Added sign up support. Tested on mastodon

But required test on GoToSocial.
Confirmation inside bloat-fe not supported

service/service.go

@@ -920,6 +920,72 @@ func (s *service) Signin(c *client, code string) (err error) {
 	return c.setSession(c.s)
 }
 
+func (s *service) NewSessionRegister(c *client, instance string, reason string, username string, email string, password string, agreement bool, locale string, registerCredintals mastodon.RegisterCredintals) (rurl string, sess *model.Session, err error) {
+	var instanceURL string
+	if strings.HasPrefix(instance, "https://") {
+		instanceURL = instance
+		instance = strings.TrimPrefix(instance, "https://")
+	} else {
+		instanceURL = "https://" + instance
+	}
+
+	sid, err := util.NewSessionID()
+	if err != nil {
+		return
+	}
+	csrf, err := util.NewCSRFToken()
+	if err != nil {
+		return
+	}
+
+	app, err := mastodon.RegisterApp(c.ctx, &mastodon.AppConfig{
+		Server:       instanceURL,
+		ClientName:   s.cname,
+		Scopes:       s.cscope,
+		Website:      s.cwebsite,
+		RedirectURIs: s.cwebsite + "/oauth_callback",
+	})
+	if err != nil {
+		return
+	}
+	registerCredintals.App = app
+	bearer, err := mastodon.AuthApp(c.ctx, app, instance)
+	if err != nil {
+		return
+	}
+	token, err := mastodon.RegisterAccount(c.ctx, instance, reason, username, email, password, agreement, locale, registerCredintals, *bearer)
+
+	if err != nil {
+		return
+	}
+	sess = &model.Session{
+		ID:           sid,
+		Instance:     instance,
+		UserID:	      "1",
+		ClientID:     app.ClientID,
+		ClientSecret: app.ClientSecret,
+		AccessToken:  *token,
+		CSRFToken:    csrf,
+		Settings:     *model.NewSettings(),
+	}
+
+	u, err := url.Parse("/oauth/authorize")
+	if err != nil {
+		return
+	}
+
+	q := make(url.Values)
+	q.Set("scope", "read write follow")
+	q.Set("client_id", app.ClientID)
+	q.Set("response_type", "code")
+	q.Set("redirect_uri", s.cwebsite+"/oauth_callback")
+	u.RawQuery = q.Encode()
+
+	rurl = instanceURL + u.String()
+	return
+}
+
+
 func (s *service) Post(c *client, content string, replyToID string,
 	format string, visibility string, isNSFW bool, spoilerText string,
 	files []*multipart.FileHeader, edit string) (id string, err error) {

service/transport.go

@@ -254,6 +254,32 @@ func NewHandler(s *service, logger *log.Logger, staticDir string) http.Handler {
 		return nil
 	}, NOAUTH, HTML)
 
+	signup := handle(func(c *client) error {
+		instance := c.r.FormValue("instanceup")
+		reason := c.r.FormValue("reason")
+		username := c.r.FormValue("username")
+		email := c.r.FormValue("email")
+		password := c.r.FormValue("password")
+		agreement := c.r.FormValue("agreement") == "true"
+		locale := c.r.FormValue("locale")
+		url, sess, err := s.NewSessionRegister(c, instance, reason, username, email, password, agreement, locale, mastodon.RegisterCredintals{
+		Server: "https://"+instance,
+		Reason: reason,
+		Username: username,
+		Email: email,
+		Password: password,
+		Agreement: agreement,
+		Locale: locale,
+		})
+		if err != nil {
+			return err
+		}
+		c.setSession(sess)
+		url = "/confirmation"
+		c.redirect(url)
+		return nil
+	}, NOAUTH, HTML)
+
 	oauthCallback := handle(func(c *client) error {
 		q := c.r.URL.Query()
 		token := q.Get("code")
@@ -786,6 +812,7 @@ func NewHandler(s *service, logger *log.Logger, staticDir string) http.Handler {
 	r.HandleFunc("/settings", settingsPage).Methods(http.MethodGet)
 	r.HandleFunc("/filters", filtersPage).Methods(http.MethodGet)
 	r.HandleFunc("/signin", signin).Methods(http.MethodPost)
+	r.HandleFunc("/signup", signup).Methods(http.MethodPost)
 	r.HandleFunc("/oauth_callback", oauthCallback).Methods(http.MethodGet)
 	r.HandleFunc("/post", post).Methods(http.MethodPost)
 	r.HandleFunc("/like/{id}", like).Methods(http.MethodPost)