[feature] Email notifications for new / closed moderation reports (#1628)

* start fiddling about with email sending to allow multiple recipients

* do some fiddling

* notifs working

* notify on closed report

* finishing up

* envparsing

* use strings.ContainsAny

10 files changed, 361 insertions, 240 deletions

diff --git a/internal/email/common.go b/internal/email/common.go
new file mode 100644
index 000000000..ab4176895
--- /dev/null
+++ b/internal/email/common.go
@@ -0,0 +1,112 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package email
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"net/smtp"
+	"os"
+	"path/filepath"
+	"strings"
+	"text/template"
+
+	"github.com/superseriousbusiness/gotosocial/internal/config"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+)
+
+func (s *sender) sendTemplate(template string, subject string, data any, toAddresses ...string) error {
+	buf := &bytes.Buffer{}
+	if err := s.template.ExecuteTemplate(buf, template, data); err != nil {
+		return err
+	}
+
+	msg, err := assembleMessage(subject, buf.String(), s.from, toAddresses...)
+	if err != nil {
+		return err
+	}
+
+	if err := smtp.SendMail(s.hostAddress, s.auth, s.from, toAddresses, msg); err != nil {
+		return gtserror.SetType(err, gtserror.TypeSMTP)
+	}
+
+	return nil
+}
+
+func loadTemplates(templateBaseDir string) (*template.Template, error) {
+	if !filepath.IsAbs(templateBaseDir) {
+		cwd, err := os.Getwd()
+		if err != nil {
+			return nil, fmt.Errorf("error getting current working directory: %s", err)
+		}
+		templateBaseDir = filepath.Join(cwd, templateBaseDir)
+	}
+
+	// look for all templates that start with 'email_'
+	return template.ParseGlob(filepath.Join(templateBaseDir, "email_*"))
+}
+
+// assembleMessage assembles a valid email message following:
+//   - https://datatracker.ietf.org/doc/html/rfc2822
+//   - https://pkg.go.dev/net/smtp#SendMail
+func assembleMessage(mailSubject string, mailBody string, mailFrom string, mailTo ...string) ([]byte, error) {
+	if strings.ContainsAny(mailSubject, "\r\n") {
+		return nil, errors.New("email subject must not contain newline characters")
+	}
+
+	if strings.ContainsAny(mailFrom, "\r\n") {
+		return nil, errors.New("email from address must not contain newline characters")
+	}
+
+	for _, to := range mailTo {
+		if strings.ContainsAny(to, "\r\n") {
+			return nil, errors.New("email to address must not contain newline characters")
+		}
+	}
+
+	// Normalize the message body to use CRLF line endings
+	const CRLF = "\r\n"
+	mailBody = strings.ReplaceAll(mailBody, CRLF, "\n")
+	mailBody = strings.ReplaceAll(mailBody, "\n", CRLF)
+
+	msg := bytes.Buffer{}
+	switch {
+	case len(mailTo) == 1:
+		// Address email directly to the one recipient.
+		msg.WriteString("To: " + mailTo[0] + CRLF)
+	case config.GetSMTPDiscloseRecipients():
+		// Simply address To all recipients.
+		msg.WriteString("To: " + strings.Join(mailTo, ", ") + CRLF)
+	default:
+		// Address To anonymous group.
+		//
+		// Email will be sent to all recipients but we shouldn't include Bcc header.
+		//
+		// From the smtp.SendMail function: 'Sending "Bcc" messages is accomplished by
+		// including an email address in the to parameter but not including it in the
+		// msg headers.'
+		msg.WriteString("To: Undisclosed Recipients:;" + CRLF)
+	}
+	msg.WriteString("Subject: " + mailSubject + CRLF)
+	msg.WriteString(CRLF)
+	msg.WriteString(mailBody)
+	msg.WriteString(CRLF)
+
+	return msg.Bytes(), nil
+}
diff --git a/internal/email/confirm.go b/internal/email/confirm.go
index a6548e7d1..9f05a4f71 100644
--- a/internal/email/confirm.go
+++ b/internal/email/confirm.go
@@ -17,15 +17,8 @@
 
 package email
 
-import (
-	"bytes"
-	"net/smtp"
-
-	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
-)
-
 const (
-	confirmTemplate = "email_confirm_text.tmpl"
+	confirmTemplate = "email_confirm.tmpl"
 	confirmSubject  = "GoToSocial Email Confirmation"
 )
 
@@ -43,20 +36,5 @@ type ConfirmData struct {
 }
 
 func (s *sender) SendConfirmEmail(toAddress string, data ConfirmData) error {
-	buf := &bytes.Buffer{}
-	if err := s.template.ExecuteTemplate(buf, confirmTemplate, data); err != nil {
-		return err
-	}
-	confirmBody := buf.String()
-
-	msg, err := assembleMessage(confirmSubject, confirmBody, toAddress, s.from)
-	if err != nil {
-		return err
-	}
-
-	if err := smtp.SendMail(s.hostAddress, s.auth, s.from, []string{toAddress}, msg); err != nil {
-		return gtserror.SetType(err, gtserror.TypeSMTP)
-	}
-
-	return nil
+	return s.sendTemplate(confirmTemplate, confirmSubject, data, toAddress)
 }
diff --git a/internal/email/email_test.go b/internal/email/email_test.go
index 2fa52ec4a..91d128ef8 100644
--- a/internal/email/email_test.go
+++ b/internal/email/email_test.go
@@ -18,7 +18,10 @@
 package email_test
 
 import (
+	"testing"
+
 	"github.com/stretchr/testify/suite"
+	"github.com/superseriousbusiness/gotosocial/internal/config"
 	"github.com/superseriousbusiness/gotosocial/internal/email"
 	"github.com/superseriousbusiness/gotosocial/testrig"
 )
@@ -36,3 +39,152 @@ func (suite *EmailTestSuite) SetupTest() {
 	suite.sentEmails = make(map[string]string)
 	suite.sender = testrig.NewEmailSender("../../web/template/", suite.sentEmails)
 }
+
+func (suite *EmailTestSuite) TestTemplateConfirm() {
+	confirmData := email.ConfirmData{
+		Username:     "test",
+		InstanceURL:  "https://example.org",
+		InstanceName: "Test Instance",
+		ConfirmLink:  "https://example.org/confirm_email?token=ee24f71d-e615-43f9-afae-385c0799b7fa",
+	}
+
+	suite.sender.SendConfirmEmail("user@example.org", confirmData)
+	suite.Len(suite.sentEmails, 1)
+	suite.Equal("To: user@example.org\r\nSubject: GoToSocial Email Confirmation\r\n\r\nHello test!\r\n\r\nYou are receiving this mail because you've requested an account on https://example.org.\r\n\r\nWe just need to confirm that this is your email address. To confirm your email, paste the following in your browser's address bar:\r\n\r\nhttps://example.org/confirm_email?token=ee24f71d-e615-43f9-afae-385c0799b7fa\r\n\r\nIf you believe you've been sent this email in error, feel free to ignore it, or contact the administrator of https://example.org\r\n\r\n", suite.sentEmails["user@example.org"])
+}
+
+func (suite *EmailTestSuite) TestTemplateReset() {
+	resetData := email.ResetData{
+		Username:     "test",
+		InstanceURL:  "https://example.org",
+		InstanceName: "Test Instance",
+		ResetLink:    "https://example.org/reset_email?token=ee24f71d-e615-43f9-afae-385c0799b7fa",
+	}
+
+	suite.sender.SendResetEmail("user@example.org", resetData)
+	suite.Len(suite.sentEmails, 1)
+	suite.Equal("To: user@example.org\r\nSubject: GoToSocial Password Reset\r\n\r\nHello test!\r\n\r\nYou are receiving this mail because a password reset has been requested for your account on https://example.org.\r\n\r\nTo reset your password, paste the following in your browser's address bar:\r\n\r\nhttps://example.org/reset_email?token=ee24f71d-e615-43f9-afae-385c0799b7fa\r\n\r\nIf you believe you've been sent this email in error, feel free to ignore it, or contact the administrator of https://example.org.\r\n\r\n", suite.sentEmails["user@example.org"])
+}
+
+func (suite *EmailTestSuite) TestTemplateReportRemoteToLocal() {
+	// Someone from a remote instance has reported one of our users.
+	reportData := email.NewReportData{
+		InstanceURL:        "https://example.org",
+		InstanceName:       "Test Instance",
+		ReportURL:          "https://example.org/settings/admin/reports/01GVJHN1RTYZCZTCXVPPPKBX6R",
+		ReportDomain:       "fossbros-anonymous.io",
+		ReportTargetDomain: "",
+	}
+
+	if err := suite.sender.SendNewReportEmail([]string{"user@example.org"}, reportData); err != nil {
+		suite.FailNow(err.Error())
+	}
+	suite.Len(suite.sentEmails, 1)
+	suite.Equal("To: user@example.org\r\nSubject: GoToSocial New Report\r\n\r\nHello moderator of Test Instance (https://example.org)!\r\n\r\nSomeone from fossbros-anonymous.io has reported a user from your instance.\r\n\r\nTo view the report, paste the following link into your browser: https://example.org/settings/admin/reports/01GVJHN1RTYZCZTCXVPPPKBX6R\r\n\r\n", suite.sentEmails["user@example.org"])
+}
+
+func (suite *EmailTestSuite) TestTemplateReportLocalToRemote() {
+	// Someone from our instance has reported a remote user.
+	reportData := email.NewReportData{
+		InstanceURL:        "https://example.org",
+		InstanceName:       "Test Instance",
+		ReportURL:          "https://example.org/settings/admin/reports/01GVJHN1RTYZCZTCXVPPPKBX6R",
+		ReportDomain:       "",
+		ReportTargetDomain: "fossbros-anonymous.io",
+	}
+
+	if err := suite.sender.SendNewReportEmail([]string{"user@example.org"}, reportData); err != nil {
+		suite.FailNow(err.Error())
+	}
+	suite.Len(suite.sentEmails, 1)
+	suite.Equal("To: user@example.org\r\nSubject: GoToSocial New Report\r\n\r\nHello moderator of Test Instance (https://example.org)!\r\n\r\nSomeone from your instance has reported a user from fossbros-anonymous.io.\r\n\r\nTo view the report, paste the following link into your browser: https://example.org/settings/admin/reports/01GVJHN1RTYZCZTCXVPPPKBX6R\r\n\r\n", suite.sentEmails["user@example.org"])
+}
+
+func (suite *EmailTestSuite) TestTemplateReportLocalToLocal() {
+	// Someone from our instance has reported another user on our instance.
+	reportData := email.NewReportData{
+		InstanceURL:        "https://example.org",
+		InstanceName:       "Test Instance",
+		ReportURL:          "https://example.org/settings/admin/reports/01GVJHN1RTYZCZTCXVPPPKBX6R",
+		ReportDomain:       "",
+		ReportTargetDomain: "",
+	}
+
+	if err := suite.sender.SendNewReportEmail([]string{"user@example.org"}, reportData); err != nil {
+		suite.FailNow(err.Error())
+	}
+	suite.Len(suite.sentEmails, 1)
+	suite.Equal("To: user@example.org\r\nSubject: GoToSocial New Report\r\n\r\nHello moderator of Test Instance (https://example.org)!\r\n\r\nSomeone from your instance has reported another user from your instance.\r\n\r\nTo view the report, paste the following link into your browser: https://example.org/settings/admin/reports/01GVJHN1RTYZCZTCXVPPPKBX6R\r\n\r\n", suite.sentEmails["user@example.org"])
+}
+
+func (suite *EmailTestSuite) TestTemplateReportMoreThanOneModeratorAddress() {
+	reportData := email.NewReportData{
+		InstanceURL:        "https://example.org",
+		InstanceName:       "Test Instance",
+		ReportURL:          "https://example.org/settings/admin/reports/01GVJHN1RTYZCZTCXVPPPKBX6R",
+		ReportDomain:       "fossbros-anonymous.io",
+		ReportTargetDomain: "",
+	}
+
+	// Send the email to multiple addresses
+	if err := suite.sender.SendNewReportEmail([]string{"user@example.org", "admin@example.org"}, reportData); err != nil {
+		suite.FailNow(err.Error())
+	}
+	suite.Len(suite.sentEmails, 1)
+	suite.Equal("To: Undisclosed Recipients:;\r\nSubject: GoToSocial New Report\r\n\r\nHello moderator of Test Instance (https://example.org)!\r\n\r\nSomeone from fossbros-anonymous.io has reported a user from your instance.\r\n\r\nTo view the report, paste the following link into your browser: https://example.org/settings/admin/reports/01GVJHN1RTYZCZTCXVPPPKBX6R\r\n\r\n", suite.sentEmails["user@example.org"])
+}
+
+func (suite *EmailTestSuite) TestTemplateReportMoreThanOneModeratorAddressDisclose() {
+	config.SetSMTPDiscloseRecipients(true)
+
+	reportData := email.NewReportData{
+		InstanceURL:        "https://example.org",
+		InstanceName:       "Test Instance",
+		ReportURL:          "https://example.org/settings/admin/reports/01GVJHN1RTYZCZTCXVPPPKBX6R",
+		ReportDomain:       "fossbros-anonymous.io",
+		ReportTargetDomain: "",
+	}
+
+	// Send the email to multiple addresses
+	if err := suite.sender.SendNewReportEmail([]string{"user@example.org", "admin@example.org"}, reportData); err != nil {
+		suite.FailNow(err.Error())
+	}
+	suite.Len(suite.sentEmails, 1)
+	suite.Equal("To: user@example.org, admin@example.org\r\nSubject: GoToSocial New Report\r\n\r\nHello moderator of Test Instance (https://example.org)!\r\n\r\nSomeone from fossbros-anonymous.io has reported a user from your instance.\r\n\r\nTo view the report, paste the following link into your browser: https://example.org/settings/admin/reports/01GVJHN1RTYZCZTCXVPPPKBX6R\r\n\r\n", suite.sentEmails["user@example.org"])
+}
+
+func (suite *EmailTestSuite) TestTemplateReportClosedOK() {
+	reportClosedData := email.ReportClosedData{
+		InstanceURL:          "https://example.org",
+		InstanceName:         "Test Instance",
+		ReportTargetUsername: "foss_satan",
+		ReportTargetDomain:   "fossbros-anonymous.io",
+		ActionTakenComment:   "User was yeeted. Thank you for reporting!",
+	}
+
+	if err := suite.sender.SendReportClosedEmail("user@example.org", reportClosedData); err != nil {
+		suite.FailNow(err.Error())
+	}
+	suite.Len(suite.sentEmails, 1)
+	suite.Equal("To: user@example.org\r\nSubject: GoToSocial Report Closed\r\n\r\nHello !\r\n\r\nYou recently reported the account @foss_satan@fossbros-anonymous.io to the moderator(s) of Test Instance (https://example.org).\r\n\r\nThe report you submitted has now been closed.\r\n\r\nThe moderator who closed the report left the following comment: User was yeeted. Thank you for reporting!\r\n\r\n", suite.sentEmails["user@example.org"])
+}
+
+func (suite *EmailTestSuite) TestTemplateReportClosedLocalAccountNoComment() {
+	reportClosedData := email.ReportClosedData{
+		InstanceURL:          "https://example.org",
+		InstanceName:         "Test Instance",
+		ReportTargetUsername: "1happyturtle",
+		ReportTargetDomain:   "",
+		ActionTakenComment:   "",
+	}
+
+	if err := suite.sender.SendReportClosedEmail("user@example.org", reportClosedData); err != nil {
+		suite.FailNow(err.Error())
+	}
+	suite.Len(suite.sentEmails, 1)
+	suite.Equal("To: user@example.org\r\nSubject: GoToSocial Report Closed\r\n\r\nHello !\r\n\r\nYou recently reported the account @1happyturtle to the moderator(s) of Test Instance (https://example.org).\r\n\r\nThe report you submitted has now been closed.\r\n\r\nThe moderator who closed the report did not leave a comment.\r\n\r\n", suite.sentEmails["user@example.org"])
+}
+
+func TestEmailTestSuite(t *testing.T) {
+	suite.Run(t, new(EmailTestSuite))
+}
diff --git a/internal/email/noopsender.go b/internal/email/noopsender.go
index 7164440f3..0ed7ff747 100644
--- a/internal/email/noopsender.go
+++ b/internal/email/noopsender.go
@@ -49,62 +49,40 @@ type noopSender struct {
 }
 
 func (s *noopSender) SendConfirmEmail(toAddress string, data ConfirmData) error {
-	buf := &bytes.Buffer{}
-	if err := s.template.ExecuteTemplate(buf, confirmTemplate, data); err != nil {
-		return err
-	}
-	confirmBody := buf.String()
-
-	msg, err := assembleMessage(confirmSubject, confirmBody, toAddress, "test@example.org")
-	if err != nil {
-		return err
-	}
-
-	log.Tracef(nil, "NOT SENDING confirmation email to %s with contents: %s", toAddress, msg)
-
-	if s.sendCallback != nil {
-		s.sendCallback(toAddress, string(msg))
-	}
-	return nil
+	return s.sendTemplate(confirmTemplate, confirmSubject, data, toAddress)
 }
 
 func (s *noopSender) SendResetEmail(toAddress string, data ResetData) error {
-	buf := &bytes.Buffer{}
-	if err := s.template.ExecuteTemplate(buf, resetTemplate, data); err != nil {
-		return err
-	}
-	resetBody := buf.String()
-
-	msg, err := assembleMessage(resetSubject, resetBody, toAddress, "test@example.org")
-	if err != nil {
-		return err
-	}
+	return s.sendTemplate(resetTemplate, resetSubject, data, toAddress)
+}
 
-	log.Tracef(nil, "NOT SENDING reset email to %s with contents: %s", toAddress, msg)
+func (s *noopSender) SendTestEmail(toAddress string, data TestData) error {
+	return s.sendTemplate(testTemplate, testSubject, data, toAddress)
+}
 
-	if s.sendCallback != nil {
-		s.sendCallback(toAddress, string(msg))
-	}
+func (s *noopSender) SendNewReportEmail(toAddresses []string, data NewReportData) error {
+	return s.sendTemplate(newReportTemplate, newReportSubject, data, toAddresses...)
+}
 
-	return nil
+func (s *noopSender) SendReportClosedEmail(toAddress string, data ReportClosedData) error {
+	return s.sendTemplate(reportClosedTemplate, reportClosedSubject, data, toAddress)
 }
 
-func (s *noopSender) SendTestEmail(toAddress string, data TestData) error {
+func (s *noopSender) sendTemplate(template string, subject string, data any, toAddresses ...string) error {
 	buf := &bytes.Buffer{}
-	if err := s.template.ExecuteTemplate(buf, testTemplate, data); err != nil {
+	if err := s.template.ExecuteTemplate(buf, template, data); err != nil {
 		return err
 	}
-	testBody := buf.String()
 
-	msg, err := assembleMessage(testSubject, testBody, toAddress, "test@example.org")
+	msg, err := assembleMessage(subject, buf.String(), "test@example.org", toAddresses...)
 	if err != nil {
 		return err
 	}
 
-	log.Tracef(nil, "NOT SENDING test email to %s with contents: %s", toAddress, msg)
+	log.Tracef(nil, "NOT SENDING email to %s with contents: %s", toAddresses, msg)
 
 	if s.sendCallback != nil {
-		s.sendCallback(toAddress, string(msg))
+		s.sendCallback(toAddresses[0], string(msg))
 	}
 
 	return nil
diff --git a/internal/email/report.go b/internal/email/report.go
new file mode 100644
index 000000000..7c4c10c69
--- /dev/null
+++ b/internal/email/report.go
@@ -0,0 +1,64 @@
+// GoToSocial
+// Copyright (C) GoToSocial Authors admin@gotosocial.org
+// SPDX-License-Identifier: AGPL-3.0-or-later
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+package email
+
+const (
+	newReportTemplate    = "email_new_report.tmpl"
+	newReportSubject     = "GoToSocial New Report"
+	reportClosedTemplate = "email_report_closed.tmpl"
+	reportClosedSubject  = "GoToSocial Report Closed"
+)
+
+type NewReportData struct {
+	// URL of the instance to present to the receiver.
+	InstanceURL string
+	// Name of the instance to present to the receiver.
+	InstanceName string
+	// URL to open the report in the settings panel.
+	ReportURL string
+	// Domain from which the report originated.
+	// Can be empty string for local reports.
+	ReportDomain string
+	// Domain targeted by the report.
+	// Can be empty string for local reports targeting local users.
+	ReportTargetDomain string
+}
+
+func (s *sender) SendNewReportEmail(toAddresses []string, data NewReportData) error {
+	return s.sendTemplate(newReportTemplate, newReportSubject, data, toAddresses...)
+}
+
+type ReportClosedData struct {
+	// Username to be addressed.
+	Username string
+	// URL of the instance to present to the receiver.
+	InstanceURL string
+	// Name of the instance to present to the receiver.
+	InstanceName string
+	// Username of the report target.
+	ReportTargetUsername string
+	// Domain of the report target.
+	// Can be empty string for local reports targeting local users.
+	ReportTargetDomain string
+	// Comment left by the admin who closed the report.
+	ActionTakenComment string
+}
+
+func (s *sender) SendReportClosedEmail(toAddress string, data ReportClosedData) error {
+	return s.sendTemplate(reportClosedTemplate, reportClosedSubject, data, toAddress)
+}
diff --git a/internal/email/reset.go b/internal/email/reset.go
index cb1da9fee..eb931a312 100644
--- a/internal/email/reset.go
+++ b/internal/email/reset.go
@@ -17,15 +17,8 @@
 
 package email
 
-import (
-	"bytes"
-	"net/smtp"
-
-	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
-)
-
 const (
-	resetTemplate = "email_reset_text.tmpl"
+	resetTemplate = "email_reset.tmpl"
 	resetSubject  = "GoToSocial Password Reset"
 )
 
@@ -43,20 +36,5 @@ type ResetData struct {
 }
 
 func (s *sender) SendResetEmail(toAddress string, data ResetData) error {
-	buf := &bytes.Buffer{}
-	if err := s.template.ExecuteTemplate(buf, resetTemplate, data); err != nil {
-		return err
-	}
-	resetBody := buf.String()
-
-	msg, err := assembleMessage(resetSubject, resetBody, toAddress, s.from)
-	if err != nil {
-		return err
-	}
-
-	if err := smtp.SendMail(s.hostAddress, s.auth, s.from, []string{toAddress}, msg); err != nil {
-		return gtserror.SetType(err, gtserror.TypeSMTP)
-	}
-
-	return nil
+	return s.sendTemplate(resetTemplate, resetSubject, data, toAddress)
 }
diff --git a/internal/email/sender.go b/internal/email/sender.go
index 13dd26531..b0d883d9d 100644
--- a/internal/email/sender.go
+++ b/internal/email/sender.go
@@ -35,6 +35,17 @@ type Sender interface {
 
 	// SendTestEmail sends a 'testing email sending' style email to the given toAddress, with the given data.
 	SendTestEmail(toAddress string, data TestData) error
+
+	// SendNewReportEmail sends an email notification to the given addresses, letting them
+	// know that a new report has been created targeting a user on this instance.
+	//
+	// It is expected that the toAddresses have already been filtered to ensure that they
+	// all belong to admins + moderators.
+	SendNewReportEmail(toAddresses []string, data NewReportData) error
+
+	// SendReportClosedEmail sends an email notification to the given address, letting them
+	// know that a report that they created has been closed / resolved by an admin.
+	SendReportClosedEmail(toAddress string, data ReportClosedData) error
 }
 
 // NewSender returns a new email Sender interface with the given configuration, or an error if something goes wrong.
diff --git a/internal/email/test.go b/internal/email/test.go
index 1e411f161..7d6ac2b3b 100644
--- a/internal/email/test.go
+++ b/internal/email/test.go
@@ -17,15 +17,8 @@
 
 package email
 
-import (
-	"bytes"
-	"net/smtp"
-
-	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
-)
-
 const (
-	testTemplate = "email_test_text.tmpl"
+	testTemplate = "email_test.tmpl"
 	testSubject  = "GoToSocial Test Email"
 )
 
@@ -39,20 +32,5 @@ type TestData struct {
 }
 
 func (s *sender) SendTestEmail(toAddress string, data TestData) error {
-	buf := &bytes.Buffer{}
-	if err := s.template.ExecuteTemplate(buf, testTemplate, data); err != nil {
-		return err
-	}
-	testBody := buf.String()
-
-	msg, err := assembleMessage(testSubject, testBody, toAddress, s.from)
-	if err != nil {
-		return err
-	}
-
-	if err := smtp.SendMail(s.hostAddress, s.auth, s.from, []string{toAddress}, msg); err != nil {
-		return gtserror.SetType(err, gtserror.TypeSMTP)
-	}
-
-	return nil
+	return s.sendTemplate(testTemplate, testSubject, data, toAddress)
 }
diff --git a/internal/email/util.go b/internal/email/util.go
deleted file mode 100644
index bd024a3e0..000000000
--- a/internal/email/util.go
+++ /dev/null
@@ -1,71 +0,0 @@
-// GoToSocial
-// Copyright (C) GoToSocial Authors admin@gotosocial.org
-// SPDX-License-Identifier: AGPL-3.0-or-later
-//
-// This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
-//
-// You should have received a copy of the GNU Affero General Public License
-// along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
-package email
-
-import (
-	"errors"
-	"fmt"
-	"os"
-	"path/filepath"
-	"strings"
-	"text/template"
-)
-
-func loadTemplates(templateBaseDir string) (*template.Template, error) {
-	if !filepath.IsAbs(templateBaseDir) {
-		cwd, err := os.Getwd()
-		if err != nil {
-			return nil, fmt.Errorf("error getting current working directory: %s", err)
-		}
-		templateBaseDir = filepath.Join(cwd, templateBaseDir)
-	}
-
-	// look for all templates that start with 'email_'
-	return template.ParseGlob(filepath.Join(templateBaseDir, "email_*"))
-}
-
-// https://datatracker.ietf.org/doc/html/rfc2822
-// I did not read the RFC, I just copy and pasted from
-// https://pkg.go.dev/net/smtp#SendMail
-// and it did seem to work.
-func assembleMessage(mailSubject string, mailBody string, mailTo string, mailFrom string) ([]byte, error) {
-	if strings.Contains(mailSubject, "\r") || strings.Contains(mailSubject, "\n") {
-		return nil, errors.New("email subject must not contain newline characters")
-	}
-
-	if strings.Contains(mailFrom, "\r") || strings.Contains(mailFrom, "\n") {
-		return nil, errors.New("email from address must not contain newline characters")
-	}
-
-	if strings.Contains(mailTo, "\r") || strings.Contains(mailTo, "\n") {
-		return nil, errors.New("email to address must not contain newline characters")
-	}
-
-	// normalize the message body to use CRLF line endings
-	mailBody = strings.ReplaceAll(mailBody, "\r\n", "\n")
-	mailBody = strings.ReplaceAll(mailBody, "\n", "\r\n")
-
-	msg := []byte(
-		"To: " + mailTo + "\r\n" +
-			"Subject: " + mailSubject + "\r\n" +
-			"\r\n" +
-			mailBody + "\r\n",
-	)
-
-	return msg, nil
-}
diff --git a/internal/email/util_test.go b/internal/email/util_test.go
deleted file mode 100644
index 281d5630b..000000000
--- a/internal/email/util_test.go
+++ /dev/null
@@ -1,59 +0,0 @@
-// GoToSocial
-// Copyright (C) GoToSocial Authors admin@gotosocial.org
-// SPDX-License-Identifier: AGPL-3.0-or-later
-//
-// This program is free software: you can redistribute it and/or modify
-// it under the terms of the GNU Affero General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-//
-// This program is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU Affero General Public License for more details.
-//
-// You should have received a copy of the GNU Affero General Public License
-// along with this program.  If not, see <http://www.gnu.org/licenses/>.
-
-package email_test
-
-import (
-	"testing"
-
-	"github.com/stretchr/testify/suite"
-	"github.com/superseriousbusiness/gotosocial/internal/email"
-)
-
-type UtilTestSuite struct {
-	EmailTestSuite
-}
-
-func (suite *UtilTestSuite) TestTemplateConfirm() {
-	confirmData := email.ConfirmData{
-		Username:     "test",
-		InstanceURL:  "https://example.org",
-		InstanceName: "Test Instance",
-		ConfirmLink:  "https://example.org/confirm_email?token=ee24f71d-e615-43f9-afae-385c0799b7fa",
-	}
-
-	suite.sender.SendConfirmEmail("user@example.org", confirmData)
-	suite.Len(suite.sentEmails, 1)
-	suite.Equal("To: user@example.org\r\nSubject: GoToSocial Email Confirmation\r\n\r\nHello test!\r\n\r\nYou are receiving this mail because you've requested an account on https://example.org.\r\n\r\nWe just need to confirm that this is your email address. To confirm your email, paste the following in your browser's address bar:\r\n\r\nhttps://example.org/confirm_email?token=ee24f71d-e615-43f9-afae-385c0799b7fa\r\n\r\nIf you believe you've been sent this email in error, feel free to ignore it, or contact the administrator of https://example.org\r\n\r\n", suite.sentEmails["user@example.org"])
-}
-
-func (suite *UtilTestSuite) TestTemplateReset() {
-	resetData := email.ResetData{
-		Username:     "test",
-		InstanceURL:  "https://example.org",
-		InstanceName: "Test Instance",
-		ResetLink:    "https://example.org/reset_email?token=ee24f71d-e615-43f9-afae-385c0799b7fa",
-	}
-
-	suite.sender.SendResetEmail("user@example.org", resetData)
-	suite.Len(suite.sentEmails, 1)
-	suite.Equal("To: user@example.org\r\nSubject: GoToSocial Password Reset\r\n\r\nHello test!\r\n\r\nYou are receiving this mail because a password reset has been requested for your account on https://example.org.\r\n\r\nTo reset your password, paste the following in your browser's address bar:\r\n\r\nhttps://example.org/reset_email?token=ee24f71d-e615-43f9-afae-385c0799b7fa\r\n\r\nIf you believe you've been sent this email in error, feel free to ignore it, or contact the administrator of https://example.org.\r\n\r\n", suite.sentEmails["user@example.org"])
-}
-
-func TestUtilTestSuite(t *testing.T) {
-	suite.Run(t, &UtilTestSuite{})
-}