feat: transaction activity audit and account activity audit

internal/service/transaction_audit_log.go

@@ -0,0 +1,78 @@
+package service
+
+import (
+	"encoding/json"
+	"fmt"
+	"log/slog"
+	"time"
+
+	"git.juancwu.dev/juancwu/budgit/internal/model"
+	"git.juancwu.dev/juancwu/budgit/internal/repository"
+	"github.com/google/uuid"
+)
+
+type TransactionAuditLogService struct {
+	repo repository.TransactionAuditLogRepository
+}
+
+func NewTransactionAuditLogService(repo repository.TransactionAuditLogRepository) *TransactionAuditLogService {
+	return &TransactionAuditLogService{repo: repo}
+}
+
+type TransactionRecordOptions struct {
+	TransactionID string
+	ActorID       string
+	Action        model.TransactionAuditAction
+	Metadata      map[string]any
+}
+
+// Record persists a transaction audit entry. Failures are logged but never bubble up —
+// auditing must not break the user-facing action that triggered it. A nil receiver is
+// a no-op so tests can omit the dependency.
+func (s *TransactionAuditLogService) Record(opts TransactionRecordOptions) {
+	if s == nil {
+		return
+	}
+	entry := &model.TransactionAuditLog{
+		ID:            uuid.NewString(),
+		TransactionID: opts.TransactionID,
+		Action:        opts.Action,
+		CreatedAt:     time.Now(),
+	}
+	if opts.ActorID != "" {
+		actor := opts.ActorID
+		entry.ActorID = &actor
+	}
+	if len(opts.Metadata) > 0 {
+		raw, err := json.Marshal(opts.Metadata)
+		if err != nil {
+			slog.Error("failed to marshal transaction audit metadata", "error", err, "action", opts.Action)
+		} else {
+			entry.Metadata = raw
+		}
+	}
+
+	if err := s.repo.Create(entry); err != nil {
+		slog.Error("failed to record transaction audit log",
+			"error", err,
+			"transaction_id", opts.TransactionID,
+			"action", opts.Action,
+		)
+	}
+}
+
+func (s *TransactionAuditLogService) List(transactionID string, limit, offset int) ([]*model.TransactionAuditLogWithActor, error) {
+	logs, err := s.repo.ListByTransaction(transactionID, limit, offset)
+	if err != nil {
+		return nil, fmt.Errorf("failed to list transaction audit logs: %w", err)
+	}
+	return logs, nil
+}
+
+func (s *TransactionAuditLogService) Count(transactionID string) (int, error) {
+	count, err := s.repo.CountByTransaction(transactionID)
+	if err != nil {
+		return 0, fmt.Errorf("failed to count transaction audit logs: %w", err)
+	}
+	return count, nil
+}