package weixinapi

import (
	"crypto/aes"
	"crypto/cipher"
	"net/http"
	"strings"
	"sync"

	"git.rosy.net.cn/baseapi/platformapi"
	"git.rosy.net.cn/baseapi/utils"
)

const (
	prodURL = "https://api.weixin.qq.com"
)

const (
	actionGetToken = "token"
)

const (
	ResponseCodeBusy    = -1
	ResponseCodeSuccess = 0
)

type TokenInfo struct {
	AccessToken string `json:"access_token"`
	ExpiresIn   int    `json:"expires_in"`
}

type ErrorInfo struct {
	ErrCode int    `json:"errcode"`
	ErrMsg  string `json:"errmsg"`
}

type API struct {
	token  string
	appID  string
	secret string
	client *http.Client
	config *platformapi.APIConfig
	locker sync.RWMutex
}

type SNSTokenInfo struct {
	AccessToken  string `json:"access_token"`
	ExpiresIn    int    `json:"expires_in"`
	RefreshToken string `json:"refresh_token"`
	OpenID       string `json:"openid"`
	Scope        string `json:"scope"`
}

type SNSUserInfo struct {
	OpenID     string      `json:"openid"`
	NickName   string      `json:"nickname"`
	Sex        int         `json:"sex"`
	Province   string      `json:"province"`
	City       string      `json:"city"`
	Country    string      `json:"country"`
	HeadImgURL string      `json:"headimgurl"`
	Privilege  interface{} `json:"privilege"`
	UnionID    string      `json:"unionid"`
}

type SessionInfo struct {
	OpenID     string `json:"openid"`
	SessionKey string `json:"session_key"`
	UnionID    string `json:"unionid"`
}

func New(appID, secret string, config ...*platformapi.APIConfig) *API {
	curConfig := platformapi.DefAPIConfig
	if len(config) > 0 {
		curConfig = *config[0]
	}
	return &API{
		appID:  appID,
		secret: secret,
		client: &http.Client{Timeout: curConfig.ClientTimeout},
		config: &curConfig,
	}
}

func (a *API) GetAppID() string {
	return a.appID
}

func (a *API) GetSecret() string {
	return a.secret
}

func (a *API) SetToken(newToken string) bool {
	curToken := a.GetToken()
	if curToken != newToken {
		a.locker.Lock()
		defer a.locker.Unlock()
		a.token = newToken
		return true
	}
	return false
}

func (a *API) GetToken() string {
	a.locker.RLock()
	defer a.locker.RUnlock()
	return a.token
}

func isSNSAction(action string) bool {
	return strings.Index(action, "sns/") == 0
}

func (a *API) AccessAPI(action string, params map[string]interface{}, body string) (retVal map[string]interface{}, err error) {
	if params != nil && body != "" {
		panic("params and body can not all non-empty")
	}
	params2 := make(map[string]interface{})
	for k, v := range params {
		params2[k] = v
	}

	if params2["grant_type"] != nil {
		params2["appid"] = a.appID
		params2["secret"] = a.secret
	} else if !isSNSAction(action) {
		accessToken := a.GetToken()
		if accessToken == "" {
			panic("token is empty!")
		}
		params2["access_token"] = accessToken
	}

	fullURL := utils.GenerateGetURL(prodURL, action, params2)
	// baseapi.SugarLogger.Debug(fullURL)

	err = platformapi.AccessPlatformAPIWithRetry(a.client,
		func() *http.Request {
			var request *http.Request
			if body == "" {
				request, _ = http.NewRequest(http.MethodGet, fullURL, nil)
			} else {
				request, _ = http.NewRequest(http.MethodPost, fullURL, strings.NewReader(body))
			}
			request.Close = true // todo try to fix EOF error when accessing weixin api.
			return request
		},
		a.config,
		func(jsonResult1 map[string]interface{}) (result string, err error) {
			var errInfo *ErrorInfo
			// 微信的返回值，在错误与正常情况下，结构是完全不一样的
			if errCode, ok := jsonResult1["errcode"]; ok {
				errInfo = &ErrorInfo{
					ErrCode: int(utils.MustInterface2Int64(errCode)),
					ErrMsg:  jsonResult1["errmsg"].(string),
				}
				if errInfo.ErrCode == 0 {
					retVal = jsonResult1
				}
			} else {
				retVal = jsonResult1
			}
			if retVal != nil {
				return platformapi.ErrLevelSuccess, nil
			}
			newErr := utils.NewErrorIntCode(errInfo.ErrMsg, errInfo.ErrCode)
			if errInfo.ErrCode == ResponseCodeBusy {
				return platformapi.ErrLevelRecoverableErr, newErr
			}
			return platformapi.ErrLevelCodeIsNotOK, newErr
		})
	return retVal, err
}

func (a *API) RefreshToken() (tokenInfo *TokenInfo, err error) {
	result, err := a.AccessAPI("cgi-bin/token", utils.Params2Map("grant_type", "client_credential"), "")
	if err != nil {
		return nil, err
	}
	tokenInfo = &TokenInfo{
		AccessToken: utils.Interface2String(result["access_token"]),
		ExpiresIn:   int(utils.MustInterface2Int64(result["expires_in"])),
	}
	// update my token too.
	a.SetToken(tokenInfo.AccessToken)
	return tokenInfo, nil
}

func (a *API) MessageTemplateSend(userOpenID, templateID, downloadURL string, miniProgram, data interface{}) (err error) {
	bodyJson := map[string]interface{}{
		"touser":      userOpenID,
		"template_id": templateID,
		"url":         downloadURL,
		"data":        data,
	}
	if downloadURL != "" {
		bodyJson["url"] = downloadURL
	}
	if miniProgram != nil {
		bodyJson["miniprogram"] = miniProgram
	}
	_, err = a.AccessAPI("cgi-bin/message/template/send", nil, string(utils.MustMarshal(bodyJson)))
	return err
}

func mapData2SNSToken(result map[string]interface{}) *SNSTokenInfo {
	return &SNSTokenInfo{
		AccessToken:  utils.Interface2String(result["access_token"]),
		ExpiresIn:    int(utils.MustInterface2Int64(result["expires_in"])),
		RefreshToken: utils.Interface2String(result["refresh_token"]),
		OpenID:       utils.Interface2String(result["openid"]),
		Scope:        utils.Interface2String(result["scope"]),
	}
}

func (a *API) SNSGetToken(code string) (tokenInfo *SNSTokenInfo, err error) {
	result, err := a.AccessAPI("sns/oauth2/access_token", utils.Params2Map("grant_type", "authorization_code", "code", code), "")
	if err != nil {
		return nil, err
	}
	return mapData2SNSToken(result), nil
}

func (a *API) SNSRefreshToken(refreshToken string) (tokenInfo *SNSTokenInfo, err error) {
	result, err := a.AccessAPI("sns/oauth2/refresh_token", utils.Params2Map("grant_type", "refresh_token", "refresh_token", refreshToken), "")
	if err != nil {
		return nil, err
	}
	return mapData2SNSToken(result), nil
}

func (a *API) SNSGetUserInfo(accessToken, openid string) (*SNSUserInfo, error) {
	result, err := a.AccessAPI("sns/userinfo", map[string]interface{}{
		"access_token": accessToken,
		"openid":       openid,
	}, "")
	if err == nil {
		retVal := &SNSUserInfo{
			OpenID:     utils.Interface2String(result["openid"]),
			NickName:   utils.Interface2String(result["nickname"]),
			Sex:        int(utils.MustInterface2Int64(result["sex"])),
			Province:   utils.Interface2String(result["province"]),
			City:       utils.Interface2String(result["city"]),
			Country:    utils.Interface2String(result["country"]),
			HeadImgURL: utils.Interface2String(result["headimgurl"]),
			Privilege:  result["privilege"],
			UnionID:    utils.Interface2String(result["unionid"]),
		}
		return retVal, nil
	}
	return nil, err
}

func (a *API) SNSIsOpenIDValid(accessToken, openid string) (bool, error) {
	_, err := a.AccessAPI("sns/auth", map[string]interface{}{
		"access_token": accessToken,
		"openid":       openid,
	}, "")
	if err == nil {
		return true, nil
	}
	return false, err
}

func (a *API) SNSCode2Session(code string) (sessionInfo *SessionInfo, err error) {
	result, err := a.AccessAPI("sns/jscode2session", map[string]interface{}{
		"js_code":    code,
		"grant_type": "authorization_code",
	}, "")
	if err == nil {
		return &SessionInfo{
			OpenID:     utils.Interface2String(result["openid"]),
			SessionKey: utils.Interface2String(result["session_key"]),
			UnionID:    utils.Interface2String(result["unionid"]),
		}, nil
	}
	return nil, err
}

func (a *API) SNSDecodeMiniProgramData(encryptedData, sessionKey, iv string) (decryptedData []byte, err error) {
	decodedDataList, err := utils.Base64DecodeMultiString(encryptedData, sessionKey, iv)
	if err != nil {
		return nil, err
	}
	c, err := aes.NewCipher(decodedDataList[1])
	if err != nil {
		return nil, err
	}
	cfbdec := cipher.NewCBCDecrypter(c, decodedDataList[2][:c.BlockSize()])
	decryptedData = make([]byte, len(decodedDataList[0]))
	cfbdec.CryptBlocks(decryptedData, decodedDataList[0])
	decryptedData = PKCS7UnPadding(decryptedData)
	return decryptedData, nil
}

func PKCS7UnPadding(origData []byte) []byte {
	length := len(origData)
	unpadding := int(origData[length-1])
	return origData[:(length - unpadding)]
}