import { Readable } from 'stream';
export type AuditDocType = 'stage1_report' | 'stage2_report' | 'attendance' | 'nc_form' | 'support_docs';
export declare class AuditReportStorageService {
    private readonly logger;
    isNewPath(dbPath: string | null | undefined): boolean;
    resolveAbsolutePath(dbPath: string): string;
    saveReport(docType: AuditDocType, rowId: number, file: {
        originalname: string;
        mimetype: string;
        buffer: Buffer;
        size: number;
    }): Promise<{
        dbPath: string;
        absolutePath: string;
        size: number;
    }>;
    openFile(dbPath: string): Promise<{
        stream: Readable;
        size: number;
        mimeType: string;
        filename: string;
    }>;
    deleteNewFile(dbPath: string): Promise<boolean>;
    private validate;
    private sanitizeFilename;
    private guessMimeType;
}