func GetAuthorizationCode(c *Context, service string, props map[string]string, loginHint string) (string, *model.AppError) {

	sso := utils.Cfg.GetSSOService(service)
	if sso != nil && !sso.Enable {
		return "", model.NewLocAppError("GetAuthorizationCode", "api.user.get_authorization_code.unsupported.app_error", nil, "service="+service)
	}

	clientId := sso.Id
	endpoint := sso.AuthEndpoint
	scope := sso.Scope

	props["hash"] = model.HashPassword(clientId)
	state := b64.StdEncoding.EncodeToString([]byte(model.MapToJson(props)))

	redirectUri := c.GetSiteURL() + "/signup/" + service + "/complete"

	authUrl := endpoint + "?response_type=code&client_id=" + clientId + "&redirect_uri=" + url.QueryEscape(redirectUri) + "&state=" + url.QueryEscape(state)

	if len(scope) > 0 {
		authUrl += "&scope=" + utils.UrlEncode(scope)
	}

	if len(loginHint) > 0 {
		authUrl += "&login_hint=" + utils.UrlEncode(loginHint)
	}

	return authUrl, nil
}

func GetAuthorizationCode(c *Context, w http.ResponseWriter, r *http.Request, teamName, service, redirectUri, loginHint string) {

	sso := utils.Cfg.GetSSOService(service)
	if sso != nil && !sso.Enable {
		c.Err = model.NewAppError("GetAuthorizationCode", "Unsupported OAuth service provider", "service="+service)
		c.Err.StatusCode = http.StatusBadRequest
		return
	}

	clientId := sso.Id
	endpoint := sso.AuthEndpoint
	scope := sso.Scope

	stateProps := map[string]string{"team": teamName, "hash": model.HashPassword(clientId)}
	state := b64.StdEncoding.EncodeToString([]byte(model.MapToJson(stateProps)))

	authUrl := endpoint + "?response_type=code&client_id=" + clientId + "&redirect_uri=" + url.QueryEscape(redirectUri) + "&state=" + url.QueryEscape(state)

	if len(scope) > 0 {
		authUrl += "&scope=" + utils.UrlEncode(scope)
	}

	if len(loginHint) > 0 {
		authUrl += "&login_hint=" + utils.UrlEncode(loginHint)
	}

	http.Redirect(w, r, authUrl, http.StatusFound)
}

func uploadFile(c *Context, w http.ResponseWriter, r *http.Request) {
	if !utils.IsS3Configured() && !utils.Cfg.ServiceSettings.UseLocalStorage {
		c.Err = model.NewAppError("uploadFile", "Unable to upload file. Amazon S3 not configured and local server storage turned off. ", "")
		c.Err.StatusCode = http.StatusNotImplemented
		return
	}

	err := r.ParseMultipartForm(model.MAX_FILE_SIZE)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	m := r.MultipartForm

	props := m.Value

	if len(props["channel_id"]) == 0 {
		c.SetInvalidParam("uploadFile", "channel_id")
		return
	}
	channelId := props["channel_id"][0]
	if len(channelId) == 0 {
		c.SetInvalidParam("uploadFile", "channel_id")
		return
	}

	cchan := Srv.Store.Channel().CheckPermissionsTo(c.Session.TeamId, channelId, c.Session.UserId)

	files := m.File["files"]

	resStruct := &model.FileUploadResponse{
		Filenames: []string{},
		ClientIds: []string{},
	}

	imageNameList := []string{}
	imageDataList := [][]byte{}

	if !c.HasPermissionsToChannel(cchan, "uploadFile") {
		return
	}

	for i, _ := range files {
		file, err := files[i].Open()
		defer file.Close()
		if err != nil {
			http.Error(w, err.Error(), http.StatusInternalServerError)
			return
		}

		buf := bytes.NewBuffer(nil)
		io.Copy(buf, file)

		filename := filepath.Base(files[i].Filename)

		uid := model.NewId()

		path := "teams/" + c.Session.TeamId + "/channels/" + channelId + "/users/" + c.Session.UserId + "/" + uid + "/" + filename

		if err := writeFile(buf.Bytes(), path); err != nil {
			c.Err = err
			return
		}

		if model.IsFileExtImage(filepath.Ext(files[i].Filename)) {
			imageNameList = append(imageNameList, uid+"/"+filename)
			imageDataList = append(imageDataList, buf.Bytes())
		}

		encName := utils.UrlEncode(filename)

		fileUrl := "/" + channelId + "/" + c.Session.UserId + "/" + uid + "/" + encName
		resStruct.Filenames = append(resStruct.Filenames, fileUrl)
	}

	for _, clientId := range props["client_ids"] {
		resStruct.ClientIds = append(resStruct.ClientIds, clientId)
	}

	fireAndForgetHandleImages(imageNameList, imageDataList, c.Session.TeamId, channelId, c.Session.UserId)

	w.Write([]byte(resStruct.ToJson()))
}