package utils

import (
	"crypto/hmac"
	"crypto/sha1"
	"encoding/base64"
	"encoding/json"
	"errors"
	"fmt"
	"io/ioutil"
	"math/rand"
	"net/http"
	"net/url"
	"strconv"
	"strings"
	"time"
)

const sortQueryStringFmt string = "AccessKeyId=%s" +
	"&Action=SendSms" +
	"&Format=JSON" +
	"&OutId=123" +
	"&PhoneNumbers=%s" +
	"&RegionId=cn-hangzhou" +
	"&SignName=%s" +
	"&SignatureMethod=HMAC-SHA1" +
	"&SignatureNonce=%s" +
	"&SignatureVersion=1.0" +
	"&TemplateCode=%s" +
	"&TemplateParam=%s" +
	"&Timestamp=%s" +
	"&Version=2017-05-25"

func encodeLocal(encodeStr string) string {
	urlEncode := url.QueryEscape(encodeStr)
	urlEncode = strings.Replace(urlEncode, "+", "%%20", -1)
	urlEncode = strings.Replace(urlEncode, "*", "%2A", -1)
	urlEncode = strings.Replace(urlEncode, "%%7E", "~", -1)
	urlEncode = strings.Replace(urlEncode, "/", "%%2F", -1)
	return urlEncode
}

// SendSmsReply 发送短信返回
type SendSmsReply struct {
	Code    string `json:"Code,omitempty"`
	Message string `json:"Message,omitempty"`
}

func SendSms(phone string, paramStr string, signName string, templateCode string) error {
	const token string = "IP2dC1XDM15A6mCt3yTRDk3ZWHri19&" // 阿里云 accessSecret 注意这个地方要添加一个 &

	AccessKeyId := "LTAI5t6oHZUFW5bqNTbDwd5n" // 自己的阿里云 accessKeyID

	SignatureNonce := strconv.Itoa(GenerateRandNumByCount(9))
	TemplateParam := url.QueryEscape(paramStr)
	Timestamp := url.QueryEscape(time.Now().UTC().Format("2006-01-02T15:04:05Z"))

	sortQueryString := fmt.Sprintf(sortQueryStringFmt,
		AccessKeyId,
		phone,
		url.QueryEscape(signName),
		SignatureNonce,
		templateCode,
		TemplateParam,
		Timestamp,
	)

	urlencode := encodeLocal(sortQueryString)
	sign_str := fmt.Sprintf("GET&%%2F&%s", urlencode)

	key := []byte(token)
	mac := hmac.New(sha1.New, key)
	mac.Write([]byte(sign_str))
	signature := base64.StdEncoding.EncodeToString(mac.Sum(nil))
	signature = encodeLocal(signature)
	resp, err := http.Get("http://dysmsapi.aliyuncs.com/?Signature=" + signature + "&" + sortQueryString)
	if err != nil {
		fmt.Println(err)
		return err
	}
	defer resp.Body.Close()
	body, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		fmt.Println(err)
		return err
	}

	ssr := &SendSmsReply{}

	if err := json.Unmarshal(body, ssr); err != nil {
		return err
	}

	if ssr.Code == "SignatureNonceUsed" {
		return SendSms(phone, paramStr, signName, templateCode)
	} else if ssr.Code != "OK" {
		return errors.New(ssr.Code)
	}
	return nil
}

func GenerateRandNumByCount(count int) int {
	rand.Seed(time.Now().Unix())
	rnd := rand.Intn(9*int(exponent(10, uint64(count-1)))-1) + int(exponent(10, uint64(count-1)))
	return rnd
}

func exponent(a, n uint64) uint64 {
	result := uint64(1)
	for i := n; i > 0; i >>= 1 {
		if i&1 != 0 {
			result *= a
		}
		a *= a
	}
	return result
}

func SendMessageNotice(phone string, content string, signName string, templateCode string) {
	const token string = "IXvbHeyNLAWJHC08mg4quGYQtmf84h&" // 阿里云 accessSecret 注意这个地方要添加一个 &

	AccessKeyId := "LTAIZSh7LB8zkmtO" // 自己的阿里云 accessKeyID

	SignatureNonce := strconv.Itoa(GenerateRandNumByCount(9))
	//TemplateCode := "SMS_140625198"
	TemplateParam := url.QueryEscape("{\"content\":\"" + content + "\"}")
	Timestamp := url.QueryEscape(time.Now().UTC().Format("2006-01-02T15:04:05Z"))

	sortQueryString := fmt.Sprintf(sortQueryStringFmt,
		AccessKeyId,
		phone,
		url.QueryEscape(signName),
		SignatureNonce,
		templateCode,
		TemplateParam,
		Timestamp,
	)

	urlEncode := encodeLocal(sortQueryString)
	signStr := fmt.Sprintf("GET&%%2F&%s", urlEncode)

	key := []byte(token)
	mac := hmac.New(sha1.New, key)
	mac.Write([]byte(signStr))
	signature := base64.StdEncoding.EncodeToString(mac.Sum(nil))
	signature = encodeLocal(signature)
	resp, err := http.Get("http://dysmsapi.aliyuncs.com/?Signature=" + signature + "&" + sortQueryString)
	if err != nil {
		fmt.Println(err)
		return
	}
	defer resp.Body.Close()
	body, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		fmt.Println(err)
		return
	}

	ssr := &SendSmsReply{}

	if err := json.Unmarshal(body, ssr); err != nil {
		return
	}

	if ssr.Code == "SignatureNonceUsed" {
		SendMessageNotice(phone, content, signName, templateCode)
		return
	} else if ssr.Code != "OK" {
		return
	}
	return
}