package stringutil

import (
	"strings"

	"github.com/mozillazg/go-pinyin"
)

// ZhToPinyin 中文转拼音
func ZhToPinyin(zh, sep string) string {
	args := pinyin.NewArgs()
	p := pinyin.Pinyin(zh, args)

	names := make([]string, 0, len(p))
	for _, v := range p {
		if len(v) > 0 {
			if len(v) == 1 {
				names = append(names, v[0])
			} else {
				names = append(names, strings.Join(v, ""))
			}
		}
	}

	return strings.Join(names, sep)
}

type CamelType int

const (
	CamelSmall CamelType = 1 // a_bc aBc
	CamelBig   CamelType = 2 // a_bc ABc
)

// CamelToSnake 驼峰转蛇形
func CamelToSnake(s string) string {
	data := make([]byte, 0, len(s)*2)
	j := false
	num := len(s)
	for i := 0; i < num; i++ {
		d := s[i]
		// or通过ASCII码进行大小写的转化
		// 65-90（A-Z），97-122（a-z）
		// 判断如果字母为大写的A-Z就在前面拼接一个_
		if i > 0 && d >= 'A' && d <= 'Z' && j {
			data = append(data, '_')
		}
		if d != '_' {
			j = true
		}
		data = append(data, d)
	}
	// ToLower把大写字母统一转小写
	return strings.ToLower(string(data[:]))
}

// SnakeToCamel 蛇形转驼峰 a_b to AB
func SnakeToCamel(s string, camel CamelType) string {
	data := make([]byte, 0, len(s))
	j := false
	k := false
	num := len(s) - 1
	for i := 0; i <= num; i++ {
		d := s[i]
		if k == false && d >= 'A' && d <= 'Z' {
			k = true
		}
		if d >= 'a' && d <= 'z' && (j || k == false) {
			d = d - 32
			j = false
			k = true
		}
		if k && d == '_' && num > i && s[i+1] >= 'a' && s[i+1] <= 'z' {
			j = true
			continue
		}
		data = append(data, d)
	}

	str := string(data[:])
	switch camel {
	case CamelSmall:
		return strings.ToLower(str[0:1]) + str[1:]
	case CamelBig:
		return str
	default:
		return str
	}
}