feat: add email notifications for issue events (#202)

apps/api/internal/mail/notification.go

@@ -0,0 +1,94 @@
+package mail
+
+import "fmt"
+
+// NotificationEmailData holds data for building notification email content.
+type NotificationEmailData struct {
+	ReceiverName   string
+	ActorName      string
+	IssueRef       string
+	IssueTitle     string
+	IssueURL       string
+	WorkspaceName  string
+	CommentPreview string
+	FieldName      string
+	OldValue       string
+	NewValue       string
+}
+
+// BuildNotificationEmail returns subject and body for a notification email.
+// sender is one of: "assigned", "mentioned", "commented", "state_changed", "subscribed"
+func BuildNotificationEmail(sender string, data NotificationEmailData) (subject, body string) {
+	subject = buildNotificationSubject(sender, data)
+	body = buildNotificationBody(sender, data)
+	return subject, body
+}
+
+func buildNotificationSubject(sender string, data NotificationEmailData) string {
+	switch sender {
+	case "assigned":
+		return fmt.Sprintf("%s assigned you to %s", data.ActorName, data.IssueRef)
+	case "mentioned":
+		return fmt.Sprintf("%s mentioned you in %s", data.ActorName, data.IssueRef)
+	case "commented":
+		return fmt.Sprintf("%s commented on %s", data.ActorName, data.IssueRef)
+	case "state_changed":
+		if data.OldValue != "" && data.NewValue != "" {
+			return fmt.Sprintf("%s moved %s from %s to %s", data.ActorName, data.IssueRef, data.OldValue, data.NewValue)
+		}
+		return fmt.Sprintf("%s changed the state of %s", data.ActorName, data.IssueRef)
+	case "subscribed":
+		if data.FieldName != "" {
+			return fmt.Sprintf("%s updated %s on %s", data.ActorName, data.FieldName, data.IssueRef)
+		}
+		return fmt.Sprintf("%s updated %s", data.ActorName, data.IssueRef)
+	default:
+		return fmt.Sprintf("Update on %s", data.IssueRef)
+	}
+}
+
+func buildNotificationBody(sender string, data NotificationEmailData) string {
+	greeting := fmt.Sprintf("Hi %s,\n\n", data.ReceiverName)
+	footer := fmt.Sprintf("\n\nView issue: %s\n\nWorkspace: %s\n\n---\nYou're receiving this because you're watching this issue.", data.IssueURL, data.WorkspaceName)
+
+	switch sender {
+	case "assigned":
+		return greeting + fmt.Sprintf("%s assigned you to %s: %s", data.ActorName, data.IssueRef, data.IssueTitle) + footer
+
+	case "mentioned":
+		return greeting + fmt.Sprintf("%s mentioned you in %s: %s", data.ActorName, data.IssueRef, data.IssueTitle) + footer
+
+	case "commented":
+		msg := fmt.Sprintf("%s commented on %s: %s", data.ActorName, data.IssueRef, data.IssueTitle)
+		if data.CommentPreview != "" {
+			msg += fmt.Sprintf("\n\nComment preview:\n%s", data.CommentPreview)
+		}
+		return greeting + msg + footer
+
+	case "state_changed":
+		msg := fmt.Sprintf("%s changed the state of %s: %s", data.ActorName, data.IssueRef, data.IssueTitle)
+		if data.OldValue != "" && data.NewValue != "" {
+			msg += fmt.Sprintf("\nFrom: %s\nTo: %s", data.OldValue, data.NewValue)
+		} else if data.NewValue != "" {
+			msg += fmt.Sprintf("\nTo: %s", data.NewValue)
+		}
+		return greeting + msg + footer
+
+	case "subscribed":
+		var msg string
+		if data.FieldName != "" {
+			msg = fmt.Sprintf("%s updated %s on %s: %s", data.ActorName, data.FieldName, data.IssueRef, data.IssueTitle)
+		} else {
+			msg = fmt.Sprintf("%s updated %s: %s", data.ActorName, data.IssueRef, data.IssueTitle)
+		}
+		if data.OldValue != "" && data.NewValue != "" {
+			msg += fmt.Sprintf("\nFrom: %s\nTo: %s", data.OldValue, data.NewValue)
+		} else if data.NewValue != "" {
+			msg += fmt.Sprintf("\nTo: %s", data.NewValue)
+		}
+		return greeting + msg + footer
+
+	default:
+		return greeting + fmt.Sprintf("%s updated %s: %s", data.ActorName, data.IssueRef, data.IssueTitle) + footer
+	}
+}

apps/api/internal/mail/notification_test.go

@@ -0,0 +1,189 @@
+package mail
+
+import (
+	"strings"
+	"testing"
+)
+
+func TestBuildNotificationEmail_Assigned(t *testing.T) {
+	data := NotificationEmailData{
+		ReceiverName:  "Alice",
+		ActorName:     "Bob",
+		IssueRef:      "DEV-123",
+		IssueTitle:    "Fix login bug",
+		IssueURL:      "https://app.devlane.io/issue/abc-123",
+		WorkspaceName: "Engineering",
+	}
+
+	subject, body := BuildNotificationEmail("assigned", data)
+
+	expectedSubject := "Bob assigned you to DEV-123"
+	if subject != expectedSubject {
+		t.Errorf("subject mismatch: got %q, want %q", subject, expectedSubject)
+	}
+
+	if !strings.Contains(body, "Hi Alice") {
+		t.Error("body should contain greeting")
+	}
+	if !strings.Contains(body, "Bob assigned you to DEV-123: Fix login bug") {
+		t.Error("body should contain assignment message")
+	}
+	if !strings.Contains(body, data.IssueURL) {
+		t.Error("body should contain issue URL")
+	}
+	if !strings.Contains(body, "Engineering") {
+		t.Error("body should contain workspace name")
+	}
+}
+
+func TestBuildNotificationEmail_Mentioned(t *testing.T) {
+	data := NotificationEmailData{
+		ReceiverName:  "Charlie",
+		ActorName:     "Dana",
+		IssueRef:      "PROD-456",
+		IssueTitle:    "Deploy to production",
+		IssueURL:      "https://app.devlane.io/issue/def-456",
+		WorkspaceName: "Operations",
+	}
+
+	subject, body := BuildNotificationEmail("mentioned", data)
+
+	expectedSubject := "Dana mentioned you in PROD-456"
+	if subject != expectedSubject {
+		t.Errorf("subject mismatch: got %q, want %q", subject, expectedSubject)
+	}
+
+	if !strings.Contains(body, "Dana mentioned you in PROD-456") {
+		t.Error("body should contain mention message")
+	}
+}
+
+func TestBuildNotificationEmail_Commented(t *testing.T) {
+	data := NotificationEmailData{
+		ReceiverName:   "Eve",
+		ActorName:      "Frank",
+		IssueRef:       "BUG-789",
+		IssueTitle:     "Performance issue",
+		IssueURL:       "https://app.devlane.io/issue/ghi-789",
+		WorkspaceName:  "Backend",
+		CommentPreview: "I think we should optimize the database query here",
+	}
+
+	subject, body := BuildNotificationEmail("commented", data)
+
+	expectedSubject := "Frank commented on BUG-789"
+	if subject != expectedSubject {
+		t.Errorf("subject mismatch: got %q, want %q", subject, expectedSubject)
+	}
+
+	if !strings.Contains(body, "Frank commented on BUG-789") {
+		t.Error("body should contain comment message")
+	}
+	if !strings.Contains(body, "Comment preview:") {
+		t.Error("body should contain comment preview label")
+	}
+	if !strings.Contains(body, data.CommentPreview) {
+		t.Error("body should contain comment preview text")
+	}
+}
+
+func TestBuildNotificationEmail_StateChanged(t *testing.T) {
+	data := NotificationEmailData{
+		ReceiverName:  "Grace",
+		ActorName:     "Henry",
+		IssueRef:      "FEAT-111",
+		IssueTitle:    "Add dark mode",
+		IssueURL:      "https://app.devlane.io/issue/jkl-111",
+		WorkspaceName: "Frontend",
+		OldValue:      "In Progress",
+		NewValue:      "Done",
+	}
+
+	subject, body := BuildNotificationEmail("state_changed", data)
+
+	expectedSubject := "Henry moved FEAT-111 from In Progress to Done"
+	if subject != expectedSubject {
+		t.Errorf("subject mismatch: got %q, want %q", subject, expectedSubject)
+	}
+
+	if !strings.Contains(body, "From: In Progress") {
+		t.Error("body should contain old state")
+	}
+	if !strings.Contains(body, "To: Done") {
+		t.Error("body should contain new state")
+	}
+}
+
+func TestBuildNotificationEmail_Subscribed(t *testing.T) {
+	data := NotificationEmailData{
+		ReceiverName:  "Ivan",
+		ActorName:     "Jane",
+		IssueRef:      "TASK-222",
+		IssueTitle:    "Update documentation",
+		IssueURL:      "https://app.devlane.io/issue/mno-222",
+		WorkspaceName: "Documentation",
+		FieldName:     "priority",
+		OldValue:      "Low",
+		NewValue:      "High",
+	}
+
+	subject, body := BuildNotificationEmail("subscribed", data)
+
+	expectedSubject := "Jane updated priority on TASK-222"
+	if subject != expectedSubject {
+		t.Errorf("subject mismatch: got %q, want %q", subject, expectedSubject)
+	}
+
+	if !strings.Contains(body, "Jane updated priority on TASK-222") {
+		t.Error("body should contain field change message")
+	}
+	if !strings.Contains(body, "From: Low") {
+		t.Error("body should contain old value")
+	}
+	if !strings.Contains(body, "To: High") {
+		t.Error("body should contain new value")
+	}
+}
+
+func TestBuildNotificationEmail_CommentedWithoutPreview(t *testing.T) {
+	data := NotificationEmailData{
+		ReceiverName:  "Kevin",
+		ActorName:     "Laura",
+		IssueRef:      "FIX-333",
+		IssueTitle:    "Memory leak",
+		IssueURL:      "https://app.devlane.io/issue/pqr-333",
+		WorkspaceName: "Infrastructure",
+	}
+
+	_, body := BuildNotificationEmail("commented", data)
+
+	if strings.Contains(body, "Comment preview:") {
+		t.Error("body should not contain comment preview label when no preview provided")
+	}
+}
+
+func TestBuildNotificationEmail_StateChangedWithoutOldValue(t *testing.T) {
+	data := NotificationEmailData{
+		ReceiverName:  "Mike",
+		ActorName:     "Nancy",
+		IssueRef:      "ISSUE-444",
+		IssueTitle:    "Test coverage",
+		IssueURL:      "https://app.devlane.io/issue/stu-444",
+		WorkspaceName: "QA",
+		NewValue:      "In Review",
+	}
+
+	subject, body := BuildNotificationEmail("state_changed", data)
+
+	expectedSubject := "Nancy changed the state of ISSUE-444"
+	if subject != expectedSubject {
+		t.Errorf("subject mismatch: got %q, want %q", subject, expectedSubject)
+	}
+
+	if !strings.Contains(body, "To: In Review") {
+		t.Error("body should contain new state")
+	}
+	if strings.Contains(body, "From:") {
+		t.Error("body should not contain 'From:' when old value is empty")
+	}
+}

apps/api/internal/model/email_notification_log.go

@@ -0,0 +1,36 @@
+package model
+
+import (
+	"time"
+
+	"github.com/google/uuid"
+	"gorm.io/gorm"
+)
+
+// EmailNotificationLog tracks notification emails queued/sent for audit.
+// Maps to the existing email_notification_logs table.
+type EmailNotificationLog struct {
+	ID               uuid.UUID  `gorm:"type:uuid;primaryKey;default:gen_random_uuid()" json:"id"`
+	ReceiverID       uuid.UUID  `gorm:"type:uuid;not null" json:"receiver_id"`
+	TriggeredByID    *uuid.UUID `gorm:"type:uuid" json:"triggered_by_id,omitempty"`
+	Subject          string     `gorm:"type:text" json:"subject"`
+	EntityIdentifier *uuid.UUID `gorm:"type:uuid" json:"entity_identifier,omitempty"`
+	EntityName       string     `gorm:"type:varchar(255)" json:"entity_name,omitempty"`
+	Data             JSONMap    `gorm:"type:jsonb;serializer:json" json:"data,omitempty"`
+	ProcessedAt      *time.Time `gorm:"type:timestamptz" json:"processed_at,omitempty"`
+	SentAt           *time.Time `gorm:"type:timestamptz" json:"sent_at,omitempty"`    // When queued to RabbitMQ
+	Entity           string     `gorm:"type:varchar(200)" json:"entity,omitempty"`    // Legacy
+	OldValue         string     `gorm:"type:varchar(300)" json:"old_value,omitempty"` // Legacy
+	NewValue         string     `gorm:"type:varchar(300)" json:"new_value,omitempty"` // Legacy
+	CreatedAt        time.Time  `json:"created_at"`
+	UpdatedAt        time.Time  `json:"updated_at"`
+}
+
+func (EmailNotificationLog) TableName() string { return "email_notification_logs" }
+
+func (e *EmailNotificationLog) BeforeCreate(tx *gorm.DB) error {
+	if e.ID == uuid.Nil {
+		e.ID = uuid.New()
+	}
+	return nil
+}

apps/api/internal/router/router.go

@@ -157,6 +157,13 @@ func New(cfg Config) *gin.Engine {
 	notificationSvc.SetLogger(cfg.Log)
 	notificationSvc.SetSubscriberStore(issueSubscriberStore)
 	notificationSvc.SetPreferenceStore(userNotifPrefStore)
+	// Wire email notification infrastructure if queue is available
+	if cfg.Queue != nil {
+		emailLogStore := store.NewEmailNotificationLogStore(cfg.DB)
+		notificationSvc.SetEmailLogStore(emailLogStore)
+		notificationSvc.SetQueue(cfg.Queue)
+		notificationSvc.SetAppBaseURL(appBaseURL)
+	}
 	issueSvc.SetNotificationService(notificationSvc)
 	issueSvc.SetSubscriberStore(issueSubscriberStore)
 	issueReactionStore := store.NewIssueReactionStore(cfg.DB)