//==================================
//  * Name：Jerry
//  * Tel：18017448610
//  * DateTime：2019/1/13 14:42
//==================================
package gopay

import (
	"bytes"
	"crypto"
	"crypto/rand"
	"crypto/rsa"
	"crypto/sha1"
	"crypto/sha256"
	"crypto/x509"
	"encoding/base64"
	"encoding/pem"
	"errors"
	"hash"
	"net/url"
	"sort"
)

//	AppId      string `json:"app_id"`      //支付宝分配给开发者的应用ID
//	Method     string `json:"method"`      //接口名称
//	Format     string `json:"format"`      //仅支持 JSON
//	ReturnUrl  string `json:"return_url"`  //HTTP/HTTPS开头字符串
//	Charset    string `json:"charset"`     //请求使用的编码格式，如UTF-8,GBK,GB2312等，推荐使用 UTF-8
//	SignType   string `json:"sign_type"`   //商户生成签名字符串所使用的签名算法类型，目前支持RSA2和RSA，推荐使用 RSA2
//	Sign       string `json:"sign"`        //商户请求参数的签名串
//	Timestamp  string `json:"timestamp"`   //发送请求的时间，格式"yyyy-MM-dd HH:mm:ss"
//	Version    string `json:"version"`     //调用的接口版本，固定为：1.0
//	NotifyUrl  string `json:"notify_url"`  //支付宝服务器主动通知商户服务器里指定的页面http/https路径。
//	BizContent string `json:"biz_content"` //业务请求参数的集合，最大长度不限，除公共参数外所有请求参数都必须放在这个参数中传递，具体参照各产品快速接入文档

//设置支付后的ReturnUrl
func (this *aliPayClient) SetReturnUrl(url string) (client *aliPayClient) {
	this.ReturnUrl = url
	return this
}

//设置支付宝服务器主动通知商户服务器里指定的页面http/https路径。
func (this *aliPayClient) SetNotifyUrl(url string) (client *aliPayClient) {
	this.NotifyUrl = url
	return this
}

//设置编码格式，如UTF-8,GBK,GB2312等，推荐使用 UTF-8
func (this *aliPayClient) SetCharset(charset string) (client *aliPayClient) {
	if charset == null {
		this.Charset = "UTF-8"
	} else {
		this.Charset = charset
	}
	return this
}

//设置签名算法类型，目前支持RSA2和RSA，推荐使用 RSA2
func (this *aliPayClient) SetSignType(signType string) (client *aliPayClient) {
	if signType == null {
		this.SignType = "RSA2"
	} else {
		this.SignType = signType
	}
	return this
}

//设置应用授权
func (this *aliPayClient) SetAppAuthToken(appAuthToken string) (client *aliPayClient) {
	this.AppAuthToken = appAuthToken
	return this
}

//获取参数签名
func getRsaSign(body BodyMap, signType, privateKey string) (sign string, err error) {
	var (
		h              hash.Hash
		key            *rsa.PrivateKey
		hashs          crypto.Hash
		signStr        string
		encryptedBytes []byte
	)
	//解析秘钥
	block, _ := pem.Decode([]byte(privateKey))
	if block == nil {
		return null, errors.New("秘钥错误")
	}
	//log.Println(block.Type)
	key, err = x509.ParsePKCS1PrivateKey(block.Bytes)
	if err != nil {
		//log.Println("x509.ParsePKCS1PrivateKey:", err)
		return null, err
	}

	switch signType {
	case "RSA":
		h = sha1.New()
		hashs = crypto.SHA1
	case "RSA2":
		h = sha256.New()
		hashs = crypto.SHA256
	default:
		h = sha256.New()
		hashs = crypto.SHA256
	}

	signStr = sortAliPaySignParams(body)
	//fmt.Println("原始字符串：", signStr)
	_, err = h.Write([]byte(signStr))
	if err != nil {
		return null, err
	}
	encryptedBytes, err = rsa.SignPKCS1v15(rand.Reader, key, hashs, h.Sum(nil))
	if err != nil {
		//log.Println("rsa.SignPKCS1v15:", err)
		return null, err
	}
	secretData := base64.StdEncoding.EncodeToString(encryptedBytes)
	return secretData, nil
}

//获取根据Key排序后的请求参数字符串
func sortAliPaySignParams(body BodyMap) string {
	keyList := make([]string, 0)
	for k := range body {
		keyList = append(keyList, k)
	}
	sort.Strings(keyList)
	//fmt.Println(keyList)
	buffer := new(bytes.Buffer)
	for _, k := range keyList {
		buffer.WriteString(k)
		buffer.WriteString("=")

		valueStr := convert2String(body[k])
		buffer.WriteString(valueStr)
		buffer.WriteString("&")
	}
	s := buffer.String()
	i := buffer.Len()
	//fmt.Println("排序后参数：", s[:i-1])
	return s[:i-1]
}

//格式化请求URL参数
func FormatAliPayURLParam(body BodyMap) (urlParam string) {
	v := url.Values{}
	for key, value := range body {
		v.Add(key, value.(string))
	}
	urlParam = v.Encode()
	//fmt.Println("Encode后参数:", urlParam)
	return
}