package tools

import (
	"crypto/md5"
	"crypto/rand"
	"crypto/sha256"
	"encoding/hex"
	"fmt"
	"math/big"

	"golang.org/x/crypto/bcrypt"
)

// HashPassword 使用bcrypt加密密码
func HashPassword(password string) (string, error) {
	bytes, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
	return string(bytes), err
}

// CheckPassword 验证密码
func CheckPassword(password, hash string) bool {
	err := bcrypt.CompareHashAndPassword([]byte(hash), []byte(password))
	return err == nil
}

// MD5 计算MD5哈希值
func MD5(text string) string {
	hash := md5.Sum([]byte(text))
	return hex.EncodeToString(hash[:])
}

// SHA256 计算SHA256哈希值
func SHA256(text string) string {
	hash := sha256.Sum256([]byte(text))
	return hex.EncodeToString(hash[:])
}

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

// GenerateRandomNumber 生成指定长度的随机数字字符串
func GenerateRandomNumber(length int) string {
	const charset = "0123456789"
	b := make([]byte, length)
	for i := range b {
		num, _ := rand.Int(rand.Reader, big.NewInt(int64(len(charset))))
		b[i] = charset[num.Int64()]
	}
	return string(b)
}

// GenerateSMSCode 生成短信验证码
func GenerateSMSCode() string {
	return GenerateRandomNumber(6)
}

// GenerateOrderNo 生成订单号
func GenerateOrderNo(prefix string) string {
	timestamp := GetTimestamp()
	random := GenerateRandomNumber(6)
	return fmt.Sprintf("%s%d%s", prefix, timestamp, random)
}

// GeneratePaymentNo 生成支付单号
func GeneratePaymentNo() string {
	return GenerateOrderNo("PAY")
}

// GenerateRefundNo 生成退款单号
func GenerateRefundNo() string {
	return GenerateOrderNo("RF")
}

// GenerateTransferNo 生成调拨单号
func GenerateTransferNo() string {
	return GenerateOrderNo("TF")
}