import type { ParsedEmail } from "../types.js";
import type { EmailLogger } from "../utils/logger.js";
export declare function ensureDownloadDir(): Promise<string>;
/**
 * Sanitize an attachment filename to prevent path traversal attacks.
 *
 * - Rejects filenames containing null bytes (potential null byte injection).
 * - Strips all directory components via path.basename so that crafted names
 *   like "../../etc/passwd" or "/etc/passwd" resolve to just "passwd".
 * - Falls back to "attachment" when the result would be empty.
 */
export declare function sanitizeAttachmentFilename(filename: string): string;
/**
 * Parse email headers from IMAP message
 */
export declare function parseEmailHeaders(headers: Record<string, string | undefined>): {
    from: string;
    to: string[];
    cc: string[];
    bcc: string[];
    subject: string;
    messageId: string;
    references: string[];
    inReplyTo: string | null;
};
/**
 * Parse full email from raw source
 */
export declare function parseEmail(raw: Buffer | string, uid: number, log?: EmailLogger): Promise<ParsedEmail>;
/**
 * Extract subject from text (first line)
 */
export declare function extractSubject(text: string): string;