package service

import (
	"encoding/base64"
	"encoding/json"
	"errors"
	"fmt"
	"io/ioutil"
	"net/http"
	"net/url"
)

type DemoConfig struct {
	ClientSecret string
	ClientId     string
	TokenUrl     string
	RootUrlOrder string
	AccessToken  string
}

func GetDefaultConfig() *DemoConfig {
	var demoConfig DemoConfig
	// TODO: (clientId, clientSecret, tokenUrl)请使用实际值替换
	// App secret, 在AppGallery Connect创建应用之后，系统自动分配的公钥
	demoConfig.ClientSecret = "524921589d516c7216951aa389c030681923cd22dfc4477871f9306430eefb6d"
	// client id指的是您的APP ID
	// App ID, 在AppGallery Connect创建应用之后，系统自动分配的唯一标识符
	demoConfig.ClientId = "112487401"
	// 用于获取authorization token的url，具体请参见基于OAuth 2.0开放鉴权
	demoConfig.TokenUrl = "https://oauth-login.cloud.huawei.com/oauth2/v3/token"

	return &demoConfig
}

type AtResponse struct {
	AccessToken string `json:"access_token"`
}

type AtClient struct {
}

var AtDemo = &AtClient{}

func (atDemo *AtClient) GetAppAt() (string, error) {
	demoConfig := GetDefaultConfig()
	urlValue := url.Values{"grant_type": {"client_credentials"}, "client_secret": {demoConfig.ClientSecret}, "client_id": {demoConfig.ClientId}}
	resp, err := http.PostForm(demoConfig.TokenUrl, urlValue)
	if err != nil {
		return "", err
	}
	defer resp.Body.Close()
	bodyBytes, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		return "", err
	}
	var atResponse AtResponse
	json.Unmarshal(bodyBytes, &atResponse)
	if atResponse.AccessToken != "" {
		return atResponse.AccessToken, nil
	} else {
		return "", errors.New("Get token fail, " + string(bodyBytes))
	}
}

func BuildAuthorization() (string, error) {
	appAt, err := AtDemo.GetAppAt()
	if err != nil {
		return "", err
	}
	oriString := fmt.Sprintf("APPAT:%s", appAt)
	var authString = base64.StdEncoding.EncodeToString([]byte(oriString))
	var authHeaderString = fmt.Sprintf("Basic %s", authString)
	return authHeaderString, nil
}