package main

import (
	"encoding/json"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"net/url"
	"strings"

	"gin_server_admin/wechatjiexi/wxbizjsonmsgcrypt"
)

const token = "gY1AGR3mjBhzy"
const receiverId = "wwabfd0cec7171e769"
const encodingAeskey = "g8VGfQEqluUhoKOlyjmmll8Q9C5tVFUTX5T2qkmI9Sv"

func getString(str, endstr string, start int, msg *string) int {
	end := strings.Index(str, endstr)
	*msg = str[start:end]
	return end + len(endstr)
}

func VerifyURL(w http.ResponseWriter, r *http.Request) {
	//httpstr := `&{GET /?msg_signature=825075c093249d5a60967fe4a613cae93146636b&timestamp=1597998748&nonce=1597483820&echostr=neLB8CftccHiz19tluVb%2BUBnUVMT3xpUMZU8qvDdD17eH8XfEsbPYC%2FkJyPsZOOc6GdsCeu8jSIa2noSJ%2Fez2w%3D%3D HTTP/1.1 1 1 map[Cache-Control:[no-cache] Accept:[*/*] Pragma:[no-cache] User-Agent:[Mozilla/4.0]] 0x86c180 0 [] false 100.108.211.112:8893 map[] map[] <nil> map[] 100.108.79.233:59663 /?msg_signature=825075c093249d5a60967fe4a613cae93146636b&timestamp=1597998748&nonce=1597483820&echostr=neLB8CftccHiz19tluVb%2BUBnUVMT3xpUMZU8qvDdD17eH8XfEsbPYC%2FkJyPsZOOc6GdsCeu8jSIa2noSJ%2Fez2w%3D%3D <nil>}`
	fmt.Println(r, r.Body)
	httpstr := r.URL.RawQuery
	start := strings.Index(httpstr, "msg_signature=")
	start += len("msg_signature=")

	var msg_signature string
	next := getString(httpstr, "&timestamp=", start, &msg_signature)

	var timestamp string
	next = getString(httpstr, "&nonce=", next, &timestamp)

	var nonce string
	next = getString(httpstr, "&echostr=", next, &nonce)

	echostr := httpstr[next:len(httpstr)]

	echostr, _ = url.QueryUnescape(echostr)
	fmt.Println(msg_signature, timestamp, nonce, echostr, next)

	wxcpt := wxbizjsonmsgcrypt.NewWXBizMsgCrypt(token, encodingAeskey, receiverId, wxbizjsonmsgcrypt.JsonType)
	echoStr, cryptErr := wxcpt.VerifyURL(msg_signature, timestamp, nonce, echostr)
	if nil != cryptErr {
		fmt.Println("verifyUrl fail", cryptErr)
	}
	fmt.Println("verifyUrl success echoStr", string(echoStr))
	fmt.Fprintf(w, string(echoStr))

}

type MsgContent struct {
	ToUsername   string `json:"ToUserName"`
	FromUsername string `json:"FromUserName"`
	CreateTime   uint32 `json:"CreateTime"`
	MsgType      string `json:"MsgType"`
	Content      string `json:"Content"`
	Msgid        uint64 `json:"MsgId"`
	Agentid      uint32 `json:"AgentId"`
}

func MsgHandler(w http.ResponseWriter, r *http.Request) {
	httpstr := r.URL.RawQuery
	start := strings.Index(httpstr, "msg_signature=")
	start += len("msg_signature=")

	var msg_signature string
	next := getString(httpstr, "&timestamp=", start, &msg_signature)

	var timestamp string
	next = getString(httpstr, "&nonce=", next, &timestamp)

	nonce := httpstr[next:len(httpstr)]
	fmt.Println(msg_signature, timestamp, nonce)

	body, err := ioutil.ReadAll(r.Body)
	fmt.Println(string(body), err)
	wxcpt := wxbizjsonmsgcrypt.NewWXBizMsgCrypt(token, encodingAeskey, receiverId, wxbizjsonmsgcrypt.JsonType)

	msg, err_ := wxcpt.DecryptMsg(msg_signature, timestamp, nonce, body)
	fmt.Println(string(msg), err_)
	var msgContent MsgContent
	err = json.Unmarshal(msg, &msgContent)
	if nil != err {
		fmt.Println("Unmarshal fail", err)
	} else {
		fmt.Println("struct", msgContent)
	}

	fmt.Println(msgContent, err)
	ToUsername := msgContent.ToUsername
	msgContent.ToUsername = msgContent.FromUsername
	msgContent.FromUsername = ToUsername
	fmt.Println("replaymsg", msgContent)
	replayJson, err := json.Marshal(&msgContent)

	encryptMsg, cryptErr := wxcpt.EncryptMsg(string(replayJson), "1409659589", "1409659589")
	if nil != cryptErr {
		fmt.Println("DecryptMsg fail", cryptErr)
	}

	sEncryptMsg := string(encryptMsg)

	fmt.Println("after encrypt sEncryptMsg: ", sEncryptMsg)
	fmt.Fprintf(w, sEncryptMsg)
}

func CallbackHandler(w http.ResponseWriter, r *http.Request) {
	httpstr := r.URL.RawQuery
	echo := strings.Index(httpstr, "echostr")
	if echo != -1 {
		VerifyURL(w, r)
	} else {
		MsgHandler(w, r)
	}

	fmt.Println("finished CallbackHandler", httpstr)
}

func main() {
	http.HandleFunc("/", CallbackHandler) //      设置访问路由
	log.Fatal(http.ListenAndServe(":8893", nil))
}