package utils

import (
	crand "crypto/rand"
	"fmt"
	"math/big"
	"math/rand"
	"strconv"
	"time"
)

func RandString(l int, c ...string) string {
	var (
		chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
		str   string
		num   *big.Int
	)
	if len(c) > 0 {
		chars = c[0]
	}
	chrLen := int64(len(chars))
	for len(str) < l {
		num, _ = crand.Int(crand.Reader, big.NewInt(chrLen))
		str += string(chars[num.Int64()])
	}
	return str
}

func RandNum() string {
	seed := time.Now().UnixNano() + rand.Int63()
	return fmt.Sprintf("%05v", rand.New(rand.NewSource(seed)).Int31n(1000000))
}
func GenerateUniqueRandomNumbers(n int) string {
	rand.Seed(time.Now().UnixNano()) // 初始化随机种子
	numbers := make([]int, n)        // 创建一个切片来保存随机数
	for i := range numbers {
		j := 0
		for {
			b := rand.Intn(10) // 生成0-9之间的随机数
			numbers[i] = b
			for _, num := range numbers[:i] {
				if num == b {
					j++
					break
				}
			}
			if j == 0 {
				break
			}
		}
	}

	var numbersStr string
	for _, v := range numbers {
		numbersStr += strconv.Itoa(v)
	}
	return numbersStr
}