feat(storage): add audit persistence

backend/internal/repository/audit_repository.go

@@ -0,0 +1,80 @@
+package repository
+
+import (
+	"context"
+	"database/sql"
+	"fmt"
+
+	"card-to-iban/internal/audit"
+)
+
+type AuditRepository struct {
+	db *sql.DB
+}
+
+func NewAuditRepository(
+	db *sql.DB,
+) *AuditRepository {
+	return &AuditRepository{
+		db: db,
+	}
+}
+
+func (r *AuditRepository) Save(
+	ctx context.Context,
+	record audit.Record,
+) error {
+	var clientIP any
+
+	if record.ClientIP != nil {
+		clientIP = *record.ClientIP
+	}
+
+	var upstreamHTTPStatus any
+
+	if record.UpstreamHTTPStatus != nil {
+		upstreamHTTPStatus = *record.UpstreamHTTPStatus
+	}
+
+	var responseJSON any
+
+	if len(record.ResponseJSON) > 0 {
+		responseJSON = string(record.ResponseJSON)
+	}
+
+	const query = `
+		INSERT INTO audit_records (
+			request_id,
+			created_at,
+			duration_ms,
+			client_ip,
+			final_status,
+			upstream_http_status,
+			masked_card,
+			response_json
+		)
+		VALUES (?, ?, ?, ?, ?, ?, ?, ?)
+	`
+
+	_, err := r.db.ExecContext(
+		ctx,
+		query,
+		record.RequestID,
+		record.CreatedAt.UTC().Format("2006-01-02T15:04:05.000000000Z07:00"),
+		record.Duration.Milliseconds(),
+		clientIP,
+		string(record.Status),
+		upstreamHTTPStatus,
+		record.MaskedCard,
+		responseJSON,
+	)
+
+	if err != nil {
+		return fmt.Errorf(
+			"insert audit record: %w",
+			err,
+		)
+	}
+
+	return nil
+}