package maths

import (
	"math/big"
	"strings"

	uuid "github.com/satori/go.uuid"
)

const CODE62 = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
const CodeLenth = 62

/**
 * 10进制 为 62进制 字符串。大数字类型
 *
 * param: *big.Int number 待转换的数字，非常大的
 * return: string
 */
func From10To62Big(number *big.Int) string {
	tmpNumber := big.NewInt(0)
	var result []byte
	for number.Cmp(big.NewInt(0)) != 0 {
		var tmp []byte
		tmpNumber.Rem(number, big.NewInt(CodeLenth))
		tmp = append(tmp, CODE62[tmpNumber.Int64()])
		result = append(tmp, result...)
		number.Div(number, big.NewInt(CodeLenth))
	}
	return string(result)
}

/**
 * 10进制 为 62进制 字符串。大数字类型
 *
 * param: int64 num 待转换的数字
 * return: string
 */
func From10To62(number int64) string {
	var result []byte
	for number != 0 {
		var tmp []byte
		number1 := number % CodeLenth
		tmp = append(tmp, CODE62[number1])
		result = append(tmp, result...)
		number = number / CodeLenth
	}
	return string(result)
}

func GenUUID() string {
	u1 := uuid.Must(uuid.NewV4(), nil).String()
	uuidStr := strings.Replace(u1, "-", "", -1)
	number, _ := new(big.Int).SetString(uuidStr, 16)
	return From10To62Big(number)
}

func Abs(n int64) int64 {
	if n < 0 {
		return -n
	}
	return n
}

func Gen32String() string {
	u1 := uuid.Must(uuid.NewV4(), nil).String()
	uuidStr := strings.Replace(u1, "-", "", -1)
	return uuidStr
}