package utils

import (
	"crypto/rand"
	"encoding/base64"
	"math/big"
)

// GenerateRandomString 生成随机字符串
func GenerateRandomString(length int) string {
	const charset = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
	b := make([]byte, length)
	for i := range b {
		n, _ := rand.Int(rand.Reader, big.NewInt(int64(len(charset))))
		b[i] = charset[n.Int64()]
	}
	return string(b)
}

// GenerateRandomNumber 生成随机数字
func GenerateRandomNumber(length int) string {
	const charset = "0123456789"
	b := make([]byte, length)
	for i := range b {
		n, _ := rand.Int(rand.Reader, big.NewInt(int64(len(charset))))
		b[i] = charset[n.Int64()]
	}
	return string(b)
}

// GenerateCardKey 生成卡密
func GenerateCardKey(prefix string, length int) string {
	randomPart := GenerateRandomString(length)
	return prefix + "-" + randomPart
}

// GenerateBase64Token 生成Base64令牌
func GenerateBase64Token(length int) string {
	b := make([]byte, length)
	rand.Read(b)
	return base64.URLEncoding.EncodeToString(b)
}