package main

import (
	"crypto"
	"crypto/rand"
	"crypto/rsa"
	"crypto/sha256"
	"crypto/x509"
	"encoding/base64"
	"encoding/json"
	"encoding/pem"
	"errors"
	"hash"
	"io/ioutil"
	"net/http"
	"net/url"
	"strings"
	"time"
)

// DoRequest 支付宝支付统一HTTP调用接口
func DoRequest(appId, bizCcontent, curl, methodType string, privateKey *rsa.PrivateKey) (*map[string]interface{}, error) {
	var data = url.Values{}
	data.Add("app_id", appId)
	data.Add("method", methodType)
	data.Add("format", "json")
	data.Add("charset", "UTF-8")
	data.Add("sign_type", "RSA2")
	data.Add("timestamp", time.Now().Format("2006-01-02 15:04:05"))
	data.Add("version", "1.0")
	data.Add("biz_content", bizCcontent)
	signContentBytes, _ := url.QueryUnescape(data.Encode())
	signature, err := getSign([]byte(signContentBytes), privateKey)
	if err != nil {
		return nil, err
	}
	data.Add("sign", signature)

	url := curl + "?" + data.Encode()
	client := http.Client{Jar: nil}
	req, _ := http.NewRequest("POST", url, nil)
	res, err := client.Do(req)
	if err != nil {
		return nil, err
	}
	bArr, err := ioutil.ReadAll(res.Body)
	if err != nil {
		return nil, err
	}
	m := map[string]interface{}{}
	err = json.Unmarshal(bArr, &m)
	return &m, nil
}

// 生成加密token
func getSign(data []byte, PrivateKey *rsa.PrivateKey) (signature string, err error) {
	var h hash.Hash
	var hType crypto.Hash
	h = sha256.New()
	hType = crypto.SHA256
	h.Write(data)
	d := h.Sum(nil)
	bs, err := rsa.SignPKCS1v15(rand.Reader, PrivateKey, hType, d)

	if err != nil {
		return "", err
	}
	signature = base64.StdEncoding.EncodeToString(bs)
	return
}

// 加载秘钥
func parsePrivateKey(key string) (*rsa.PrivateKey, error) {
	block, _ := pem.Decode([]byte(key))
	if block == nil {
		return nil, errors.New("私钥格式不正确，无法解析PEM块")
	}
	if strings.ToUpper(block.Type) != "RSA PRIVATE KEY" {
		return nil, errors.New("私钥类型不正确，期望为RSA PRIVATE KEY但得到的是" + block.Type)
	}

	// 注意：这里使用x509.ParsePKCS1PrivateKey来解析PKCS#1格式的私钥
	rsaPrivateKey, err := x509.ParsePKCS8PrivateKey(block.Bytes)
	if err != nil {
		return nil, err
	}

	return rsaPrivateKey.(*rsa.PrivateKey), nil
}