/**
 * R2 Presigned URL Generator
 *
 * A lightweight, zero-dependency library for generating presigned URLs for Cloudflare R2 storage
 * using AWS Signature Version 4. Compatible with Cloudflare Workers and Node.js environments.
 *
 * @packageDocumentation
 */
export interface R2Credentials {
    /** Cloudflare R2 Access Key ID */
    R2_ACCESS_KEY_ID: string;
    /** Cloudflare R2 Secret Access Key */
    R2_SECRET_ACCESS_KEY: string;
    /** Cloudflare Account ID */
    R2_ACCOUNT_ID: string;
    /** R2 Bucket name (optional, defaults to 'development') */
    R2_BUCKET?: string;
}
export interface PresignedUrlOptions {
    /** The object key (path) in the R2 bucket */
    key: string;
    /** MIME type of the file being uploaded */
    contentType: string;
    /** URL expiration time in seconds (max 604800 = 7 days) */
    expiresIn: number;
    /** HTTP method for the presigned URL (default: 'PUT') */
    method?: "PUT" | "GET" | "POST";
}
export interface TestResult {
    success: boolean;
    url?: string;
    error?: string;
    debug?: {
        canonicalRequest: string;
        stringToSign: string;
        signature: string;
    };
}
/**
 * Generate a presigned URL for R2 uploads using AWS Signature Version 4
 * Compatible with Cloudflare Workers (no Node.js dependencies)
 *
 * @param options - Configuration options for the presigned URL
 * @param credentials - R2 credentials
 * @returns Promise<string> - The presigned URL
 *
 * @example
 * ```typescript
 * import { generateR2PresignedUrl } from 'r2-presigned-url';
 *
 * const credentials = {
 *   R2_ACCESS_KEY_ID: 'your-access-key',
 *   R2_SECRET_ACCESS_KEY: 'your-secret-key',
 *   R2_ACCOUNT_ID: 'your-account-id',
 *   R2_BUCKET: 'my-bucket'
 * };
 *
 * const url = await generateR2PresignedUrl(
 *   {
 *     key: 'uploads/file.jpg',
 *     contentType: 'image/jpeg',
 *     expiresIn: 3600
 *   },
 *   credentials
 * );
 * ```
 */
export declare function generateR2PresignedUrl(options: PresignedUrlOptions, credentials: R2Credentials): Promise<string>;
/**
 * Test function to validate presigned URL generation
 * This can be used for debugging purposes
 *
 * @param credentials - R2 credentials to test with
 * @returns Promise<TestResult> - Test results with success status and debug info
 *
 * @example
 * ```typescript
 * const result = await testPresignedUrlGeneration(credentials);
 * if (result.success) {
 *   console.log('Test passed:', result.url);
 *   console.log('Signature:', result.debug?.signature);
 * } else {
 *   console.error('Test failed:', result.error);
 * }
 * ```
 */
export declare function testPresignedUrlGeneration(credentials: R2Credentials): Promise<TestResult>;