import type { ChatParticipant } from '../../types/ChatParticipant';
/**
 * Minimal participant visuals needed by chat exports.
 *
 * @private internal utility of chat save format definitions
 */
export type ChatExportParticipantVisuals = {
    readonly displayName: string;
    readonly accentColor: string;
};
/**
 * Formats exported timestamps into a compact human-readable label.
 *
 * @private internal utility of chat save format definitions
 */
export declare function formatChatExportTimestamp(value?: string | Date): string;
/**
 * Builds a participant lookup indexed by both raw and upper-cased names.
 *
 * @private internal utility of chat save format definitions
 */
export declare function buildChatExportParticipantMap(participants: ReadonlyArray<ChatParticipant>): ReadonlyMap<string, ChatParticipant>;
/**
 * Resolves the display label and accent color for one message sender.
 *
 * @private internal utility of chat save format definitions
 */
export declare function resolveChatExportParticipantVisuals(participants: ReadonlyMap<string, ChatParticipant>, sender: string): ChatExportParticipantVisuals;