feat: backend service

backend/internal/notification/deps.go

@@ -0,0 +1,99 @@
+package notification
+
+import (
+	"context"
+	"time"
+
+	"galaxy/backend/internal/config"
+	"galaxy/backend/internal/user"
+
+	"github.com/google/uuid"
+	"go.uber.org/zap"
+)
+
+// PushPublisher is the publisher contract notification uses to emit a
+// `client_event` push frame to gateway. The real implementation lives
+// in `backend/internal/push` ; NewNoopPushPublisher satisfies
+// the interface for tests that do not exercise push behaviour.
+//
+// Implementations must be concurrency-safe. The deviceSessionID pointer
+// narrows the event to a single device session when non-nil; nil means
+// fan out to every active session of userID. eventID, requestID and
+// traceID are correlation identifiers that gateway forwards verbatim
+// into the signed client envelope; empty strings are forwarded
+// unchanged.
+type PushPublisher interface {
+	PublishClientEvent(ctx context.Context, userID uuid.UUID, deviceSessionID *uuid.UUID, kind string, payload map[string]any, eventID, requestID, traceID string) error
+}
+
+// Mailer is the email surface notification uses for outbound mail. The
+// canonical implementation is `*mail.Service.EnqueueTemplate`; tests
+// substitute a recording fake. The contract matches mail's existing
+// signature so the wiring layer can pass the concrete service directly.
+type Mailer interface {
+	EnqueueTemplate(ctx context.Context, templateID, recipient string, payload map[string]any, idempotencyKey string) error
+}
+
+// AccountResolver looks up the recipient profile (email + preferred
+// language) by user_id. The canonical implementation is
+// `*user.Service.GetAccount`. The narrow interface keeps the Service
+// from depending on every part of the user surface.
+type AccountResolver interface {
+	GetAccount(ctx context.Context, userID uuid.UUID) (user.Account, error)
+}
+
+// Deps aggregates every collaborator the Service depends on.
+//
+// Store, Mail, and Accounts must be non-nil. Push defaults to the no-op
+// publisher when omitted; Now defaults to time.Now; Logger defaults to
+// zap.NewNop. Config carries the worker interval, the max-attempts cap,
+// and the optional admin-email destination from `BACKEND_NOTIFICATION_*`.
+type Deps struct {
+	Store *Store
+	Mail Mailer
+	Push PushPublisher
+	Accounts AccountResolver
+	Config config.NotificationConfig
+	// Now overrides time.Now for deterministic tests. A nil Now defaults
+	// to time.Now in NewService.
+	Now func() time.Time
+	// Logger is named under "notification" by NewService. Nil falls back
+	// to zap.NewNop.
+	Logger *zap.Logger
+}
+
+// NewNoopPushPublisher returns a PushPublisher that logs every event
+// at debug level and returns nil. The canonical publisher lives in
+// `backend/internal/push`; this constructor exists for tests.
+func NewNoopPushPublisher(logger *zap.Logger) PushPublisher {
+	if logger == nil {
+		logger = zap.NewNop()
+	}
+	return &noopPushPublisher{logger: logger.Named("push.noop")}
+}
+
+type noopPushPublisher struct {
+	logger *zap.Logger
+}
+
+func (p *noopPushPublisher) PublishClientEvent(_ context.Context, userID uuid.UUID, deviceSessionID *uuid.UUID, kind string, payload map[string]any, eventID, requestID, traceID string) error {
+	fields := []zap.Field{
+		zap.String("user_id", userID.String()),
+		zap.String("kind", kind),
+		zap.Int("payload_keys", len(payload)),
+	}
+	if deviceSessionID != nil {
+		fields = append(fields, zap.String("device_session_id", deviceSessionID.String()))
+	}
+	if eventID != "" {
+		fields = append(fields, zap.String("event_id", eventID))
+	}
+	if requestID != "" {
+		fields = append(fields, zap.String("request_id", requestID))
+	}
+	if traceID != "" {
+		fields = append(fields, zap.String("trace_id", traceID))
+	}
+	p.logger.Debug("client event (noop publisher)", fields...)
+	return nil
+}