package wechat

import (
	"bytes"
	"encoding/json"
	"encoding/xml"
	"errors"
	"fmt"
	"math/rand"
	"sort"
	"strings"
	"sync"
	"time"

	"git.chuangxin1.com/cx/util"
)

const (
	// TokenExpires token expires time 1 hours
	TokenExpires = 60 * 60
	// BaseURL api host
	BaseURL = `https://api.weixin.qq.com`
	// OpenURL open host
	OpenURL = `https://open.weixin.qq.com`
)

// ResponseMsg response
type ResponseMsg struct {
	ErrCode int    `json:"errcode"`
	ErrMsg  string `json:"errmsg"`
}

// Response response
type Response struct {
	ErrCode int    `json:"errcode"`
	ErrMsg  string `json:"errmsg"`

	// token
	AccessToken string `json:"access_token"`
	ExpiresIn   int    `json:"expires_in"`

	// openid
	RefreshToken string `json:"refresh_token"`
	OpenID       string `json:"openid"`
	Scope        string `json:"scope"`

	// user info
	NickName   string `json:"nickname"`
	Sex        string `json:"sex"`
	Province   string `json:"province"`
	City       string `json:"city"`
	Country    string `json:"country"`
	HeadImgURL string `json:"headimgurl"`
	Privilege  string `json:"privilege"`
	UnionID    string `json:"unionid"`

	// template message
	MsgID int64 `json:"msgid"`

	// jsapi_ticket
	Ticket string `json:"ticket"`
}

// FormSignature signature
type FormSignature struct {
	TimeStamp string `form:"timestamp" json:"timestamp"`
	Nonce     string `form:"nonce" json:"nonce"`
	Signature string `form:"signature" json:"signature"`
	Echostr   string `form:"echostr" json:"echostr"`
}

// Message message
type Message struct {
	XMLName      xml.Name `xml:"xml"`
	ToUserName   string   `xml:"ToUserName" json:"ToUserName"`
	FromUserName string   `xml:"FromUserName" json:"FromUserName"`
	CreateTime   int32    `xml:"CreateTime" json:"CreateTime"`
	MsgType      string   `xml:"MsgType" json:"MsgType"`
	MsgID        int64    `xml:"MsgId" json:"MsgId"`
}

// EventTemplateReply event reply
type EventTemplateReply struct {
	XMLName      xml.Name `xml:"xml"`
	ToUserName   string   `xml:"ToUserName"`
	FromUserName string   `xml:"FromUserName"`
	CreateTime   string   `xml:"CreateTime"`
	MsgType      string   `xml:"MsgType"`
	Event        string   `xml:"Event"`
	MsgID        string   `xml:"MsgID"`
	Status       string   `xml:"Status"`
}

var (
	cache sync.Map
)

// Sign 微信计算签名的函数
func Sign(req map[string]interface{}, key string) (sign string) {
	keys := make([]string, 0)

	for k := range req {
		keys = append(keys, k)
	}

	sort.Strings(keys)

	var s string
	for _, k := range keys {
		value := fmt.Sprintf("%v", req[k])
		if value != "" {
			s = s + k + "=" + value + "&"
		}
	}

	if key != "" {
		s = s + "key=" + key
	}

	sign = strings.ToUpper(util.MD5(s))

	return
}

// Random 指定长度的随机字符串(字母或数字)
func Random(n int) string {
	str := "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
	bytes := []byte(str)
	result := []byte{}

	r := rand.New(rand.NewSource(time.Now().UnixNano()))
	n1 := len(bytes)
	for i := 0; i < n; i++ {
		result = append(result, bytes[r.Intn(n1)])
	}
	return string(result)
}

func makeSignature(token, signature, timestamp, nonce string) bool {
	sl := []string{token, timestamp, nonce}
	sort.Strings(sl)
	return strings.Compare(signature, util.SHA1(strings.Join(sl, ""))) == 0
}

func checkErrorWithBody(msg util.Message) (body []byte, err error) {
	if msg.StatusCode == 200 {
		var res ResponseMsg
		err = json.Unmarshal(msg.Body, &res)
		if err == nil {
			if res.ErrCode != 0 {
				err = errors.New(res.ErrMsg)
			} else {
				body = msg.Body
			}
		}
	} else {
		err = errors.New(`HTTP StatusCode not 200`)
	}
	return
}

func checkError(msg util.Message) (res Response, err error) {
	if msg.StatusCode == 200 {
		err = json.Unmarshal(msg.Body, &res)
		if err == nil {
			if res.ErrCode != 0 {
				err = errors.New(res.ErrMsg)
			}
		}
	} else {
		err = errors.New(`HTTP StatusCode not 200`)
	}
	return
}

func getJSON(uri string) (res Response, err error) {
	var msg util.Message
	if msg, err = util.Get(uri, "", "", map[string]string{}); err != nil {
		return
	}
	res, err = checkError(msg)
	return
}

func getBody(uri string) (body []byte, err error) {
	var msg util.Message
	if msg, err = util.Get(uri, "", "", map[string]string{}); err != nil {
		return
	}
	body, err = checkErrorWithBody(msg)
	return
}

func postXML(url string, data []byte) (res Response, err error) {
	var (
		msg     util.Message
		headers = make(map[string]string)
	)

	headers["Accept"] = "application/json"
	headers["Content-Type"] = "application/xml; charset=utf-8"
	msg, err = util.Post(url, "", "", headers, bytes.NewReader(data))
	if err != nil {
		return
	}
	res, err = checkError(msg)
	return
}

func postJSON(url string, data []byte) (res Response, err error) {
	var (
		msg     util.Message
		headers = make(map[string]string)
	)

	headers["Accept"] = "application/json"
	headers["Content-Type"] = "application/json; charset=utf-8"
	msg, err = util.Post(url, "", "", headers, bytes.NewReader(data))
	if err != nil {
		return
	}
	res, err = checkError(msg)
	return
}

func postBody(uri string, data []byte) (body []byte, err error) {
	var (
		msg     util.Message
		headers = make(map[string]string)
	)

	headers["Accept"] = "application/json"
	headers["Content-Type"] = "application/json; charset=utf-8"
	msg, err = util.Post(uri, "", "", headers, bytes.NewReader(data))
	if err != nil {
		return
	}
	body, err = checkErrorWithBody(msg)

	return
}