import { IWebchatButton, IWebchatQuickReply } from '../types';
/**
 * Gets the label for a button
 * Returns "Call" for phone_number buttons without title
 */
export declare function getWebchatButtonLabel(button: IWebchatButton | IWebchatQuickReply): string | undefined;
/**
 * Interpolates a template string with replacements
 * Example: interpolateString("{position} of {total}", { position: "1", total: "4" })
 * Returns: "1 of 4"
 */
export declare function interpolateString(template: string, replacements: Record<string, string>): string;
/**
 * Generates a random ID with optional prefix
 */
export declare function getRandomId(prefix?: string): string;
/**
 * Move focus to the visually hidden focus target
 * This prevents focus loss for keyboard users
 */
export declare function moveFocusToMessageFocusTarget(dataMessageId: string): void;
/**
 * Helper function that replaces URLs in a string with HTML anchor elements
 * - Works with URLs starting with http/https, www., or just domain/subdomain
 * - Will only match URLs at the beginning or following whitespace
 * - Will not work with emails
 * - URLs are escaped to prevent injection attacks
 */
export declare function replaceUrlsWithHTMLanchorElem(text: string): string;
/**
 * Sanitizes a URL for use in CSS background-image property
 * Returns url("...") string or undefined if invalid
 */
export declare function getBackgroundImage(url: string): string | undefined;
/**
 * Extracts filename without extension
 * Example: "document.pdf" → "document."
 */
export declare function getFileName(fileNameWithExtension: string): string;
/**
 * Extracts file extension
 * Example: "document.pdf" → "pdf"
 */
export declare function getFileExtension(fileNameWithExtension: string): string | null;
/**
 * Formats file size in MB or KB
 * Example: 1500000 → "1.50 MB"
 */
export declare function getSizeLabel(size: number): string;
/**
 * Valid image MIME types for file attachments (Set for O(1) lookup)
 */
export declare const VALID_IMAGE_MIME_TYPES: Set<string>;
/**
 * Checks if attachment is a valid image type
 */
export declare function isImageAttachment(mimeType: string): boolean;