/**
 * Formatting utilities for the OpenRouter Kit library.
 */
import { Message } from '../types';
/**
 * Formats an array of message objects for sending to the OpenRouter/OpenAI API.
 * Ensures only the necessary fields (`role`, `content`, `name`, `tool_call_id`, `tool_calls`)
 * are included and `content` is explicitly `null` if missing (as required by API).
 *
 * @param history - Array of history messages (`Message[]`).
 * @returns A new array containing formatted `Message` objects suitable for the API.
 *          Returns an empty array if the input is not a valid array.
 */
export declare function formatMessages(history: Message[]): Message[];
/**
 * Formats a Date object or a timestamp string into an ISO 8601 UTC string.
 * Uses the current time if no valid input is provided.
 *
 * @param timestamp - Optional: A Date object, or a string parsable by `new Date()`.
 * @returns Date and time string in ISO 8601 UTC format (e.g., "2023-10-27T10:30:00.123Z").
 */
export declare function formatDateTime(timestamp?: string | Date): string;
/**
 * @deprecated Functionality is context-dependent and better handled by `_parseAndValidateJsonResponse` in client.ts.
 * Avoid using this function for response parsing.
 */
export declare function formatResponseByType(responseText: string, type?: string): any;
/**
 * Ensures all messages in an array have a `timestamp` field.
 * Adds the current timestamp (in ISO 8601 UTC format) if missing.
 * Modifies the array in place? No, returns a new array.
 *
 * @param messages - Array of messages (`Message[]`) to process.
 * @returns A new array of messages, each guaranteed to have a `timestamp`.
 *          Returns an empty array if the input is not a valid array.
 */
export declare function addRenderingInfoToMessages(messages: Message[]): Message[];
/**
 * Formats model response content (of any type) into a string suitable for display or logging.
 * Objects and arrays are pretty-printed as JSON strings.
 * Handles primitives, null, and undefined appropriately.
 *
 * @param content - The response content (can be string, object, array, number, boolean, null, undefined).
 * @returns A string representation of the content.
 */
export declare function formatResponseForDisplay(content: any): string;