import { FileSystemAdapter } from '../../infrastructure/adapters/filesystem.adapter';
/**
 * File Naming Service
 * Handles file naming logic including deduplication and extension detection
 */
export declare class FileNamingService {
    private fsAdapter;
    private readonly MAX_ATTEMPTS;
    private readonly CONTENT_TYPE_MAP;
    constructor(fsAdapter: FileSystemAdapter);
    /**
     * Ensures the filename has an extension
     * Priority: existing extension > content-type header > default .jpg
     * @param filename - Original filename
     * @param contentType - HTTP Content-Type header (optional)
     * @returns Filename with extension
     */
    ensureExtension(filename: string, contentType: string | null): string;
    /**
     * Ensures the filename is unique in the target directory
     * Appends _1, _2, _3, etc. if file already exists
     * @param targetDir - Target directory path
     * @param filename - Desired filename
     * @returns Unique filename
     */
    ensureUniqueFilename(targetDir: string, filename: string): Promise<string>;
    /**
     * Extracts file extension from Content-Type header
     * @param contentType - HTTP Content-Type header
     * @returns File extension without dot, or null if not found
     */
    private getExtensionFromContentType;
}
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