package wx

import (
	"bytes"
	"crypto/tls"
	"encoding/json"
	"encoding/xml"
	"errors"
	"fmt"
	"io"
	"io/ioutil"
	"net/http"
	"net/url"
	"time"
)

type AccessToken struct {
	TokenStr  string `json:"access_token"`
	ExpiresAt int64  `json:"expires_at"`
}

func (token *AccessToken) IsExpired() bool {
	return time.Now().Unix()+10 > token.ExpiresAt
}

type AccessTokenResponse struct {
	ErrCode     int    `json:"errcode"`
	ErrMsg      string `json:"errmsg"`
	AccessToken string `json:"access_token"`
	ExpiresIn   int64  `json:"expires_in"`
}

type Message map[string]interface{}

type Weixin interface {
	GetAccessToken() (*AccessTokenResponse, error)
	PrepareOrder(reqInfo UnionPayRequest) (*UnionPayResponse, error)
	OrderQuery(reqInfo UnionPayRequest) (map[string]string, error)
	Refund(param UnionPayRequest, certFile, keyFile string) (map[string]string, error)
	Send(msg Message, token string) error
	SendTpl(msg string, token, wxType string) error
	SendRedpack(param UnionPayRequest, certFile, keyFile string) (map[string]string, error)
	GetHBInfo(param UnionPayRequest, certFile, keyFile string) (map[string]string, error)
}

var appInfo struct {
	appid, secret string
	isInit        bool
}

func Init(appid, secret string) Weixin {
	appInfo.appid = appid
	appInfo.secret = secret
	appInfo.isInit = true
	return NewWeixin(appid, secret)
}

func NewWeixin(appid, secret string) Weixin {
	if appid == "" && appInfo.isInit {
		appid = appInfo.appid
	}
	if secret == "" && appInfo.isInit {
		secret = appInfo.secret
	}
	return &defaultWeixin{
		AppId:  appid,
		Secret: secret,
	}
}

type defaultWeixin struct {
	AppId  string
	Secret string
}

func (weixin *defaultWeixin) GetAccessToken() (*AccessTokenResponse, error) {
	var serviceUrl string = "https://api.weixin.qq.com/cgi-bin/token"
	reqParams := url.Values{}
	reqParams.Add("grant_type", "client_credential")
	reqParams.Add("appid", weixin.AppId)
	reqParams.Add("secret", weixin.Secret)
	serviceUrl += "?" + reqParams.Encode()
	res, err := http.Get(serviceUrl)
	if err != nil {
		return nil, err
	}
	defer res.Body.Close()
	resBuf, err := ioutil.ReadAll(res.Body)
	if err != nil {
		return nil, err
	}
	tokenRes := &AccessTokenResponse{}
	err = json.Unmarshal(resBuf, tokenRes)
	if err != nil {
		//return nil, err
		return nil, fmt.Errorf("%s", string(resBuf))
	}
	if tokenRes.ErrCode != 0 {
		return nil, fmt.Errorf("%d::%s", tokenRes.ErrCode, tokenRes.ErrMsg)
	}
	return tokenRes, nil
}

func (weixin *defaultWeixin) PrepareOrder(reqInfo UnionPayRequest) (*UnionPayResponse, error) {
	var serviceUrl string = "https://api.mch.weixin.qq.com/pay/unifiedorder"
	reqBytes, err := xml.Marshal(reqInfo)
	if err != nil {
		return nil, err
	}
	reader := bytes.NewReader(reqBytes)
	resp, err := http.Post(serviceUrl, "application/xml", reader)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	resBuf, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}
	payRes := &UnionPayResponse{}
	err = xml.Unmarshal(resBuf, payRes)
	return payRes, err
}

func (weixin *defaultWeixin) OrderQuery(reqInfo UnionPayRequest) (map[string]string, error) {
	var serviceUrl string = "https://api.mch.weixin.qq.com/pay/orderquery"
	reqBytes, err := xml.Marshal(reqInfo)
	if err != nil {
		return nil, err
	}
	reader := bytes.NewReader(reqBytes)
	resp, err := http.Post(serviceUrl, "application/xml", reader)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	/*resBuf, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return nil, err
	}
	//qRes := &UnionPayResult{}
	//err = xml.Unmarshal(resBuf, qRes)
	fmt.Println(string(resBuf))
	*/
	qRes := xmlToMap(resp.Body)
	return qRes, nil

}

func (weixin *defaultWeixin) Refund(params UnionPayRequest, certFile, keyFile string) (map[string]string, error) {
	var serviceUrl string = "https://api.mch.weixin.qq.com/secapi/pay/refund"
	return secureRequest(serviceUrl, params, certFile, keyFile)
}

func (weixin *defaultWeixin) SendRedpack(params UnionPayRequest, certFile, keyFile string) (map[string]string, error) {
	var serviceUrl string = "https://api.mch.weixin.qq.com/mmpaymkttransfers/sendredpack"
	//var serviceUrl string = "https://api.mch.weixin.qq.com/sandboxnew/mmpaymkttransfers/sendredpack"
	return secureRequest(serviceUrl, params, certFile, keyFile)
}

func (weixin *defaultWeixin) GetHBInfo(params UnionPayRequest, certFile, keyFile string) (map[string]string, error) {
	var serviceUrl string = "https://api.mch.weixin.qq.com/mmpaymkttransfers/gethbinfo"
	return secureRequest(serviceUrl, params, certFile, keyFile)
}

func secureRequest(serviceUrl string, params UnionPayRequest, certFile, keyFile string) (map[string]string, error) {
	reqBytes, err := xml.Marshal(params)
	if err != nil {
		return nil, err
	}
	reader := bytes.NewReader(reqBytes)
	client, err := getSecureClient(certFile, keyFile)
	if err != nil {
		return nil, err
	}
	resp, err := client.Post(serviceUrl, "application/xml", reader)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	ret := xmlToMap(resp.Body)

	return ret, nil
}

func (weixin *defaultWeixin) Send(msg Message, token string) error {
	var serviceUrl string = "https://api.weixin.qq.com/cgi-bin/message/custom/send?access_token=" + token
	var buffer bytes.Buffer

	enc := json.NewEncoder(&buffer)
	enc.SetEscapeHTML(false)
	err := enc.Encode(msg)
	if err != nil {
		return err
	}
	reader := bytes.NewReader(buffer.Bytes())
	resp, err := http.Post(serviceUrl, "application/json", reader)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	buf, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return err
	}
	var httpRes = struct {
		ErrCode uint16 `json:"errcode"`
		ErrMsg  string `json:"errmsg"`
	}{}
	err = json.Unmarshal(buf, &httpRes)
	if err != nil {
		return err
	}
	if httpRes.ErrCode == 0 {
		return nil
	} else {
		return errors.New(httpRes.ErrMsg)
	}
}

func (weixin *defaultWeixin) SendTpl(msg string, token, wxType string) error {
	var serviceUrl string = "https://api.weixin.qq.com/cgi-bin/message/template/send?access_token="
	if wxType == "mp" {
		serviceUrl = "https://api.weixin.qq.com/cgi-bin/message/wxopen/template/send?access_token="
	}
	serviceUrl += token
	reader := bytes.NewReader([]byte(msg))
	resp, err := http.Post(serviceUrl, "application/json", reader)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	buf, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return err
	}
	var httpRes = struct {
		ErrCode uint16 `json:"errcode"`
		ErrMsg  string `json:"errmsg"`
		MsgId   uint64 `json:"msgid"`
	}{}
	err = json.Unmarshal(buf, &httpRes)
	if err != nil {
		//return err
		return fmt.Errorf("%s", string(buf))
	}
	if httpRes.ErrCode == 0 {
		return nil
	} else {
		//return errors.New(httpRes.ErrMsg)
		return fmt.Errorf("%d::%s", httpRes.ErrCode, httpRes.ErrMsg)
	}
}

func getSecureClient(certFile, keyFile string) (*http.Client, error) {
	cert, err := tls.LoadX509KeyPair(certFile, keyFile)
	if err != nil {
		return nil, err
	}
	ssl := &tls.Config{
		Certificates: []tls.Certificate{cert},
	}
	return &http.Client{
		Transport: &http.Transport{
			TLSClientConfig: ssl,
		},
	}, nil
}

func xmlToMap(r io.Reader) map[string]string {
	m := make(map[string]string)
	// the current value stack
	values := make([]string, 0)

	p := xml.NewDecoder(r)
	for token, err := p.Token(); err == nil; token, err = p.Token() {
		switch t := token.(type) {
		case xml.CharData:
			// push
			values = append(values, string([]byte(t)))
		case xml.EndElement:
			if t.Name.Local == "xml" {
				continue
			}
			m[t.Name.Local] = values[len(values)-1]
			// pop
			values = values[:len(values)]
		}
	}
	return m
}