import { BatchDeleteResult, CopyResult, HealthStatus, IStorageProvider, ListResult, MoveResult, PreSignedUploadInfo, S3StorageOptions, UploadResult } from '../interfaces/storage-provider.interface';
import { FileBuffer } from '../interfaces/file-buffer.interface';
import { UploadOptions } from '../interfaces/upload-options.interface';
import { FileMetadata } from '../interfaces/file-metadata.interface';
/**
 * AWS S3 存储提供者
 * 使用动态导入，只在实际使用时加载 AWS SDK
 */
export declare class S3StorageProvider implements IStorageProvider {
    private readonly options;
    name: string;
    private readonly logger;
    private initialized;
    private s3Client;
    private S3Commands;
    private s3GetSignedUrl;
    constructor(options: S3StorageOptions);
    /**
     * 初始化存储配置
     * 动态导入 AWS S3 SDK
     */
    initialize(): Promise<void>;
    /**
     * 上传文件
     */
    upload(file: FileBuffer, options: UploadOptions): Promise<UploadResult>;
    /**
     * 下载文件
     */
    download(key: string): Promise<FileBuffer>;
    /**
     * 删除文件
     */
    delete(key: string): Promise<void>;
    /**
     * 批量删除
     */
    deleteBatch(keys: string[]): Promise<BatchDeleteResult>;
    /**
     * 检查文件是否存在
     */
    exists(key: string): Promise<boolean>;
    /**
     * 获取文件元数据
     */
    getMetadata(key: string): Promise<FileMetadata>;
    /**
     * 获取预签名URL（下载）
     */
    getSignedUrl(key: string, expiresIn?: number): Promise<string>;
    /**
     * 获取预签名上传URL
     */
    getSignedUploadUrl(key: string, expiresIn?: number, contentType?: string): Promise<PreSignedUploadInfo>;
    /**
     * 复制文件
     */
    copy(sourceKey: string, destinationKey: string): Promise<CopyResult>;
    /**
     * 移动文件（复制后删除）
     */
    move(sourceKey: string, destinationKey: string): Promise<MoveResult>;
    /**
     * 列出文件
     */
    list(prefix?: string, limit?: number): Promise<ListResult>;
    /**
     * 健康检查
     */
    healthCheck(): Promise<HealthStatus>;
    /**
     * 生成文件 Key
     */
    private generateKey;
    /**
     * 获取文件访问 URL
     */
    private getFileUrl;
    /**
     * 将流转换为 Buffer（带超时和大小限制）
     */
    private streamToBuffer;
    /**
     * 确保已初始化
     */
    private ensureInitialized;
}