remove unusable signup feature

mastodon/apps.go

@@ -92,50 +92,3 @@ func RegisterApp(ctx context.Context, appConfig *AppConfig) (*Application, error
 
 	return &app, nil
 }
-
-type AppAuth struct {
-	http.Client
-}
-
-// RegisterApp make auth application and return app token.
-func AuthApp(ctx context.Context, appConfig *Application, instance string) (*string, error) {
-	var appAuth AppAuth
-	params := url.Values{}
-	params.Set("client_id", appConfig.ClientID)
-	params.Set("client_secret", appConfig.ClientSecret)
-	params.Set("redirect_uris", "urn:ietf:wg:oauth:2.0:oob")
-	params.Set("grant_type", "client_credentials")
-	params.Set("scope", "read write follow")
-
-	u, err := url.Parse("https://" + instance)
-	if err != nil {
-		return nil, err
-	}
-	u.Path = path.Join(u.Path, "/oauth/token")
-
-	req, err := http.NewRequest(http.MethodPost, u.String(), strings.NewReader(params.Encode()))
-	if err != nil {
-		return nil, err
-	}
-	req = req.WithContext(ctx)
-	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
-	resp, err := appAuth.Do(req)
-	if err != nil {
-		return nil, err
-	}
-	defer resp.Body.Close()
-
-	if resp.StatusCode != http.StatusOK {
-		return nil, parseAPIError("bad request", resp)
-	}
-	
-	var res struct {
-		AccessToken string `json:"access_token"`
-	}
-	err = json.NewDecoder(resp.Body).Decode(&res)
-	if err != nil {
-		return nil, err
-	}
-
-	return &res.AccessToken, nil
-}