package utils

import (
	"crypto/hmac"
	"crypto/sha1"
	"encoding/base64"
	"fmt"
	"math"
	"math/rand"
	"strconv"
	"strings"
	"time"
)

/*
		RandomString 产生随机数
	  - size 随机码的位数
	  - kind 0    // 纯数字
	    1    // 小写字母
	    2    // 大写字母
	    3    // 数字、大小写字母
*/
func RandomString(size int, kind int) string {
	iKind, kinds, rsBytes := kind, [][]int{[]int{10, 48}, []int{26, 97}, []int{26, 65}}, make([]byte, size)
	isAll := kind > 2 || kind < 0
	rand.Seed(time.Now().UnixNano())
	for i := 0; i < size; i++ {
		if isAll { // random iKind
			iKind = rand.Intn(3)
		}
		scope, base := kinds[iKind][0], kinds[iKind][1]
		rsBytes[i] = uint8(base + rand.Intn(scope))
	}
	return string(rsBytes)
}

func GetUserSha1Pass(pass, salt string) string {
	key := []byte(salt)
	mac := hmac.New(sha1.New, key)
	mac.Write([]byte(pass))
	//进行base64编码
	res := base64.StdEncoding.EncodeToString(mac.Sum(nil))
	return res
}

// GetMilepost 里程桩加减里程，返回里程桩
func GetMilepost(start, num, upDown string) string {
	arr := strings.Split(start, "+")
	var (
		kilometre, meter, milepost, counter, res, resMilepost, resMeter float64
	)
	if len(arr) == 1 {
		meter = 0
	} else {
		meter, _ = strconv.ParseFloat(arr[1], 64)
	}
	str := strings.Replace(arr[0], "k", "", -1)
	str = strings.Replace(str, "K", "", -1)
	kilometre, _ = strconv.ParseFloat(str, 64)
	milepost = kilometre + meter/1000
	counter, _ = strconv.ParseFloat(num, 64)
	if upDown == "D" {
		res = milepost - counter
	} else {
		res = milepost + counter
	}
	resMilepost = math.Floor(res)
	resMeter = (res - resMilepost) * 100
	return fmt.Sprintf("K%d+%.2f", int(resMilepost), resMeter)
}