[feature] New user sign-up via web page (#2796)

* [feature] User sign-up form and admin notifs

* add chosen + filtered languages to migration

* remove stray comment

* chosen languages schmosen schmanguages

* proper error on local account missing

4 files changed, 136 insertions, 48 deletions

diff --git a/internal/processing/workers/fromclientapi.go b/internal/processing/workers/fromclientapi.go
index c7e78fee2..ed513c331 100644
--- a/internal/processing/workers/fromclientapi.go
+++ b/internal/processing/workers/fromclientapi.go
@@ -209,18 +209,23 @@ func (p *Processor) ProcessFromClientAPI(ctx context.Context, cMsg messages.From
 }
 
 func (p *clientAPI) CreateAccount(ctx context.Context, cMsg messages.FromClientAPI) error {
-	account, ok := cMsg.GTSModel.(*gtsmodel.Account)
+	newUser, ok := cMsg.GTSModel.(*gtsmodel.User)
 	if !ok {
-		return gtserror.Newf("%T not parseable as *gtsmodel.Account", cMsg.GTSModel)
+		return gtserror.Newf("%T not parseable as *gtsmodel.User", cMsg.GTSModel)
+	}
+
+	// Notify mods of the new signup.
+	if err := p.surface.notifySignup(ctx, newUser); err != nil {
+		log.Errorf(ctx, "error notifying mods of new sign-up: %v", err)
 	}
 
-	// Send a confirmation email to the newly created account.
-	user, err := p.state.DB.GetUserByAccountID(ctx, account.ID)
-	if err != nil {
-		return gtserror.Newf("db error getting user for account id %s: %w", account.ID, err)
+	// Send "new sign up" email to mods.
+	if err := p.surface.emailAdminNewSignup(ctx, newUser); err != nil {
+		log.Errorf(ctx, "error emailing new signup: %v", err)
 	}
 
-	if err := p.surface.emailPleaseConfirm(ctx, user, account.Username); err != nil {
+	// Send "please confirm your address" email to the new user.
+	if err := p.surface.emailUserPleaseConfirm(ctx, newUser); err != nil {
 		log.Errorf(ctx, "error emailing confirm: %v", err)
 	}
 
@@ -458,7 +463,7 @@ func (p *clientAPI) UpdateReport(ctx context.Context, cMsg messages.FromClientAP
 		return nil
 	}
 
-	if err := p.surface.emailReportClosed(ctx, report); err != nil {
+	if err := p.surface.emailUserReportClosed(ctx, report); err != nil {
 		log.Errorf(ctx, "error emailing report closed: %v", err)
 	}
 
@@ -644,7 +649,7 @@ func (p *clientAPI) ReportAccount(ctx context.Context, cMsg messages.FromClientA
 		}
 	}
 
-	if err := p.surface.emailReportOpened(ctx, report); err != nil {
+	if err := p.surface.emailAdminReportOpened(ctx, report); err != nil {
 		log.Errorf(ctx, "error emailing report opened: %v", err)
 	}
 
diff --git a/internal/processing/workers/fromfediapi.go b/internal/processing/workers/fromfediapi.go
index 2fc3b4b26..7b0e72490 100644
--- a/internal/processing/workers/fromfediapi.go
+++ b/internal/processing/workers/fromfediapi.go
@@ -473,7 +473,7 @@ func (p *fediAPI) CreateFlag(ctx context.Context, fMsg messages.FromFediAPI) err
 	// TODO: handle additional side effects of flag creation:
 	// - notify admins by dm / notification
 
-	if err := p.surface.emailReportOpened(ctx, incomingReport); err != nil {
+	if err := p.surface.emailAdminReportOpened(ctx, incomingReport); err != nil {
 		log.Errorf(ctx, "error emailing report opened: %v", err)
 	}
 
diff --git a/internal/processing/workers/surfaceemail.go b/internal/processing/workers/surfaceemail.go
index a6c97f48f..c00b22c86 100644
--- a/internal/processing/workers/surfaceemail.go
+++ b/internal/processing/workers/surfaceemail.go
@@ -31,41 +31,9 @@ import (
 	"github.com/superseriousbusiness/gotosocial/internal/uris"
 )
 
-func (s *surface) emailReportOpened(ctx context.Context, report *gtsmodel.Report) error {
-	instance, err := s.state.DB.GetInstance(ctx, config.GetHost())
-	if err != nil {
-		return gtserror.Newf("error getting instance: %w", err)
-	}
-
-	toAddresses, err := s.state.DB.GetInstanceModeratorAddresses(ctx)
-	if err != nil {
-		if errors.Is(err, db.ErrNoEntries) {
-			// No registered moderator addresses.
-			return nil
-		}
-		return gtserror.Newf("error getting instance moderator addresses: %w", err)
-	}
-
-	if err := s.state.DB.PopulateReport(ctx, report); err != nil {
-		return gtserror.Newf("error populating report: %w", err)
-	}
-
-	reportData := email.NewReportData{
-		InstanceURL:        instance.URI,
-		InstanceName:       instance.Title,
-		ReportURL:          instance.URI + "/settings/admin/reports/" + report.ID,
-		ReportDomain:       report.Account.Domain,
-		ReportTargetDomain: report.TargetAccount.Domain,
-	}
-
-	if err := s.emailSender.SendNewReportEmail(toAddresses, reportData); err != nil {
-		return gtserror.Newf("error emailing instance moderators: %w", err)
-	}
-
-	return nil
-}
-
-func (s *surface) emailReportClosed(ctx context.Context, report *gtsmodel.Report) error {
+// emailUserReportClosed emails the user who created the
+// given report, to inform them the report has been closed.
+func (s *surface) emailUserReportClosed(ctx context.Context, report *gtsmodel.Report) error {
 	user, err := s.state.DB.GetUserByAccountID(ctx, report.Account.ID)
 	if err != nil {
 		return gtserror.Newf("db error getting user: %w", err)
@@ -104,7 +72,9 @@ func (s *surface) emailReportClosed(ctx context.Context, report *gtsmodel.Report
 	return s.emailSender.SendReportClosedEmail(user.Email, reportClosedData)
 }
 
-func (s *surface) emailPleaseConfirm(ctx context.Context, user *gtsmodel.User, username string) error {
+// emailUserPleaseConfirm emails the given user
+// to ask them to confirm their email address.
+func (s *surface) emailUserPleaseConfirm(ctx context.Context, user *gtsmodel.User) error {
 	if user.UnconfirmedEmail == "" ||
 		user.UnconfirmedEmail == user.Email {
 		// User has already confirmed this
@@ -130,7 +100,7 @@ func (s *surface) emailPleaseConfirm(ctx context.Context, user *gtsmodel.User, u
 	if err := s.emailSender.SendConfirmEmail(
 		user.UnconfirmedEmail,
 		email.ConfirmData{
-			Username:     username,
+			Username:     user.Account.Username,
 			InstanceURL:  instance.URI,
 			InstanceName: instance.Title,
 			ConfirmLink:  confirmLink,
@@ -158,3 +128,77 @@ func (s *surface) emailPleaseConfirm(ctx context.Context, user *gtsmodel.User, u
 
 	return nil
 }
+
+// emailAdminReportOpened emails all active moderators/admins
+// of this instance that a new report has been created.
+func (s *surface) emailAdminReportOpened(ctx context.Context, report *gtsmodel.Report) error {
+	instance, err := s.state.DB.GetInstance(ctx, config.GetHost())
+	if err != nil {
+		return gtserror.Newf("error getting instance: %w", err)
+	}
+
+	toAddresses, err := s.state.DB.GetInstanceModeratorAddresses(ctx)
+	if err != nil {
+		if errors.Is(err, db.ErrNoEntries) {
+			// No registered moderator addresses.
+			return nil
+		}
+		return gtserror.Newf("error getting instance moderator addresses: %w", err)
+	}
+
+	if err := s.state.DB.PopulateReport(ctx, report); err != nil {
+		return gtserror.Newf("error populating report: %w", err)
+	}
+
+	reportData := email.NewReportData{
+		InstanceURL:        instance.URI,
+		InstanceName:       instance.Title,
+		ReportURL:          instance.URI + "/settings/admin/reports/" + report.ID,
+		ReportDomain:       report.Account.Domain,
+		ReportTargetDomain: report.TargetAccount.Domain,
+	}
+
+	if err := s.emailSender.SendNewReportEmail(toAddresses, reportData); err != nil {
+		return gtserror.Newf("error emailing instance moderators: %w", err)
+	}
+
+	return nil
+}
+
+// emailAdminNewSignup emails all active moderators/admins of this
+// instance that a new account sign-up has been submitted to the instance.
+func (s *surface) emailAdminNewSignup(ctx context.Context, newUser *gtsmodel.User) error {
+	instance, err := s.state.DB.GetInstance(ctx, config.GetHost())
+	if err != nil {
+		return gtserror.Newf("error getting instance: %w", err)
+	}
+
+	toAddresses, err := s.state.DB.GetInstanceModeratorAddresses(ctx)
+	if err != nil {
+		if errors.Is(err, db.ErrNoEntries) {
+			// No registered moderator addresses.
+			return nil
+		}
+		return gtserror.Newf("error getting instance moderator addresses: %w", err)
+	}
+
+	// Ensure user populated.
+	if err := s.state.DB.PopulateUser(ctx, newUser); err != nil {
+		return gtserror.Newf("error populating user: %w", err)
+	}
+
+	newSignupData := email.NewSignupData{
+		InstanceURL:    instance.URI,
+		InstanceName:   instance.Title,
+		SignupEmail:    newUser.UnconfirmedEmail,
+		SignupUsername: newUser.Account.Username,
+		SignupReason:   newUser.Reason,
+		SignupURL:      "TODO",
+	}
+
+	if err := s.emailSender.SendNewSignupEmail(toAddresses, newSignupData); err != nil {
+		return gtserror.Newf("error emailing instance moderators: %w", err)
+	}
+
+	return nil
+}
diff --git a/internal/processing/workers/surfacenotify.go b/internal/processing/workers/surfacenotify.go
index a8c36248c..9c82712f2 100644
--- a/internal/processing/workers/surfacenotify.go
+++ b/internal/processing/workers/surfacenotify.go
@@ -333,6 +333,45 @@ func (s *surface) notifyPollClose(ctx context.Context, status *gtsmodel.Status)
 	return errs.Combine()
 }
 
+func (s *surface) notifySignup(ctx context.Context, newUser *gtsmodel.User) error {
+	modAccounts, err := s.state.DB.GetInstanceModerators(ctx)
+	if err != nil {
+		if errors.Is(err, db.ErrNoEntries) {
+			// No registered
+			// mod accounts.
+			return nil
+		}
+
+		// Real error.
+		return gtserror.Newf("error getting instance moderator accounts: %w", err)
+	}
+
+	// Ensure user + account populated.
+	if err := s.state.DB.PopulateUser(ctx, newUser); err != nil {
+		return gtserror.Newf("db error populating new user: %w", err)
+	}
+
+	if err := s.state.DB.PopulateAccount(ctx, newUser.Account); err != nil {
+		return gtserror.Newf("db error populating new user's account: %w", err)
+	}
+
+	// Notify each moderator.
+	var errs gtserror.MultiError
+	for _, mod := range modAccounts {
+		if err := s.notify(ctx,
+			gtsmodel.NotificationSignup,
+			mod,
+			newUser.Account,
+			"",
+		); err != nil {
+			errs.Appendf("error notifying moderator %s: %w", mod.ID, err)
+			continue
+		}
+	}
+
+	return errs.Combine()
+}
+
 // notify creates, inserts, and streams a new
 // notification to the target account if it
 // doesn't yet exist with the given parameters.
@@ -342,7 +381,7 @@ func (s *surface) notifyPollClose(ctx context.Context, status *gtsmodel.Status)
 // targets into this function without filtering
 // for non-local first.
 //
-// targetAccountID and originAccountID must be
+// targetAccount and originAccount must be
 // set, but statusID can be an empty string.
 func (s *surface) notify(
 	ctx context.Context,