callbacks service draft

api/edge/callbacks/internal/events/service.go

@@ -0,0 +1,86 @@
+package events
+
+import (
+	"context"
+	"encoding/json"
+	"strings"
+	"time"
+
+	"github.com/tech/sendico/pkg/merrors"
+	"github.com/tech/sendico/pkg/mlogger"
+	"go.uber.org/zap"
+)
+
+type parserService struct {
+	logger mlogger.Logger
+}
+
+// New creates event parser/payload builder service.
+func New(logger mlogger.Logger) Service {
+	if logger == nil {
+		logger = zap.NewNop()
+	}
+	return &parserService{logger: logger.Named("events")}
+}
+
+func (s *parserService) Parse(data []byte) (*Envelope, error) {
+	if len(data) == 0 {
+		return nil, merrors.InvalidArgument("event payload is empty", "data")
+	}
+
+	var envelope Envelope
+	if err := json.Unmarshal(data, &envelope); err != nil {
+		return nil, merrors.InvalidArgumentWrap(err, "event payload is not valid JSON", "data")
+	}
+
+	if strings.TrimSpace(envelope.EventID) == "" {
+		return nil, merrors.InvalidArgument("event_id is required", "event_id")
+	}
+	if strings.TrimSpace(envelope.Type) == "" {
+		return nil, merrors.InvalidArgument("type is required", "type")
+	}
+	if strings.TrimSpace(envelope.ClientID) == "" {
+		return nil, merrors.InvalidArgument("client_id is required", "client_id")
+	}
+	if envelope.OccurredAt.IsZero() {
+		return nil, merrors.InvalidArgument("occurred_at is required", "occurred_at")
+	}
+	if len(envelope.Data) == 0 {
+		envelope.Data = []byte("{}")
+	}
+
+	envelope.EventID = strings.TrimSpace(envelope.EventID)
+	envelope.Type = strings.TrimSpace(envelope.Type)
+	envelope.ClientID = strings.TrimSpace(envelope.ClientID)
+	envelope.OccurredAt = envelope.OccurredAt.UTC()
+	if !envelope.PublishedAt.IsZero() {
+		envelope.PublishedAt = envelope.PublishedAt.UTC()
+	}
+
+	return &envelope, nil
+}
+
+func (s *parserService) BuildPayload(_ context.Context, envelope *Envelope) ([]byte, error) {
+	if envelope == nil {
+		return nil, merrors.InvalidArgument("event envelope is required", "envelope")
+	}
+
+	payload := Payload{
+		EventID:    envelope.EventID,
+		Type:       envelope.Type,
+		ClientID:   envelope.ClientID,
+		OccurredAt: envelope.OccurredAt.UTC().Format(time.RFC3339Nano),
+		Data:       envelope.Data,
+	}
+	if !envelope.PublishedAt.IsZero() {
+		payload.PublishedAt = envelope.PublishedAt.UTC().Format(time.RFC3339Nano)
+	}
+
+	data, err := json.Marshal(payload)
+	if err != nil {
+		s.logger.Warn("Failed to marshal callback payload", zap.Error(err), zap.String("event_id", envelope.EventID))
+		return nil, merrors.InternalWrap(err, "failed to marshal callback payload")
+	}
+
+	return data, nil
+}