package helper

import (
	"unicode"
)

// CamelString 将某字符串转成驼峰写法
func CamelString(s string) 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)
	}
	return string(data[:])
}

// UnderLine 将某字符串转成下划线写法
func UnderLine(s string) string {
	var output []rune
	for i, r := range s {
		if i == 0 {
			output = append(output, unicode.ToLower(r))
			continue
		}
		if unicode.IsUpper(r) {
			output = append(output, '_')
		}
		output = append(output, unicode.ToLower(r))
	}
	return string(output)
}

// Ul 将某字符串转成下划线写法-简化用法
func Ul(s string) string {
	return UnderLine(s)
}