
		if rv = RealValue(rv); rv.IsValid() && rv.CanInterface() && rv.Kind() != reflect.Pointer {
			return Int64(rv.Interface())
		}
	}
	return 0
}

func Uint(value any) uint { return uint(Uint64(value)) }

func Uint64(value any) uint64 {
	if value == nil {
		return 0
	}
	switch realValue := value.(type) {
	case int:
		return uint64(realValue)
	case int8:
		return uint64(realValue)
	case int16:
		return uint64(realValue)
	case int32:
		return uint64(realValue)
	case int64:
		return uint64(realValue)
	case uint:
		return uint64(realValue)
	case uint8:
		return uint64(realValue)
	case uint16:
		return uint64(realValue)
	case uint32:
		return uint64(realValue)
	case uint64:
		return realValue
	case float32:
		return uint64(realValue)
	case float64:
		return uint64(realValue)
	case bool:
		return If(realValue, uint64(1), uint64(0))
	case []byte:
		return parseUint(string(realValue))
	case string:
		return parseUint(realValue)
	}
	rv := reflect.ValueOf(value)
	if rv.Kind() == reflect.Pointer || rv.Kind() == reflect.Interface {
		if rv = RealValue(rv); rv.IsValid() && rv.CanInterface() && rv.Kind() != reflect.Pointer {
			return Uint64(rv.Interface())
		}
	}
	return 0
}

func Float(value any) float32 { return float32(Float64(value)) }

func Float64(value any) float64 {
	if value == nil {
		return 0
	}
	switch realValue := value.(type) {
	case int, int8, int16, int32, int64:
		return float64(Int64(realValue))
	case uint, uint8, uint16, uint32, uint64:
		return float64(Uint64(realValue))
	case float32:
		return float64(realValue)
	case float64:
		return realValue
	case bool:
		return If(realValue, 1.0, 0.0)
	case []byte:
		i, err := strconv.ParseFloat(string(realValue), 64)
		if err == nil {
			return i
		}
	case string:
		i, err := strconv.ParseFloat(realValue, 64)
		if err == nil {
			return i
		}
	}
	rv := reflect.ValueOf(value)
	if rv.Kind() == reflect.Pointer || rv.Kind() == reflect.Interface {
		if rv = RealValue(rv); rv.IsValid() && rv.CanInterface() && rv.Kind() != reflect.Pointer {
			return Float64(rv.Interface())
		}
	}
	return 0
}

func String(value any) string {
	if value == nil {
		return ""
	}
	switch realValue := value.(type) {
	case int, int8, int16, int32, int64:
		return strconv.FormatInt(Int64(realValue), 10)
	case uint, uint8, uint16, uint32, uint64:
		return strconv.FormatUint(Uint64(realValue), 10)
	case float32:
		return strconv.FormatFloat(float64(realValue), 'f', -1, 32)
	case float64:
		return strconv.FormatFloat(realValue, 'f', -1, 64)
	case bool:
		return If(realValue, "true", "false")
	case string:
		return realValue
	case []byte:
		return string(realValue)
	}
	rv := reflect.ValueOf(value)
	if rv.Kind() == reflect.Pointer || rv.Kind() == reflect.Interface {
		if rv = RealValue(rv); rv.IsValid() && rv.CanInterface() && rv.Kind() != reflect.Pointer {
			return String(rv.Interface())
		}
	}
	return fmt.Sprint(value)
}

func Bool(value any) bool {
	switch realValue := value.(type) {
	case int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64, float32, float64:
		return Uint64(realValue) != 0
	case bool:
		return realValue
	case []byte:
		s := strings.ToLower(string(realValue))
		return s == "1" || s == "t" || s == "true"
	case string:
		s := strings.ToLower(realValue)
		return s == "1" || s == "t" || s == "true"
	}
	rv := reflect.ValueOf(value)
	if rv.Kind() == reflect.Pointer || rv.Kind() == reflect.Interface {
		if rv = RealValue(rv); rv.IsValid() && rv.CanInterface() && rv.Kind() != reflect.Pointer {
			return Bool(rv.Interface())
		}
	}
	return false
}

func Duration(value any) time.Duration {
	if value == nil {
		return 0
	}
	switch realValue := value.(type) {
	case int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64:
		return time.Duration(Int64(realValue))
	case float32, float64:
		return time.Duration(Float64(realValue) * float64(time.Second))
	case []byte, string:
		if result, err := time.ParseDuration(String(realValue)); err == nil {
			return result
		}
	}
	rv := reflect.ValueOf(value)
	if rv.Kind() == reflect.Pointer || rv.Kind() == reflect.Interface {
		if rv = RealValue(rv); rv.IsValid() && rv.CanInterface() && rv.Kind() != reflect.Pointer {
			return Duration(rv.Interface())
		}
	}
	return 0
}

func ToJSONBytes(value any) []byte {
	return As(fastToJSONBytes(value))
}

func ToJSONDesensitizeBytes(value any, keys []string) []byte {
	return As(fastToJSONBytes(value, keys...))
}

func ToJSON(value any) string {
	return string(ToJSONBytes(value))
}

func PrettyToJSON(value any) string {
	j := ToJSONBytes(value)
	r := &bytes.Buffer{}
	if err := json.Indent(r, j, "", "  "); err == nil {
		return r.String()
	}
	return string(j)
}

func toBytes(data any) []byte {
	if data == nil {
		return nil
	}
	switch v := data.(type) {
	case []byte:
		return v
	case string:
		return []byte(v)
	}
	return []byte(String(data))
}

func UnmarshalJSON(data any, value any) error {
	b := toBytes(data)
	if b == nil {
		return fmt.Errorf("nil data")
	}
	return fastUnmarshalJSONBytes(b, value)
}

func FromJSON[T any](data any) T {
	var v T
	_ = UnmarshalJSON(data, &v)
	return v
}

// --- Others (Keep logic but clean style) ---

func Split(s, sep string) []string {
	ss := strings.Split(s, sep)
	out := make([]string, 0, len(ss))
	for _, s1 := range ss {
		if s2 := strings.TrimSpace(s1); s2 != "" {
			out = append(out, s2)
		}
	}
	return out
}

func SplitArgs(s string) []string {
	var res []string
	var builder strings.Builder
	inQuote := false
	escaped := false

	chars := []rune(s)
	for i := 0; i < len(chars); i++ {
		c := chars[i]

		if escaped {
			builder.WriteRune(c)
			escaped = false
			continue
		}

		if c == '\\' {
			escaped = true
			continue
		}

		if c == '"' {
			inQuote = !inQuote
			continue
		}

		if c == ' ' && !inQuote {
			if builder.Len() > 0 {
				res = append(res, builder.String())
				builder.Reset()
			}
			continue
		}

		builder.WriteRune(c)
	}

	if builder.Len() > 0 {
		res = append(res, builder.String())
	}
	return res
}

func JoinArgs(arr []string, sep string) string {
	var builder strings.Builder
	for i, s := range arr {
		if i > 0 {
			builder.WriteString(sep)
		}
		// 如果包含空格或引号，则需要包裹引号并转义内部引号
		if strings.ContainsRune(s, ' ') || strings.ContainsRune(s, '"') {
			builder.WriteByte('"')
			builder.WriteString(strings.ReplaceAll(s, "\"", "\\\""))
			builder.WriteByte('"')
		} else {
			builder.WriteString(s)
		}
	}
	return builder.String()
}

func UniqueAppend(to []string, from ...any) []string {
	exists := make(map[string]struct{}, len(to))
	for _, s := range to {
		exists[s] = struct{}{}
	}
	for _, a := range from {
		s := String(a)
		if _, ok := exists[s]; !ok {
			to = append(to, s)
			exists[s] = struct{}{}
		}
	}
	return to
}

func ArrayToBoolMap[T comparable](arr []T) map[T]bool {
	r := map[T]bool{}
	for _, s := range arr {
		r[s] = true
	}
	return r
}

// ToMap 泛型构建新 Map
func ToMap[K comparable, V any](source any) map[K]V {
	m := make(map[K]V)
	fillToMap(reflect.ValueOf(m), source)
	return m
}

// ToSlice 泛型构建新 Slice
func ToSlice[T any](source any) []T {
	var s []T
	fillToSlice(reflect.ValueOf(&s).Elem(), source)
	return s
}

// FillMap 将 source 填充到目标 map 中 (兼容旧 API 逻辑)
func FillMap(target any, source any) {
	rv := reflect.ValueOf(target)
	for rv.Kind() == reflect.Pointer {
		if rv.IsNil() {
			if !rv.CanSet() {
				return
			}
			elemType := rv.Type().Elem()
			if elemType.Kind() == reflect.Map || elemType.Kind() == reflect.Pointer || elemType.Kind() == reflect.Struct {
				rv.Set(reflect.New(elemType))
			} else {
				return
			}
		}
		rv = rv.Elem()
	}

	if rv.Kind() != reflect.Map {
		return
	}

	if rv.IsNil() {
		if rv.CanSet() {
			rv.Set(reflect.MakeMap(rv.Type()))
		} else {
			return
		}
	}
	fillToMap(rv, source)
}

func fillToMap(rv reflect.Value, source any) {
	kt := rv.Type().Key()
	vt := rv.Type().Elem()

	sv := RealValue(reflect.ValueOf(source))
	switch sv.Kind() {
	case reflect.Struct:
		fillMapFromStruct(rv, sv, kt, vt)
	case reflect.Slice, reflect.Array:
		for i := 0; i < sv.Len(); i += 2 {
			k := sv.Index(i).Interface()
			var v any
			if i+1 < sv.Len() {
				v = sv.Index(i+1).Interface()
			}
			rv.SetMapIndex(reflectCast(k, kt), reflectCast(v, vt))
		}
	case reflect.Map:
		iter := sv.MapRange()
		for iter.Next() {
			rv.SetMapIndex(reflectCast(iter.Key().Interface(), kt), reflectCast(iter.Value().Interface(), vt))
		}
	}
}

func fillMapFromStruct(targetMap, sv reflect.Value, kt, vt reflect.Type) {
	st := sv.Type()
	for i := 0; i < sv.NumField(); i++ {
		field := st.Field(i)
		if !field.IsExported() {
			continue
		}
		if field.Anonymous {
			fillMapFromStruct(targetMap, sv.Field(i), kt, vt)
			continue
		}
		targetMap.SetMapIndex(reflectCast(GetLowerName(field.Name), kt), reflectCast(sv.Field(i).Interface(), vt))
	}
}

// FillSlice 将 source 填充到目标 slice 中 (兼容旧 API 逻辑)
func FillSlice(target any, source any) {
	rv := reflect.ValueOf(target)
	if rv.Kind() != reflect.Pointer || rv.Elem().Kind() != reflect.Slice {
		return
	}
	fillToSlice(rv.Elem(), source)
}

func fillToSlice(sliceRv reflect.Value, source any) {
	et := sliceRv.Type().Elem()
	sv := RealValue(reflect.ValueOf(source))
	switch sv.Kind() {
	case reflect.Map:
		keys := sv.MapKeys()
		sort.Slice(keys, func(i, j int) bool {
			return String(keys[i].Interface()) < String(keys[j].Interface())
		})
		for _, key := range keys {
			sliceRv.Set(reflect.Append(sliceRv, reflectCast(key.Interface(), et)))
			sliceRv.Set(reflect.Append(sliceRv, reflectCast(sv.MapIndex(key).Interface(), et)))
		}
	case reflect.Slice, reflect.Array:
		for i := 0; i < sv.Len(); i++ {
			sliceRv.Set(reflect.Append(sliceRv, reflectCast(sv.Index(i).Interface(), et)))
		}
	case reflect.Invalid:
		// Nil source, do nothing
	default:
		sliceRv.Set(reflect.Append(sliceRv, reflectCast(source, et)))
	}
}

func reflectCast(value any, t reflect.Type) reflect.Value {
	return As(reflectCastE(value, t))
}

// 补充缺失的 Key 转换工具
func GetLowerName(s string) string {
	if len(s) > 0 && s[0] >= 'A' && s[0] <= 'Z' {
		hasLower := false
		for i := 0; i < len(s); i++ {
			if s[i] >= 'a' && s[i] <= 'z' {
				hasLower = true
				break
			}
		}
		if hasLower {
			return strings.ToLower(s[:1]) + s[1:]
		}
	}
	return s
}

func GetUpperName(s string) string {
	if s == "" {
		return ""
	}
	return strings.ToUpper(s[:1]) + s[1:]
}

// 指针工具
func Ptr[T any](v T) *T { return &v }

// FixUpperCase (保留以支持历史复杂的 Key 转换需求)
func FixUpperCase(data []byte, excludesKeys []string) {
	// 原有逻辑保持
	n := len(data)
	types, keys, tpos := make([]bool, 0), make([]string, 0), -1
	for i := 0; i < n-1; i++ {
		if tpos+1 >= len(types) {
			types = append(types, false)
			keys = append(keys, "")
		}
		switch data[i] {
		case '{':
			tpos++
			types[tpos] = true
			keys[tpos] = ""
		case '}':
			tpos--
		case '[':
			tpos++
			types[tpos] = false
			keys[tpos] = ""
		case ']':
			tpos--
		case '"':
			keyPos := -1
			if i > 0 && (data[i-1] == '{' || (data[i-1] == ',' && tpos >= 0 && types[tpos])) {
				keyPos = i + 1
			}
			i++
			for ; i < n-1; i++ {
				if data[i] == '\\' {
					i++
					continue
				}
				if data[i] == '"' {
					if keyPos >= 0 && len(excludesKeys) > 0 {
						keys[tpos] = string(data[keyPos:i])
					}
					break
				}
			}
			if keyPos >= 0 && (data[keyPos] >= 'A' && data[keyPos] <= 'Z') {
				excluded := false
				if len(excludesKeys) > 0 {
					checkStr := strings.Join(keys[0:tpos+1], ".")
					for _, ek := range excludesKeys {
						if strings.HasSuffix(ek, ".") {
							excluded = strings.HasPrefix(checkStr, ek)
						} else {
							excluded = checkStr == ek
						}
						if excluded {
							break
						}
					}
				}
				if !excluded {
					hasLower := false
					for _, b := range data[keyPos:i] {
						if b >= 'a' && b <= 'z' {
							hasLower = true
							break
						}
					}
					if hasLower {
						data[keyPos] |= 0x20
					}
				}
			}
		}
	}
}