package rand

import (
	"math/rand"
	"strconv"
)

// 包含大小写和数字
func (rr *Rand) RandomString(n int) string {
	letters := []byte("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ123456789")
	//var letters = []byte("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ123456789")
	result := make([]byte, n)
	//rand.Seed(time.Now().Unix())
	for i := range result {
		result[i] = letters[rand.Intn(len(letters))]
	}

	return string(result)

}

// 生成指定位数的数字字符串，第一位不为0
func (rr *Rand) RandomCode(n int) string {
	numbers := []byte("0123456789")
	numbers_no_zero := []byte("123456789")
	result := make([]byte, n)
	//rand.Seed(time.Now().Unix())
	//code := fmt.Sprintf("%06v", rand.New(rand.NewSource(time.Now().UnixNano())).Int31n(1000000))
	for i := range result {
		result[i] = numbers[rand.Intn(len(numbers))]
	}
	//阿里大于验证码短信首字母不能为0
	if result[0] == 0 {
		{
			result[0] = numbers_no_zero[rand.Intn(len(numbers_no_zero))]
		}
	}
	return string(result)

}

// 6位随机验证码
func (rr *Rand) GetNum6() string {
	//deltaNumber := exponent(10,6)
	//baseNumber := exponent(10,7)
	//rand.Seed(time.Now().UnixNano())
	code := rand.Intn(899999) + 100000
	//code := rand.Intn(baseNumber-baseNumber-1) + deltaNumber
	res := strconv.Itoa(code) //转字符串返回
	return res
}